diff --git a/test/hotspot/jtreg/runtime/Thread/libAsyncExceptionOnMonitorEnter.cpp b/test/hotspot/jtreg/runtime/Thread/libAsyncExceptionOnMonitorEnter.cpp
index 1b5833d8042..0249235bc18 100644
--- a/test/hotspot/jtreg/runtime/Thread/libAsyncExceptionOnMonitorEnter.cpp
+++ b/test/hotspot/jtreg/runtime/Thread/libAsyncExceptionOnMonitorEnter.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,7 +26,7 @@
 
 extern "C" {
 
-static jvmtiEnv* jvmti = NULL;
+static jvmtiEnv* jvmti = nullptr;
 static jrawMonitorID monitor;
 
 JNIEXPORT jint JNICALL
diff --git a/test/hotspot/jtreg/runtime/Thread/libStopAtExit.cpp b/test/hotspot/jtreg/runtime/Thread/libStopAtExit.cpp
index 1204915050b..8432912876b 100644
--- a/test/hotspot/jtreg/runtime/Thread/libStopAtExit.cpp
+++ b/test/hotspot/jtreg/runtime/Thread/libStopAtExit.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,7 +26,7 @@
 
 extern "C" {
 
-static jvmtiEnv* jvmti = NULL;
+static jvmtiEnv* jvmti = nullptr;
 
 #define LOG(...) \
   do { \
diff --git a/test/hotspot/jtreg/runtime/Thread/libSuspendAtExit.cpp b/test/hotspot/jtreg/runtime/Thread/libSuspendAtExit.cpp
index 2a64e1a249f..b49cbf2c924 100644
--- a/test/hotspot/jtreg/runtime/Thread/libSuspendAtExit.cpp
+++ b/test/hotspot/jtreg/runtime/Thread/libSuspendAtExit.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,7 +26,7 @@
 
 extern "C" {
 
-static jvmtiEnv* jvmti = NULL;
+static jvmtiEnv* jvmti = nullptr;
 
 #define LOG(...) \
   do { \
diff --git a/test/hotspot/jtreg/runtime/clinit/libClassInitBarrier.cpp b/test/hotspot/jtreg/runtime/clinit/libClassInitBarrier.cpp
index 521c51ce6af..dce5c1057a8 100644
--- a/test/hotspot/jtreg/runtime/clinit/libClassInitBarrier.cpp
+++ b/test/hotspot/jtreg/runtime/clinit/libClassInitBarrier.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,38 +39,38 @@ static jfieldID test_A_f_id;
 extern "C" {
     JNIEXPORT jboolean JNICALL Java_ClassInitBarrier_init(JNIEnv* env, jclass cls) {
         jclass runnable = env->FindClass("java/lang/Runnable");
-        if (runnable == NULL)  return JNI_FALSE;
+        if (runnable == nullptr)  return JNI_FALSE;
 
         methodId = env->GetMethodID(runnable, "run", "()V");
-        if (methodId == NULL)  return JNI_FALSE;
+        if (methodId == nullptr)  return JNI_FALSE;
 
         return JNI_TRUE;
     }
 
     JNIEXPORT jboolean JNICALL Java_ClassInitBarrier_00024Test_00024A_init(JNIEnv* env, jclass cls, jclass arg1) {
         test_class_A = (jclass)env->NewGlobalRef(cls);
-        if (test_class_A == NULL)  return JNI_FALSE;
+        if (test_class_A == nullptr)  return JNI_FALSE;
 
         test_class_B = (jclass)env->NewGlobalRef(arg1);
-        if (test_class_B == NULL)  return JNI_FALSE;
+        if (test_class_B == nullptr)  return JNI_FALSE;
 
         test_staticM_id = env->GetStaticMethodID(test_class_A, "staticM", "(Ljava/lang/Runnable;)V");
-        if (test_staticM_id == NULL)  return JNI_FALSE;
+        if (test_staticM_id == nullptr)  return JNI_FALSE;
 
         test_staticS_id = env->GetStaticMethodID(test_class_A, "staticS", "(Ljava/lang/Runnable;)V");
-        if (test_staticS_id == NULL)  return JNI_FALSE;
+        if (test_staticS_id == nullptr)  return JNI_FALSE;
 
         test_staticN_id = env->GetStaticMethodID(test_class_A, "staticN", "(Ljava/lang/Runnable;)V");
-        if (test_staticN_id == NULL)  return JNI_FALSE;
+        if (test_staticN_id == nullptr)  return JNI_FALSE;
 
         test_A_m_id = env->GetMethodID(test_class_A, "m", "()V");
-        if (test_A_m_id == NULL)  return JNI_FALSE;
+        if (test_A_m_id == nullptr)  return JNI_FALSE;
 
         test_staticF_id = env->GetStaticFieldID(test_class_A, "staticF", "I");
-        if (test_staticF_id == NULL)  return JNI_FALSE;
+        if (test_staticF_id == nullptr)  return JNI_FALSE;
 
         test_A_f_id = env->GetFieldID(test_class_A, "f", "I");
-        if (test_A_f_id == NULL)  return JNI_FALSE;
+        if (test_A_f_id == nullptr)  return JNI_FALSE;
 
         return JNI_TRUE;
     }
@@ -105,11 +105,11 @@ extern "C" {
     JNIEXPORT jobject JNICALL Java_ClassInitBarrier_00024Test_testNewInstanceAJNI(JNIEnv* env, jclass cls, jobject action) {
         jobject obj = env->AllocObject(test_class_A); // A obj = new A();
         if (env->ExceptionOccurred()) {
-          return NULL;
-        } else if (obj == NULL) {
+          return nullptr;
+        } else if (obj == nullptr) {
           jclass errorClass = env->FindClass("java/lang/AssertionError");
           int ret = env->ThrowNew(errorClass, "JNI: AllocObject: allocation failed, but no exception thrown");
-          return NULL;
+          return nullptr;
         }
         env->CallVoidMethod(action, methodId);        // action.run();
         return obj;
@@ -118,11 +118,11 @@ extern "C" {
     JNIEXPORT jobject JNICALL Java_ClassInitBarrier_00024Test_testNewInstanceBJNI(JNIEnv* env, jclass cls, jobject action) {
         jobject obj = env->AllocObject(test_class_B); // B obj = new B();
         if (env->ExceptionOccurred()) {
-          return NULL;
-        } else if (obj == NULL) {
+          return nullptr;
+        } else if (obj == nullptr) {
           jclass errorClass = env->FindClass("java/lang/AssertionError");
           int ret = env->ThrowNew(errorClass, "JNI: AllocObject: allocation failed, but no exception thrown");
-          return NULL;
+          return nullptr;
         }
         env->CallVoidMethod(action, methodId);        // action.run();
         return obj;
diff --git a/test/hotspot/jtreg/serviceability/AsyncGetCallTrace/libAsyncGetCallTraceTest.cpp b/test/hotspot/jtreg/serviceability/AsyncGetCallTrace/libAsyncGetCallTraceTest.cpp
index e8886f4bb67..ccdaf985d57 100644
--- a/test/hotspot/jtreg/serviceability/AsyncGetCallTrace/libAsyncGetCallTraceTest.cpp
+++ b/test/hotspot/jtreg/serviceability/AsyncGetCallTrace/libAsyncGetCallTraceTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2024, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2019, Google and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -35,7 +35,7 @@ template <class T>
 class JvmtiDeallocator {
  public:
   JvmtiDeallocator() {
-    elem_ = NULL;
+    elem_ = nullptr;
   }
 
   ~JvmtiDeallocator() {
@@ -100,7 +100,7 @@ extern "C" {
 static
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     fprintf(stderr, "Error: wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -129,13 +129,13 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     fprintf(stderr, "AgentInitialize: Error in SetEventNotificationMode for CLASS_LOAD: %d\n", err);
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_PREPARE, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_PREPARE, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     fprintf(stderr,
             "AgentInitialize: Error in SetEventNotificationMode for CLASS_PREPARE: %d\n",
@@ -143,7 +143,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     fprintf(
         stderr, "AgentInitialize: Error in SetEventNotificationMode for VM_INIT: %d\n",
@@ -194,12 +194,12 @@ Java_MyPackage_ASGCTBaseTest_checkAsyncGetCallTraceCall(JNIEnv* env, jclass cls)
   trace.env_id = env;
   trace.num_frames = 0;
 
-  if (agct == NULL) {
+  if (agct == nullptr) {
     fprintf(stderr, "AsyncGetCallTrace not found.\n");
     return false;
   }
 
-  agct(&trace, MAX_DEPTH, NULL);
+  agct(&trace, MAX_DEPTH, nullptr);
 
   // For now, just check that the first frame is (-3, checkAsyncGetCallTraceCall).
   if (trace.num_frames <= 0) {
@@ -214,19 +214,19 @@ Java_MyPackage_ASGCTBaseTest_checkAsyncGetCallTraceCall(JNIEnv* env, jclass cls)
   }
 
   JvmtiDeallocator<char*> name;
-  if (trace.frames[0].method_id == NULL) {
-    fprintf(stderr, "First frame method_id is NULL\n");
+  if (trace.frames[0].method_id == nullptr) {
+    fprintf(stderr, "First frame method_id is null\n");
     return false;
   }
 
-  jvmtiError err = jvmti->GetMethodName(trace.frames[0].method_id, name.get_addr(), NULL, NULL);
+  jvmtiError err = jvmti->GetMethodName(trace.frames[0].method_id, name.get_addr(), nullptr, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     fprintf(stderr, "checkAsyncGetCallTrace: Error in GetMethodName: %d\n", err);
     return false;
   }
 
-  if (name.get() == NULL) {
-    fprintf(stderr, "Name is NULL\n");
+  if (name.get() == nullptr) {
+    fprintf(stderr, "Name is null\n");
     return false;
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/CompiledMethodLoad/libCompiledZombie.cpp b/test/hotspot/jtreg/serviceability/jvmti/CompiledMethodLoad/libCompiledZombie.cpp
index fbff3c847f1..3bf2988dd0f 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/CompiledMethodLoad/libCompiledZombie.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/CompiledMethodLoad/libCompiledZombie.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,7 +45,7 @@ void JNICALL CompiledMethodLoad(jvmtiEnv* jvmti, jmethodID method,
 
 // Continuously generate CompiledMethodLoad events for all currently compiled methods
 void JNICALL GenerateEventsThread(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
-    jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL);
+    jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, nullptr);
     int count = 0;
 
     while (true) {
@@ -64,7 +64,7 @@ void JNICALL VMInit(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
     jmethodID thread_constructor = jni->GetMethodID(thread_class, "<init>", "()V");
     jthread agent_thread = jni->NewObject(thread_class, thread_constructor);
 
-    jvmti->RunAgentThread(agent_thread, GenerateEventsThread, NULL, JVMTI_THREAD_NORM_PRIORITY);
+    jvmti->RunAgentThread(agent_thread, GenerateEventsThread, nullptr, JVMTI_THREAD_NORM_PRIORITY);
 }
 
 JNIEXPORT
@@ -83,7 +83,7 @@ jint JNICALL Agent_OnLoad(JavaVM* vm, char* options, void* reserved) {
     callbacks.VMInit = VMInit;
     callbacks.CompiledMethodLoad = CompiledMethodLoad;
     jvmti->SetEventCallbacks(&callbacks, sizeof(callbacks));
-    jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+    jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
 
     return 0;
 }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/DynamicCodeGenerated/libDynamicCodeGenerated.cpp b/test/hotspot/jtreg/serviceability/jvmti/DynamicCodeGenerated/libDynamicCodeGenerated.cpp
index 6ede1fe2eb9..f13ba00aa41 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/DynamicCodeGenerated/libDynamicCodeGenerated.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/DynamicCodeGenerated/libDynamicCodeGenerated.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,7 +25,7 @@
 #include <jvmti.h>
 #include "jvmti_common.h"
 
-static jvmtiEnv* jvmti = NULL;
+static jvmtiEnv* jvmti = nullptr;
 
 #ifdef __cplusplus
 extern "C" {
@@ -34,8 +34,8 @@ extern "C" {
 JNIEXPORT
 void JNICALL Java_DynamicCodeGeneratedTest_changeEventNotificationMode(JNIEnv* jni, jclass cls) {
   while (true) {
-    jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_DYNAMIC_CODE_GENERATED, NULL);
-    jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_DYNAMIC_CODE_GENERATED, NULL);
+    jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_DYNAMIC_CODE_GENERATED, nullptr);
+    jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_DYNAMIC_CODE_GENERATED, nullptr);
   }
 }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/GenerateEvents/libGenerateEvents1.cpp b/test/hotspot/jtreg/serviceability/jvmti/GenerateEvents/libGenerateEvents1.cpp
index 846ba45d274..fa60c07f8db 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/GenerateEvents/libGenerateEvents1.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/GenerateEvents/libGenerateEvents1.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,9 +28,9 @@ extern "C" {
 
 #define AGENT_NAME "agent1"
 
-static JavaVM *java_vm = NULL;
-static jthread exp_thread = NULL;
-static jvmtiEnv *jvmti1 = NULL;
+static JavaVM *java_vm = nullptr;
+static jthread exp_thread = nullptr;
+static jvmtiEnv *jvmti1 = nullptr;
 static jint agent1_event_count = 0;
 static bool fail_status = false;
 
@@ -48,10 +48,10 @@ CompiledMethodLoad(jvmtiEnv* jvmti, jmethodID method,
                    jint code_size, const void* code_addr,
                    jint map_length, const jvmtiAddrLocationMap* map,
                    const void* compile_info) {
-  JNIEnv* env = NULL;
-  jthread thread = NULL;
-  char* name = NULL;
-  char* sign = NULL;
+  JNIEnv* env = nullptr;
+  jthread thread = nullptr;
+  char* name = nullptr;
+  char* sign = nullptr;
   jvmtiError err;
 
   // Posted on JavaThread's, so it is legal to obtain JNIEnv*
@@ -67,7 +67,7 @@ CompiledMethodLoad(jvmtiEnv* jvmti, jmethodID method,
   }
   agent1_event_count++;
 
-  err = jvmti->GetMethodName(method, &name, &sign, NULL);
+  err = jvmti->GetMethodName(method, &name, &sign, nullptr);
   check_jvmti_status(env, err, "CompiledMethodLoad: Error in JVMTI GetMethodName");
 
   printf("%s: CompiledMethodLoad: %s%s\n", AGENT_NAME, name, sign);
@@ -111,7 +111,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
 
 JNIEXPORT void JNICALL
 Java_MyPackage_GenerateEventsTest_agent1GenerateEvents(JNIEnv *env, jclass cls) {
-  jthread thread = NULL;
+  jthread thread = nullptr;
   jvmtiError err;
 
   err = jvmti1->GetCurrentThread(&thread);
@@ -119,13 +119,13 @@ Java_MyPackage_GenerateEventsTest_agent1GenerateEvents(JNIEnv *env, jclass cls)
 
   exp_thread = (jthread)env->NewGlobalRef(thread);
 
-  err = jvmti1->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL);
+  err = jvmti1->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, nullptr);
   check_jvmti_status(env, err, "generateEvents1: Error in JVMTI SetEventNotificationMode: JVMTI_ENABLE");
 
   err = jvmti1->GenerateEvents(JVMTI_EVENT_COMPILED_METHOD_LOAD);
   check_jvmti_status(env, err, "generateEvents1: Error in JVMTI GenerateEvents");
 
-  err = jvmti1->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL);
+  err = jvmti1->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, nullptr);
   check_jvmti_status(env, err, "generateEvents1: Error in JVMTI SetEventNotificationMode: JVMTI_DISABLE");
 }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/GenerateEvents/libGenerateEvents2.cpp b/test/hotspot/jtreg/serviceability/jvmti/GenerateEvents/libGenerateEvents2.cpp
index 7cec9624cf3..7af061196a1 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/GenerateEvents/libGenerateEvents2.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/GenerateEvents/libGenerateEvents2.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,9 +28,9 @@ extern "C" {
 
 #define AGENT_NAME "agent2"
 
-static JavaVM *java_vm = NULL;
-static jthread exp_thread = NULL;
-static jvmtiEnv *jvmti2 = NULL;
+static JavaVM *java_vm = nullptr;
+static jthread exp_thread = nullptr;
+static jvmtiEnv *jvmti2 = nullptr;
 static jint agent2_event_count = 0;
 static bool fail_status = false;
 
@@ -48,10 +48,10 @@ CompiledMethodLoad(jvmtiEnv* jvmti, jmethodID method,
                    jint code_size, const void* code_addr,
                    jint map_length, const jvmtiAddrLocationMap* map,
                    const void* compile_info) {
-  JNIEnv* env = NULL;
-  jthread thread = NULL;
-  char* name = NULL;
-  char* sign = NULL;
+  JNIEnv* env = nullptr;
+  jthread thread = nullptr;
+  char* name = nullptr;
+  char* sign = nullptr;
   jvmtiError err;
 
   // Posted on JavaThread's, so it is legal to obtain JNIEnv*
@@ -67,7 +67,7 @@ CompiledMethodLoad(jvmtiEnv* jvmti, jmethodID method,
   }
   agent2_event_count++;
 
-  err = jvmti->GetMethodName(method, &name, &sign, NULL);
+  err = jvmti->GetMethodName(method, &name, &sign, nullptr);
   check_jvmti_status(env, err, "CompiledMethodLoad: Error in JVMTI GetMethodName");
 
   printf("%s: CompiledMethodLoad: %s%s\n", AGENT_NAME, name, sign);
@@ -113,7 +113,7 @@ Java_MyPackage_GenerateEventsTest_agent2SetThread(JNIEnv *env, jclass cls, jthre
 
   exp_thread = (jthread)env->NewGlobalRef(thread);
 
-  err = jvmti2->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL);
+  err = jvmti2->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, nullptr);
   check_jvmti_status(env, err, "setThread2: Error in JVMTI SetEventNotificationMode: JVMTI_ENABLE");
 }
 
@@ -121,7 +121,7 @@ JNIEXPORT jboolean JNICALL
 Java_MyPackage_GenerateEventsTest_agent2FailStatus(JNIEnv *env, jclass cls) {
   jvmtiError err;
 
-  err = jvmti2->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL);
+  err = jvmti2->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, nullptr);
   check_jvmti_status(env, err, "check2: Error in JVMTI SetEventNotificationMode: JVMTI_DISABLE");
 
   printf("\n");
diff --git a/test/hotspot/jtreg/serviceability/jvmti/GetClassFields/FilteredFields/libFilteredFieldsTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/GetClassFields/FilteredFields/libFilteredFieldsTest.cpp
index 521242a1c29..24c36444ac2 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/GetClassFields/FilteredFields/libFilteredFieldsTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/GetClassFields/FilteredFields/libFilteredFieldsTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,12 +28,12 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res = jvm->GetEnv((void **)&jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         fflush(0);
         return JNI_ERR;
@@ -51,7 +51,7 @@ JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM *jvm, char *options, void *reserved
 
 JNIEXPORT jint JNICALL
 Java_FilteredFieldsTest_getJVMTIFieldCount(JNIEnv *env, jclass cls, jclass clazz) {
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         env->FatalError("JVMTI agent was not properly loaded");
     }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/GetClassMethods/libOverpassMethods.cpp b/test/hotspot/jtreg/serviceability/jvmti/GetClassMethods/libOverpassMethods.cpp
index 17025c1b9aa..414c3149298 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/GetClassMethods/libOverpassMethods.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/GetClassMethods/libOverpassMethods.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -31,7 +31,7 @@ extern "C" {
 
 #define ACC_STATIC 0x0008
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 JNIEXPORT
 jint JNICALL JNI_OnLoad(JavaVM *jvm, void *reserved) {
@@ -41,7 +41,7 @@ jint JNICALL JNI_OnLoad(JavaVM *jvm, void *reserved) {
 JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *vm, char *options, void *reserved) {
   vm->GetEnv((void **)&jvmti, JVMTI_VERSION_11);
 
-  if (options != NULL && strcmp(options, "maintain_original_method_order") == 0) {
+  if (options != nullptr && strcmp(options, "maintain_original_method_order") == 0) {
     printf("Enabled capability: maintain_original_method_order\n");
     jvmtiCapabilities caps;
     memset(&caps, 0, sizeof(caps));
@@ -58,22 +58,22 @@ JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *vm, char *options, void *reserved) {
 
 JNIEXPORT jobjectArray JNICALL Java_OverpassMethods_getJVMTIDeclaredMethods(JNIEnv *env, jclass static_klass, jclass klass) {
   jint method_count = 0;
-  jmethodID* methods = NULL;
+  jmethodID* methods = nullptr;
   jvmtiError err = jvmti->GetClassMethods(klass, &method_count, &methods);
   if (err != JVMTI_ERROR_NONE) {
     printf("GetClassMethods failed with error: %d\n", err);
-    return NULL;
+    return nullptr;
   }
 
   jclass method_cls = env->FindClass("java/lang/reflect/Method");
-  if (method_cls == NULL) {
+  if (method_cls == nullptr) {
     printf("FindClass (Method) failed\n");
-    return NULL;
+    return nullptr;
   }
-  jobjectArray array = env->NewObjectArray(method_count, method_cls, NULL);
-  if (array == NULL) {
+  jobjectArray array = env->NewObjectArray(method_count, method_cls, nullptr);
+  if (array == nullptr) {
     printf("NewObjectArray failed\n");
-    return NULL;
+    return nullptr;
   }
 
   for (int i = 0; i < method_count; i++) {
@@ -81,13 +81,13 @@ JNIEXPORT jobjectArray JNICALL Java_OverpassMethods_getJVMTIDeclaredMethods(JNIE
     err = jvmti->GetMethodModifiers(methods[i], &modifiers);
     if (err != JVMTI_ERROR_NONE) {
       printf("GetMethodModifiers failed with error: %d\n", err);
-      return NULL;
+      return nullptr;
     }
 
     jobject m = env->ToReflectedMethod(klass, methods[i], (modifiers & ACC_STATIC) == ACC_STATIC);
-    if (array == NULL) {
+    if (array == nullptr) {
       printf("ToReflectedMethod failed\n");
-      return NULL;
+      return nullptr;
     }
     env->SetObjectArrayElement(array, i, m);
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/GetLocalVariable/libGetLocalVars.cpp b/test/hotspot/jtreg/serviceability/jvmti/GetLocalVariable/libGetLocalVars.cpp
index 08a61427dde..e0c3e0664d0 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/GetLocalVariable/libGetLocalVars.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/GetLocalVariable/libGetLocalVars.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define TranslateError(err) "JVMTI error"
 
 static jint result = STATUS_PASSED;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 #define DECL_TEST_FUNC(type, Type) \
 static void \
@@ -167,7 +167,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   static jvmtiCapabilities caps;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     printf("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -223,16 +223,16 @@ Java_GetLocalVars_testLocals(JNIEnv *env, jclass cls, jobject thread) {
   static const int IntSlot = 4;
   static const int InvalidSlot = 5;
 
-  jmethodID mid = NULL;
+  jmethodID mid = nullptr;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     printf("JVMTI client was not properly loaded!\n");
     result = STATUS_FAILED;
     return;
   }
 
   mid = env->GetStaticMethodID(cls, METHOD_NAME, METHOD_SIGN);
-  if (mid == NULL) {
+  if (mid == nullptr) {
     printf("Cannot find Method ID for %s%s\n", METHOD_NAME, METHOD_SIGN);
     result = STATUS_FAILED;
     return;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/GetLocalVariable/libGetSetLocalUnsuspended.cpp b/test/hotspot/jtreg/serviceability/jvmti/GetLocalVariable/libGetSetLocalUnsuspended.cpp
index 3cb048bda98..9ae5005ee6c 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/GetLocalVariable/libGetSetLocalUnsuspended.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/GetLocalVariable/libGetSetLocalUnsuspended.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ enum Slots {
   SlotDouble = 6,
 };
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 static void
 check_jvmti_error_not_suspended(JNIEnv* jni, const char* func_name, jvmtiError err) {
@@ -55,7 +55,7 @@ test_GetLocal(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread) {
   jvmtiError err;
   const int depth = 0;
 
-  jobject msg = NULL;
+  jobject msg = nullptr;
   jint ii = 0;
   jlong ll = 0L;
   jfloat ff = 0.0;
@@ -101,7 +101,7 @@ test_SetLocal(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread) {
   jvmtiError err;
   const int depth = 0;
 
-  const jobject msg = NULL;
+  const jobject msg = nullptr;
   const jint ii = 0;
   const jlong ll = 0L;
   const jfloat ff = 0.0;
@@ -163,7 +163,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
 JNIEXPORT void JNICALL
 Java_GetSetLocalUnsuspended_testUnsuspendedThread(JNIEnv *jni, jclass klass, jthread thread) {
   char* tname = get_thread_name(jvmti, jni, thread);
-  jmethodID method = NULL;
+  jmethodID method = nullptr;
   jlocation location = 0;
 
   LOG("\ntestUnsuspendedThread: started for thread: %s\n", tname);
diff --git a/test/hotspot/jtreg/serviceability/jvmti/GetThreadListStackTraces/libOneGetThreadListStackTraces.cpp b/test/hotspot/jtreg/serviceability/jvmti/GetThreadListStackTraces/libOneGetThreadListStackTraces.cpp
index 2c5ec19e93c..56db0b74797 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/GetThreadListStackTraces/libOneGetThreadListStackTraces.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/GetThreadListStackTraces/libOneGetThreadListStackTraces.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2020, NTT DATA.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -35,7 +35,7 @@
 extern "C" {
 #endif
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   return jvm->GetEnv(reinterpret_cast<void**>(&jvmti), JVMTI_VERSION_11);
@@ -103,7 +103,7 @@ JNIEXPORT void JNICALL Java_OneGetThreadListStackTraces_checkCallStacks(JNIEnv *
 
   /* Find jvmtiStackInfo for `thread` (in arguments) */
   jboolean is_same;
-  target_info = NULL;
+  target_info = nullptr;
   for (jint i = 0; i < num_threads; i++) {
     is_same = env->IsSameObject(stack_info[i].thread, thread);
     if (env->ExceptionOccurred()) {
@@ -115,7 +115,7 @@ JNIEXPORT void JNICALL Java_OneGetThreadListStackTraces_checkCallStacks(JNIEnv *
       break;
     }
   }
-  if (target_info == NULL) {
+  if (target_info == nullptr) {
     env->FatalError("Target thread not found");
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/Heap/libIterateHeapWithEscapeAnalysisEnabled.cpp b/test/hotspot/jtreg/serviceability/jvmti/Heap/libIterateHeapWithEscapeAnalysisEnabled.cpp
index e090bf29709..9cddba2e89a 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/Heap/libIterateHeapWithEscapeAnalysisEnabled.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/Heap/libIterateHeapWithEscapeAnalysisEnabled.cpp
@@ -64,7 +64,7 @@ JNI_OnLoad(JavaVM *jvm, void *reserved) {
   JNIEnv *env;
 
   res = jvm->GetEnv((void **) &env, JNI_VERSION_9);
-  if (res != JNI_OK || env == NULL) {
+  if (res != JNI_OK || env == nullptr) {
     fprintf(stderr, "Error: GetEnv call failed(%d)!\n", res);
     return JNI_ERR;
   }
@@ -79,7 +79,7 @@ Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   printf("Agent_OnLoad started\n");
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     fprintf(stderr, "Error: wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -257,9 +257,9 @@ Java_IterateHeapWithEscapeAnalysisEnabled_countAndTagInstancesOfClass(JNIEnv *en
 
   if (env->IsSameObject(method, method_IterateOverReachableObjects)) {
     method_found = JNI_TRUE;
-    err = jvmti->IterateOverReachableObjects(NULL /*jvmtiHeapRootCallback*/,
+    err = jvmti->IterateOverReachableObjects(nullptr /*jvmtiHeapRootCallback*/,
                                              __stackReferenceCallback,
-                                             NULL /* jvmtiObjectReferenceCallback */,
+                                             nullptr /* jvmtiObjectReferenceCallback */,
                                              &data);
     if (err != JVMTI_ERROR_NONE) {
       ShowErrorMessage(jvmti, err,
@@ -294,8 +294,8 @@ Java_IterateHeapWithEscapeAnalysisEnabled_countAndTagInstancesOfClass(JNIEnv *en
     method_found = JNI_TRUE;
     callbacks.heap_reference_callback = __jvmtiHeapReferenceCallback;
     err = jvmti->FollowReferences(0 /* filter nothing */,
-                                  NULL /* no class filter */,
-                                  NULL /* no initial object, follow roots */,
+                                  nullptr /* no class filter */,
+                                  nullptr /* no initial object, follow roots */,
                                   &callbacks,
                                   &data);
     if (err != JVMTI_ERROR_NONE) {
@@ -308,7 +308,7 @@ Java_IterateHeapWithEscapeAnalysisEnabled_countAndTagInstancesOfClass(JNIEnv *en
     method_found = JNI_TRUE;
     callbacks.heap_iteration_callback = __jvmtiHeapIterationCallback;
     err = jvmti->IterateThroughHeap(0 /* filter nothing */,
-                                    NULL /* no class filter */,
+                                    nullptr /* no class filter */,
                                     &callbacks,
                                     &data);
     if (err != JVMTI_ERROR_NONE) {
diff --git a/test/hotspot/jtreg/serviceability/jvmti/HeapMonitor/libHeapMonitorTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/HeapMonitor/libHeapMonitorTest.cpp
index f672a143144..035aaef827e 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/HeapMonitor/libHeapMonitorTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/HeapMonitor/libHeapMonitorTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2018, Google and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -34,8 +34,8 @@ extern "C" {
 #define FALSE 0
 #define PRINT_OUT 0
 
-static jvmtiEnv *jvmti = NULL;
-static jvmtiEnv *second_jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jvmtiEnv *second_jvmti = nullptr;
 
 typedef struct _ObjectTrace{
   jweak object;
@@ -138,7 +138,7 @@ static void print_out_frames(JNIEnv* env, ObjectTrace* trace) {
     // Get basic information out of the trace.
     jlocation bci = frames[i].location;
     jmethodID methodid = frames[i].method;
-    char *name = NULL, *signature = NULL, *file_name = NULL;
+    char *name = nullptr, *signature = nullptr, *file_name = nullptr;
     jclass declaring_class;
     int line_number;
     jvmtiError err;
@@ -166,18 +166,18 @@ static void print_out_frames(JNIEnv* env, ObjectTrace* trace) {
       continue;
     }
 
-    // Compare now, none should be NULL.
-    if (name == NULL) {
+    // Compare now, none should be null.
+    if (name == nullptr) {
       fprintf(stderr, "\tUnknown name\n");
       continue;
     }
 
-    if (file_name == NULL) {
+    if (file_name == nullptr) {
       fprintf(stderr, "\tUnknown file\n");
       continue;
     }
 
-    if (signature == NULL) {
+    if (signature == nullptr) {
       fprintf(stderr, "\tUnknown signature\n");
       continue;
     }
@@ -204,7 +204,7 @@ static jboolean check_sample_content(JNIEnv* env,
     // Get basic information out of the trace.
     jlocation bci = frames[i].location;
     jmethodID methodid = frames[i].method;
-    char *name = NULL, *signature = NULL, *file_name = NULL;
+    char *name = nullptr, *signature = nullptr, *file_name = nullptr;
     jclass declaring_class;
     int line_number;
     jboolean differ;
@@ -227,16 +227,16 @@ static jboolean check_sample_content(JNIEnv* env,
       return FALSE;
     }
 
-    // Compare now, none should be NULL.
-    if (name == NULL) {
+    // Compare now, none should be null.
+    if (name == nullptr) {
       return FALSE;
     }
 
-    if (file_name == NULL) {
+    if (file_name == nullptr) {
       return FALSE;
     }
 
-    if (signature == NULL) {
+    if (signature == nullptr) {
       return FALSE;
     }
 
@@ -267,14 +267,14 @@ static int fill_native_frames(JNIEnv* env, jobjectArray frames,
                               ExpectedContentFrame* native_frames, size_t size) {
   size_t i;
   for (i = 0; i < size; i++) {
-    jclass frame_class = NULL;
+    jclass frame_class = nullptr;
     jfieldID line_number_field_id = 0;
     int line_number = 0;
     jfieldID string_id = 0;
-    jstring string_object = NULL;
-    const char* method = NULL;
-    const char* file_name = NULL;
-    const char* signature = NULL;
+    jstring string_object = nullptr;
+    const char* method = nullptr;
+    const char* file_name = nullptr;
+    const char* signature = nullptr;
 
     jobject obj = env->GetObjectArrayElement(frames, (jsize) i);
 
@@ -410,7 +410,7 @@ static void event_storage_add_garbage_collected_object(EventStorage* storage,
                                                        ObjectTrace* object) {
   int idx = storage->garbage_history_index;
   ObjectTrace* old_object = storage->garbage_collected_objects[idx];
-  if (old_object != NULL) {
+  if (old_object != nullptr) {
     free(old_object->frames);
     free(storage->garbage_collected_objects[idx]);
   }
@@ -496,7 +496,7 @@ static jboolean event_storage_garbage_contains(JNIEnv* env,
   for (i = 0; i < storage->garbage_history_size; i++) {
     ObjectTrace* trace = storage->garbage_collected_objects[i];
 
-    if (trace == NULL) {
+    if (trace == nullptr) {
       continue;
     }
 
@@ -587,14 +587,14 @@ static void event_storage_compact(EventStorage* storage, JNIEnv* jni) {
     ObjectTrace* live_object = live_objects[i];
     jweak object = live_object->object;
 
-    if (!jni->IsSameObject(object, NULL)) {
+    if (!jni->IsSameObject(object, nullptr)) {
       if (dest != i) {
         live_objects[dest] = live_object;
         dest++;
       }
     } else {
       jni->DeleteWeakGlobalRef(object);
-      live_object->object = NULL;
+      live_object->object = nullptr;
 
       event_storage_add_garbage_collected_object(storage, live_object);
     }
@@ -607,7 +607,7 @@ static void event_storage_compact(EventStorage* storage, JNIEnv* jni) {
 static void event_storage_free_objects(ObjectTrace** array, int max) {
   int i;
   for (i = 0; i < max; i++) {
-    free(array[i]), array[i] = NULL;
+    free(array[i]), array[i] = nullptr;
   }
 }
 
@@ -620,7 +620,7 @@ static void event_storage_reset(EventStorage* storage) {
   storage->live_object_additions = 0;
   storage->live_object_size = 0;
   storage->live_object_count = 0;
-  free(storage->live_objects), storage->live_objects = NULL;
+  free(storage->live_objects), storage->live_objects = nullptr;
 
   event_storage_free_objects(storage->garbage_collected_objects,
                              storage->garbage_history_size);
@@ -799,13 +799,13 @@ void JNICALL GarbageCollectionFinish(jvmtiEnv *jvmti_env) {
 
 static int enable_notifications() {
   if (check_error(jvmti->SetEventNotificationMode(
-      JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, NULL),
+      JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, nullptr),
                      "Set event notifications")) {
     return 1;
   }
 
   return check_error(jvmti->SetEventNotificationMode(
-      JVMTI_ENABLE, JVMTI_EVENT_SAMPLED_OBJECT_ALLOC, NULL),
+      JVMTI_ENABLE, JVMTI_EVENT_SAMPLED_OBJECT_ALLOC, nullptr),
                      "Set event notifications");
 }
 
@@ -816,14 +816,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jvmtiCapabilities caps;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     fprintf(stderr, "Error: wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
 
   // Get second jvmti environment.
   res = jvm->GetEnv((void **) &second_jvmti, JVMTI_VERSION);
-  if (res != JNI_OK || second_jvmti == NULL) {
+  if (res != JNI_OK || second_jvmti == nullptr) {
     fprintf(stderr, "Error: wrong result of a valid second call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -893,11 +893,11 @@ Java_MyPackage_HeapMonitor_enableSamplingEvents(JNIEnv* env, jclass cls) {
 JNIEXPORT void JNICALL
 Java_MyPackage_HeapMonitor_disableSamplingEvents(JNIEnv* env, jclass cls) {
   check_error(jvmti->SetEventNotificationMode(
-      JVMTI_DISABLE, JVMTI_EVENT_SAMPLED_OBJECT_ALLOC, NULL),
+      JVMTI_DISABLE, JVMTI_EVENT_SAMPLED_OBJECT_ALLOC, nullptr),
               "Set event notifications");
 
   check_error(jvmti->SetEventNotificationMode(
-      JVMTI_DISABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, NULL),
+      JVMTI_DISABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, nullptr),
               "Garbage Collection Finish");
 }
 
@@ -912,8 +912,8 @@ static ExpectedContentFrame *get_native_frames(JNIEnv* env, jclass cls,
 
   native_frames = reinterpret_cast<ExpectedContentFrame*> (malloc(size * sizeof(*native_frames)));
 
-  if (native_frames == NULL) {
-    env->FatalError("Error in get_native_frames: malloc returned NULL\n");
+  if (native_frames == nullptr) {
+    env->FatalError("Error in get_native_frames: malloc returned null\n");
   }
 
   if (fill_native_frames(env, frames, native_frames, size) != 0) {
@@ -934,7 +934,7 @@ Java_MyPackage_HeapMonitor_obtainedEvents(JNIEnv* env, jclass cls,
   result = event_storage_contains(env, &global_event_storage, native_frames,
                                   size, check_lines);
 
-  free(native_frames), native_frames = NULL;
+  free(native_frames), native_frames = nullptr;
   return result;
 }
 
@@ -949,7 +949,7 @@ Java_MyPackage_HeapMonitor_garbageContains(JNIEnv* env, jclass cls,
   result = event_storage_garbage_contains(env, &global_event_storage,
                                           native_frames, size, check_lines);
 
-  free(native_frames), native_frames = NULL;
+  free(native_frames), native_frames = nullptr;
   return result;
 }
 
@@ -964,7 +964,7 @@ Java_MyPackage_HeapMonitor_getSize(JNIEnv* env, jclass cls,
   result = event_storage_get_size(env, &global_event_storage,
                                   native_frames, size, check_lines);
 
-  free(native_frames), native_frames = NULL;
+  free(native_frames), native_frames = nullptr;
   return result;
 }
 
@@ -1083,7 +1083,7 @@ Java_MyPackage_HeapMonitorTwoAgentsTest_enablingSamplingInSecondaryAgent(
 JNIEXPORT void JNICALL
 Java_MyPackage_HeapMonitor_enableVMEvents(JNIEnv* env, jclass cls) {
   check_error(jvmti->SetEventNotificationMode(
-      JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, NULL),
+      JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, nullptr),
               "Set vm event notifications");
 }
 
@@ -1103,19 +1103,19 @@ static jobject allocate_object(JNIEnv* env) {
   jmethodID constructor;
   jobject result;
 
-  if (env->ExceptionOccurred() || cls == NULL) {
+  if (env->ExceptionOccurred() || cls == nullptr) {
     env->FatalError("Error in jni FindClass: Cannot find Object class\n");
   }
 
   constructor = env->GetMethodID(cls, "<init>", "()V");
-  if (env->ExceptionOccurred() || constructor == NULL) {
+  if (env->ExceptionOccurred() || constructor == nullptr) {
     env->FatalError("Error in jni GetMethodID: Cannot find Object class constructor\n");
   }
 
   // Call back constructor to allocate a new instance, with an int argument
   result = env->NewObject(cls, constructor);
 
-  if (env->ExceptionOccurred() || result == NULL) {
+  if (env->ExceptionOccurred() || result == nullptr) {
     env->FatalError("Error in jni NewObject: Cannot allocate an object\n");
   }
   return result;
@@ -1135,8 +1135,8 @@ void JNICALL RecursiveSampledObjectAlloc(jvmtiEnv *jvmti_env,
   // infinite recursion here.
   int i;
   for (i = 0; i < 1000; i++) {
-    if (allocate_object(jni_env) == NULL) {
-      jni_env->FatalError("allocate_object returned NULL\n");
+    if (allocate_object(jni_env) == nullptr) {
+      jni_env->FatalError("allocate_object returned null\n");
     }
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/HiddenClass/libHiddenClassSigTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/HiddenClass/libHiddenClassSigTest.cpp
index 5d94a3879fe..ad9da9e5301 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/HiddenClass/libHiddenClassSigTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/HiddenClass/libHiddenClassSigTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -31,7 +31,7 @@ static const char* SIG_START      = "LP/Q/HiddenClassSig";
 static const size_t SIG_START_LEN = strlen(SIG_START);
 static const int    ACC_INTERFACE = 0x0200; // Interface class modifiers bit
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint class_load_count = 0;
 static jint class_prep_count = 0;
 static bool failed = false;
@@ -50,18 +50,18 @@ static bool failed = false;
 /* Return the jmethodID of j.l.Class.isHidden() method. */
 static jmethodID
 is_hidden_mid(JNIEnv* jni) {
-  char* csig = NULL;
+  char* csig = nullptr;
   jint count = 0;
-  jmethodID *methods = NULL;
+  jmethodID *methods = nullptr;
   jclass clazz  = jni->FindClass("java/lang/Class");
-  if (clazz == NULL) {
-    jni->FatalError("is_hidden_mid: Error: FindClass returned NULL for java/lang/Class\n");
-    return NULL;
+  if (clazz == nullptr) {
+    jni->FatalError("is_hidden_mid: Error: FindClass returned null for java/lang/Class\n");
+    return nullptr;
   }
 
   // find the jmethodID of j.l.Class.isHidden() method
   jmethodID mid = jni->GetMethodID(clazz, "isHidden", "()Z");
-  if (mid == NULL) {
+  if (mid == nullptr) {
     jni->FatalError("is_hidden_mid: Error in jni GetMethodID: Cannot find j.l.Class.isHidden method\n");
   }
   return mid;
@@ -70,9 +70,9 @@ is_hidden_mid(JNIEnv* jni) {
 /* Return true if the klass is hidden. */
 static bool
 is_hidden(JNIEnv* jni, jclass klass) {
-  static jmethodID is_hid_mid = NULL;
+  static jmethodID is_hid_mid = nullptr;
 
-  if (is_hid_mid == NULL) {
+  if (is_hid_mid == nullptr) {
     is_hid_mid = is_hidden_mid(jni);
   }
   // invoke j.l.Class.isHidden() method
@@ -88,8 +88,8 @@ is_hidden(JNIEnv* jni, jclass klass) {
 static void
 check_class_signature(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass, bool is_hidden, const char* exp_sig) {
   jint class_modifiers = 0;
-  char* sig = NULL;
-  char* gsig = NULL;
+  char* sig = nullptr;
+  char* gsig = nullptr;
   jvmtiError err;
 
   // get class signature
@@ -103,8 +103,8 @@ check_class_signature(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass, bool is_hidden
     LOG2("check_class_signature: FAIL: Hidden class signature %s does not match expected: %s\n", sig, exp_sig);
     failed = true;
   }
-  if (is_hidden && gsig == NULL) {
-    LOG0("check_class_signature: FAIL: unexpected NULL generic signature for hidden class\n");
+  if (is_hidden && gsig == nullptr) {
+    LOG0("check_class_signature: FAIL: unexpected null generic signature for hidden class\n");
     failed = true;
   }
 }
@@ -152,8 +152,8 @@ check_hidden_class_flags(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass) {
 static void
 check_hidden_class_loader(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass) {
   jint count = 0;
-  jobject loader = NULL;
-  jclass* loader_classes = NULL;
+  jobject loader = nullptr;
+  jclass* loader_classes = nullptr;
   jboolean found = false;
   jvmtiError err;
 
@@ -166,7 +166,7 @@ check_hidden_class_loader(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass) {
   CHECK_JVMTI_ERROR(jni, err, "check_hidden_class_loader: Error in JVMTI GetClassLoaderClasses");
 
   for (int idx = 0; idx < count; idx++) {
-    char* sig = NULL;
+    char* sig = nullptr;
     jclass kls = loader_classes[idx];
 
     // GetClassLoaderClasses should not return any hidden classes
@@ -174,7 +174,7 @@ check_hidden_class_loader(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass) {
       continue;
     }
     // get class signature
-    err = jvmti->GetClassSignature(kls, &sig, NULL);
+    err = jvmti->GetClassSignature(kls, &sig, nullptr);
     CHECK_JVMTI_ERROR(jni, err, "check_hidden_class_loader: Error in JVMTI GetClassSignature");
 
     LOG1("check_hidden_class_loader: FAIL: JVMTI GetClassLoaderClasses returned hidden class: %s\n", sig);
@@ -187,9 +187,9 @@ check_hidden_class_loader(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass) {
 /* Test the hidden class implements expected interface. */
 static void
 check_hidden_class_impl_interf(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass) {
-  char* sig = NULL;
+  char* sig = nullptr;
   jint count = 0;
-  jclass* interfaces = NULL;
+  jclass* interfaces = nullptr;
   jvmtiError err;
 
   // check that hidden class implements just one interface
@@ -201,7 +201,7 @@ check_hidden_class_impl_interf(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass) {
     return;
   }
   // get interface signature
-  err = jvmti->GetClassSignature(interfaces[0], &sig, NULL);
+  err = jvmti->GetClassSignature(interfaces[0], &sig, nullptr);
   CHECK_JVMTI_ERROR(jni, err, "check_hidden_class_impl_interf: Error in JVMTI GetClassSignature for implemented interface");
 
   // check the interface signature is matching the expected
@@ -215,7 +215,7 @@ check_hidden_class_impl_interf(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass) {
 /* Test hidden class. */
 static void
 check_hidden_class(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass, const char* exp_sig) {
-  char* source_file_name = NULL;
+  char* source_file_name = nullptr;
 
   LOG1("\n### Native agent: check_hidden_class started: class: %s\n", exp_sig);
 
@@ -237,7 +237,7 @@ check_hidden_class(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass, const char* exp_s
 /* Test hidden class array. */
 static void
 check_hidden_class_array(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass_array, const char* exp_sig) {
-  char* source_file_name = NULL;
+  char* source_file_name = nullptr;
 
   LOG1("\n### Native agent: check_hidden_class_array started: array: %s\n", exp_sig);
 
@@ -250,8 +250,8 @@ check_hidden_class_array(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass_array, const
 /* Process a CLASS_LOAD or aClassPrepare event. */
 static void process_class_event(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass,
                                 jint* event_count_ptr, const char* event_name) {
-  char* sig = NULL;
-  char* gsig = NULL;
+  char* sig = nullptr;
+  char* gsig = nullptr;
   jvmtiError err;
 
   // get class signature
@@ -263,8 +263,8 @@ static void process_class_event(jvmtiEnv* jvmti, JNIEnv* jni, jclass klass,
       strncmp(sig, SIG_START, SIG_START_LEN) == 0 &&
       is_hidden(jni, klass)) {
     (*event_count_ptr)++;
-    if (gsig == NULL) {
-      LOG1("%s event: FAIL: GetClassSignature returned NULL generic signature for hidden class\n", event_name);
+    if (gsig == nullptr) {
+      LOG1("%s event: FAIL: GetClassSignature returned null generic signature for hidden class\n", event_name);
       failed = true;
     }
     LOG2("%s event: hidden class with sig: %s\n", event_name, sig);
@@ -293,11 +293,11 @@ VMInit(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
   fflush(stdout);
 
   // enable ClassLoad event notification mode
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, nullptr);
   CHECK_JVMTI_ERROR(jni, err, "VMInit event: Error in enabling ClassLoad events notification");
 
   // enable ClassPrepare event notification mode
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_PREPARE, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_PREPARE, nullptr);
   CHECK_JVMTI_ERROR(jni, err, "VMInit event: Error in enabling ClassPrepare events notification");
 }
 
@@ -327,7 +327,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   }
 
   // enable VM_INIT event notification mode
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG1("Agent_OnLoad: Error in JVMTI SetEventNotificationMode: %d\n", err);
     failed = true;
@@ -341,10 +341,10 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
 /* Native method: checkHiddenClass(). */
 JNIEXPORT void JNICALL
 Java_P_Q_HiddenClassSigTest_checkHiddenClass(JNIEnv *jni, jclass klass, jclass hidden_klass, jstring exp_sig_str) {
-  const char* exp_sig = jni->GetStringUTFChars(exp_sig_str, NULL);
+  const char* exp_sig = jni->GetStringUTFChars(exp_sig_str, nullptr);
 
-  if (exp_sig == NULL) {
-    jni->FatalError("check_hidden_class: Error: JNI GetStringChars returned NULL for jstring\n");
+  if (exp_sig == nullptr) {
+    jni->FatalError("check_hidden_class: Error: JNI GetStringChars returned null for jstring\n");
     return;
   }
   check_hidden_class(jvmti, jni, hidden_klass, exp_sig);
@@ -355,10 +355,10 @@ Java_P_Q_HiddenClassSigTest_checkHiddenClass(JNIEnv *jni, jclass klass, jclass h
 /* Native method: checkHiddenClassArray(). */
 JNIEXPORT void JNICALL
 Java_P_Q_HiddenClassSigTest_checkHiddenClassArray(JNIEnv *jni, jclass klass, jclass hidden_klass_array, jstring exp_sig_str) {
-  const char* exp_sig = jni->GetStringUTFChars(exp_sig_str, NULL);
+  const char* exp_sig = jni->GetStringUTFChars(exp_sig_str, nullptr);
 
-  if (exp_sig == NULL) {
-    jni->FatalError("check_hidden_class_array: Error: JNI GetStringChars returned NULL for jstring\n");
+  if (exp_sig == nullptr) {
+    jni->FatalError("check_hidden_class_array: Error: JNI GetStringChars returned null for jstring\n");
     return;
   }
   check_hidden_class_array(jvmti, jni, hidden_klass_array, exp_sig);
diff --git a/test/hotspot/jtreg/serviceability/jvmti/RedefineClasses/MissedStackMapFrames/libMissedStackMapFrames.cpp b/test/hotspot/jtreg/serviceability/jvmti/RedefineClasses/MissedStackMapFrames/libMissedStackMapFrames.cpp
index 18d4a2e5d1d..5cebf608c34 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/RedefineClasses/MissedStackMapFrames/libMissedStackMapFrames.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/RedefineClasses/MissedStackMapFrames/libMissedStackMapFrames.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -62,7 +62,7 @@ struct SavedClassBytes {
 
     jbyteArray get(JNIEnv *env) {
       if (bytes == nullptr) {
-        _log("SavedClassBytes: NULL\n");
+        _log("SavedClassBytes: null\n");
         return nullptr;
       }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/RedefineClasses/RedefineRetransform/libRedefineRetransform.cpp b/test/hotspot/jtreg/serviceability/jvmti/RedefineClasses/RedefineRetransform/libRedefineRetransform.cpp
index 9ac4f0dfc26..518e147c942 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/RedefineClasses/RedefineRetransform/libRedefineRetransform.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/RedefineClasses/RedefineRetransform/libRedefineRetransform.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -152,7 +152,7 @@ public:
 
     jbyteArray getSavedHookClassBytes() {
         if (savedClassBytes == nullptr) {
-            _log("%s: savedClassBytes is NULL\n", mode);
+            _log("%s: savedClassBytes is null\n", mode);
             return nullptr;
         }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/SetBreakpoint/libTestManyBreakpoints.cpp b/test/hotspot/jtreg/serviceability/jvmti/SetBreakpoint/libTestManyBreakpoints.cpp
index dcb8f87ddd7..b9520cc0e1c 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/SetBreakpoint/libTestManyBreakpoints.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/SetBreakpoint/libTestManyBreakpoints.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,7 +28,7 @@
 
 #define TARGET_CLASS_NAME "LTarget;"
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 static void
 check_jvmti_status(JNIEnv* jni, jvmtiError err, const char* msg) {
@@ -42,7 +42,7 @@ void JNICALL classprepare(jvmtiEnv* jvmti_env, JNIEnv* jni_env, jthread thread,
     char* buf;
     jvmtiError err;
 
-    err = jvmti->GetClassSignature(klass, &buf, NULL);
+    err = jvmti->GetClassSignature(klass, &buf, nullptr);
     check_jvmti_status(jni_env, err, "classprepare: GetClassSignature error");
 
     if (strncmp(buf, TARGET_CLASS_NAME, strlen(TARGET_CLASS_NAME)) == 0) {
@@ -95,13 +95,13 @@ JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM* vm, char* options, void* reserved) {
         return JNI_ERR;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_PREPARE, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_PREPARE, nullptr);
     if (err != JNI_OK) {
         printf("Agent_OnLoad: SetEventNotificationMode CLASS_PREPARE error\n");
         return JNI_ERR;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JNI_OK) {
         printf("Agent_OnLoad: SetEventNotificationMode BREAKPOINT error\n");
         return JNI_ERR;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/SetTag/libTagMapTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/SetTag/libTagMapTest.cpp
index cb23df82485..488d6a05fed 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/SetTag/libTagMapTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/SetTag/libTagMapTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,7 +27,7 @@
 
 namespace {
     jlong nextTag = 1;
-    jvmtiEnv *jvmti = NULL;
+    jvmtiEnv *jvmti = nullptr;
 
     void checkJvmti(int code, const char* message) {
         if (code != JVMTI_ERROR_NONE) {
@@ -55,7 +55,7 @@ extern "C" JNIEXPORT jlong JNICALL Java_TagMapTest_getTag(JNIEnv* jni_env, jclas
 }
 
 extern "C" JNIEXPORT void JNICALL Java_TagMapTest_iterate(JNIEnv* jni_env, jclass clazz, jboolean tagged) {
-    checkJvmti(jvmti->IterateOverHeap(tagged ? JVMTI_HEAP_OBJECT_TAGGED : JVMTI_HEAP_OBJECT_EITHER, &heapObjectCallback, NULL), "could not iterate");
+    checkJvmti(jvmti->IterateOverHeap(tagged ? JVMTI_HEAP_OBJECT_TAGGED : JVMTI_HEAP_OBJECT_EITHER, &heapObjectCallback, nullptr), "could not iterate");
 }
 
 extern "C" JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *vm, char *options, void *reserved) {
diff --git a/test/hotspot/jtreg/serviceability/jvmti/SuspendWithCurrentThread/libSuspendWithCurrentThread.cpp b/test/hotspot/jtreg/serviceability/jvmti/SuspendWithCurrentThread/libSuspendWithCurrentThread.cpp
index f6dfe86a8e9..61d41a33835 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/SuspendWithCurrentThread/libSuspendWithCurrentThread.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/SuspendWithCurrentThread/libSuspendWithCurrentThread.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,8 +28,8 @@
 
 extern "C" {
 
-static jvmtiEnv* jvmti = NULL;
-static jthread* threads = NULL;
+static jvmtiEnv* jvmti = nullptr;
+static jthread* threads = nullptr;
 static jsize threads_count = 0;
 
 JNIEXPORT void JNICALL
@@ -51,9 +51,9 @@ Java_SuspendWithCurrentThread_registerTestedThreads(JNIEnv *jni, jclass cls, job
 /* This function is executed on the suspender thread which is not Main thread */
 JNIEXPORT void JNICALL
 Java_ThreadToSuspend_suspendTestedThreads(JNIEnv *jni, jclass cls) {
-  jvmtiError* results = NULL;
+  jvmtiError* results = nullptr;
   jvmtiError err;
-  const char* tname = get_thread_name(jvmti, jni, NULL); // current thread name
+  const char* tname = get_thread_name(jvmti, jni, nullptr); // current thread name
 
   LOG("\nsuspendTestedThreads: started by thread: %s\n", tname);
   err = jvmti->Allocate((threads_count * sizeof(jvmtiError)),
@@ -105,7 +105,7 @@ Java_SuspendWithCurrentThread_checkTestedThreadsSuspended(JNIEnv *jni, jclass cl
 
 JNIEXPORT void JNICALL
 Java_SuspendWithCurrentThread_resumeTestedThreads(JNIEnv *jni, jclass cls) {
-  jvmtiError* results = NULL;
+  jvmtiError* results = nullptr;
   jvmtiError err;
 
   LOG("\nresumeTestedThreads: started\n");
@@ -135,7 +135,7 @@ Java_SuspendWithCurrentThread_releaseTestedThreadsInfo(JNIEnv *jni, jclass cls)
 
   LOG("\nreleaseTestedThreadsInfo: started\n");
   for (int i = 0; i < threads_count; i++) {
-    if (threads[i] != NULL) {
+    if (threads[i] != nullptr) {
       jni->DeleteGlobalRef(threads[i]);
     }
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/SuspendWithObjectMonitorEnter/libSuspendWithObjectMonitorEnter.cpp b/test/hotspot/jtreg/serviceability/jvmti/SuspendWithObjectMonitorEnter/libSuspendWithObjectMonitorEnter.cpp
index cfdbed1c6e1..f449a4e6b92 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/SuspendWithObjectMonitorEnter/libSuspendWithObjectMonitorEnter.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/SuspendWithObjectMonitorEnter/libSuspendWithObjectMonitorEnter.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,7 +26,7 @@
 
 extern "C" {
 
-static jvmtiEnv* jvmti = NULL;
+static jvmtiEnv* jvmti = nullptr;
 
 #define LOG(...) \
   do { \
diff --git a/test/hotspot/jtreg/serviceability/jvmti/SuspendWithObjectMonitorWait/libSuspendWithObjectMonitorWait.cpp b/test/hotspot/jtreg/serviceability/jvmti/SuspendWithObjectMonitorWait/libSuspendWithObjectMonitorWait.cpp
index 926f0619b59..3706cba76dc 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/SuspendWithObjectMonitorWait/libSuspendWithObjectMonitorWait.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/SuspendWithObjectMonitorWait/libSuspendWithObjectMonitorWait.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,7 +26,7 @@
 
 extern "C" {
 
-static jvmtiEnv* jvmti = NULL;
+static jvmtiEnv* jvmti = nullptr;
 
 #define LOG(...) \
   do { \
diff --git a/test/hotspot/jtreg/serviceability/jvmti/SuspendWithRawMonitorEnter/libSuspendWithRawMonitorEnter.cpp b/test/hotspot/jtreg/serviceability/jvmti/SuspendWithRawMonitorEnter/libSuspendWithRawMonitorEnter.cpp
index 476d8d67a15..9b7562d70d4 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/SuspendWithRawMonitorEnter/libSuspendWithRawMonitorEnter.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/SuspendWithRawMonitorEnter/libSuspendWithRawMonitorEnter.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,8 +26,8 @@
 
 extern "C" {
 
-static jvmtiEnv* jvmti = NULL;
-static jrawMonitorID threadLock = NULL;
+static jvmtiEnv* jvmti = nullptr;
+static jrawMonitorID threadLock = nullptr;
 static char threadLockName[] = "threadLock";
 
 #define LOG(...) \
diff --git a/test/hotspot/jtreg/serviceability/jvmti/VMObjectAlloc/libVMObjectAlloc.cpp b/test/hotspot/jtreg/serviceability/jvmti/VMObjectAlloc/libVMObjectAlloc.cpp
index fc5113f1aad..20b06c6648e 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/VMObjectAlloc/libVMObjectAlloc.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/VMObjectAlloc/libVMObjectAlloc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,8 +35,8 @@ VMObjectAlloc(jvmtiEnv *jvmti,
               jobject object,
               jclass cls,
               jlong size) {
-  char *signature = NULL;
-  jvmtiError err = jvmti->GetClassSignature(cls, &signature, NULL);
+  char *signature = nullptr;
+  jvmtiError err = jvmti->GetClassSignature(cls, &signature, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     jni->FatalError("Failed during the GetClassSignature call");
   }
@@ -80,7 +80,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC , NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC , nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/Breakpoint/breakpoint01/libbreakpoint01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/Breakpoint/breakpoint01/libbreakpoint01.cpp
index 38f0bbd2075..2f4917c13f9 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/Breakpoint/breakpoint01/libbreakpoint01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/Breakpoint/breakpoint01/libbreakpoint01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,7 +52,7 @@ static const char *THREAD_NAME = "breakpoint01Thr";
 
 static volatile int bpEvents[METH_NUM];
 static volatile jint result = PASSED;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 
 static volatile int callbacksEnabled = JNI_TRUE;
@@ -92,7 +92,7 @@ ClassLoad(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jclass klass) {
       jni->FatalError("failed to obtain a class signature\n");
     }
 
-    if (sig != NULL && (strcmp(sig, CLASS_SIG) == 0)) {
+    if (sig != nullptr && (strcmp(sig, CLASS_SIG) == 0)) {
       LOG("ClassLoad event received for the class %s setting breakpoints ...\n", sig);
       setBP(jvmti, jni, klass);
     }
@@ -116,10 +116,10 @@ Breakpoint(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jmethodID method, jloca
     return;
   }
 
-  const char* thr_name = thr_info.name == NULL ? "NULL" : thr_info.name;
+  const char* thr_name = thr_info.name == nullptr ? "null" : thr_info.name;
   const char* thr_virtual_tag = jni->IsVirtualThread(thread) == JNI_TRUE ? "virtual" : "platform";
   const char* thr_daemon_tag = thr_info.is_daemon == JNI_TRUE ? "deamon" : "user";
-  if (thr_info.name == NULL || strcmp(thr_info.name, THREAD_NAME) != 0) {
+  if (thr_info.name == nullptr || strcmp(thr_info.name, THREAD_NAME) != 0) {
     result = checkStatus = STATUS_FAILED;
     LOG("TEST FAILED: Breakpoint event with unexpected thread info:\n");
     LOG("\tname: \"%s\"\ttype: %s %s thread\n\n", thr_name, thr_virtual_tag, thr_daemon_tag);
@@ -148,14 +148,14 @@ Breakpoint(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jmethodID method, jloca
     LOG("TEST FAILED: unable to obtain a class signature during Breakpoint callback\n\n");
     return;
   }
-  if (clsSig == NULL || strcmp(clsSig, CLASS_SIG) != 0) {
+  if (clsSig == nullptr || strcmp(clsSig, CLASS_SIG) != 0) {
     result = checkStatus = STATUS_FAILED;
-    LOG("TEST FAILED: Breakpoint event with unexpected class signature: %s\n\n", (clsSig == NULL) ? "NULL" : clsSig);
+    LOG("TEST FAILED: Breakpoint event with unexpected class signature: %s\n\n", (clsSig == nullptr) ? "null" : clsSig);
   } else {
     LOG("CHECK PASSED: class signature: \"%s\"\n", clsSig);
   }
 
-  err = jvmti->GetMethodName(method, &methNam, &methSig, NULL);
+  err = jvmti->GetMethodName(method, &methNam, &methSig, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     result = checkStatus = STATUS_FAILED;
     LOG("TEST FAILED: unable to get method name during Breakpoint callback\n\n");
@@ -230,7 +230,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -268,22 +268,22 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
 
   LOG("setting event callbacks done\nenabling JVMTI events ...\n");
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_START, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_START, nullptr);
   if (err != JVMTI_ERROR_NONE)
     return JNI_ERR;
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
   if (err != JVMTI_ERROR_NONE)
     return JNI_ERR;
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, nullptr);
   if (err != JVMTI_ERROR_NONE)
     return JNI_ERR;
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
   if (err != JVMTI_ERROR_NONE)
     return JNI_ERR;
   LOG("enabling the events done\n\n");
 
   agent_lock = create_raw_monitor(jvmti, "agent_lock");
-  if (agent_lock == NULL)
+  if (agent_lock == nullptr)
     return JNI_ERR;
 
   return JNI_OK;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/ClassLoad/classload01/libclassload01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/ClassLoad/classload01/libclassload01.cpp
index 6cff11b9dda..8766b2047a9 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/ClassLoad/classload01/libclassload01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/ClassLoad/classload01/libclassload01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -75,7 +75,7 @@ static volatile int clsEvents[EXP_SIG_NUM];
 static volatile int primClsEvents[UNEXP_SIG_NUM];
 
 static jint result = PASSED;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jrawMonitorID counter_lock;
 
@@ -91,7 +91,7 @@ static void initCounters() {
 
 static int findSig(char *sig, int expected) {
   for (unsigned int i = 0; i < ((expected == 1) ? EXP_SIG_NUM : UNEXP_SIG_NUM); i++) {
-    if (sig != NULL &&
+    if (sig != nullptr &&
         strcmp(((expected == 1) ? expSigs[i] : unexpSigs[i]), sig) == 0) {
       return i; /* the signature found, return index */
     }
@@ -160,7 +160,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -197,7 +197,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   }
 
   LOG("setting event callbacks done\nenabling ClassLoad event ...\n");
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Error in SetEventNotificationMode: %d\n", err);
     return JNI_ERR;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/ClassPrepare/classprep01/libclassprep01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/ClassPrepare/classprep01/libclassprep01.cpp
index 0933fec1d00..607b1d2792f 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/ClassPrepare/classprep01/libclassprep01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/ClassPrepare/classprep01/libclassprep01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,7 +45,7 @@ typedef struct {
   jint icount;
 } class_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static size_t eventsCount = 0;
@@ -158,7 +158,7 @@ void JNICALL ClassPrepare(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jclass cls)
   LOG(">>>   %d methods:", inf.mcount);
   for (int i = 0; i < inf.mcount; i++) {
     if (i > 0) LOG(",");
-    if (methods[i] == NULL) {
+    if (methods[i] == nullptr) {
       LOG(" null");
     } else {
       err = jvmti->GetMethodName(methods[i], &name, &sig, &generic);
@@ -173,7 +173,7 @@ void JNICALL ClassPrepare(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jclass cls)
   LOG(">>>   %d fields:", inf.fcount);
   for (int i = 0; i < inf.fcount; i++) {
     if (i > 0) LOG(",");
-    if (fields[i] == NULL) {
+    if (fields[i] == nullptr) {
       LOG(" null");
     } else {
       err = jvmti->GetFieldName(cls, fields[i], &name, &sig, &generic);
@@ -188,7 +188,7 @@ void JNICALL ClassPrepare(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jclass cls)
   LOG(">>>   %d interfaces:", inf.icount);
   for (int i = 0; i < inf.icount; i++) {
     if (i > 0) LOG(",");
-    if (interfaces[i] == NULL) {
+    if (interfaces[i] == nullptr) {
       LOG(" null");
     } else {
       err = jvmti->GetClassSignature(interfaces[i], &sig, &generic);
@@ -226,7 +226,7 @@ void JNICALL ClassPrepare(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jclass cls)
     return;
   }
 
-  if (inf.sig == NULL || strcmp(inf.sig, classes[eventsCount].sig) != 0) {
+  if (inf.sig == nullptr || strcmp(inf.sig, classes[eventsCount].sig) != 0) {
     LOG("(#%" PRIuPTR ") wrong class: \"%s\"", eventsCount, inf.sig);
     LOG(", expected: \"%s\"\n", classes[eventsCount].sig);
     result = STATUS_FAILED;
@@ -262,7 +262,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -299,7 +299,7 @@ JNIEXPORT void JNICALL
 Java_classprep01_getReady(JNIEnv *jni, jclass cls, jthread thread) {
   jvmtiError err;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return;
   }
@@ -327,7 +327,7 @@ JNIEXPORT jint JNICALL
 Java_classprep01_check(JNIEnv *jni, jclass cls, jthread thread) {
   jvmtiError err;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/Exception/exception01/libexception01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/Exception/exception01/libexception01.cpp
index a044bc4387b..ebb086adcaa 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/Exception/exception01/libexception01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/Exception/exception01/libexception01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -56,7 +56,7 @@ typedef struct {
   jlocation c_loc;
 } exceptionInfo;
 
-static jvmtiEnv *jvmti_env = NULL;
+static jvmtiEnv *jvmti_env = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static exceptionInfo exs[] = {
@@ -139,13 +139,13 @@ Exception(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr,
 
   bool found = false;
   for (size_t i = 0; i < sizeof(exs)/sizeof(exceptionInfo); i++) {
-    if (ex.name != NULL && strcmp(ex.name, exs[i].name) == 0
-        && ex.t_cls != NULL && strcmp(ex.t_cls, exs[i].t_cls) == 0
-        && ex.t_name != NULL && strcmp(ex.t_name, exs[i].t_name) == 0
-        && ex.t_sig != NULL && strcmp(ex.t_sig, exs[i].t_sig) == 0
-        && ex.c_cls != NULL && strcmp(ex.c_cls, exs[i].c_cls) == 0
-        && ex.c_name != NULL && strcmp(ex.c_name, exs[i].c_name) == 0
-        && ex.c_sig != NULL && strcmp(ex.c_sig, exs[i].c_sig) == 0
+    if (ex.name != nullptr && strcmp(ex.name, exs[i].name) == 0
+        && ex.t_cls != nullptr && strcmp(ex.t_cls, exs[i].t_cls) == 0
+        && ex.t_name != nullptr && strcmp(ex.t_name, exs[i].t_name) == 0
+        && ex.t_sig != nullptr && strcmp(ex.t_sig, exs[i].t_sig) == 0
+        && ex.c_cls != nullptr && strcmp(ex.c_cls, exs[i].c_cls) == 0
+        && ex.c_name != nullptr && strcmp(ex.c_name, exs[i].c_name) == 0
+        && ex.c_sig != nullptr && strcmp(ex.c_sig, exs[i].c_sig) == 0
         && ex.t_loc == exs[i].t_loc && ex.c_loc == exs[i].c_loc) {
       jboolean isVirtual = jni->IsVirtualThread(thr);
       if (isVirtualExpected != isVirtual) {
@@ -175,7 +175,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jvmtiCapabilities caps;
 
   res = jvm->GetEnv((void **) &jvmti_env, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti_env == NULL) {
+  if (res != JNI_OK || jvmti_env == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -217,27 +217,27 @@ Java_exception01_check(JNIEnv *jni, jclass cls) {
   jclass clz;
   jmethodID mid;
 
-  if (jvmti_env == NULL) {
+  if (jvmti_env == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
   clz = jni->FindClass("exception01c");
-  if (clz == NULL) {
+  if (clz == nullptr) {
     LOG("Cannot find exception01c class!\n");
     return STATUS_FAILED;
   }
   clz = jni->FindClass("exception01b");
-  if (clz == NULL) {
+  if (clz == nullptr) {
     LOG("Cannot find exception01b class!\n");
     return STATUS_FAILED;
   }
   clz = jni->FindClass("exception01a");
-  if (clz == NULL) {
+  if (clz == nullptr) {
     LOG("Cannot find exception01a class!\n");
     return STATUS_FAILED;
   }
   mid = jni->GetStaticMethodID(clz, "run", "()V");
-  if (mid == NULL) {
+  if (mid == nullptr) {
     LOG("Cannot find method run!\n");
     return STATUS_FAILED;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/ExceptionCatch/excatch01/libexcatch01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/ExceptionCatch/excatch01/libexcatch01.cpp
index bd9d263c1b2..f7d74e6f2bf 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/ExceptionCatch/excatch01/libexcatch01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/ExceptionCatch/excatch01/libexcatch01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,7 +48,7 @@ typedef struct {
   jlocation c_loc;
 } exceptionInfo;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
@@ -107,10 +107,10 @@ ExceptionCatch(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jmethodID method, jloc
 
   bool found = false;
   for (size_t i = 0; i < sizeof(exs)/sizeof(exceptionInfo); i++) {
-    if (ex.name != NULL && strcmp(ex.name, exs[i].name) == 0
-        && ex.c_cls != NULL && strcmp(ex.c_cls, exs[i].c_cls) == 0
-        && ex.c_name != NULL && strcmp(ex.c_name, exs[i].c_name) == 0
-        && ex.c_sig != NULL && strcmp(ex.c_sig, exs[i].c_sig) == 0
+    if (ex.name != nullptr && strcmp(ex.name, exs[i].name) == 0
+        && ex.c_cls != nullptr && strcmp(ex.c_cls, exs[i].c_cls) == 0
+        && ex.c_name != nullptr && strcmp(ex.c_name, exs[i].c_name) == 0
+        && ex.c_sig != nullptr && strcmp(ex.c_sig, exs[i].c_sig) == 0
         && ex.c_loc == exs[i].c_loc) {
       jboolean isVirtual = jni->IsVirtualThread(thr);
       if (isVirtualExpected != isVirtual) {
@@ -138,7 +138,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -180,28 +180,28 @@ Java_excatch01_check(JNIEnv *jni, jclass cls) {
   jmethodID mid;
   jthread thread;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
 
   clz = jni->FindClass("excatch01c");
-  if (clz == NULL) {
+  if (clz == nullptr) {
     LOG("Cannot find excatch01c class!\n");
     return STATUS_FAILED;
   }
   clz = jni->FindClass("excatch01b");
-  if (clz == NULL) {
+  if (clz == nullptr) {
     LOG("Cannot find excatch01b class!\n");
     return STATUS_FAILED;
   }
   clz = jni->FindClass("excatch01a");
-  if (clz == NULL) {
+  if (clz == nullptr) {
     LOG("Cannot find excatch01a class!\n");
     return STATUS_FAILED;
   }
   mid = jni->GetStaticMethodID(clz, "run", "()V");
-  if (mid == NULL) {
+  if (mid == nullptr) {
     LOG("Cannot find method run!\n");
     return STATUS_FAILED;
   }
@@ -213,7 +213,7 @@ Java_excatch01_check(JNIEnv *jni, jclass cls) {
     return STATUS_FAILED;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION_CATCH, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION_CATCH, nullptr);
   if (err == JVMTI_ERROR_NONE) {
       eventsExpected = sizeof(exs)/sizeof(exceptionInfo);
   } else {
@@ -224,7 +224,7 @@ Java_excatch01_check(JNIEnv *jni, jclass cls) {
   eventsCount = 0;
   isVirtualExpected = jni->IsVirtualThread(thread);
   jni->CallStaticVoidMethod(clz, mid);
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_EXCEPTION_CATCH, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_EXCEPTION_CATCH, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Failed to disable JVMTI_EVENT_EXCEPTION_CATCH: %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc01/libfieldacc01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc01/libfieldacc01.cpp
index b0ad276a1ce..cad086cb7ef 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc01/libfieldacc01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc01/libfieldacc01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -65,45 +65,45 @@ static volatile jboolean isVirtualExpected = JNI_FALSE;
 static volatile int eventsExpected = 0;
 static volatile int eventsCount = 0;
 static watch_info watches[] = {
-    { NULL, "Lfieldacc01a;", "run", "()I", 2,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 2,
         "Lfieldacc01a;", "staticBoolean", "Z", JNI_TRUE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 6,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 6,
         "Lfieldacc01a;", "instanceBoolean", "Z", JNI_FALSE },
-    { NULL, "Lfieldacc01a;",   "run", "()I", 15,
+    { nullptr, "Lfieldacc01a;",   "run", "()I", 15,
         "Lfieldacc01a;", "staticByte", "B", JNI_TRUE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 19,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 19,
         "Lfieldacc01a;", "instanceByte", "B", JNI_FALSE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 28,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 28,
         "Lfieldacc01a;", "staticShort", "S", JNI_TRUE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 32,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 32,
         "Lfieldacc01a;", "instanceShort", "S", JNI_FALSE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 41,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 41,
         "Lfieldacc01a;", "staticInt", "I", JNI_TRUE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 45,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 45,
         "Lfieldacc01a;", "instanceInt", "I", JNI_FALSE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 54,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 54,
         "Lfieldacc01a;", "staticLong", "J", JNI_TRUE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 58,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 58,
         "Lfieldacc01a;", "instanceLong", "J", JNI_FALSE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 68,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 68,
         "Lfieldacc01a;", "staticFloat", "F", JNI_TRUE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 72,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 72,
         "Lfieldacc01a;", "instanceFloat", "F", JNI_FALSE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 82,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 82,
         "Lfieldacc01a;", "staticDouble", "D", JNI_TRUE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 86,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 86,
         "Lfieldacc01a;", "instanceDouble", "D", JNI_FALSE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 96,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 96,
         "Lfieldacc01a;", "staticChar", "C", JNI_TRUE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 100,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 100,
         "Lfieldacc01a;", "instanceChar", "C", JNI_FALSE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 109,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 109,
         "Lfieldacc01a;", "staticObject", "Ljava/lang/Object;", JNI_TRUE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 113,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 113,
         "Lfieldacc01a;", "instanceObject", "Ljava/lang/Object;", JNI_FALSE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 122,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 122,
         "Lfieldacc01a;", "staticArrInt", "[I", JNI_TRUE },
-    { NULL, "Lfieldacc01a;", "run", "()I", 128,
+    { nullptr, "Lfieldacc01a;", "run", "()I", 128,
         "Lfieldacc01a;", "instanceArrInt", "[I", JNI_FALSE }
 };
 
@@ -121,7 +121,7 @@ void JNICALL FieldAccess(jvmtiEnv *jvmti, JNIEnv *jni,
 
   watch.fid = field;
   watch.loc = location;
-  watch.is_static = (obj == NULL) ? JNI_TRUE : JNI_FALSE;
+  watch.is_static = (obj == nullptr) ? JNI_TRUE : JNI_FALSE;
   err = jvmti->GetMethodDeclaringClass(method, &cls);
   if (err != JVMTI_ERROR_NONE) {
     LOG("(GetMethodDeclaringClass) unexpected error: %s (%d)\n", TranslateError(err), err);
@@ -163,16 +163,16 @@ void JNICALL FieldAccess(jvmtiEnv *jvmti, JNIEnv *jni,
 
   for (size_t i = 0; i < sizeof(watches)/sizeof(watch_info); i++) {
     if (watch.fid == watches[i].fid) {
-      if (watch.m_cls == NULL || strcmp(watch.m_cls, watches[i].m_cls) != 0) {
+      if (watch.m_cls == nullptr || strcmp(watch.m_cls, watches[i].m_cls) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong class: \"%s\", expected: \"%s\"\n", i, watch.m_cls, watches[i].m_cls);
         result = STATUS_FAILED;
       }
-      if (watch.m_name == NULL || strcmp(watch.m_name, watches[i].m_name) != 0) {
+      if (watch.m_name == nullptr || strcmp(watch.m_name, watches[i].m_name) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong method name: \"%s\"", i, watch.m_name);
         LOG(", expected: \"%s\"\n", watches[i].m_name);
         result = STATUS_FAILED;
       }
-      if (watch.m_sig == NULL || strcmp(watch.m_sig, watches[i].m_sig) != 0) {
+      if (watch.m_sig == nullptr || strcmp(watch.m_sig, watches[i].m_sig) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong method sig: \"%s\"", i, watch.m_sig);
         LOG(", expected: \"%s\"\n", watches[i].m_sig);
         result = STATUS_FAILED;
@@ -182,12 +182,12 @@ void JNICALL FieldAccess(jvmtiEnv *jvmti, JNIEnv *jni,
         LOG(", expected: 0x%x%08x\n", (jint)(watches[i].loc >> 32), (jint)watches[i].loc);
         result = STATUS_FAILED;
       }
-      if (watch.f_name == NULL || strcmp(watch.f_name, watches[i].f_name) != 0) {
+      if (watch.f_name == nullptr || strcmp(watch.f_name, watches[i].f_name) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong field name: \"%s\"", i, watch.f_name);
         LOG(", expected: \"%s\"\n", watches[i].f_name);
         result = STATUS_FAILED;
       }
-      if (watch.f_sig == NULL || strcmp(watch.f_sig, watches[i].f_sig) != 0) {
+      if (watch.f_sig == nullptr || strcmp(watch.f_sig, watches[i].f_sig) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong field sig: \"%s\"", i, watch.f_sig);
         LOG(", expected: \"%s\"\n", watches[i].f_sig);
         result = STATUS_FAILED;
@@ -216,7 +216,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -245,7 +245,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
       return JNI_ERR;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_ACCESS, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_ACCESS, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       LOG("Failed to enable JVMTI_EVENT_FIELD_ACCESS: %s (%d)\n", TranslateError(err), err);
       return JNI_ERR;
@@ -267,7 +267,7 @@ Java_fieldacc01_getReady(JNIEnv *jni, jclass klass) {
   LOG(">>> setting field access watches ...\n");
 
   cls = jni->FindClass("fieldacc01a");
-  if (cls == NULL) {
+  if (cls == nullptr) {
     LOG("Cannot find fieldacc01a class!\n");
     result = STATUS_FAILED;
     return;
@@ -289,7 +289,7 @@ Java_fieldacc01_getReady(JNIEnv *jni, jclass klass) {
     } else {
       watches[i].fid = jni->GetFieldID(cls, watches[i].f_name, watches[i].f_sig);
     }
-    if (watches[i].fid == NULL) {
+    if (watches[i].fid == nullptr) {
       LOG("Cannot find field \"%s\"!\n", watches[i].f_name);
       result = STATUS_FAILED;
       return;
@@ -317,7 +317,7 @@ Java_fieldacc01_check(JNIEnv *jni, jclass klass) {
   }
 
   cls = jni->FindClass("fieldacc01a");
-  if (cls == NULL) {
+  if (cls == nullptr) {
     LOG("Cannot find fieldacc01a class!\n");
     result = STATUS_FAILED;
     return result;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc02/libfieldacc02.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc02/libfieldacc02.cpp
index 59d4150e4c2..c733fb1cbc7 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc02/libfieldacc02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc02/libfieldacc02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -65,46 +65,46 @@ static volatile jboolean isVirtualExpected = JNI_FALSE;
 static int eventsExpected = 0;
 static int eventsCount = 0;
 static watch_info watches[] = {
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "staticBoolean", "Z", JNI_TRUE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "staticByte", "B", JNI_TRUE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "staticShort", "S", JNI_TRUE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "staticInt", "I", JNI_TRUE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "staticLong", "J", JNI_TRUE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "staticFloat", "F", JNI_TRUE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "staticDouble", "D", JNI_TRUE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "staticChar", "C", JNI_TRUE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "staticObject", "Ljava/lang/Object;", JNI_TRUE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "staticArrInt", "[I", JNI_TRUE },
 
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "instanceBoolean", "Z", JNI_FALSE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "instanceByte", "B", JNI_FALSE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "instanceShort", "S", JNI_FALSE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "instanceInt", "I", JNI_FALSE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "instanceLong", "J", JNI_FALSE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "instanceFloat", "F", JNI_FALSE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "instanceDouble", "D", JNI_FALSE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "instanceChar", "C", JNI_FALSE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "instanceObject", "Ljava/lang/Object;", JNI_FALSE },
-    { NULL, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldacc02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldacc02a;", "instanceArrInt", "[I", JNI_FALSE }
 };
 
@@ -121,7 +121,7 @@ void JNICALL FieldAccess(jvmtiEnv *jvmti, JNIEnv *jni,
 
   watch.fid = field;
   watch.loc = location;
-  watch.is_static = (obj == NULL) ? JNI_TRUE : JNI_FALSE;
+  watch.is_static = (obj == nullptr) ? JNI_TRUE : JNI_FALSE;
   err = jvmti->GetMethodDeclaringClass(method, &cls);
   if (err != JVMTI_ERROR_NONE) {
     LOG("(GetMethodDeclaringClass) unexpected error: %s (%d)\n", TranslateError(err), err);
@@ -162,16 +162,16 @@ void JNICALL FieldAccess(jvmtiEnv *jvmti, JNIEnv *jni,
 
   for (size_t i = 0; i < sizeof(watches)/sizeof(watch_info); i++) {
     if (watch.fid == watches[i].fid) {
-      if (watch.m_cls == NULL || strcmp(watch.m_cls, watches[i].m_cls) != 0) {
+      if (watch.m_cls == nullptr || strcmp(watch.m_cls, watches[i].m_cls) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong class: \"%s\", expected: \"%s\"\n", i, watch.m_cls, watches[i].m_cls);
         result = STATUS_FAILED;
       }
-      if (watch.m_name == NULL || strcmp(watch.m_name, watches[i].m_name) != 0) {
+      if (watch.m_name == nullptr || strcmp(watch.m_name, watches[i].m_name) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong method name: \"%s\"", i, watch.m_name);
         LOG(", expected: \"%s\"\n", watches[i].m_name);
         result = STATUS_FAILED;
       }
-      if (watch.m_sig == NULL || strcmp(watch.m_sig, watches[i].m_sig) != 0) {
+      if (watch.m_sig == nullptr || strcmp(watch.m_sig, watches[i].m_sig) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong method sig: \"%s\"", i, watch.m_sig);
         LOG(", expected: \"%s\"\n", watches[i].m_sig);
         result = STATUS_FAILED;
@@ -181,12 +181,12 @@ void JNICALL FieldAccess(jvmtiEnv *jvmti, JNIEnv *jni,
         LOG(", expected: 0x%x%08x\n", (jint)(watches[i].loc >> 32), (jint)watches[i].loc);
         result = STATUS_FAILED;
       }
-      if (watch.f_name == NULL || strcmp(watch.f_name, watches[i].f_name) != 0) {
+      if (watch.f_name == nullptr || strcmp(watch.f_name, watches[i].f_name) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong field name: \"%s\"", i, watch.f_name);
         LOG(", expected: \"%s\"\n", watches[i].f_name);
         result = STATUS_FAILED;
       }
-      if (watch.f_sig == NULL || strcmp(watch.f_sig, watches[i].f_sig) != 0) {
+      if (watch.f_sig == nullptr || strcmp(watch.f_sig, watches[i].f_sig) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong field sig: \"%s\"", i, watch.f_sig);
         LOG(", expected: \"%s\"\n", watches[i].f_sig);
         result = STATUS_FAILED;
@@ -214,7 +214,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -243,7 +243,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
       return JNI_ERR;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_ACCESS, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_ACCESS, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       LOG("Failed to enable JVMTI_EVENT_FIELD_ACCESS: %s (%d)\n",
              TranslateError(err), err);
@@ -264,7 +264,7 @@ JNIEXPORT void JNICALL Java_fieldacc02_getReady(JNIEnv *jni, jclass clz) {
   LOG(">>> setting field access watches ...\n");
 
   cls = jni->FindClass("fieldacc02a");
-  if (cls == NULL) {
+  if (cls == nullptr) {
     LOG("Cannot find fieldacc02a class!\n");
     result = STATUS_FAILED;
     return;
@@ -287,7 +287,7 @@ JNIEXPORT void JNICALL Java_fieldacc02_getReady(JNIEnv *jni, jclass clz) {
     } else {
       watches[i].fid = jni->GetFieldID(cls, watches[i].f_name, watches[i].f_sig);
     }
-    if (watches[i].fid == NULL) {
+    if (watches[i].fid == nullptr) {
       LOG("Cannot find field \"%s\"!\n", watches[i].f_name);
       result = STATUS_FAILED;
       return;
@@ -313,7 +313,7 @@ Java_fieldacc02_check(JNIEnv *jni, jclass clz, jobject obj) {
   LOG(">>> accessing fields ...\n");
 
   cls = jni->FindClass("fieldacc02a");
-  if (cls == NULL) {
+  if (cls == nullptr) {
     LOG("Cannot find fieldacc02a class!\n");
     return STATUS_FAILED;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc03/libfieldacc03.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc03/libfieldacc03.cpp
index 97c7d145918..769a26c9c7d 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc03/libfieldacc03.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc03/libfieldacc03.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -65,25 +65,25 @@ static volatile jboolean isVirtualExpected = JNI_FALSE;
 static int eventsExpected = 0;
 static int eventsCount = 0;
 static watch_info watches[] = {
-    { NULL, "Lfieldacc03a;", "run", "()I", 3,
+    { nullptr, "Lfieldacc03a;", "run", "()I", 3,
         "Lfieldacc03a;", "extendsBoolean", "Z", JNI_FALSE },
-    { NULL, "Lfieldacc03a;", "run", "()I", 14,
+    { nullptr, "Lfieldacc03a;", "run", "()I", 14,
         "Lfieldacc03a;", "extendsByte", "B", JNI_FALSE },
-    { NULL, "Lfieldacc03a;", "run", "()I", 25,
+    { nullptr, "Lfieldacc03a;", "run", "()I", 25,
         "Lfieldacc03a;", "extendsShort", "S", JNI_FALSE },
-    { NULL, "Lfieldacc03a;", "run", "()I", 36,
+    { nullptr, "Lfieldacc03a;", "run", "()I", 36,
         "Lfieldacc03a;", "extendsInt", "I", JNI_FALSE },
-    { NULL, "Lfieldacc03a;", "run", "()I", 47,
+    { nullptr, "Lfieldacc03a;", "run", "()I", 47,
         "Lfieldacc03a;", "extendsLong", "J", JNI_FALSE },
-    { NULL, "Lfieldacc03a;", "run", "()I", 61,
+    { nullptr, "Lfieldacc03a;", "run", "()I", 61,
         "Lfieldacc03a;", "extendsFloat", "F", JNI_FALSE },
-    { NULL, "Lfieldacc03a;", "run", "()I", 74,
+    { nullptr, "Lfieldacc03a;", "run", "()I", 74,
         "Lfieldacc03a;", "extendsDouble", "D", JNI_FALSE },
-    { NULL, "Lfieldacc03a;", "run", "()I", 88,
+    { nullptr, "Lfieldacc03a;", "run", "()I", 88,
         "Lfieldacc03a;", "extendsChar", "C", JNI_FALSE },
-    { NULL, "Lfieldacc03a;", "run", "()I", 100,
+    { nullptr, "Lfieldacc03a;", "run", "()I", 100,
         "Lfieldacc03a;", "extendsObject", "Ljava/lang/Object;", JNI_FALSE },
-    { NULL, "Lfieldacc03a;", "run", "()I", 111,
+    { nullptr, "Lfieldacc03a;", "run", "()I", 111,
         "Lfieldacc03a;", "extendsArrInt", "[I", JNI_FALSE }
 };
 
@@ -100,7 +100,7 @@ void JNICALL FieldAccess(jvmtiEnv *jvmti, JNIEnv *jni,
 
   watch.fid = field;
   watch.loc = location;
-  watch.is_static = (obj == NULL) ? JNI_TRUE : JNI_FALSE;
+  watch.is_static = (obj == nullptr) ? JNI_TRUE : JNI_FALSE;
   err = jvmti->GetMethodDeclaringClass(method, &cls);
   if (err != JVMTI_ERROR_NONE) {
     LOG("(GetMethodDeclaringClass) unexpected error: %s (%d)\n", TranslateError(err), err);
@@ -142,16 +142,16 @@ void JNICALL FieldAccess(jvmtiEnv *jvmti, JNIEnv *jni,
 
   for (size_t i = 0; i < sizeof(watches)/sizeof(watch_info); i++) {
     if (watch.fid == watches[i].fid) {
-      if (watch.m_cls == NULL || strcmp(watch.m_cls, watches[i].m_cls) != 0) {
+      if (watch.m_cls == nullptr || strcmp(watch.m_cls, watches[i].m_cls) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong class: \"%s\", expected: \"%s\"\n", i, watch.m_cls, watches[i].m_cls);
         result = STATUS_FAILED;
       }
-      if (watch.m_name == NULL || strcmp(watch.m_name, watches[i].m_name) != 0) {
+      if (watch.m_name == nullptr || strcmp(watch.m_name, watches[i].m_name) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong method name: \"%s\"", i, watch.m_name);
         LOG(", expected: \"%s\"\n", watches[i].m_name);
         result = STATUS_FAILED;
       }
-      if (watch.m_sig == NULL || strcmp(watch.m_sig, watches[i].m_sig) != 0) {
+      if (watch.m_sig == nullptr || strcmp(watch.m_sig, watches[i].m_sig) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong method sig: \"%s\"", i, watch.m_sig);
         LOG(", expected: \"%s\"\n", watches[i].m_sig);
         result = STATUS_FAILED;
@@ -161,12 +161,12 @@ void JNICALL FieldAccess(jvmtiEnv *jvmti, JNIEnv *jni,
         LOG(", expected: 0x%x%08x\n", (jint)(watches[i].loc >> 32), (jint)watches[i].loc);
         result = STATUS_FAILED;
       }
-      if (watch.f_name == NULL || strcmp(watch.f_name, watches[i].f_name) != 0) {
+      if (watch.f_name == nullptr || strcmp(watch.f_name, watches[i].f_name) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong field name: \"%s\"", i, watch.f_name);
         LOG(", expected: \"%s\"\n", watches[i].f_name);
         result = STATUS_FAILED;
       }
-      if (watch.f_sig == NULL || strcmp(watch.f_sig, watches[i].f_sig) != 0) {
+      if (watch.f_sig == nullptr || strcmp(watch.f_sig, watches[i].f_sig) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong field sig: \"%s\"", i, watch.f_sig);
         LOG(", expected: \"%s\"\n", watches[i].f_sig);
         result = STATUS_FAILED;
@@ -194,7 +194,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -223,7 +223,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
       return JNI_ERR;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_ACCESS, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_ACCESS, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       LOG("Failed to enable JVMTI_EVENT_FIELD_ACCESS: %s (%d)\n", TranslateError(err), err);
       return JNI_ERR;
@@ -256,7 +256,7 @@ Java_fieldacc03_getReady(JNIEnv *jni, jclass klass) {
 
   for (size_t i = 0; i < sizeof(watches)/sizeof(watch_info); i++) {
     cls = jni->FindClass(watches[i].f_cls);
-    if (cls == NULL) {
+    if (cls == nullptr) {
       LOG("Cannot find %s class!\n", watches[i].f_cls);
       result = STATUS_FAILED;
       return;
@@ -266,7 +266,7 @@ Java_fieldacc03_getReady(JNIEnv *jni, jclass klass) {
     } else {
       watches[i].fid = jni->GetFieldID(cls, watches[i].f_name, watches[i].f_sig);
     }
-    if (watches[i].fid == NULL) {
+    if (watches[i].fid == nullptr) {
       LOG("Cannot get field ID for \"%s:%s\"\n", watches[i].f_name, watches[i].f_sig);
       result = STATUS_FAILED;
       return;
@@ -291,7 +291,7 @@ Java_fieldacc03_check(JNIEnv *jni, jclass clz) {
   }
   for (size_t i = 0; i < sizeof(watches)/sizeof(watch_info); i++) {
     jclass cls = jni->FindClass(watches[i].f_cls);
-    if (cls == NULL) {
+    if (cls == nullptr) {
       LOG("Cannot find %s class!\n", watches[i].f_cls);
       result = STATUS_FAILED;
       return result;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc04/libfieldacc04.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc04/libfieldacc04.cpp
index 1b1f9df96b7..2239294c52c 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc04/libfieldacc04.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/FieldAccess/fieldacc04/libfieldacc04.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -65,10 +65,10 @@ static volatile jboolean isVirtualExpected = JNI_FALSE;
 static int eventsExpected = 0;
 static int eventsCount = 0;
 static watch_info watches[] = {
-    { NULL, "Lfieldacc04a;", "run", "()I", 2,
+    { nullptr, "Lfieldacc04a;", "run", "()I", 2,
         "Lfieldacc04a;", "interfaceObject",
         "Ljava/lang/Object;", JNI_TRUE },
-    { NULL, "Lfieldacc04a;", "run", "()I", 12,
+    { nullptr, "Lfieldacc04a;", "run", "()I", 12,
         "Lfieldacc04a;", "interfaceArrInt",
         "[I", JNI_TRUE }
 };
@@ -87,7 +87,7 @@ void JNICALL FieldAccess(jvmtiEnv *jvmti, JNIEnv *jni,
 
   watch.fid = field;
   watch.loc = location;
-  watch.is_static = (obj == NULL) ? JNI_TRUE : JNI_FALSE;
+  watch.is_static = (obj == nullptr) ? JNI_TRUE : JNI_FALSE;
   err = jvmti->GetMethodDeclaringClass(method, &cls);
   if (err != JVMTI_ERROR_NONE) {
     LOG("(GetMethodDeclaringClass) unexpected error: %s (%d)\n", TranslateError(err), err);
@@ -129,16 +129,16 @@ void JNICALL FieldAccess(jvmtiEnv *jvmti, JNIEnv *jni,
 
   for (size_t i = 0; i < sizeof(watches)/sizeof(watch_info); i++) {
     if (watch.fid == watches[i].fid) {
-      if (watch.m_cls == NULL ||  strcmp(watch.m_cls, watches[i].m_cls) != 0) {
+      if (watch.m_cls == nullptr ||  strcmp(watch.m_cls, watches[i].m_cls) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong class: \"%s\", expected: \"%s\"\n", i, watch.m_cls, watches[i].m_cls);
         result = STATUS_FAILED;
       }
-      if (watch.m_name == NULL || strcmp(watch.m_name, watches[i].m_name) != 0) {
+      if (watch.m_name == nullptr || strcmp(watch.m_name, watches[i].m_name) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong method name: \"%s\"", i, watch.m_name);
         LOG(", expected: \"%s\"\n", watches[i].m_name);
         result = STATUS_FAILED;
       }
-      if (watch.m_sig == NULL || strcmp(watch.m_sig, watches[i].m_sig) != 0) {
+      if (watch.m_sig == nullptr || strcmp(watch.m_sig, watches[i].m_sig) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong method sig: \"%s\"", i, watch.m_sig);
         LOG(", expected: \"%s\"\n", watches[i].m_sig);
         result = STATUS_FAILED;
@@ -148,12 +148,12 @@ void JNICALL FieldAccess(jvmtiEnv *jvmti, JNIEnv *jni,
         LOG(", expected: 0x%x%08x\n", (jint)(watches[i].loc >> 32), (jint)watches[i].loc);
         result = STATUS_FAILED;
       }
-      if (watch.f_name == NULL || strcmp(watch.f_name, watches[i].f_name) != 0) {
+      if (watch.f_name == nullptr || strcmp(watch.f_name, watches[i].f_name) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong field name: \"%s\"", i, watch.f_name);
         LOG(", expected: \"%s\"\n", watches[i].f_name);
         result = STATUS_FAILED;
       }
-      if (watch.f_sig == NULL || strcmp(watch.f_sig, watches[i].f_sig) != 0) {
+      if (watch.f_sig == nullptr || strcmp(watch.f_sig, watches[i].f_sig) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong field sig: \"%s\"", i, watch.f_sig);
         LOG(", expected: \"%s\"\n", watches[i].f_sig);
         result = STATUS_FAILED;
@@ -181,7 +181,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -210,7 +210,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
       return JNI_ERR;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_ACCESS, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_ACCESS, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       LOG("Failed to enable JVMTI_EVENT_FIELD_ACCESS: %s (%d)\n", TranslateError(err), err);
       return JNI_ERR;
@@ -243,7 +243,7 @@ Java_fieldacc04_getReady(JNIEnv *jni, jclass klass) {
 
   for (size_t i = 0; i < sizeof(watches)/sizeof(watch_info); i++) {
     cls = jni->FindClass(watches[i].f_cls);
-    if (cls == NULL) {
+    if (cls == nullptr) {
       LOG("Cannot find %s class!\n", watches[i].f_cls);
       result = STATUS_FAILED;
       return;
@@ -253,7 +253,7 @@ Java_fieldacc04_getReady(JNIEnv *jni, jclass klass) {
     } else {
       watches[i].fid = jni->GetFieldID(cls, watches[i].f_name, watches[i].f_sig);
     }
-    if (watches[i].fid == NULL) {
+    if (watches[i].fid == nullptr) {
       LOG("Cannot get field ID for \"%s:%s\"\n", watches[i].f_name, watches[i].f_sig);
       result = STATUS_FAILED;
       return;
@@ -279,7 +279,7 @@ Java_fieldacc04_check(JNIEnv *jni, jclass clz) {
   }
   for (size_t i = 0; i < sizeof(watches)/sizeof(watch_info); i++) {
     jclass cls = jni->FindClass(watches[i].f_cls);
-    if (cls == NULL) {
+    if (cls == nullptr) {
       LOG("Cannot find %s class!\n", watches[i].f_cls);
       result = STATUS_FAILED;
       return result;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/FieldModification/fieldmod01/libfieldmod01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/FieldModification/fieldmod01/libfieldmod01.cpp
index cfd53a3f861..26da8fedefb 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/FieldModification/fieldmod01/libfieldmod01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/FieldModification/fieldmod01/libfieldmod01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -67,46 +67,46 @@ static volatile jboolean isVirtualExpected = JNI_FALSE;
 static int eventsExpected = 0;
 static int eventsCount = 0;
 static watch_info watches[] = {
-    { NULL, "Lfieldmod01a;", "run", "()V", 1,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 1,
         "Lfieldmod01a;", "staticBoolean", "Z", JNI_TRUE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 5,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 5,
         "Lfieldmod01a;", "staticByte", "B", JNI_TRUE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 9,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 9,
         "Lfieldmod01a;", "staticShort", "S", JNI_TRUE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 13,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 13,
         "Lfieldmod01a;", "staticInt", "I", JNI_TRUE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 19,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 19,
         "Lfieldmod01a;", "staticLong", "J", JNI_TRUE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 24,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 24,
         "Lfieldmod01a;", "staticFloat", "F", JNI_TRUE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 30,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 30,
         "Lfieldmod01a;", "staticDouble", "D", JNI_TRUE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 35,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 35,
         "Lfieldmod01a;", "staticChar", "C", JNI_TRUE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 41,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 41,
         "Lfieldmod01a;", "staticObject", "Ljava/lang/Object;", JNI_TRUE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 47,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 47,
         "Lfieldmod01a;", "staticArrInt", "[I", JNI_TRUE, {} },
 
-    { NULL, "Lfieldmod01a;", "run", "()V", 52,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 52,
         "Lfieldmod01a;", "instanceBoolean", "Z", JNI_FALSE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 58,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 58,
         "Lfieldmod01a;", "instanceByte", "B", JNI_FALSE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 64,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 64,
         "Lfieldmod01a;", "instanceShort", "S", JNI_FALSE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 70,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 70,
         "Lfieldmod01a;", "instanceInt", "I", JNI_FALSE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 77,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 77,
         "Lfieldmod01a;", "instanceLong", "J", JNI_FALSE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 83,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 83,
         "Lfieldmod01a;", "instanceFloat", "F", JNI_FALSE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 90,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 90,
         "Lfieldmod01a;", "instanceDouble", "D", JNI_FALSE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 96,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 96,
         "Lfieldmod01a;", "instanceChar", "C", JNI_FALSE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 103,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 103,
         "Lfieldmod01a;", "instanceObject", "Ljava/lang/Object;", JNI_FALSE, {} },
-    { NULL, "Lfieldmod01a;", "run", "()V", 110,
+    { nullptr, "Lfieldmod01a;", "run", "()V", 110,
         "Lfieldmod01a;", "instanceArrInt", "[I", JNI_FALSE, {} }
 };
 
@@ -187,7 +187,7 @@ void JNICALL FieldModification(jvmtiEnv *jvmti, JNIEnv *jni,
   watch.fid = field;
   watch.loc = location;
   watch.val = new_value;
-  watch.is_static = (obj == NULL) ? JNI_TRUE : JNI_FALSE;
+  watch.is_static = (obj == nullptr) ? JNI_TRUE : JNI_FALSE;
   err = jvmti->GetMethodDeclaringClass(method, &cls);
   if (err != JVMTI_ERROR_NONE) {
     LOG("(GetMethodDeclaringClass) unexpected error: %s (%d)\n", TranslateError(err), err);
@@ -231,16 +231,16 @@ void JNICALL FieldModification(jvmtiEnv *jvmti, JNIEnv *jni,
 
   for (size_t i = 0; i < sizeof(watches)/sizeof(watch_info); i++) {
     if (watch.fid == watches[i].fid) {
-      if (watch.m_cls == NULL || strcmp(watch.m_cls, watches[i].m_cls) != 0) {
+      if (watch.m_cls == nullptr || strcmp(watch.m_cls, watches[i].m_cls) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong class: \"%s\", expected: \"%s\"\n", i, watch.m_cls, watches[i].m_cls);
         result = STATUS_FAILED;
       }
-      if (watch.m_name == NULL || strcmp(watch.m_name, watches[i].m_name) != 0) {
+      if (watch.m_name == nullptr || strcmp(watch.m_name, watches[i].m_name) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong method name: \"%s\"", i, watch.m_name);
         LOG(", expected: \"%s\"\n", watches[i].m_name);
         result = STATUS_FAILED;
       }
-      if (watch.m_sig == NULL || strcmp(watch.m_sig, watches[i].m_sig) != 0) {
+      if (watch.m_sig == nullptr || strcmp(watch.m_sig, watches[i].m_sig) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong method sig: \"%s\"", i, watch.m_sig);
         LOG(", expected: \"%s\"\n", watches[i].m_sig);
         result = STATUS_FAILED;
@@ -250,12 +250,12 @@ void JNICALL FieldModification(jvmtiEnv *jvmti, JNIEnv *jni,
         LOG(", expected: 0x%x%08x\n", (jint)(watches[i].loc >> 32), (jint)watches[i].loc);
         result = STATUS_FAILED;
       }
-      if (watch.f_name == NULL || strcmp(watch.f_name, watches[i].f_name) != 0) {
+      if (watch.f_name == nullptr || strcmp(watch.f_name, watches[i].f_name) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong field name: \"%s\"", i, watch.f_name);
         LOG(", expected: \"%s\"\n", watches[i].f_name);
         result = STATUS_FAILED;
       }
-      if (watch.f_sig == NULL || strcmp(watch.f_sig, watches[i].f_sig) != 0) {
+      if (watch.f_sig == nullptr || strcmp(watch.f_sig, watches[i].f_sig) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong field sig: \"%s\"", i, watch.f_sig);
         LOG(", expected: \"%s\"\n", watches[i].f_sig);
         result = STATUS_FAILED;
@@ -291,7 +291,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -321,7 +321,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
       return JNI_ERR;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_MODIFICATION, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_MODIFICATION, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       LOG("Failed to enable JVMTI_EVENT_FIELD_MODIFICATION: %s (%d)\n", TranslateError(err), err);
       return JNI_ERR;
@@ -353,7 +353,7 @@ Java_fieldmod01_getReady(JNIEnv *jni, jclass klass, jobject obj1, jobject obj2,
   LOG(">>> setting field modification watches ...\n");
 
   cls = jni->FindClass("fieldmod01a");
-  if (cls == NULL) {
+  if (cls == nullptr) {
     LOG("Cannot find fieldmod01a class!\n");
     result = STATUS_FAILED;
     return;
@@ -364,7 +364,7 @@ Java_fieldmod01_getReady(JNIEnv *jni, jclass klass, jobject obj1, jobject obj2,
     } else {
       watches[i].fid = jni->GetFieldID(cls, watches[i].f_name, watches[i].f_sig);
     }
-    if (watches[i].fid == NULL) {
+    if (watches[i].fid == nullptr) {
       LOG("Cannot get field ID for \"%s:%s\"\n", watches[i].f_name, watches[i].f_sig);
       result = STATUS_FAILED;
       return;
@@ -412,7 +412,7 @@ Java_fieldmod01_check(JNIEnv *jni, jclass clz) {
   }
 
   jclass cls = jni->FindClass("fieldmod01a");
-  if (cls == NULL) {
+  if (cls == nullptr) {
     LOG("Cannot find fieldmod01a class!\n");
     result = STATUS_FAILED;
     return result;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/FieldModification/fieldmod02/libfieldmod02.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/FieldModification/fieldmod02/libfieldmod02.cpp
index 7c0dae284eb..23e3c5f22d9 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/FieldModification/fieldmod02/libfieldmod02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/FieldModification/fieldmod02/libfieldmod02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -67,46 +67,46 @@ static volatile jboolean isVirtualExpected = JNI_FALSE;
 static int eventsExpected = 0;
 static int eventsCount = 0;
 static watch_info watches[] = {
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "staticBoolean", "Z", JNI_TRUE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "staticByte", "B", JNI_TRUE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "staticShort", "S", JNI_TRUE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "staticInt", "I", JNI_TRUE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "staticLong", "J", JNI_TRUE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "staticFloat", "F", JNI_TRUE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "staticDouble", "D", JNI_TRUE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "staticChar", "C", JNI_TRUE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "staticObject", "Ljava/lang/Object;", JNI_TRUE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "staticArrInt", "[I", JNI_TRUE, {} },
 
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "instanceBoolean", "Z", JNI_FALSE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "instanceByte", "B", JNI_FALSE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "instanceShort", "S", JNI_FALSE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "instanceInt", "I", JNI_FALSE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "instanceLong", "J", JNI_FALSE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "instanceFloat", "F", JNI_FALSE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "instanceDouble", "D", JNI_FALSE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "instanceChar", "C", JNI_FALSE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "instanceObject", "Ljava/lang/Object;", JNI_FALSE, {} },
-    { NULL, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
+    { nullptr, "Lfieldmod02;", "check", "(Ljava/lang/Object;)I", 0,
         "Lfieldmod02a;", "instanceArrInt", "[I", JNI_FALSE, {} }
 };
 
@@ -187,7 +187,7 @@ void JNICALL FieldModification(jvmtiEnv *jvmti, JNIEnv *jni,
 
   watch.fid = field;
   watch.loc = location;
-  watch.is_static = (obj == NULL) ? JNI_TRUE : JNI_FALSE;
+  watch.is_static = (obj == nullptr) ? JNI_TRUE : JNI_FALSE;
   watch.val = new_value;
   err = jvmti->GetMethodDeclaringClass(method, &cls);
   if (err != JVMTI_ERROR_NONE) {
@@ -232,16 +232,16 @@ void JNICALL FieldModification(jvmtiEnv *jvmti, JNIEnv *jni,
 
   for (size_t i = 0; i < sizeof(watches)/sizeof(watch_info); i++) {
     if (watch.fid == watches[i].fid) {
-      if (watch.m_cls == NULL || strcmp(watch.m_cls, watches[i].m_cls) != 0) {
+      if (watch.m_cls == nullptr || strcmp(watch.m_cls, watches[i].m_cls) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong class: \"%s\", expected: \"%s\"\n", i, watch.m_cls, watches[i].m_cls);
         result = STATUS_FAILED;
       }
-      if (watch.m_name == NULL || strcmp(watch.m_name, watches[i].m_name) != 0) {
+      if (watch.m_name == nullptr || strcmp(watch.m_name, watches[i].m_name) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong method name: \"%s\"", i, watch.m_name);
         LOG(", expected: \"%s\"\n", watches[i].m_name);
         result = STATUS_FAILED;
       }
-      if (watch.m_sig == NULL || strcmp(watch.m_sig, watches[i].m_sig) != 0) {
+      if (watch.m_sig == nullptr || strcmp(watch.m_sig, watches[i].m_sig) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong method sig: \"%s\"", i, watch.m_sig);
         LOG(", expected: \"%s\"\n", watches[i].m_sig);
         result = STATUS_FAILED;
@@ -251,12 +251,12 @@ void JNICALL FieldModification(jvmtiEnv *jvmti, JNIEnv *jni,
         LOG(", expected: 0x%x%08x\n", (jint)(watches[i].loc >> 32), (jint)watches[i].loc);
         result = STATUS_FAILED;
       }
-      if (watch.f_name == NULL || strcmp(watch.f_name, watches[i].f_name) != 0) {
+      if (watch.f_name == nullptr || strcmp(watch.f_name, watches[i].f_name) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong field name: \"%s\"", i, watch.f_name);
         LOG(", expected: \"%s\"\n", watches[i].f_name);
         result = STATUS_FAILED;
       }
-      if (watch.f_sig == NULL || strcmp(watch.f_sig, watches[i].f_sig) != 0) {
+      if (watch.f_sig == nullptr || strcmp(watch.f_sig, watches[i].f_sig) != 0) {
         LOG("(watch#%" PRIuPTR ") wrong field sig: \"%s\"", i, watch.f_sig);
         LOG(", expected: \"%s\"\n", watches[i].f_sig);
         result = STATUS_FAILED;
@@ -292,7 +292,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -321,7 +321,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
       return JNI_ERR;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_MODIFICATION, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_MODIFICATION, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       LOG("Failed to enable JVMTI_EVENT_FIELD_MODIFICATION: %s (%d)\n", TranslateError(err), err);
       return JNI_ERR;
@@ -356,7 +356,7 @@ Java_fieldmod02_getReady(JNIEnv *jni, jclass clz) {
   LOG(">>> setting field modification watches ...\n");
 
   cls = jni->FindClass("fieldmod02a");
-  if (cls == NULL) {
+  if (cls == nullptr) {
     LOG("Cannot find fieldmod02a class!\n");
     result = STATUS_FAILED;
     return;
@@ -367,7 +367,7 @@ Java_fieldmod02_getReady(JNIEnv *jni, jclass clz) {
     } else {
       watches[i].fid = jni->GetFieldID(cls, watches[i].f_name, watches[i].f_sig);
     }
-    if (watches[i].fid == NULL) {
+    if (watches[i].fid == nullptr) {
       LOG("Cannot get field ID for \"%s:%s\"\n", watches[i].f_name, watches[i].f_sig);
       result = STATUS_FAILED;
       return;
@@ -422,7 +422,7 @@ Java_fieldmod02_check(JNIEnv *jni, jclass clz, jobject obj) {
 
 
   cls = jni->FindClass("fieldmod02a");
-  if (cls == NULL) {
+  if (cls == nullptr) {
     LOG("Cannot find fieldmod02a class!\n");
     return STATUS_FAILED;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/FramePop/framepop01/libframepop01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/FramePop/framepop01/libframepop01.cpp
index d757e2eff4c..04eb17d6d4c 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/FramePop/framepop01/libframepop01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/FramePop/framepop01/libframepop01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ typedef struct {
   jlocation loc;
 } pop_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static volatile jboolean isVirtualExpected = JNI_FALSE;
@@ -111,17 +111,17 @@ void JNICALL FramePop(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread_obj, jmethodI
   LOG(">>> ... done\n");
 
   if (eventsCount < sizeof(pops)/sizeof(pop_info)) {
-    if (cls_sig == NULL || strcmp(cls_sig, pops[eventsCount].cls_sig) != 0) {
+    if (cls_sig == nullptr || strcmp(cls_sig, pops[eventsCount].cls_sig) != 0) {
       LOG("(pop#%" PRIuPTR ") wrong class: \"%s\"", eventsCount, cls_sig);
       LOG(", expected: \"%s\"\n", pops[eventsCount].cls_sig);
       result = STATUS_FAILED;
     }
-    if (name == NULL || strcmp(name, pops[eventsCount].name) != 0) {
+    if (name == nullptr || strcmp(name, pops[eventsCount].name) != 0) {
       LOG("(pop#%" PRIuPTR ") wrong method name: \"%s\"", eventsCount, name);
       LOG(", expected: \"%s\"\n", pops[eventsCount].name);
       result = STATUS_FAILED;
     }
-    if (sig == NULL || strcmp(sig, pops[eventsCount].sig) != 0) {
+    if (sig == nullptr || strcmp(sig, pops[eventsCount].sig) != 0) {
       LOG("(pop#%" PRIuPTR ") wrong method sig: \"%s\"", eventsCount, sig);
       LOG(", expected: \"%s\"\n", pops[eventsCount].sig);
       result = STATUS_FAILED;
@@ -152,7 +152,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -203,7 +203,7 @@ Java_framepop01_check(JNIEnv *jni, jclass cls) {
     return STATUS_FAILED;
   }
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
@@ -218,19 +218,19 @@ Java_framepop01_check(JNIEnv *jni, jclass cls) {
     LOG("Failed to SetBreakpoint: %s (%d)\n", TranslateError(err), err);
     return STATUS_FAILED;
   }
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Failed to enable JVMTI_EVENT_FRAME_POP event: %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
   }
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Failed to enable BREAKPOINT event: %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
   }
 
   clz = jni->FindClass("framepop01a");
-  if (clz == NULL) {
+  if (clz == nullptr) {
     LOG("Cannot find framepop01a class!\n");
     result = STATUS_FAILED;
     return STATUS_FAILED;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/FramePop/framepop02/libframepop02.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/FramePop/framepop02/libframepop02.cpp
index bc8f36114a2..21e8f4e7e06 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/FramePop/framepop02/libframepop02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/FramePop/framepop02/libframepop02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,7 +45,7 @@ typedef struct thr {
   item_t tos;
 } thr;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jrawMonitorID event_lock;
 static jboolean printdump = JNI_TRUE;
@@ -116,7 +116,7 @@ void pop(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jmethodID method, int depth)
     fatal(jni, "Unknown thread:\n");
   }
 
-  if (threads[i].tos == NULL) {
+  if (threads[i].tos == nullptr) {
     watch_events = JNI_FALSE;
     printInfo(jni, jvmti, thr, method, depth);
     fatal(jni, "Stack underflow:\n");
@@ -131,7 +131,7 @@ void pop(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jmethodID method, int depth)
       return;
     }
     free(old);
-  } while (threads[i].tos != NULL);
+  } while (threads[i].tos != nullptr);
 
   watch_events = JNI_FALSE;
   printInfo(jni, jvmti, thr, method, depth);
@@ -155,11 +155,11 @@ void push(JNIEnv *jni, jthread thr, jmethodID method, int depth) {
       fatal(jni, "Out of threads\n");
     }
     threads[i].thread = jni->NewGlobalRef(thr);
-    threads[i].tos = NULL;
+    threads[i].tos = nullptr;
   }
 
   new_item = (item_t)malloc(sizeof(item));
-  if (new_item == NULL) {
+  if (new_item == nullptr) {
     fatal(jni, "Out of memory\n");
   }
 
@@ -246,7 +246,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jvmtiError err;
 
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -280,11 +280,11 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
     LOG("(SetEventCallbacks) unexpected error: %s (%d)\n", TranslateError(err), err);
     return JNI_ERR;
   }
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_START, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_START, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
@@ -295,18 +295,18 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
 }
 
 JNIEXPORT void JNICALL Java_framepop02_getReady(JNIEnv *jni, jclass cls) {
-  check_jvmti_status(jni, jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, NULL),
+  check_jvmti_status(jni, jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, nullptr),
                      "Error in SetEventNotificationMode");
-  check_jvmti_status(jni, jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, NULL),
+  check_jvmti_status(jni, jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, nullptr),
                      "Error in SetEventNotificationMode");
   watch_events = JNI_TRUE;
 }
 
 JNIEXPORT void JNICALL Java_framepop02_check(JNIEnv *jni, jclass cls) {
   watch_events = JNI_FALSE;
-  check_jvmti_status(jni, jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_FRAME_POP, NULL),
+  check_jvmti_status(jni, jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_FRAME_POP, nullptr),
                      "Error in SetEventNotificationMode");
-  check_jvmti_status(jni, jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_METHOD_ENTRY, NULL),
+  check_jvmti_status(jni, jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_METHOD_ENTRY, nullptr),
                      "Error in SetEventNotificationMode");
 
   if (printdump == JNI_TRUE) {
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/MethodEntry/mentry01/libmentry01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/MethodEntry/mentry01/libmentry01.cpp
index 780438d02f5..b5dec318029 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/MethodEntry/mentry01/libmentry01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/MethodEntry/mentry01/libmentry01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,7 +45,7 @@ typedef struct {
   const jlocation loc;
 } entry_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
@@ -78,7 +78,7 @@ void JNICALL MethodEntry(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread_obj, jmeth
     result = STATUS_FAILED;
     return;
   }
-  if (cls_sig != NULL && strcmp(cls_sig, "Lmentry01;") == 0) {
+  if (cls_sig != nullptr && strcmp(cls_sig, "Lmentry01;") == 0) {
     LOG(">>> retrieving method entry info ...\n");
 
     err = jvmti->GetMethodName(method, &entry.name, &entry.sig, &generic);
@@ -100,12 +100,12 @@ void JNICALL MethodEntry(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread_obj, jmeth
     LOG(">>> ... done\n");
 
     if (eventsCount < sizeof(entries)/sizeof(entry_info)) {
-      if (entry.name == NULL || strcmp(entry.name, entries[eventsCount].name) != 0) {
+      if (entry.name == nullptr || strcmp(entry.name, entries[eventsCount].name) != 0) {
         LOG("(entry#%" PRIuPTR ") wrong method name: \"%s\"", eventsCount, entry.name);
         LOG(", expected: \"%s\"\n", entries[eventsCount].name);
         result = STATUS_FAILED;
       }
-      if (entry.sig == NULL || strcmp(entry.sig, entries[eventsCount].sig) != 0) {
+      if (entry.sig == nullptr || strcmp(entry.sig, entries[eventsCount].sig) != 0) {
         LOG("(entry#%" PRIuPTR ") wrong method sig: \"%s\"", eventsCount, entry.sig);
         LOG(", expected: \"%s\"\n", entries[eventsCount].sig);
         result = STATUS_FAILED;
@@ -137,7 +137,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -176,7 +176,7 @@ JNIEXPORT void JNICALL
 Java_mentry01_enable(JNIEnv *jni, jclass cls) {
   jvmtiError err;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     return;
   }
 
@@ -188,7 +188,7 @@ Java_mentry01_enable(JNIEnv *jni, jclass cls) {
   }
   isVirtualExpected = jni->IsVirtualThread(thread);
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, nullptr);
   if (err == JVMTI_ERROR_NONE) {
     eventsExpected = sizeof(entries)/sizeof(entry_info);
     eventsCount = 0;
@@ -202,7 +202,7 @@ JNIEXPORT jint JNICALL
 Java_mentry01_check(JNIEnv *jni, jclass cls) {
 
   jmethodID mid = jni->GetStaticMethodID(cls, "dummy", "()V");
-  if (mid == NULL) {
+  if (mid == nullptr) {
     LOG("Cannot find metod \"dummy()\"!\n");
     return STATUS_FAILED;
   }
@@ -219,13 +219,13 @@ JNIEXPORT void JNICALL
 Java_mentry01_chain(JNIEnv *jni, jclass cls) {
   jvmtiError err;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     result = STATUS_FAILED;
     return;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_METHOD_ENTRY, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_METHOD_ENTRY, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Failed to disable JVMTI_EVENT_METHOD_ENTRY event: %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/MethodEntry/mentry02/libmentry02.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/MethodEntry/mentry02/libmentry02.cpp
index 90b62dcee7a..43202de0ad7 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/MethodEntry/mentry02/libmentry02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/MethodEntry/mentry02/libmentry02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean isVirtualExpected = JNI_FALSE;
@@ -40,7 +40,7 @@ static int MethodEntriesExpected = 0;
 static int MethodExitsExpected = 0;
 static int MethodEntriesCount = 0;
 static int MethodExitsCount = 0;
-static jmethodID mid = NULL;
+static jmethodID mid = nullptr;
 
 void JNICALL MethodEntry(jvmtiEnv *jvmti, JNIEnv *jni,
                          jthread thread_obj, jmethodID method) {
@@ -75,7 +75,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jvmtiError err;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -116,7 +116,7 @@ JNIEXPORT void JNICALL
 Java_mentry02_getReady(JNIEnv *jni, jclass cls, jint i) {
   jvmtiError err;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return;
   }
@@ -130,13 +130,13 @@ Java_mentry02_getReady(JNIEnv *jni, jclass cls, jint i) {
   isVirtualExpected = jni->IsVirtualThread(thread);
 
   mid = jni->GetStaticMethodID(cls, "emptyMethod", "()V");
-  if (mid == NULL) {
+  if (mid == nullptr) {
     LOG("Cannot find Method ID for emptyMethod\n");
     result = STATUS_FAILED;
     return;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, nullptr);
   if (err == JVMTI_ERROR_NONE) {
     MethodEntriesCount = 0;
     MethodEntriesExpected = i;
@@ -145,7 +145,7 @@ Java_mentry02_getReady(JNIEnv *jni, jclass cls, jint i) {
     result = STATUS_FAILED;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_EXIT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_EXIT, nullptr);
   if (err == JVMTI_ERROR_NONE) {
     MethodExitsCount = 0;
     MethodExitsExpected = i;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/MethodExit/mexit01/libmexit01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/MethodExit/mexit01/libmexit01.cpp
index 616b599a59b..c6980f10484 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/MethodExit/mexit01/libmexit01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/MethodExit/mexit01/libmexit01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ typedef struct {
   jlocation loc;
 } method_location_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean isVirtualExpected = JNI_FALSE;
@@ -73,7 +73,7 @@ void JNICALL MethodExit(jvmtiEnv *jvmti, JNIEnv *jni,
     result = STATUS_FAILED;
     return;
   }
-  if (cls_sig != NULL && strcmp(cls_sig, "Lmexit01a;") == 0) {
+  if (cls_sig != nullptr && strcmp(cls_sig, "Lmexit01a;") == 0) {
 
     LOG(">>> retrieving method exit info ...\n");
     err = jvmti->GetMethodName(method, &name, &sig, &generic);
@@ -95,17 +95,17 @@ void JNICALL MethodExit(jvmtiEnv *jvmti, JNIEnv *jni,
     LOG(">>> ... done\n");
 
     if (eventsCount < sizeof(exits) / sizeof(method_location_info)) {
-      if (cls_sig == NULL || strcmp(cls_sig, exits[eventsCount].cls_sig) != 0) {
+      if (cls_sig == nullptr || strcmp(cls_sig, exits[eventsCount].cls_sig) != 0) {
         LOG("(exit#%" PRIuPTR ") wrong class: \"%s\"", eventsCount, cls_sig);
         LOG(", expected: \"%s\"\n", exits[eventsCount].cls_sig);
         result = STATUS_FAILED;
       }
-      if (name == NULL || strcmp(name, exits[eventsCount].name) != 0) {
+      if (name == nullptr || strcmp(name, exits[eventsCount].name) != 0) {
         LOG("(exit#%" PRIuPTR ") wrong method name: \"%s\"", eventsCount, name);
         LOG(", expected: \"%s\"\n", exits[eventsCount].name);
         result = STATUS_FAILED;
       }
-      if (sig == NULL || strcmp(sig, exits[eventsCount].sig) != 0) {
+      if (sig == nullptr || strcmp(sig, exits[eventsCount].sig) != 0) {
         LOG("(exit#%" PRIuPTR ") wrong method sig: \"%s\"", eventsCount, sig);
         LOG(", expected: \"%s\"\n", exits[eventsCount].sig);
         result = STATUS_FAILED;
@@ -137,7 +137,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -177,12 +177,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 JNIEXPORT jint JNICALL
 Java_mexit01_init0(JNIEnv *jni, jclass cls) {
   jvmtiError err;
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_EXIT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_EXIT, nullptr);
   if (err == JVMTI_ERROR_NONE) {
     eventsExpected = sizeof(exits)/sizeof(method_location_info);
     eventsCount = 0;
@@ -200,7 +200,7 @@ Java_mexit01_check(JNIEnv *jni, jclass cls) {
   jclass clz;
   jmethodID mid;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
@@ -214,20 +214,20 @@ Java_mexit01_check(JNIEnv *jni, jclass cls) {
   isVirtualExpected = jni->IsVirtualThread(thread);
 
   clz = jni->FindClass("mexit01a");
-  if (clz == NULL) {
+  if (clz == nullptr) {
     LOG("Cannot find MethodExit.mexit01a class!\n");
     return STATUS_FAILED;
   }
 
   mid = jni->GetStaticMethodID(clz, "dummy", "()V");
-  if (mid == NULL) {
+  if (mid == nullptr) {
     LOG("Cannot find metod \"dummy()\"!\n");
     return STATUS_FAILED;
   }
 
   jni->CallStaticVoidMethod(clz, mid);
 
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_METHOD_EXIT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_METHOD_EXIT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Failed to disable JVMTI_EVENT_METHOD_EXIT event: %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/MethodExit/mexit02/libmexit02.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/MethodExit/mexit02/libmexit02.cpp
index 140a9932c14..d7d24a3f4e6 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/MethodExit/mexit02/libmexit02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/MethodExit/mexit02/libmexit02.cpp
@@ -1,5 +1,5 @@
 /*
-* Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+* Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ typedef struct {
   jlocation loc;
 } method_location_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean isVirtualExpected = JNI_FALSE;
@@ -73,7 +73,7 @@ void JNICALL MethodExit(jvmtiEnv *jvmti, JNIEnv *jni,
     result = STATUS_FAILED;
     return;
   }
-  if (cls_sig != NULL && strcmp(cls_sig, "Lmexit02a;") == 0) {
+  if (cls_sig != nullptr && strcmp(cls_sig, "Lmexit02a;") == 0) {
     LOG(">>> retrieving method exit info ...\n");
 
     err = jvmti->GetMethodName(method, &name, &sig, &generic);
@@ -100,17 +100,17 @@ void JNICALL MethodExit(jvmtiEnv *jvmti, JNIEnv *jni,
     }
 
     if (eventsCount < sizeof(exits)/sizeof(method_location_info)) {
-      if (cls_sig == NULL || strcmp(cls_sig, exits[eventsCount].cls_sig) != 0) {
+      if (cls_sig == nullptr || strcmp(cls_sig, exits[eventsCount].cls_sig) != 0) {
         LOG("(exit#%" PRIuPTR ") wrong class: \"%s\"", eventsCount, cls_sig);
         LOG(", expected: \"%s\"\n", exits[eventsCount].cls_sig);
         result = STATUS_FAILED;
       }
-      if (name == NULL || strcmp(name, exits[eventsCount].name) != 0) {
+      if (name == nullptr || strcmp(name, exits[eventsCount].name) != 0) {
         LOG("(exit#%" PRIuPTR ") wrong method name: \"%s\"", eventsCount, name);
         LOG(", expected: \"%s\"\n", exits[eventsCount].name);
         result = STATUS_FAILED;
       }
-      if (sig == NULL || strcmp(sig, exits[eventsCount].sig) != 0) {
+      if (sig == nullptr || strcmp(sig, exits[eventsCount].sig) != 0) {
         LOG("(exit#%" PRIuPTR ") wrong method sig: \"%s\"", eventsCount, sig);
         LOG(", expected: \"%s\"\n", exits[eventsCount].sig);
         result = STATUS_FAILED;
@@ -137,7 +137,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -178,7 +178,7 @@ Java_mexit02_check(JNIEnv *jni, jclass cls) {
   jclass clz;
   jmethodID mid;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
@@ -192,18 +192,18 @@ Java_mexit02_check(JNIEnv *jni, jclass cls) {
   isVirtualExpected = jni->IsVirtualThread(thread);
 
   clz = jni->FindClass("mexit02a");
-  if (clz == NULL) {
+  if (clz == nullptr) {
     LOG("Failed to find class \"mexit02a\"!\n");
     return STATUS_FAILED;
   }
 
   mid = jni->GetStaticMethodID(clz, "dummy", "()V");
-  if (mid == NULL) {
+  if (mid == nullptr) {
     LOG("Failed to get method \"dummy\"!\n");
     return STATUS_FAILED;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_EXIT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_EXIT, nullptr);
   if (err == JVMTI_ERROR_NONE) {
     eventsExpected = sizeof(exits)/sizeof(method_location_info);
     eventsCount = 0;
@@ -214,7 +214,7 @@ Java_mexit02_check(JNIEnv *jni, jclass cls) {
 
   jni->CallStaticVoidMethod(clz, mid);
 
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_METHOD_EXIT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_METHOD_EXIT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Failed to disable JVMTI_EVENT_METHOD_EXIT event: %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/MonitorContendedEnter/mcontenter01/libmcontenter01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/MonitorContendedEnter/mcontenter01/libmcontenter01.cpp
index 023cb075a88..77ea808dc23 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/MonitorContendedEnter/mcontenter01/libmcontenter01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/MonitorContendedEnter/mcontenter01/libmcontenter01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,13 +35,13 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread expected_thread = NULL;
-static jobject expected_object = NULL;
+static jthread expected_thread = nullptr;
+static jobject expected_object = nullptr;
 static volatile int eventsCount = 0;
 
 /* ========================================================================== */
@@ -53,12 +53,12 @@ MonitorContendedEnter(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jobject obj) {
 
   print_thread_info(jvmti, jni, thr);
 
-  if (expected_thread == NULL) {
-    jni->FatalError("expected_thread is NULL.");
+  if (expected_thread == nullptr) {
+    jni->FatalError("expected_thread is null.");
   }
 
-  if (expected_object == NULL) {
-    jni->FatalError("expected_object is NULL.");
+  if (expected_object == nullptr) {
+    jni->FatalError("expected_object is null.");
   }
 
   /* check if event is for tested thread and for tested object */
@@ -72,7 +72,7 @@ MonitorContendedEnter(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jobject obj) {
 /* ========================================================================== */
 
 static int prepare() {
-  jvmtiError err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, NULL);
+  jvmtiError err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     jni->FatalError("Error enabling JVMTI_EVENT_MONITOR_CONTENDED_ENTER.");
   }
@@ -82,7 +82,7 @@ static int prepare() {
 static int clean() {
   LOG("Disabling events\n");
   /* disable MonitorContendedEnter event */
-  jvmtiError err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, NULL);
+  jvmtiError err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     set_agent_fail_status();
   }
@@ -139,7 +139,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   LOG("Timeout: %d msc\n", (int) timeout);
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -177,7 +177,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   }
 
   /* register agent proc and arg */
-  set_agent_proc(agentProc, NULL);
+  set_agent_proc(agentProc, nullptr);
 
   return JNI_OK;
 }
@@ -190,13 +190,13 @@ JNIEXPORT void JNICALL Java_mcontenter01_setExpected(JNIEnv *jni, jobject clz, j
   LOG("Remembering global reference for monitor object is %p\n", obj);
   /* make object accessible for a long time */
   expected_object = jni->NewGlobalRef(obj);
-  if (expected_object == NULL) {
+  if (expected_object == nullptr) {
     jni->FatalError("Error saving global reference to monitor.\n");
   }
 
   /* make thread accessable for a long time */
   expected_thread = jni->NewGlobalRef(thread);
-  if (thread == NULL) {
+  if (thread == nullptr) {
     jni->FatalError("Error saving global reference to thread.\n");
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/MonitorContendedEntered/mcontentered01/libmcontentered01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/MonitorContendedEntered/mcontentered01/libmcontentered01.cpp
index 6589f5dabd7..c46ccac6933 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/MonitorContendedEntered/mcontentered01/libmcontentered01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/MonitorContendedEntered/mcontentered01/libmcontentered01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,13 +32,13 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread expected_thread = NULL;
-static jobject expected_object = NULL;
+static jthread expected_thread = nullptr;
+static jobject expected_object = nullptr;
 static volatile int eventsCount = 0;
 
 
@@ -51,12 +51,12 @@ MonitorContendedEntered(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jobject obj)
 
   print_thread_info(jvmti, jni, thr);
 
-  if (expected_thread == NULL) {
-    jni->FatalError("expected_thread is NULL.");
+  if (expected_thread == nullptr) {
+    jni->FatalError("expected_thread is null.");
   }
 
-  if (expected_object == NULL) {
-    jni->FatalError("expected_object is NULL.");
+  if (expected_object == nullptr) {
+    jni->FatalError("expected_object is null.");
   }
 
   /* check if event is for tested thread and for tested object */
@@ -73,12 +73,12 @@ MonitorContendedEnter(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jobject obj) {
   LOG("MonitorContendedEnter event:\n\tthread: %p, object: %p, expected object: %p\n",thr, obj, expected_object);
   print_thread_info(jvmti, jni, thr);
 
-  if (expected_thread == NULL) {
-    jni->FatalError("expected_thread is NULL.");
+  if (expected_thread == nullptr) {
+    jni->FatalError("expected_thread is null.");
   }
 
-  if (expected_object == NULL) {
-    jni->FatalError("expected_object is NULL.");
+  if (expected_object == nullptr) {
+    jni->FatalError("expected_object is null.");
   }
 
   /* check if event is for tested thread and for tested object */
@@ -97,14 +97,14 @@ static int prepare() {
   LOG("Prepare: find tested thread\n");
 
   /* enable MonitorContendedEntered event */
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Prepare: 11\n");
     return JNI_FALSE;
   }
 
   /* enable MonitorContendedEnter event */
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Prepare: 11\n");
     return JNI_FALSE;
@@ -116,7 +116,7 @@ static int prepare() {
 static int clean() {
   jvmtiError err;
   /* disable MonitorContendedEntered event */
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE,JVMTI_EVENT_MONITOR_CONTENDED_ENTERED,NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE,JVMTI_EVENT_MONITOR_CONTENDED_ENTERED,nullptr);
   if (err != JVMTI_ERROR_NONE) {
     set_agent_fail_status();
   }
@@ -173,7 +173,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   LOG("Timeout: %d msc\n", (int) timeout);
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -214,7 +214,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   }
 
   /* register agent proc and arg */
-  set_agent_proc(agentProc, NULL);
+  set_agent_proc(agentProc, nullptr);
 
   return JNI_OK;
 }
@@ -227,13 +227,13 @@ JNIEXPORT void JNICALL Java_mcontentered01_setExpected(JNIEnv *jni, jobject clz,
   LOG("Remembering global reference for monitor object is %p\n", obj);
   /* make object accessible for a long time */
   expected_object = jni->NewGlobalRef(obj);
-  if (expected_object == NULL) {
+  if (expected_object == nullptr) {
     jni->FatalError("Error saving global reference to monitor.\n");
   }
 
   /* make thread accessable for a long time */
   expected_thread = jni->NewGlobalRef(thread);
-  if (thread == NULL) {
+  if (thread == nullptr) {
     jni->FatalError("Error saving global reference to thread.\n");
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/MonitorWait/monitorwait01/libmonitorwait01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/MonitorWait/monitorwait01/libmonitorwait01.cpp
index 6467a6b3dcb..b85fa20ca16 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/MonitorWait/monitorwait01/libmonitorwait01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/MonitorWait/monitorwait01/libmonitorwait01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -31,13 +31,13 @@
 extern "C" {
 
 /* scaffold objects */
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread expected_thread = NULL;
-static jobject expected_object = NULL;
+static jthread expected_thread = nullptr;
+static jobject expected_object = nullptr;
 static volatile int eventsCount = 0;
 
 void JNICALL
@@ -47,12 +47,12 @@ MonitorWait(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jobject obj, jlong tout)
 
   print_thread_info(jvmti, jni, thr);
 
-  if (expected_thread == NULL) {
-    jni->FatalError("expected_thread is NULL.");
+  if (expected_thread == nullptr) {
+    jni->FatalError("expected_thread is null.");
   }
 
-  if (expected_object == NULL) {
-    jni->FatalError("expected_object is NULL.");
+  if (expected_object == nullptr) {
+    jni->FatalError("expected_object is null.");
   }
 
 /* check if event is for tested thread and for tested object */
@@ -70,7 +70,7 @@ MonitorWait(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jobject obj, jlong tout)
 
 static int prepare() {
   /* enable MonitorWait event */
-  jvmtiError err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAIT, NULL);
+  jvmtiError err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAIT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Prepare: 11\n");
     return JNI_FALSE;
@@ -80,7 +80,7 @@ static int prepare() {
 
 static int clean() {
   /* disable MonitorWait event */
-  jvmtiError err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_WAIT, NULL);
+  jvmtiError err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_WAIT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     set_agent_fail_status();
   }
@@ -135,7 +135,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   LOG("Timeout: %d msc\n", (int) timeout);
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -173,7 +173,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   }
 
   /* register agent proc and arg */
-  set_agent_proc(agentProc, NULL);
+  set_agent_proc(agentProc, nullptr);
 
   return JNI_OK;
 }
@@ -182,13 +182,13 @@ JNIEXPORT void JNICALL Java_monitorwait01_setExpected(JNIEnv *jni, jobject clz,
   LOG("Remembering global reference for monitor object is %p\n", obj);
   /* make object accessible for a long time */
   expected_object = jni->NewGlobalRef(obj);
-  if (expected_object == NULL) {
+  if (expected_object == nullptr) {
     jni->FatalError("Error saving global reference to monitor.\n");
   }
 
   /* make thread accessable for a long time */
   expected_thread = jni->NewGlobalRef(thread);
-  if (thread == NULL) {
+  if (thread == nullptr) {
     jni->FatalError("Error saving global reference to thread.\n");
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/MonitorWaited/monitorwaited01/libmonitorwaited01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/MonitorWaited/monitorwaited01/libmonitorwaited01.cpp
index 2eaeefce2fc..013dbd66d81 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/MonitorWaited/monitorwaited01/libmonitorwaited01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/MonitorWaited/monitorwaited01/libmonitorwaited01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -31,13 +31,13 @@
 extern "C" {
 
 /* scaffold objects */
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread expected_thread = NULL;
-static jobject expected_object = NULL;
+static jthread expected_thread = nullptr;
+static jobject expected_object = nullptr;
 static volatile int eventsCount = 0;
 
 void JNICALL
@@ -48,12 +48,12 @@ MonitorWaited(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jobject obj, jboolean t
 
   print_thread_info(jvmti, jni, thr);
 
-  if (expected_thread == NULL) {
-    jni->FatalError("expected_thread is NULL.");
+  if (expected_thread == nullptr) {
+    jni->FatalError("expected_thread is null.");
   }
 
-  if (expected_object == NULL) {
-    jni->FatalError("expected_object is NULL.");
+  if (expected_object == nullptr) {
+    jni->FatalError("expected_object is null.");
   }
 
   /* check if event is for tested thread and for tested object */
@@ -71,7 +71,7 @@ MonitorWaited(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jobject obj, jboolean t
 
 static int prepare() {
   /* enable MonitorWait event */
-  jvmtiError err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAITED, NULL);
+  jvmtiError err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAITED, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Prepare: 11\n");
     return JNI_FALSE;
@@ -81,7 +81,7 @@ static int prepare() {
 
 static int clean() {
   /* disable MonitorWaited event */
-  jvmtiError err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_WAITED, NULL);
+  jvmtiError err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_WAITED, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     set_agent_fail_status();
   }
@@ -136,7 +136,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   LOG("Timeout: %d msc\n", (int) timeout);
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -176,7 +176,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   }
 
   /* register agent proc and arg */
-  set_agent_proc(agentProc, NULL);
+  set_agent_proc(agentProc, nullptr);
 
   return JNI_OK;
 }
@@ -185,13 +185,13 @@ JNIEXPORT void JNICALL Java_monitorwaited01_setExpected(JNIEnv *jni, jobject clz
   LOG("Remembering global reference for monitor object is %p\n", obj);
   /* make object accessible for a long time */
   expected_object = jni->NewGlobalRef(obj);
-  if (expected_object == NULL) {
+  if (expected_object == nullptr) {
     jni->FatalError("Error saving global reference to monitor.\n");
   }
 
   /* make thread accessable for a long time */
   expected_thread = jni->NewGlobalRef(thread);
-  if (thread == NULL) {
+  if (thread == nullptr) {
     jni->FatalError("Error saving global reference to thread.\n");
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind01/libnativemethbind01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind01/libnativemethbind01.cpp
index e363de01b02..c0f7261b38f 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind01/libnativemethbind01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind01/libnativemethbind01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,7 +49,7 @@ static const char *CLASS_SIG =
     "Lnativemethbind01$TestedClass;";
 
 static volatile jint result = PASSED;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jrawMonitorID counter_lock;
 
@@ -76,7 +76,7 @@ NativeMethodBind(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread,
     return;
   }
 
-  err = jvmti->GetMethodName(method, &methNam, &methSig, NULL);
+  err = jvmti->GetMethodName(method, &methNam, &methSig, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     result = STATUS_FAILED;
     LOG("TEST FAILED: unable to get method name during NativeMethodBind callback\n\n");
@@ -118,7 +118,7 @@ anotherNativeMethod(JNIEnv *jni, jobject obj) {
 /* dummy method used only to provoke NativeMethodBind event */
 JNIEXPORT void JNICALL
 Java_nativemethbind01_nativeMethod(JNIEnv *jni, jobject obj, jboolean registerNative) {
-  jclass testedCls = NULL;
+  jclass testedCls = nullptr;
   JNINativeMethod meth;
 
   LOG("Inside the nativeMethod()\n");
@@ -126,7 +126,7 @@ Java_nativemethbind01_nativeMethod(JNIEnv *jni, jobject obj, jboolean registerNa
   if (registerNative == JNI_TRUE) {
     LOG("Finding class \"%s\" ...\n", CLASS_SIG);
     testedCls = jni->FindClass(CLASS_SIG);
-    if (testedCls == NULL) {
+    if (testedCls == nullptr) {
       result = STATUS_FAILED;
       COMPLAIN("TEST FAILURE: unable to find class \"%s\"\n\n", CLASS_SIG);
       return;
@@ -168,7 +168,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -203,7 +203,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
 
   LOG("setting event callbacks done\nenabling JVMTI events ...\n");
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, nullptr);
   if (err != JVMTI_ERROR_NONE){
       return JNI_ERR;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind02/libnativemethbind02.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind02/libnativemethbind02.cpp
index 2d5dcefe557..747952d4a10 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind02/libnativemethbind02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind02/libnativemethbind02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,7 +36,7 @@ extern "C" {
 static volatile int wrongBindEv = 0;
 
 static volatile jint result = PASSED;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jrawMonitorID counter_lock;
 
@@ -46,7 +46,7 @@ NativeMethodBind(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread,
                  jmethodID method, void *addr, void **new_addr) {
   jvmtiPhase phase;
   jvmtiError err;
-  char *methNam = NULL, *methSig = NULL;
+  char *methNam = nullptr, *methSig = nullptr;
 
   RawMonitorLocker rml(jvmti, jni, counter_lock);
   err = jvmti->GetPhase(&phase);
@@ -60,7 +60,7 @@ NativeMethodBind(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread,
     return;
   }
 
-  err = jvmti->GetMethodName(method, &methNam, &methSig, NULL);
+  err = jvmti->GetMethodName(method, &methNam, &methSig, nullptr);
 
   if (err != JVMTI_ERROR_NONE) {
     result = STATUS_FAILED;
@@ -70,7 +70,7 @@ NativeMethodBind(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread,
     LOG("NativeMethodBind received for \"%s %s\"\n", methNam, methSig);
   }
 
-  if (methNam != NULL) {
+  if (methNam != nullptr) {
     err = jvmti->Deallocate((unsigned char *) methNam);
     if (err != JVMTI_ERROR_NONE) {
       result = STATUS_FAILED;
@@ -78,7 +78,7 @@ NativeMethodBind(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread,
     }
   }
 
-  if (methSig != NULL) {
+  if (methSig != nullptr) {
     err = jvmti->Deallocate((unsigned char *) methSig);
     if (err != JVMTI_ERROR_NONE) {
       result = STATUS_FAILED;
@@ -116,7 +116,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -150,11 +150,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
 
   LOG("setting event callbacks done\nenabling JVMTI events ...\n");
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind03/libnativemethbind03.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind03/libnativemethbind03.cpp
index 19d94f560c8..d637f7dc713 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind03/libnativemethbind03.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind03/libnativemethbind03.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -46,7 +46,7 @@ static const char *CLASS_SIG =
     "Lnativemethbind03$TestedClass;";
 
 static volatile jint result = PASSED;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jrawMonitorID counter_lock;
 
@@ -72,7 +72,7 @@ NativeMethodBind(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jmethodID method,
     return;
   }
 
-  err = jvmti->GetMethodName(method, &methNam, &methSig, NULL);
+  err = jvmti->GetMethodName(method, &methNam, &methSig, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     result = STATUS_FAILED;
     COMPLAIN("TEST FAILED: unable to get method name during NativeMethodBind callback\n\n");
@@ -84,7 +84,7 @@ NativeMethodBind(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jmethodID method,
     LOG("\tmethod: \"%s %s\"\n", methNam, methSig);
   }
 
-  if (methNam != NULL) {
+  if (methNam != nullptr) {
     err = jvmti->Deallocate((unsigned char *) methNam);
     if (err != JVMTI_ERROR_NONE) {
       result = STATUS_FAILED;
@@ -92,7 +92,7 @@ NativeMethodBind(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jmethodID method,
     }
   }
 
-  if (methSig != NULL) {
+  if (methSig != nullptr) {
     err = jvmti->Deallocate((unsigned char *) methSig);
     if (err != JVMTI_ERROR_NONE) {
       result = STATUS_FAILED;
@@ -133,13 +133,13 @@ nativeMethod(JNIEnv *jni, jobject obj) {
 /* dummy method used only to provoke NativeMethodBind event */
 JNIEXPORT void JNICALL
 Java_nativemethbind03_registerNative(JNIEnv *jni, jobject obj) {
-  jclass testedCls = NULL;
+  jclass testedCls = nullptr;
   JNINativeMethod meth;
 
   LOG("Inside the registerNative()\n"
       "Finding class \"%s\" ...\n", CLASS_SIG);
   testedCls = jni->FindClass(CLASS_SIG);
-  if (testedCls == NULL) {
+  if (testedCls == nullptr) {
     result = STATUS_FAILED;
     COMPLAIN("TEST FAILURE: unable to find class \"%s\"\n\n", CLASS_SIG);
     return;
@@ -171,7 +171,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -207,11 +207,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
 
   LOG("setting event callbacks done\nenabling JVMTI events ...\n");
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind04/libnativemethbind04.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind04/libnativemethbind04.cpp
index 174084d0494..871028423ef 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind04/libnativemethbind04.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/NativeMethodBind/nativemethbind04/libnativemethbind04.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@ static volatile int origCalls = 0;
 static volatile int redirCalls = 0;
 
 static volatile jint result = PASSED;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jrawMonitorID counter_lock;
 
@@ -84,7 +84,7 @@ NativeMethodBind(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jmethodID method,
     return;
   }
 
-  err = jvmti->GetMethodName(method, &methNam, &methSig, NULL);
+  err = jvmti->GetMethodName(method, &methNam, &methSig, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     result = STATUS_FAILED;
     LOG("TEST FAILED: unable to get method name during NativeMethodBind callback\n\n");
@@ -97,7 +97,7 @@ NativeMethodBind(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jmethodID method,
     *new_addr = (void *) redirNativeMethod;
   }
 
-  if (methNam != NULL) {
+  if (methNam != nullptr) {
     err = jvmti->Deallocate((unsigned char *) methNam);
     if (err != JVMTI_ERROR_NONE) {
       result = STATUS_FAILED;
@@ -105,7 +105,7 @@ NativeMethodBind(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jmethodID method,
     }
   }
 
-  if (methSig != NULL) {
+  if (methSig != nullptr) {
     err = jvmti->Deallocate((unsigned char *) methSig);
     if (err != JVMTI_ERROR_NONE) {
       result = STATUS_FAILED;
@@ -146,7 +146,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -179,7 +179,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
 
   LOG("setting event callbacks done\nenabling JVMTI events ...\n");
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/SingleStep/singlestep01/libsinglestep01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/SingleStep/singlestep01/libsinglestep01.cpp
index 003cc55e425..7c4d6ef2ea7 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/SingleStep/singlestep01/libsinglestep01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/SingleStep/singlestep01/libsinglestep01.cpp
@@ -50,7 +50,7 @@ static const char *CLASS_SIG =
     "Lsinglestep01;";
 
 static volatile jint result = PASSED;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 static volatile jboolean isVirtualExpected = JNI_FALSE;
 
@@ -62,7 +62,7 @@ static void setBP(jvmtiEnv *jvmti, JNIEnv *jni, jclass klass) {
   jvmtiError err;
 
   mid = jni->GetMethodID(klass, METHODS[0], METHOD_SIGS[0]);
-  if (mid == NULL) {
+  if (mid == nullptr) {
     jni->FatalError("failed to get ID for the java method\n");
   }
 
@@ -86,7 +86,7 @@ ClassLoad(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jclass klass) {
     if (err != JVMTI_ERROR_NONE) {
       jni->FatalError("failed to obtain a class signature\n");
     }
-    if (sig != NULL && (strcmp(sig, CLASS_SIG) == 0)) {
+    if (sig != nullptr && (strcmp(sig, CLASS_SIG) == 0)) {
       LOG("ClassLoad event received for the class \"%s\"\n"
           "\tsetting breakpoint ...\n", sig);
       setBP(jvmti, jni, klass);
@@ -117,7 +117,7 @@ Breakpoint(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jmethodID method, jlocatio
     jni->FatalError("Breakpoint: failed to obtain a class signature\n");
   }
 
-  if (sig != NULL && (strcmp(sig, CLASS_SIG) == 0)) {
+  if (sig != nullptr && (strcmp(sig, CLASS_SIG) == 0)) {
     LOG("method declaring class \"%s\"\n\tenabling SingleStep events ...\n", sig);
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, thr);
     if (err != JVMTI_ERROR_NONE) {
@@ -145,7 +145,7 @@ SingleStep(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jmethodID method, jloca
 
   print_thread_info(jvmti, jni, thread);
 
-  err = jvmti->GetMethodName(method, &methNam, &methSig, NULL);
+  err = jvmti->GetMethodName(method, &methNam, &methSig, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     result = STATUS_FAILED;
     COMPLAIN("TEST FAILED: unable to get method name during SingleStep callback\n\n");
@@ -166,7 +166,7 @@ SingleStep(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jmethodID method, jloca
     return;
   }
 
-  if (sig != NULL) {
+  if (sig != nullptr) {
     LOG("\tmethod name: \"%s\"\n"
         "\tsignature: \"%s\"\n"
         "\tmethod declaring class: \"%s\"\n",
@@ -244,7 +244,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -284,19 +284,19 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   }
 
   LOG("setting event callbacks done\nenabling JVMTI events ...\n");
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_START, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_START, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/SingleStep/singlestep02/libsinglestep02.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/SingleStep/singlestep02/libsinglestep02.cpp
index e80903ac243..f5437de1f3d 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/SingleStep/singlestep02/libsinglestep02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/SingleStep/singlestep02/libsinglestep02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,7 +35,7 @@ extern "C" {
 static volatile jint result = PASSED;
 static volatile long wrongStepEv = 0;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 /** callback functions **/
 void JNICALL
@@ -78,7 +78,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -113,11 +113,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   }
 
   LOG("setting event callbacks done\nenabling JVMTI events ...\n");
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/SingleStep/singlestep03/libsinglestep03.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/SingleStep/singlestep03/libsinglestep03.cpp
index e8455006590..51ac700efad 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/SingleStep/singlestep03/libsinglestep03.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/SingleStep/singlestep03/libsinglestep03.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -53,7 +53,7 @@ static const char *CLASS_SIG =
     "Lsinglestep03;";
 
 static volatile jint result = PASSED;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 
 static volatile int callbacksEnabled = JNI_FALSE;
@@ -64,7 +64,7 @@ static void setBP(jvmtiEnv *jvmti, JNIEnv *jni, jclass klass) {
   jvmtiError err;
 
   mid = jni->GetMethodID(klass, METHODS[0][0], METHODS[0][1]);
-  if (mid == NULL) {
+  if (mid == nullptr) {
     jni->FatalError("failed to get ID for the java method\n");
   }
 
@@ -91,7 +91,7 @@ ClassLoad(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jclass klass) {
     jni->FatalError("failed to obtain a class signature\n");
   }
 
-  if (sig != NULL && (strcmp(sig, CLASS_SIG) == 0)) {
+  if (sig != nullptr && (strcmp(sig, CLASS_SIG) == 0)) {
     LOG("ClassLoad event received for the class \"%s\"\n"
         "\tsetting breakpoint ...\n", sig);
     setBP(jvmti, jni, klass);
@@ -133,7 +133,7 @@ Breakpoint(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr, jmethodID method, jlocatio
     jni->FatalError("Breakpoint: failed to obtain a class signature\n");
   }
 
-  if (sig != NULL && (strcmp(sig, CLASS_SIG) == 0)) {
+  if (sig != nullptr && (strcmp(sig, CLASS_SIG) == 0)) {
     LOG("method declaring class \"%s\"\n\tenabling SingleStep events ...\n", sig);
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, thr);
     if (err != JVMTI_ERROR_NONE) {
@@ -159,7 +159,7 @@ SingleStep(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jmethodID method, jloca
 
   LOG(">>>> SingleStep event received\n");
 
-  err = jvmti->GetMethodName(method, &methNam, &methSig, NULL);
+  err = jvmti->GetMethodName(method, &methNam, &methSig, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     result = STATUS_FAILED;
     COMPLAIN("TEST FAILED: unable to get method name during SingleStep callback\n\n");
@@ -180,7 +180,7 @@ SingleStep(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jmethodID method, jloca
     return;
   }
 
-  if (sig != NULL) {
+  if (sig != nullptr) {
     if (stepEv[METH_NUM - 1][0] == 1) {
       result = STATUS_FAILED;
       COMPLAIN("TEST FAILED: SingleStep event received after disabling the event generation\n\n");
@@ -272,7 +272,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -310,19 +310,19 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   }
 
   LOG("setting event callbacks done\nenabling JVMTI events ...\n");
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_START, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_START, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/ThreadEnd/threadend01/libthreadend01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/ThreadEnd/threadend01/libthreadend01.cpp
index 6cfb057902b..b39276eeb00 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/ThreadEnd/threadend01/libthreadend01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/ThreadEnd/threadend01/libthreadend01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,12 +34,12 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static int eventsCount = 0;
 static int eventsExpected = 0;
-static const char *prefix = NULL;
+static const char *prefix = nullptr;
 
 void JNICALL ThreadEnd(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread) {
   jvmtiError err;
@@ -54,10 +54,10 @@ void JNICALL ThreadEnd(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread) {
 
   print_thread_info(jvmti, jni, thread);
 
-  if (inf.name != NULL && strstr(inf.name, prefix) == inf.name) {
+  if (inf.name != nullptr && strstr(inf.name, prefix) == inf.name) {
     eventsCount++;
     snprintf(name, sizeof(name), "%s%d", prefix, eventsCount);
-    if (inf.name == NULL || strcmp(name, inf.name) != 0) {
+    if (inf.name == nullptr || strcmp(name, inf.name) != 0) {
       LOG("(#%d) wrong thread name: \"%s\"",eventsCount, inf.name);
       LOG(", expected: \"%s\"\n", name);
       result = STATUS_FAILED;
@@ -70,7 +70,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -89,19 +89,19 @@ JNIEXPORT void JNICALL
 Java_threadend01_getReady(JNIEnv *jni, jclass cls, jint i, jstring name) {
   jvmtiError err;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return;
   }
 
-  prefix = jni->GetStringUTFChars(name, NULL);
-  if (prefix == NULL) {
+  prefix = jni->GetStringUTFChars(name, nullptr);
+  if (prefix == nullptr) {
     LOG("Failed to copy UTF-8 string!\n");
     result = STATUS_FAILED;
     return;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_END, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_END, nullptr);
   if (err == JVMTI_ERROR_NONE) {
     eventsExpected = i;
   } else {
@@ -112,12 +112,12 @@ Java_threadend01_getReady(JNIEnv *jni, jclass cls, jint i, jstring name) {
 
 JNIEXPORT jint JNICALL
 Java_threadend01_check(JNIEnv *jni, jclass cls) {
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
 
-jvmtiError err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_THREAD_END, NULL);
+jvmtiError err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_THREAD_END, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Failed to disable JVMTI_EVENT_THREAD_END: %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/ThreadEnd/threadend02/libthreadend02.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/ThreadEnd/threadend02/libthreadend02.cpp
index 1d2cfe36de3..2ffc67d3d8e 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/ThreadEnd/threadend02/libthreadend02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/ThreadEnd/threadend02/libthreadend02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@
 extern "C" {
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 static int eventCount = 0;
@@ -52,7 +52,7 @@ enableEvent(jvmtiEventMode enable, jvmtiEvent event) {
     LOG("disabling %s\n", TranslateEvent(event));
   }
 
-  err = jvmti->SetEventNotificationMode(enable, event, NULL);
+  err = jvmti->SetEventNotificationMode(enable, event, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     set_agent_fail_status();
     return JNI_FALSE;
@@ -129,7 +129,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   timeout = 60 * 1000;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -150,7 +150,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  set_agent_proc(agentProc, NULL);
+  set_agent_proc(agentProc, nullptr);
 
   return JNI_OK;
 }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/ThreadStart/threadstart01/libthreadstart01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/ThreadStart/threadstart01/libthreadstart01.cpp
index 935f4fc1002..2ebaf2d9f0f 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/ThreadStart/threadstart01/libthreadstart01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/ThreadStart/threadstart01/libthreadstart01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,12 +34,12 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static int eventsCount = 0;
 static int eventsExpected = 0;
-static const char *prefix = NULL;
+static const char *prefix = nullptr;
 
 void JNICALL
 ThreadStart(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread) {
@@ -54,7 +54,7 @@ ThreadStart(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread) {
 
   LOG(">>> %s\n", inf.name);
 
-  if (inf.name != NULL && strstr(inf.name, prefix) == inf.name) {
+  if (inf.name != nullptr && strstr(inf.name, prefix) == inf.name) {
     snprintf(name, sizeof(name), "%s%d", prefix, eventsCount);
     if (strcmp(name, inf.name) != 0) {
       LOG("(#%d) wrong thread name: \"%s\"", eventsCount, inf.name);
@@ -70,7 +70,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -89,19 +89,19 @@ JNIEXPORT void JNICALL
 Java_threadstart01_getReady(JNIEnv *jni, jclass cls, jint i, jstring name) {
   jvmtiError err;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return;
   }
 
-  prefix = jni->GetStringUTFChars(name, NULL);
-  if (prefix == NULL) {
+  prefix = jni->GetStringUTFChars(name, nullptr);
+  if (prefix == nullptr) {
     LOG("Failed to copy UTF-8 string!\n");
     result = STATUS_FAILED;
     return;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, nullptr);
   if (err == JVMTI_ERROR_NONE) {
     eventsExpected = i;
   } else {
@@ -114,12 +114,12 @@ JNIEXPORT jint JNICALL
 Java_threadstart01_check(JNIEnv *jni, jclass cls) {
   jvmtiError err;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_THREAD_START, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_THREAD_START, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Failed to disable JVMTI_EVENT_THREAD_START: %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/ThreadStart/threadstart02/libthreadstart02.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/ThreadStart/threadstart02/libthreadstart02.cpp
index e5ae8be3107..1ab67b64603 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/ThreadStart/threadstart02/libthreadstart02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/ThreadStart/threadstart02/libthreadstart02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,16 +33,16 @@ extern "C" {
 #define STATUS_FAILED 2
 #define WAIT_TIME 20000
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 /* volatile variables */
 static jrawMonitorID agent_start_lock, thr_start_lock, thr_resume_lock, thr_event_lock;
-static volatile jthread agent_thread = NULL;
+static volatile jthread agent_thread = nullptr;
 static volatile jboolean terminate_debug_agent = JNI_FALSE;
 static volatile jboolean debug_agent_timed_out = JNI_FALSE;
 static volatile jboolean debug_agent_started = JNI_FALSE;
-static volatile jthread next_thread = NULL;
+static volatile jthread next_thread = nullptr;
 static jvmtiThreadInfo inf;
 static volatile int eventsCount = 0;
 static volatile jint result = PASSED;
@@ -128,12 +128,12 @@ debug_agent(jvmtiEnv *jvmti, JNIEnv *jni, void *p) {
   RawMonitorLocker thr_start_locker(jvmti, jni, thr_start_lock);
   while (terminate_debug_agent != JNI_TRUE) {
 
-    if (next_thread == NULL) {
+    if (next_thread == nullptr) {
     /* wait till new thread will be created and started */
       thr_start_locker.wait();
     }
 
-    if (next_thread != NULL) {
+    if (next_thread != nullptr) {
     /* hmm, why NewGlobalRef is called one more time???
      * next_thread = env->NewGlobalRef(next_thread);
      */
@@ -160,7 +160,7 @@ debug_agent(jvmtiEnv *jvmti, JNIEnv *jni, void *p) {
     }
 
     jni->DeleteGlobalRef(next_thread);
-    next_thread = NULL;
+    next_thread = nullptr;
 
     /* Notify ThreadStart callback that thread has been resumed */
 
@@ -267,38 +267,38 @@ void JNICALL ThreadStart(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread) {
 }
 
 void JNICALL VMInit(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr) {
-  jclass cls = NULL;
-  jmethodID mid = NULL;
+  jclass cls = nullptr;
+  jmethodID mid = nullptr;
 
   LOG(">>> VMInit event: start\n");
 
-  check_jvmti_status(jni, jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, NULL),
+  check_jvmti_status(jni, jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, nullptr),
     "Failed to enable JVMTI_EVENT_THREAD_START");
 
   /* Start agent thread */
   cls = jni->FindClass("java/lang/Thread");
-  if (cls == NULL) {
+  if (cls == nullptr) {
     result = STATUS_FAILED;
     COMPLAIN("TEST FAILED: Cannot start agent thread: FindClass() failed\n");
     return;
   }
 
   mid = jni->GetMethodID(cls, "<init>", "()V");
-  if (mid == NULL) {
+  if (mid == nullptr) {
     result = STATUS_FAILED;
     COMPLAIN("TEST FAILED: Cannot start agent thread: GetMethodID() failed\n");
     return;
   }
 
   agent_thread = jni->NewObject(cls, mid);
-  if (agent_thread == NULL) {
+  if (agent_thread == nullptr) {
     result = STATUS_FAILED;
     COMPLAIN("Cannot start agent thread: NewObject() failed\n");
     return;
   }
 
   agent_thread = (jthread) jni->NewGlobalRef(agent_thread);
-  if (agent_thread == NULL) {
+  if (agent_thread == nullptr) {
     result = STATUS_FAILED;
     COMPLAIN("Cannot create global reference for agent_thread\n");
     return;
@@ -311,7 +311,7 @@ void JNICALL VMInit(jvmtiEnv *jvmti, JNIEnv *jni, jthread thr) {
 
   RawMonitorLocker agent_start_locker(jvmti, jni, agent_start_lock);
 
-  check_jvmti_status(jni, jvmti->RunAgentThread(agent_thread, debug_agent, NULL, JVMTI_THREAD_NORM_PRIORITY),
+  check_jvmti_status(jni, jvmti->RunAgentThread(agent_thread, debug_agent, nullptr, JVMTI_THREAD_NORM_PRIORITY),
                      "Failed to RunAgentThread");
   agent_start_locker.wait();
   LOG(">>> VMInit event: end\n");
@@ -327,7 +327,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jvmtiError err;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -366,14 +366,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Failed to disable JVMTI_EVENT_THREAD_START: %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Failed to disable JVMTI_EVENT_THREAD_END: %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/ThreadStart/threadstart03/libthreadstart03.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/ThreadStart/threadstart03/libthreadstart03.cpp
index a14fa1dbdb3..6373f8df19c 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/ThreadStart/threadstart03/libthreadstart03.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/ThreadStart/threadstart03/libthreadstart03.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,11 +35,11 @@ extern "C" {
 #define STATUS_FAILED 2
 #define WAIT_TIME 1000
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jrawMonitorID wait_lock;
-static const char *threadName = NULL;
+static const char *threadName = nullptr;
 static int startsCount = 0;
 static int startsExpected = 0;
 static int endsCount = 0;
@@ -57,7 +57,7 @@ void JNICALL ThreadStart(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread) {
 
   LOG(">>> start: %s\n", inf.name);
 
-  if (inf.name != NULL && strcmp(inf.name, threadName) == 0) {
+  if (inf.name != nullptr && strcmp(inf.name, threadName) == 0) {
     startsCount++;
   }
 }
@@ -74,7 +74,7 @@ void JNICALL ThreadEnd(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread) {
 
   LOG(">>> end: %s\n", inf.name);
 
-  if (inf.name != NULL && strcmp(inf.name, threadName) == 0) {
+  if (inf.name != nullptr && strcmp(inf.name, threadName) == 0) {
     endsCount++;
   }
 }
@@ -84,7 +84,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -110,20 +110,20 @@ JNIEXPORT jint JNICALL
 Java_threadstart03_check(JNIEnv *jni, jclass cls, jthread thr, jstring name) {
   jvmtiError err;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
 
-  threadName = jni->GetStringUTFChars(name, NULL);
-  if (threadName == NULL) {
+  threadName = jni->GetStringUTFChars(name, nullptr);
+  if (threadName == nullptr) {
     LOG("Failed to copy UTF-8 string!\n");
     return STATUS_FAILED;
   }
 
   wait_lock = create_raw_monitor(jvmti, "_wait_lock");
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, nullptr);
   if (err == JVMTI_ERROR_NONE) {
     startsExpected = 1;
   } else {
@@ -131,7 +131,7 @@ Java_threadstart03_check(JNIEnv *jni, jclass cls, jthread thr, jstring name) {
     result = STATUS_FAILED;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_END, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_END, nullptr);
   if (err == JVMTI_ERROR_NONE) {
     endsExpected = 1;
   } else {
@@ -143,7 +143,7 @@ Java_threadstart03_check(JNIEnv *jni, jclass cls, jthread thr, jstring name) {
 
   {
     RawMonitorLocker wait_locker(jvmti, jni, wait_lock);
-    err = jvmti->RunAgentThread(thr, threadProc, NULL, JVMTI_THREAD_MAX_PRIORITY);
+    err = jvmti->RunAgentThread(thr, threadProc, nullptr, JVMTI_THREAD_MAX_PRIORITY);
     if (err != JVMTI_ERROR_NONE) {
       LOG("(RunAgentThread) unexpected error: %s (%d)\n", TranslateError(err), err);
       result = STATUS_FAILED;
@@ -164,13 +164,13 @@ Java_threadstart03_check(JNIEnv *jni, jclass cls, jthread thr, jstring name) {
 
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_THREAD_START, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_THREAD_START, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Failed to disable JVMTI_EVENT_THREAD_START: %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_THREAD_END, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_THREAD_END, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Failed to disable JVMTI_EVENT_THREAD_END: %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/events/VMObjectAlloc/vmobjalloc01/libvmobjalloc01.cpp b/test/hotspot/jtreg/serviceability/jvmti/events/VMObjectAlloc/vmobjalloc01/libvmobjalloc01.cpp
index 24cef0250c5..46006b00ad4 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/events/VMObjectAlloc/vmobjalloc01/libvmobjalloc01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/events/VMObjectAlloc/vmobjalloc01/libvmobjalloc01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -65,10 +65,10 @@ VMObjectAlloc(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread, jobject object, jcla
 
   LOG("VMObjectAlloc: \"%s\", size=%ld\n", signature, (long)size);
 
-  if (signature != NULL)
+  if (signature != nullptr)
     jvmti->Deallocate((unsigned char*)signature);
 
-  if (generic != NULL)
+  if (generic != nullptr)
     jvmti->Deallocate((unsigned char*)generic);
 
 }
@@ -92,7 +92,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 }
 
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-  jvmtiEnv* jvmti = NULL;
+  jvmtiEnv* jvmti = nullptr;
   jvmtiCapabilities caps;
   jvmtiEventCallbacks callbacks;
   jvmtiError err;
@@ -103,7 +103,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
   /* create JVMTI environment */
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -127,12 +127,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   }
 
   /* enable VMObjectAlloc event */
-  if (jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, NULL) != JVMTI_ERROR_NONE) {
+  if (jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, nullptr) != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
 
   /* register agent proc and arg */
-  set_agent_proc(agentProc, NULL);
+  set_agent_proc(agentProc, nullptr);
 
   return JNI_OK;
 }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/negative/GetAllThreadsNullTest/libGetAllThreadsNullTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/negative/GetAllThreadsNullTest/libGetAllThreadsNullTest.cpp
index 2c665df4f27..1231a9e1ce1 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/negative/GetAllThreadsNullTest/libGetAllThreadsNullTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/negative/GetAllThreadsNullTest/libGetAllThreadsNullTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,12 +28,12 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti_env = NULL;
+static jvmtiEnv *jvmti_env = nullptr;
 
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res = jvm->GetEnv((void **) &jvmti_env, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti_env == NULL) {
+  if (res != JNI_OK || jvmti_env == nullptr) {
     LOG("Wrong test_passed of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -48,14 +48,14 @@ Java_GetAllThreadsNullTest_check(JNIEnv *env, jclass cls) {
   jthread *threadsPtr;
   jboolean test_passed = JNI_TRUE;
 
-  if (jvmti_env == NULL) {
+  if (jvmti_env == nullptr) {
       LOG("JVMTI client was not properly loaded!\n");
       return JNI_FALSE;
   }
 
   LOG(">>> (threadsCountPtr) null pointer check ...\n");
 
-  err = jvmti_env->GetAllThreads(NULL, &threadsPtr);
+  err = jvmti_env->GetAllThreads(nullptr, &threadsPtr);
   if (err != JVMTI_ERROR_NULL_POINTER) {
     LOG("(threadsCountPtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
     LOG("           got: %s (%d)\n", TranslateError(err), err);
@@ -64,14 +64,14 @@ Java_GetAllThreadsNullTest_check(JNIEnv *env, jclass cls) {
 
   LOG(">>> (threadsPtr) null pointer check ...\n");
 
-  err = jvmti_env->GetAllThreads(&threadsCountPtr, NULL);
+  err = jvmti_env->GetAllThreads(&threadsCountPtr, nullptr);
   if (err != JVMTI_ERROR_NULL_POINTER) {
     LOG("(threadsPtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
     LOG("           got: %s (%d)\n", TranslateError(err), err);
     test_passed = JNI_FALSE;
   }
 
-  err = jvmti_env->GetAllThreads(NULL, NULL);
+  err = jvmti_env->GetAllThreads(nullptr, nullptr);
   if (err != JVMTI_ERROR_NULL_POINTER) {
     LOG("(threadsPtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
     LOG("           got: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/serviceability/jvmti/negative/contmon03/libcontmon03.cpp b/test/hotspot/jtreg/serviceability/jvmti/negative/contmon03/libcontmon03.cpp
index 35e6f859afd..f9188a371ff 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/negative/contmon03/libcontmon03.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/negative/contmon03/libcontmon03.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 
 JNIEXPORT jint JNICALL
@@ -42,7 +42,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jvmtiCapabilities caps;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -64,7 +64,7 @@ Java_contmon03_check(JNIEnv *env, jclass cls, jthread thread) {
   jvmtiError err;
   jobject monitor;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
@@ -80,7 +80,7 @@ Java_contmon03_check(JNIEnv *env, jclass cls, jthread thread) {
 
   LOG(">>> null pointer check ...\n");
 
-  err = jvmti->GetCurrentContendedMonitor(thread, NULL);
+  err = jvmti->GetCurrentContendedMonitor(thread, nullptr);
   if (err != JVMTI_ERROR_NULL_POINTER) {
     LOG("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
     LOG("           got: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/serviceability/jvmti/negative/framecnt02/libframecnt02.cpp b/test/hotspot/jtreg/serviceability/jvmti/negative/framecnt02/libframecnt02.cpp
index f8d76a2f882..0b4286991f7 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/negative/framecnt02/libframecnt02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/negative/framecnt02/libframecnt02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 
 JNIEXPORT jint JNICALL
@@ -40,7 +40,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv !\n");
     return JNI_ERR;
   }
@@ -54,7 +54,7 @@ Java_framecnt02_checkFrames(JNIEnv *env, jclass cls, jthread thr, jint thr_num)
   jint frameCount;
 
   if (thr_num == 0) {
-    err = jvmti->GetFrameCount(thr, NULL);
+    err = jvmti->GetFrameCount(thr, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
       LOG("Error expected: JVMTI_ERROR_NULL_POINTER, got: %s (%d)\n", TranslateError(err), err);
       result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/negative/framecnt03/libframecnt03.cpp b/test/hotspot/jtreg/serviceability/jvmti/negative/framecnt03/libframecnt03.cpp
index 74769bb29f5..b72c7b87ab1 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/negative/framecnt03/libframecnt03.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/negative/framecnt03/libframecnt03.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 
 JNIEXPORT jint JNICALL
@@ -40,7 +40,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -53,7 +53,7 @@ Java_framecnt03_check(JNIEnv *env, jclass cls) {
   jvmtiError err;
   jint countPtr;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
       LOG("JVMTI client was not properly loaded!\n");
       return STATUS_FAILED;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/negative/frameloc03/libframeloc03.cpp b/test/hotspot/jtreg/serviceability/jvmti/negative/frameloc03/libframeloc03.cpp
index 631ad8d383f..b763d0433ee 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/negative/frameloc03/libframeloc03.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/negative/frameloc03/libframeloc03.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -43,12 +43,12 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jvmtiError err;
   jint res;
 
-  if (options != NULL && strcmp(options, "printdump") == 0) {
+  if (options != nullptr && strcmp(options, "printdump") == 0) {
     printdump = JNI_TRUE;
   }
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -84,7 +84,7 @@ Java_frameloc03_check(JNIEnv *env, jclass cls, jthread thr) {
   jmethodID mid;
   jlocation loc;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
@@ -123,7 +123,7 @@ Java_frameloc03_check(JNIEnv *env, jclass cls, jthread thr) {
   if (printdump == JNI_TRUE) {
     LOG(">>> (methodPtr) null pointer check ...\n");
   }
-  err = jvmti->GetFrameLocation(thr, 0, NULL, &loc);
+  err = jvmti->GetFrameLocation(thr, 0, nullptr, &loc);
   if (err != JVMTI_ERROR_NULL_POINTER) {
     LOG("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
     LOG("        actual: %s (%d)\n", TranslateError(err), err);
@@ -133,7 +133,7 @@ Java_frameloc03_check(JNIEnv *env, jclass cls, jthread thr) {
   if (printdump == JNI_TRUE) {
     LOG(">>> (locationPtr) null pointer check ...\n");
   }
-  err = jvmti->GetFrameLocation(thr, 0, &mid, NULL);
+  err = jvmti->GetFrameLocation(thr, 0, &mid, nullptr);
   if (err != JVMTI_ERROR_NULL_POINTER) {
     LOG("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
     LOG("        actual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/serviceability/jvmti/negative/getstacktr02/libgetstacktr02.cpp b/test/hotspot/jtreg/serviceability/jvmti/negative/getstacktr02/libgetstacktr02.cpp
index 061b717af37..b12b322bba4 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/negative/getstacktr02/libgetstacktr02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/negative/getstacktr02/libgetstacktr02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -40,12 +40,12 @@ JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
-  if (options != NULL && strcmp(options, "printdump") == 0) {
+  if (options != nullptr && strcmp(options, "printdump") == 0) {
     printdump = JNI_TRUE;
   }
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -59,7 +59,7 @@ Java_getstacktr02_check(JNIEnv *env, jclass cls, jthread thread) {
   jvmtiFrameInfo frame;
   jint count;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
         LOG("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
   }
@@ -85,7 +85,7 @@ Java_getstacktr02_check(JNIEnv *env, jclass cls, jthread thread) {
   if (printdump == JNI_TRUE) {
     LOG(">>> (stack_buffer) null pointer check ...\n");
   }
-  err = jvmti->GetStackTrace(thread, 0, 1, NULL, &count);
+  err = jvmti->GetStackTrace(thread, 0, 1, nullptr, &count);
   if (err != JVMTI_ERROR_NULL_POINTER) {
     LOG("(stack_buffer) error expected: JVMTI_ERROR_NULL_POINTER,");
     LOG(" got: %s (%d)\n", TranslateError(err), err);
@@ -95,7 +95,7 @@ Java_getstacktr02_check(JNIEnv *env, jclass cls, jthread thread) {
   if (printdump == JNI_TRUE) {
     LOG(">>> (count_ptr) null pointer check ...\n");
   }
-  err = jvmti->GetStackTrace(thread, 0, 1, &frame, NULL);
+  err = jvmti->GetStackTrace(thread, 0, 1, &frame, nullptr);
   if (err != JVMTI_ERROR_NULL_POINTER) {
     LOG("(count_ptr) error expected: JVMTI_ERROR_NULL_POINTER,");
     LOG(" got: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/serviceability/jvmti/negative/getstacktr09/libgetstacktr09.cpp b/test/hotspot/jtreg/serviceability/jvmti/negative/getstacktr09/libgetstacktr09.cpp
index f9b6e4dd077..bdac7128c3b 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/negative/getstacktr09/libgetstacktr09.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/negative/getstacktr09/libgetstacktr09.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -40,12 +40,12 @@ JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
-  if (options != NULL && strcmp(options, "printdump") == 0) {
+  if (options != nullptr && strcmp(options, "printdump") == 0) {
     printdump = JNI_TRUE;
   }
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -59,7 +59,7 @@ Java_getstacktr09_check(JNIEnv *env, jclass cls, jthread thread1, jthread thread
   jvmtiFrameInfo frame;
   jint count;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/negative/thrinfo02/libthrinfo02.cpp b/test/hotspot/jtreg/serviceability/jvmti/negative/thrinfo02/libthrinfo02.cpp
index 8c47aaa7f4b..6ab0c456704 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/negative/thrinfo02/libthrinfo02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/negative/thrinfo02/libthrinfo02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -40,12 +40,12 @@ JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
-  if (options != NULL && strcmp(options, "printdump") == 0) {
+  if (options != nullptr && strcmp(options, "printdump") == 0) {
     printdump = JNI_TRUE;
   }
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -58,7 +58,7 @@ Java_thrinfo02_check(JNIEnv *env, jclass cls, jthread thr, jthreadGroup group) {
   jvmtiError err;
   jvmtiThreadInfo inf;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
@@ -66,14 +66,14 @@ Java_thrinfo02_check(JNIEnv *env, jclass cls, jthread thr, jthreadGroup group) {
   if (printdump == JNI_TRUE) {
     LOG(">>> invalid thread check ...\n");
   }
-  err = jvmti->GetThreadInfo(NULL, &inf);
+  err = jvmti->GetThreadInfo(nullptr, &inf);
   if (err != JVMTI_ERROR_NONE) {
       LOG("Error expected: JVMTI_ERROR_NONE,\n");
       LOG("           got: %s (%d)\n", TranslateError(err), err);
       result = STATUS_FAILED;
   }
 
-  if (inf.name == NULL || strcmp(inf.name, "main")) {
+  if (inf.name == nullptr || strcmp(inf.name, "main")) {
     LOG("Thread %s: incorrect name: %s\n", "main", inf.name);
     result = STATUS_FAILED;
   }
@@ -93,7 +93,7 @@ Java_thrinfo02_check(JNIEnv *env, jclass cls, jthread thr, jthreadGroup group) {
   if (printdump == JNI_TRUE) {
     LOG(">>> null pointer check ...\n");
   }
-  err = jvmti->GetThreadInfo(thr, NULL);
+  err = jvmti->GetThreadInfo(thr, nullptr);
   if (err != JVMTI_ERROR_NULL_POINTER) {
     LOG("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
     LOG("           got: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/serviceability/jvmti/negative/thrstat04/libthrstat04.cpp b/test/hotspot/jtreg/serviceability/jvmti/negative/thrstat04/libthrstat04.cpp
index 05baab36d51..b63e84d0c49 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/negative/thrstat04/libthrstat04.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/negative/thrstat04/libthrstat04.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -40,12 +40,12 @@ JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
-  if (options != NULL && strcmp(options, "printdump") == 0) {
+  if (options != nullptr && strcmp(options, "printdump") == 0) {
     printdump = JNI_TRUE;
   }
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -58,7 +58,7 @@ Java_thrstat04_check(JNIEnv *env, jclass cls, jthread thr) {
   jvmtiError err;
   jint thrState;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
@@ -66,7 +66,7 @@ Java_thrstat04_check(JNIEnv *env, jclass cls, jthread thr) {
   if (printdump == JNI_TRUE) {
     LOG(">>> (threadStatePtr) null pointer check ...\n");
   }
-  err = jvmti->GetThreadState(thr, NULL);
+  err = jvmti->GetThreadState(thr, nullptr);
   if (err != JVMTI_ERROR_NULL_POINTER) {
     LOG("(threadStatePtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
     LOG("           got: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/serviceability/jvmti/stress/StackTrace/NotSuspended/libGetStackTraceNotSuspendedStress.cpp b/test/hotspot/jtreg/serviceability/jvmti/stress/StackTrace/NotSuspended/libGetStackTraceNotSuspendedStress.cpp
index 12e685b3714..ee2dc9d2859 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/stress/StackTrace/NotSuspended/libGetStackTraceNotSuspendedStress.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/stress/StackTrace/NotSuspended/libGetStackTraceNotSuspendedStress.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ const char CONTINUATION_METHOD_NAME[] = "enter";
 static void test_stack_trace(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread) {
   jvmtiFrameInfo frames[MAX_FRAME_COUNT];
   jint count = -1;
-  jmethodID method = NULL;
+  jmethodID method = nullptr;
   jvmtiError err;
 
   err = jvmti->GetStackTrace(vthread, 0, MAX_FRAME_COUNT, frames, &count);
@@ -78,7 +78,7 @@ agentProc(jvmtiEnv * jvmti, JNIEnv * jni, void * arg) {
   LOG("Agent: started\n");
 
   while (true) {
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint count = 0;
     jvmtiError err;
 
@@ -90,7 +90,7 @@ agentProc(jvmtiEnv * jvmti, JNIEnv * jni, void * arg) {
     }
     check_jvmti_status(jni, err,  "Error in JVMTI GetAllThreads");
     for (int i = 0; i < count; i++) {
-      jthread tested_thread = NULL;
+      jthread tested_thread = nullptr;
 
       err = GetVirtualThread(jvmti, jni, threads[i], &tested_thread);
       if (err == JVMTI_ERROR_THREAD_NOT_ALIVE) {
@@ -100,7 +100,7 @@ agentProc(jvmtiEnv * jvmti, JNIEnv * jni, void * arg) {
         return;
       }
       check_jvmti_status(jni, err,  "Error in JVMTI extension GetVirtualThread");
-      if (tested_thread != NULL) {
+      if (tested_thread != nullptr) {
         test_stack_trace(jvmti, jni, tested_thread);
       }
     }
@@ -132,7 +132,7 @@ extern JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *jvm, char *options, void *res
     return JNI_ERR;
   }
 
-  if (set_agent_proc(agentProc, NULL) != JNI_TRUE) {
+  if (set_agent_proc(agentProc, nullptr) != JNI_TRUE) {
     return JNI_ERR;
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/stress/StackTrace/Suspended/libGetStackTraceSuspendedStress.cpp b/test/hotspot/jtreg/serviceability/jvmti/stress/StackTrace/Suspended/libGetStackTraceSuspendedStress.cpp
index 65e79fb33f2..639b40d4839 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/stress/StackTrace/Suspended/libGetStackTraceSuspendedStress.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/stress/StackTrace/Suspended/libGetStackTraceSuspendedStress.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -31,13 +31,13 @@
 static const char CONTINUATION_CLASS_NAME[] = "jdk/internal/vm/Continuation";
 static const char CONTINUATION_METHOD_NAME[] = "enter";
 
-static jrawMonitorID event_mon = NULL;
+static jrawMonitorID event_mon = nullptr;
 
 static void
 test_stack_trace(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread) {
   jvmtiFrameInfo frames[MAX_FRAME_COUNT];
   jint count = -1;
-  jmethodID method = NULL;
+  jmethodID method = nullptr;
   jvmtiError err;
 
   err = jvmti->GetStackTrace(vthread, 0, MAX_FRAME_COUNT, frames, &count);
@@ -93,7 +93,7 @@ check_link_consistency(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread) {
     fatal(jni, "Carrier thread is NOT expected to be suspended");
   }
 
-  if (cthread != NULL) {
+  if (cthread != nullptr) {
     jthread cthread_to_vthread = get_virtual_thread(jvmti, jni, cthread);
 
     if (!jni->IsSameObject(vthread, cthread_to_vthread)) {
@@ -118,12 +118,12 @@ check_vthread_consistency_suspended(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthrea
     jni->FatalError("Agent: check_vthread_consistency_suspended: vthread is expected to be virtual");
   }
   jthread cthread = get_carrier_thread(jvmti, jni, vthread);
-  //const char* cname = (cthread == NULL) ? "<no cthread>" : get_thread_name(jvmti, jni, cthread);
+  //const char* cname = (cthread == nullptr) ? "<no cthread>" : get_thread_name(jvmti, jni, cthread);
 
   err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, vthread);
   check_jvmti_status(jni, err, "Error in JVMTI SetEventNotificationMode: enable SINGLE_STEP");
 
-  if (cthread != NULL) { // pre-condition for reliable testing
+  if (cthread != nullptr) { // pre-condition for reliable testing
     test_stack_trace(jvmti, jni, vthread);
     check_link_consistency(jvmti, jni, vthread);
   }
@@ -145,7 +145,7 @@ SingleStep(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread,
   print_stack_trace(jvmti, jni, thread);
 
   jthread cthread = get_carrier_thread(jvmti, jni, thread);
-  if (cthread != NULL) {
+  if (cthread != nullptr) {
     print_stack_trace(jvmti, jni, cthread);
   }
 
@@ -170,7 +170,7 @@ agentProc(jvmtiEnv * jvmti, JNIEnv * jni, void * arg) {
 
   int iter = 0;
   while (true) {
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint count = 0;
     jvmtiError err;
 
@@ -182,7 +182,7 @@ agentProc(jvmtiEnv * jvmti, JNIEnv * jni, void * arg) {
 
     for (int i = 0; i < count; i++) {
       jthread cthread = threads[i];
-      jthread vthread = NULL;
+      jthread vthread = nullptr;
 
       err = GetVirtualThread(jvmti, jni, cthread, &vthread);
       if (err == JVMTI_ERROR_THREAD_NOT_ALIVE) {
@@ -192,7 +192,7 @@ agentProc(jvmtiEnv * jvmti, JNIEnv * jni, void * arg) {
         return;
       }
       check_jvmti_status(jni, err,  "Error in GetVirtualThread");
-      if (iter > 50 && vthread != NULL) {
+      if (iter > 50 && vthread != nullptr) {
         // char* cname = get_thread_name(jvmti, jni, cthread);
         // char* vname = get_thread_name(jvmti, jni, vthread);
 
@@ -256,7 +256,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  if (set_agent_proc(agentProc, NULL) != JNI_TRUE) {
+  if (set_agent_proc(agentProc, nullptr) != JNI_TRUE) {
     return JNI_ERR;
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/stress/ThreadLocalStorage/SetGetThreadLocalStorageStressTest/libSetGetThreadLocalStorageStress.cpp b/test/hotspot/jtreg/serviceability/jvmti/stress/ThreadLocalStorage/SetGetThreadLocalStorageStressTest/libSetGetThreadLocalStorageStress.cpp
index 43ddccc84a4..1c09fac92ba 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/stress/ThreadLocalStorage/SetGetThreadLocalStorageStressTest/libSetGetThreadLocalStorageStress.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/stress/ThreadLocalStorage/SetGetThreadLocalStorageStressTest/libSetGetThreadLocalStorageStress.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,15 +48,15 @@ StorageStructure* check_tls(jvmtiEnv * jvmti, JNIEnv * jni, jthread thread, cons
 
   jvmtiError err = jvmti->GetThreadLocalStorage(thread, (void **) &storage);
   if (err == JVMTI_ERROR_THREAD_NOT_ALIVE) {
-    return NULL;
+    return nullptr;
   }
   check_jvmti_status(jni, err, "Error in GetThreadLocalStorage");
   LOG("Check %s with %p in %s\n", thread_info.name, storage, source);
 
 
-  if (storage == NULL) {
+  if (storage == nullptr) {
     // Might be not set
-    return NULL;
+    return nullptr;
   }
 
   if (storage->self_pointer != storage || (strcmp(thread_info.name, storage->data) != 0)) {
@@ -71,12 +71,12 @@ StorageStructure* check_tls(jvmtiEnv * jvmti, JNIEnv * jni, jthread thread, cons
 void check_delete_tls(jvmtiEnv * jvmti, JNIEnv * jni, jthread thread, const char* source) {
   StorageStructure *storage = check_tls(jvmti, jni, thread, source);
 
-  if (storage == NULL) {
+  if (storage == nullptr) {
     return;
   }
 
   check_jvmti_status(jni, jvmti->Deallocate((unsigned char *)storage), "Deallocation failed.");
-  jvmtiError err = jvmti->SetThreadLocalStorage(thread, NULL);
+  jvmtiError err = jvmti->SetThreadLocalStorage(thread, nullptr);
   if (err == JVMTI_ERROR_THREAD_NOT_ALIVE) {
     return;
   }
@@ -125,7 +125,7 @@ agentProc(jvmtiEnv * jvmti, JNIEnv * jni, void * arg) {
   LOG("Started.....\n");
 
   while (true) {
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint count = 0;
 
     sleep_ms(10);
@@ -136,7 +136,7 @@ agentProc(jvmtiEnv * jvmti, JNIEnv * jni, void * arg) {
     }
     check_jvmti_status(jni, jvmti->GetAllThreads(&count, &threads), "Error in GetAllThreads");
     for (int i = 0; i < count; i++) {
-      jthread testedThread = NULL;
+      jthread testedThread = nullptr;
       jvmtiError err;
 
       err = GetVirtualThread(jvmti, jni, threads[i], &testedThread);
@@ -145,7 +145,7 @@ agentProc(jvmtiEnv * jvmti, JNIEnv * jni, void * arg) {
       }
       check_jvmti_status(jni, err,  "Error in GetVirtualThread");
 
-      if (testedThread == NULL) {
+      if (testedThread == nullptr) {
         testedThread = threads[i];
         continue;
       }
@@ -205,7 +205,7 @@ VirtualThreadEnd(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread) {
 
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
-  jvmtiEnv * jvmti = NULL;
+  jvmtiEnv * jvmti = nullptr;
 
   jvmtiEventCallbacks callbacks;
   jvmtiCapabilities caps;
@@ -213,7 +213,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -250,19 +250,19 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
-  jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
-  jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
-  jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, NULL);
-  jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_END, NULL);
-  jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, NULL);
-  jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_END, NULL);
+  jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
+  jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
+  jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, nullptr);
+  jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_END, nullptr);
+  jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, nullptr);
+  jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_END, nullptr);
 
   err = init_agent_data(jvmti, &agent_data);
   if (err != JVMTI_ERROR_NONE) {
     return JNI_ERR;
   }
 
-  if (set_agent_proc(agentProc, NULL) != JNI_TRUE) {
+  if (set_agent_proc(agentProc, nullptr) != JNI_TRUE) {
     return JNI_ERR;
   }
   return JNI_OK;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetAllThreads/allthr01/liballthr01.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetAllThreads/allthr01/liballthr01.cpp
index 1b3079c6e30..11ad6440928 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetAllThreads/allthr01/liballthr01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetAllThreads/allthr01/liballthr01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -93,7 +93,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti_env, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti_env == NULL) {
+  if (res != JNI_OK || jvmti_env == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -162,7 +162,7 @@ JNIEXPORT void
 Java_allthr01_startAgentThread(JNIEnv *jni) {
   RawMonitorLocker rml1 = RawMonitorLocker(jvmti_env, jni, starting_agent_thread_lock);
   jvmtiError err = jvmti_env->RunAgentThread(create_jthread(jni),
-                                             sys_thread, NULL,JVMTI_THREAD_NORM_PRIORITY);
+                                             sys_thread, nullptr,JVMTI_THREAD_NORM_PRIORITY);
   check_jvmti_status(jni, err, "Failed to run AgentThread");
   rml1.wait();
   LOG("Started Agent Thread\n");
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetCurrentContendedMonitor/contmon01/libcontmon01.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetCurrentContendedMonitor/contmon01/libcontmon01.cpp
index 4e9ef9a9c91..e3d95e113a0 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetCurrentContendedMonitor/contmon01/libcontmon01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetCurrentContendedMonitor/contmon01/libcontmon01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,13 +29,13 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
 
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv !\n");
     return JNI_ERR;
   }
@@ -54,7 +54,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
 
 JNIEXPORT void JNICALL
 Java_contmon01_checkMonitor(JNIEnv *jni, jclass cls, jint point, jthread thread, jobject lock) {
-  jobject monitor = NULL;
+  jobject monitor = nullptr;
 
   jvmtiError err = jvmti->GetCurrentContendedMonitor(thread, &monitor);
   if (err == JVMTI_ERROR_THREAD_NOT_ALIVE && point == 5) {
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetCurrentContendedMonitor/contmon02/libcontmon02.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetCurrentContendedMonitor/contmon02/libcontmon02.cpp
index dbbc63c57cd..65a2211a004 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetCurrentContendedMonitor/contmon02/libcontmon02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetCurrentContendedMonitor/contmon02/libcontmon02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
 
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv !\n");
     return JNI_ERR;
   }
@@ -56,7 +56,7 @@ Java_contmon02_checkMonitor(JNIEnv *jni, jclass cls, jint point, jthread thread)
   jobject monitor;
   jvmtiError err = jvmti->GetCurrentContendedMonitor(thread, &monitor);
   check_jvmti_status(jni, err, "Error in GetCurrentContendedMonitor");
-  if (monitor != NULL) {
+  if (monitor != nullptr) {
     LOG("(#%d) unexpected monitor object: 0x%p\n", point, monitor);
     fatal(jni, "GetCurrentContendedMonitor return unexpected monitor.");
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetFrameCount/framecnt01/libframecnt01.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetFrameCount/framecnt01/libframecnt01.cpp
index fc5319fa9c7..c9dd399138a 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetFrameCount/framecnt01/libframecnt01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetFrameCount/framecnt01/libframecnt01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,7 +27,7 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti_env = NULL;
+static jvmtiEnv *jvmti_env = nullptr;
 
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
@@ -35,7 +35,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti_env, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti_env == NULL) {
+  if (res != JNI_OK || jvmti_env == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetFrameLocation/frameloc01/libframeloc01.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetFrameLocation/frameloc01/libframeloc01.cpp
index bc4a81e8ab1..89855a8d66e 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetFrameLocation/frameloc01/libframeloc01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetFrameLocation/frameloc01/libframeloc01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -31,7 +31,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti_env = NULL;
+static jvmtiEnv *jvmti_env = nullptr;
 static jint result = PASSED;
 static jmethodID mid1;
 
@@ -40,7 +40,7 @@ static jmethodID mid1;
 jboolean checkFrame(jvmtiEnv *jvmti_env, JNIEnv *jni, jthread thr, jmethodID exp_mid,
                     jlocation exp_loc, jlocation exp_loc_alternative, jboolean mustPass) {
   jvmtiError err;
-  jmethodID mid = NULL;
+  jmethodID mid = nullptr;
   jlocation loc = -1;
   char *meth, *sig, *generic;
   jboolean isOk = JNI_FALSE;
@@ -88,7 +88,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jvmtiError err;
 
   jint res = jvm->GetEnv((void **) &jvmti_env, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti_env == NULL) {
+  if (res != JNI_OK || jvmti_env == nullptr) {
     LOG("Wrong result of a valid call to GetEnv !\n");
     return JNI_ERR;
   }
@@ -115,13 +115,13 @@ JNIEXPORT void JNICALL
 Java_frameloc01_getReady(JNIEnv *jni, jclass cls, jclass klass) {
   jvmtiError err;
   mid1 = jni->GetMethodID(klass, "meth01", "(I)V");
-  if (mid1 == NULL) {
+  if (mid1 == nullptr) {
     LOG("Cannot get jmethodID for method \"meth01\"\n");
     result = STATUS_FAILED;
     return;
   }
 
-  err = jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION_CATCH, NULL);
+  err = jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION_CATCH, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("(SetEventNotificationMode) unexpected error: %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
@@ -134,7 +134,7 @@ Java_frameloc01_checkFrame01(JNIEnv *jni, jclass cls, jthread thr, jclass klass,
   jboolean isOk = JNI_FALSE;
 
   mid = jni->GetMethodID(klass, "run", "()V");
-  if (mid == NULL) {
+  if (mid == nullptr) {
     LOG("Cannot get jmethodID for method \"run\"\n");
     result = STATUS_FAILED;
     return JNI_TRUE;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetFrameLocation/frameloc02/libframeloc02.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetFrameLocation/frameloc02/libframeloc02.cpp
index 46724b12e9f..53e9378fc8d 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetFrameLocation/frameloc02/libframeloc02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetFrameLocation/frameloc02/libframeloc02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ typedef struct {
   jlocation loc;
 } frame_info;
 
-static jvmtiEnv *jvmti_env = NULL;
+static jvmtiEnv *jvmti_env = nullptr;
 static jint result = PASSED;
 static frame_info fi =
     {"Lframeloc02;", "check",
@@ -47,7 +47,7 @@ static frame_info fi =
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res = jvm->GetEnv((void **) &jvmti_env, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti_env == NULL) {
+  if (res != JNI_OK || jvmti_env == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -98,17 +98,17 @@ Java_frameloc02_check(JNIEnv *env, jclass cls, jthread thr) {
   LOG(">>>     method: \"%s%s\"\n", name, sig);
   LOG(">>>   location: %s\n", jlong_to_string(loc, buffer));
 
-  if (cls_sig == NULL || strcmp(cls_sig, fi.cls_sig) != 0) {
+  if (cls_sig == nullptr || strcmp(cls_sig, fi.cls_sig) != 0) {
     LOG("(GetFrameLocation) wrong class: \"%s\"\n", cls_sig);
     LOG(", expected: \"%s\"\n", fi.cls_sig);
     result = STATUS_FAILED;
   }
-  if (name == NULL || strcmp(name, fi.name) != 0) {
+  if (name == nullptr || strcmp(name, fi.name) != 0) {
     LOG("(GetFrameLocation) wrong method name: \"%s\"", name);
     LOG(", expected: \"%s\"\n", fi.name);
     result = STATUS_FAILED;
   }
-  if (sig == NULL || strcmp(sig, fi.sig) != 0) {
+  if (sig == nullptr || strcmp(sig, fi.sig) != 0) {
     LOG("(GetFrameLocation) wrong method signature: \"%s\"", sig);
     LOG(", expected: \"%s\"\n", fi.sig);
     result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/GetStackTraceAndRetransformTest/libGetStackTraceAndRetransformTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/GetStackTraceAndRetransformTest/libGetStackTraceAndRetransformTest.cpp
index 3be6dcf824f..8968a6cc57d 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/GetStackTraceAndRetransformTest/libGetStackTraceAndRetransformTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/GetStackTraceAndRetransformTest/libGetStackTraceAndRetransformTest.cpp
@@ -30,14 +30,14 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
-static jmethodID* ids = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jmethodID* ids = nullptr;
 static int ids_size = 0;
 
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     printf("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -71,11 +71,11 @@ Java_GetStackTraceAndRetransformTest_check(JNIEnv *jni, jclass cls, jint expecte
     exit(2);
   }
   for (int i = 0; i < ids_size; i++) {
-    jclass rslt = NULL;
-    char* class_name = NULL;
+    jclass rslt = nullptr;
+    char* class_name = nullptr;
     jvmti->GetMethodDeclaringClass(ids[i], &rslt);
-    if (rslt != NULL) {
-        jvmti->GetClassSignature(rslt, &class_name, NULL);
+    if (rslt != nullptr) {
+        jvmti->GetClassSignature(rslt, &class_name, nullptr);
     }
   }
 }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/GetStackTraceCurrentThreadTest/libGetStackTraceCurrentThreadTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/GetStackTraceCurrentThreadTest/libGetStackTraceCurrentThreadTest.cpp
index deb494dd0aa..36e8663bb86 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/GetStackTraceCurrentThreadTest/libGetStackTraceCurrentThreadTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/GetStackTraceCurrentThreadTest/libGetStackTraceCurrentThreadTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -30,7 +30,7 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static frame_info expected_virtual_frames[] = {
     {"LGetStackTraceCurrentThreadTest;", "check", "(Ljava/lang/Thread;)V"},
     {"LGetStackTraceCurrentThreadTest;", "dummy", "()V"},
@@ -52,7 +52,7 @@ static frame_info expected_platform_frames[] = {
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     printf("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr03/libgetstacktr03.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr03/libgetstacktr03.cpp
index dc4d75be86f..a0ae45613d2 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr03/libgetstacktr03.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr03/libgetstacktr03.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,7 +29,7 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static frame_info expected_platform_frames[] = {
     {"Ljava/lang/Object;", "wait", "()V"},
     {"Lgetstacktr03;", "dummy", "()V"},
@@ -55,7 +55,7 @@ JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jvmtiError err;
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr04/libgetstacktr04.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr04/libgetstacktr04.cpp
index 873522ab531..9ef19122ec1 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr04/libgetstacktr04.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr04/libgetstacktr04.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,7 +29,7 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jmethodID mid;
 static frame_info expected_platform_frames[] = {
     {"Lgetstacktr04$TestThread;", "checkPoint", "()V"},
@@ -80,7 +80,7 @@ JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jvmtiError err;
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -108,12 +108,12 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
 JNIEXPORT void JNICALL
 Java_getstacktr04_getReady(JNIEnv *jni, jclass cls, jclass clazz) {
   mid = jni->GetMethodID(clazz, "checkPoint", "()V");
-  if (mid == NULL) {
+  if (mid == nullptr) {
     jni->FatalError("Cannot find Method ID for method checkPoint\n");
   }
 
   check_jvmti_status(jni, jvmti->SetBreakpoint(mid, 0), "SetBreakpoint failed.");
-  set_event_notification_mode(jvmti, jni, JVMTI_ENABLE,JVMTI_EVENT_BREAKPOINT, NULL);
+  set_event_notification_mode(jvmti, jni, JVMTI_ENABLE,JVMTI_EVENT_BREAKPOINT, nullptr);
 }
 
 }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr05/libgetstacktr05.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr05/libgetstacktr05.cpp
index 0cb2992b646..062e4b679e3 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr05/libgetstacktr05.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr05/libgetstacktr05.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,7 +29,7 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jmethodID mid;
@@ -102,7 +102,7 @@ JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jvmtiError err;
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -132,11 +132,11 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
 JNIEXPORT void JNICALL
 Java_getstacktr05_getReady(JNIEnv *jni, jclass cls, jclass clazz) {
   mid = jni->GetMethodID(clazz, "checkPoint", "()V");
-  if (mid == NULL) {
+  if (mid == nullptr) {
     jni->FatalError("Cannot find Method ID for method checkPoint\n");
   }
   check_jvmti_status(jni, jvmti->SetBreakpoint(mid, 0), "SetBreakpoint failed.");
-  set_event_notification_mode(jvmti, jni, JVMTI_ENABLE,JVMTI_EVENT_BREAKPOINT, NULL);
+  set_event_notification_mode(jvmti, jni, JVMTI_ENABLE,JVMTI_EVENT_BREAKPOINT, nullptr);
 }
 
 }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr06/libgetstacktr06.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr06/libgetstacktr06.cpp
index 0fd52c697f4..e72dc0c171f 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr06/libgetstacktr06.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr06/libgetstacktr06.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jmethodID mid;
@@ -67,7 +67,7 @@ void JNICALL Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *jni, jthread thr, jmethodID
   }
 
   check_jvmti_status(jni, jvmti->ClearBreakpoint(mid, 0), "ClearBreakpoint failed.");
-  set_event_notification_mode(jvmti, jni, JVMTI_DISABLE,JVMTI_EVENT_BREAKPOINT, NULL);
+  set_event_notification_mode(jvmti, jni, JVMTI_DISABLE,JVMTI_EVENT_BREAKPOINT, nullptr);
 
   set_event_notification_mode(jvmti, jni, JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, thr);
   LOG(">>> popping frame ...\n");
@@ -92,7 +92,7 @@ JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jvmtiError err;
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -128,12 +128,12 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
 JNIEXPORT void JNICALL
 Java_getstacktr06_getReady(JNIEnv *jni, jclass cls, jclass clazz) {
   mid = jni->GetMethodID(clazz, "checkPoint", "()V");
-  if (mid == NULL) {
+  if (mid == nullptr) {
     jni->FatalError("Cannot find Method ID for method checkPoint\n");
   }
 
   check_jvmti_status(jni, jvmti->SetBreakpoint(mid, 0), "SetBreakpoint failed.");
-  set_event_notification_mode(jvmti, jni, JVMTI_ENABLE,JVMTI_EVENT_BREAKPOINT, NULL);
+  set_event_notification_mode(jvmti, jni, JVMTI_ENABLE,JVMTI_EVENT_BREAKPOINT, nullptr);
 }
 
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr07/libgetstacktr07.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr07/libgetstacktr07.cpp
index a422fc0782f..2c3af86c5e5 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr07/libgetstacktr07.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr07/libgetstacktr07.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
@@ -73,7 +73,7 @@ void JNICALL Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *jni, jthread thread, jmetho
     jni->FatalError("ERROR: don't know where we get called from");
   }
 
-  if (classBytes == NULL) {
+  if (classBytes == nullptr) {
     jni->FatalError("ERROR: don't have any bytes");
   }
 
@@ -83,11 +83,11 @@ void JNICALL Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *jni, jthread thread, jmetho
 
   class_def.klass = klass;
   class_def.class_byte_count = jni->GetArrayLength(classBytes);
-  class_def.class_bytes = (unsigned char *) jni->GetByteArrayElements(classBytes, NULL);
+  class_def.class_bytes = (unsigned char *) jni->GetByteArrayElements(classBytes, nullptr);
 
   check_jvmti_status(jni, jvmti->RedefineClasses(1, &class_def), "RedefineClasses failed.");
   jni->DeleteGlobalRef(classBytes);
-  classBytes = NULL;
+  classBytes = nullptr;
 
   frame_info *expected_frames = jni->IsVirtualThread(thread)
       ? expected_virtual_frames
@@ -105,7 +105,7 @@ JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jvmtiError err;
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -137,12 +137,12 @@ Java_getstacktr07_getReady(JNIEnv *jni, jclass cls, jclass clazz, jbyteArray byt
   classBytes = (jbyteArray) jni->NewGlobalRef(bytes);
 
   mid = jni->GetMethodID(clazz, "checkPoint", "()V");
-  if (mid == NULL) {
+  if (mid == nullptr) {
     jni->FatalError("Cannot find Method ID for method checkPoint\n");
   }
 
   check_jvmti_status(jni, jvmti->SetBreakpoint(mid, 0), "SetBreakpoint failed.");
-  set_event_notification_mode(jvmti, jni, JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  set_event_notification_mode(jvmti, jni, JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
 
 }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr08/libgetstacktr08.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr08/libgetstacktr08.cpp
index 977bbf00b04..8b293a9e559 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr08/libgetstacktr08.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetStackTrace/getstacktr08/libgetstacktr08.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -30,7 +30,7 @@
 extern "C" {
 
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jboolean wasFramePop = JNI_FALSE;
 static jmethodID mid_checkPoint, mid_chain4;
@@ -116,7 +116,7 @@ void JNICALL SingleStep(jvmtiEnv *jvmti_env, JNIEnv *jni,
     }
 
 
-    if (classBytes == NULL) {
+    if (classBytes == nullptr) {
       jni->FatalError("ERROR: don't have any bytes");
     }
 
@@ -125,11 +125,11 @@ void JNICALL SingleStep(jvmtiEnv *jvmti_env, JNIEnv *jni,
 
     classDef.klass = klass;
     classDef.class_byte_count = jni->GetArrayLength(classBytes);
-    classDef.class_bytes = (unsigned char *) jni->GetByteArrayElements(classBytes, NULL);
+    classDef.class_bytes = (unsigned char *) jni->GetByteArrayElements(classBytes, nullptr);
     check_jvmti_status(jni, jvmti_env->RedefineClasses(1, &classDef), "RedefineClasses failed.");
 
     jni->DeleteGlobalRef(classBytes);
-    classBytes = NULL;
+    classBytes = nullptr;
     if (!compare_stack_trace(jvmti_env, jni, thread, 2)) {
       jni->ThrowNew(jni->FindClass("java/lang/RuntimeException"), "Stacktrace differs from expected.");
     }
@@ -140,7 +140,7 @@ JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jvmtiError err;
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -176,12 +176,12 @@ Java_getstacktr08_getReady(JNIEnv *jni, jclass cls, jclass clazz, jbyteArray byt
   mid_chain4 = jni->GetStaticMethodID(clazz, "chain4", "()V");
 
   check_jvmti_status(jni, jvmti->SetBreakpoint(mid_checkPoint, 0), "SetBreakpoint failed.");
-  set_event_notification_mode(jvmti, jni, JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  set_event_notification_mode(jvmti, jni, JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
 }
 
 JNIEXPORT void JNICALL
 Java_getstacktr08_nativeChain(JNIEnv *jni, jclass cls, jclass clazz) {
-  if (mid_chain4 != NULL) {
+  if (mid_chain4 != nullptr) {
     jni->CallStaticVoidMethod(clazz, mid_chain4);
   }
   if (!compare_stack_trace(jvmti, jni, get_current_thread(jvmti, jni), 3)) {
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadInfo/thrinfo01/libthrinfo01.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadInfo/thrinfo01/libthrinfo01.cpp
index 53f10cb7d5c..e040b88ba88 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadInfo/thrinfo01/libthrinfo01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadInfo/thrinfo01/libthrinfo01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,7 +35,7 @@ typedef struct {
   jboolean is_daemon;
 } info;
 
-static jvmtiEnv *jvmti_env = NULL;
+static jvmtiEnv *jvmti_env = nullptr;
 static info expected_info_array[] = {
     {"main", JNI_TRUE,JVMTI_THREAD_NORM_PRIORITY, JNI_FALSE},
     {"thread1",JNI_TRUE,JVMTI_THREAD_MIN_PRIORITY + 2, JNI_TRUE},
@@ -49,7 +49,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jvmtiCapabilities caps;
 
   res = jvm->GetEnv((void **) &jvmti_env, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti_env == NULL) {
+  if (res != JNI_OK || jvmti_env == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -75,8 +75,8 @@ Java_thrinfo01_checkInfo0(JNIEnv *jni, jclass cls, jthread thread, jthreadGroup
   info expected_info = expected_info_array[expected_idx];
 
   check_jvmti_status(jni, jvmti_env->GetThreadInfo(thread, &inf), "Error in GetThreadInfo.");
-  if (inf.name == NULL) {
-    LOG("Thread %s: incorrect name in NULL\n", expected_info.name);
+  if (inf.name == nullptr) {
+    LOG("Thread %s: incorrect name in null\n", expected_info.name);
     result = JNI_FALSE;
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat01/libthrstat01.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat01/libthrstat01.cpp
index 825ac1ffd75..4d54648a73f 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat01/libthrstat01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat01/libthrstat01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -31,11 +31,11 @@ extern "C" {
 #define WAIT_START 100
 #define WAIT_TIME (2*60*1000)
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 static jrawMonitorID access_lock;
 static jrawMonitorID wait_lock;
-static jthread tested_thread_thr1 = NULL;
+static jthread tested_thread_thr1 = nullptr;
 
 static jint state[] = {
     JVMTI_THREAD_STATE_RUNNABLE,
@@ -45,9 +45,9 @@ static jint state[] = {
 
 void JNICALL
 VMInit(jvmtiEnv *jvmti_env, JNIEnv *jni, jthread thr) {
-  jvmtiError err = jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, NULL);
+  jvmtiError err = jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, nullptr);
   check_jvmti_status(jni, err, "Error in SetEventNotificationMode");
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, nullptr);
   check_jvmti_status(jni, err, "Error in SetEventNotificationMode");
 }
 
@@ -58,7 +58,7 @@ ThreadStart(jvmtiEnv *jvmti_env, JNIEnv *jni, jthread thread) {
   jvmtiThreadInfo thread_info = get_thread_info(jvmti, jni, thread);
   LOG(">>> ThreadStart: \"%s\"\n", thread_info.name);
 
-  if (thread_info.name != NULL && strcmp(thread_info.name, "tested_thread_thr1") == 0) {
+  if (thread_info.name != nullptr && strcmp(thread_info.name, "tested_thread_thr1") == 0) {
     tested_thread_thr1 = jni->NewGlobalRef(thread);
     LOG(">>> ThreadStart: \"%s\", 0x%p\n", thread_info.name, tested_thread_thr1);
   }
@@ -72,7 +72,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   LOG("Agent_OnLoad started\n");
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -101,7 +101,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("(SetEventNotificationMode) unexpected error: %s (%d)\n", TranslateError(err), err);
     return JNI_ERR;
@@ -117,7 +117,7 @@ Java_thrstat01_checkStatus0(JNIEnv *jni, jclass cls, jint stat_ind) {
 
   LOG("native method checkStatus started\n");
 
-  if (tested_thread_thr1 == NULL) {
+  if (tested_thread_thr1 == nullptr) {
     LOG("Missing thread \"tested_thread_thr1\" start event\n");
     return JNI_FALSE;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat02/libthrstat02.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat02/libthrstat02.cpp
index 0de51f8e5cf..588b2268f6d 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat02/libthrstat02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat02/libthrstat02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -30,9 +30,9 @@ extern "C" {
 
 #define WAIT_START 100
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jrawMonitorID access_lock, wait_lock;
-static jthread thr_ptr = NULL;
+static jthread thr_ptr = nullptr;
 static jint wait_time = 0;
 static jint state[] = {
     JVMTI_THREAD_STATE_RUNNABLE,
@@ -55,7 +55,7 @@ void printStateFlags(jint flags) {
 
 void JNICALL
 VMInit(jvmtiEnv *jvmti_env, JNIEnv *jni, jthread thr) {
-  jvmtiError err = jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, NULL);
+  jvmtiError err = jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, nullptr);
   check_jvmti_status(jni, err, "Failed to enable THREAD_START event");
 }
 
@@ -63,7 +63,7 @@ void JNICALL
 ThreadStart(jvmtiEnv *jvmti_env, JNIEnv *jni, jthread thread) {
   RawMonitorLocker rml = RawMonitorLocker(jvmti, jni, access_lock);
   jvmtiThreadInfo thread_info = get_thread_info(jvmti_env, jni, thread);
-  if (thread_info.name != NULL && strcmp(thread_info.name, "tested_thread_thr1") == 0) {
+  if (thread_info.name != nullptr && strcmp(thread_info.name, "tested_thread_thr1") == 0) {
     thr_ptr = jni->NewGlobalRef(thread);
     LOG(">>> ThreadStart: \"%s\", 0x%p\n", thread_info.name, thr_ptr);
   }
@@ -77,7 +77,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jvmtiError err;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -103,7 +103,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Failed to enable VM_INIT event: %s (%d)\n", TranslateError(err), err);
     return JNI_ERR;
@@ -135,12 +135,12 @@ Java_thrstat02_checkStatus0(JNIEnv *jni, jclass cls, jint statInd, jboolean susp
   jboolean timeout_is_reached;
   unsigned int waited_millis;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return JNI_FALSE;
   }
 
-  if (thr_ptr == NULL) {
+  if (thr_ptr == nullptr) {
     LOG("Missing thread \"tested_thread_thr1\" start event\n");
     return JNI_FALSE;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat03/libthrstat03.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat03/libthrstat03.cpp
index 632d4136e35..36a632ff32c 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat03/libthrstat03.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat03/libthrstat03.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -30,7 +30,7 @@ extern "C" {
 
 #define WAIT_START 100
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint wait_time = 0;
 static jint state[] = {
     0,                               /*  JVMTI_THREAD_STATUS_NOT_STARTED, */
@@ -46,7 +46,7 @@ Java_thrstat03_init(JNIEnv *env, jclass cls, jint waitTime) {
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -59,7 +59,7 @@ Java_thrstat03_check(JNIEnv *jni, jclass cls, jthread thread, jint statInd) {
   jrawMonitorID wait_lock;
   jint thr_state = 0;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     LOG("JVMTI client was not properly loaded!\n");
     return JNI_FALSE;
   }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat05/libthrstat05.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat05/libthrstat05.cpp
index e96dd665f59..3fd9b535de4 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat05/libthrstat05.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/GetThreadState/thrstat05/libthrstat05.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -66,7 +66,7 @@ static int g_ThreadState[] = {
         | JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT,     /* TS_RUN_WAIT_SLEEPING */
 };
 
-static jvmtiEnv *jvmti_env = NULL;
+static jvmtiEnv *jvmti_env = nullptr;
 static int g_wait_time = 1000;
 jrawMonitorID wait_lock; /* Monitor is used just for sleeping */
 
@@ -75,7 +75,7 @@ JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res = jvm->GetEnv((void **) &jvmti_env, JVMTI_VERSION_1_1);
   if (res != JNI_OK || !jvmti_env) {
-    LOG("Agent_OnLoad: Error: GetEnv returned error or NULL\n");
+    LOG("Agent_OnLoad: Error: GetEnv returned error or null\n");
     return JNI_ERR;
   }
   wait_lock = create_raw_monitor(jvmti_env, "beast");
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThread/resumethrd01/libresumethrd01.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThread/resumethrd01/libresumethrd01.cpp
index 3e07b2aee4c..d3b2f5745b5 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThread/resumethrd01/libresumethrd01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThread/resumethrd01/libresumethrd01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,11 +48,11 @@ agentProc(jvmtiEnv *jvmti, JNIEnv *jni, void *arg) {
 
   /* perform testing */
   {
-    jthread testedThread = NULL;
+    jthread testedThread = nullptr;
 
     LOG("Find thread: %s\n", THREAD_NAME);
     testedThread = find_thread_by_name(jvmti, jni, THREAD_NAME);
-    if (testedThread == NULL) {
+    if (testedThread == nullptr) {
       return;
     }
     LOG("  ... found thread: %p\n", (void *) testedThread);
@@ -100,13 +100,13 @@ agentProc(jvmtiEnv *jvmti, JNIEnv *jni, void *arg) {
 
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
-  jvmtiEnv *jvmti = NULL;
+  jvmtiEnv *jvmti = nullptr;
 
   timeout = 60 * 1000;
   LOG("Agent_OnLoad started\n");
 
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -122,7 +122,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  if (!set_agent_proc(agentProc, NULL)) {
+  if (!set_agent_proc(agentProc, nullptr)) {
     return JNI_ERR;
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThread/resumethrd02/libresumethrd02.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThread/resumethrd02/libresumethrd02.cpp
index c9de5e4ee0d..665c1a4da93 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThread/resumethrd02/libresumethrd02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThread/resumethrd02/libresumethrd02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -43,7 +43,7 @@ static jvmtiEvent eventsList[EVENTS_COUNT] = {
 };
 
 static volatile int eventsReceived = 0;
-static jthread testedThread = NULL;
+static jthread testedThread = nullptr;
 
 /* ============================================================================= */
 
@@ -59,14 +59,14 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
   {
     LOG("Find thread: %s\n", THREAD_NAME);
     testedThread = find_thread_by_name(jvmti, jni,THREAD_NAME);
-    if (testedThread == NULL) {
+    if (testedThread == nullptr) {
       return;
     }
     LOG("  ... found thread: %p\n", (void*)testedThread);
 
     eventsReceived = 0;
     LOG("Enable event: %s\n", "THREAD_END");
-    enable_events_notifications(jvmti, jni, JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL);
+    enable_events_notifications(jvmti, jni, JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr);
 
     LOG("Suspend thread: %p\n", (void*)testedThread);
     jvmtiError err = jvmti->SuspendThread(testedThread);
@@ -102,7 +102,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     LOG("Disable event: %s\n", "THREAD_END");
-    enable_events_notifications(jvmti, jni,JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL);
+    enable_events_notifications(jvmti, jni,JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr);
 
     LOG("Wait for thread to finish\n");
     if (!agent_wait_for_sync(timeout))
@@ -123,7 +123,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 JNIEXPORT void JNICALL
 callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
   /* check if event is for tested thread */
-  if (thread != NULL && jni->IsSameObject(testedThread, thread)) {
+  if (thread != nullptr && jni->IsSameObject(testedThread, thread)) {
     LOG("  ... received THREAD_END event for tested thread: %p\n", (void*)thread);
     eventsReceived++;
   } else {
@@ -136,12 +136,12 @@ callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
 /** Agent library initialization. */
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
-  jvmtiEnv* jvmti = NULL;
+  jvmtiEnv* jvmti = nullptr;
 
   timeout =  60 * 1000;
 
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -173,7 +173,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   }
 
   /* register agent proc and arg */
-  if (!set_agent_proc(agentProc, NULL)) {
+  if (!set_agent_proc(agentProc, nullptr)) {
     return JNI_ERR;
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThreadList/resumethrdlst01/libresumethrdlst01.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThreadList/resumethrdlst01/libresumethrdlst01.cpp
index 5784ae79978..42c4a4579fe 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThreadList/resumethrdlst01/libresumethrdlst01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThreadList/resumethrdlst01/libresumethrdlst01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,8 +52,8 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
   /* perform testing */
   {
-    jthread* threads = NULL;
-    jvmtiError* results = NULL;
+    jthread* threads = nullptr;
+    jvmtiError* results = nullptr;
 
     LOG("Allocate threads array: %d threads\n", THREADS_COUNT);
     check_jvmti_status(jni, jvmti->Allocate((THREADS_COUNT * sizeof(jthread)), (unsigned char**)&threads), "");
@@ -123,7 +123,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     LOG("Delete threads references\n");
     for (int i = 0; i < THREADS_COUNT; i++) {
-      if (threads[i] != NULL)
+      if (threads[i] != nullptr)
         jni->DeleteGlobalRef(threads[i]);
     }
 
@@ -143,13 +143,13 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 static int find_threads_by_name(jvmtiEnv* jvmti, JNIEnv* jni,
                             const char name[], int foundCount, jthread foundThreads[]) {
   jint count = 0;
-  jthread* threads = NULL;
+  jthread* threads = nullptr;
 
   size_t len = strlen(name);
   int found = 0;
 
   for (int i = 0; i < foundCount; i++) {
-    foundThreads[i] = NULL;
+    foundThreads[i] = nullptr;
   }
 
   check_jvmti_status(jni, jvmti->GetAllThreads(&count, &threads), "Error in GetAllThreads");
@@ -159,7 +159,7 @@ static int find_threads_by_name(jvmtiEnv* jvmti, JNIEnv* jni,
     jvmtiThreadInfo info;
     check_jvmti_status(jni, jvmti->GetThreadInfo(threads[i], &info), "");
 
-    if (info.name != NULL && strncmp(name, info.name, len) == 0) {
+    if (info.name != nullptr && strncmp(name, info.name, len) == 0) {
       LOG("  ... found thread #%d: %p (%s)\n", found, threads[i], info.name);
       if (found < foundCount)
         foundThreads[found] = threads[i];
@@ -182,7 +182,7 @@ static int find_threads_by_name(jvmtiEnv* jvmti, JNIEnv* jni,
   LOG("Make global references for threads: %d threads\n", foundCount);
   for (int i = 0; i < foundCount; i++) {
     foundThreads[i] = (jthread) jni->NewGlobalRef(foundThreads[i]);
-    if ( foundThreads[i] == NULL) {
+    if ( foundThreads[i] == nullptr) {
       set_agent_fail_status();
       return JNI_FALSE;
     }
@@ -194,12 +194,12 @@ static int find_threads_by_name(jvmtiEnv* jvmti, JNIEnv* jni,
 
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
-  jvmtiEnv* jvmti = NULL;
+  jvmtiEnv* jvmti = nullptr;
 
   timeout =  60 * 1000;
 
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -219,7 +219,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   }
 
   /* register agent proc and arg */
-  if (!set_agent_proc(agentProc, NULL)) {
+  if (!set_agent_proc(agentProc, nullptr)) {
     return JNI_ERR;
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThreadList/resumethrdlst02/libresumethrdlst02.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThreadList/resumethrdlst02/libresumethrdlst02.cpp
index 8345a56d352..5d622b926db 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThreadList/resumethrdlst02/libresumethrdlst02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/ResumeThreadList/resumethrdlst02/libresumethrdlst02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -47,7 +47,7 @@ static jvmtiEvent eventsList[EVENTS_COUNT] = {
 };
 
 static const int THREADS_COUNT = 10;
-static jthread* threads = NULL;
+static jthread* threads = nullptr;
 
 static volatile int eventsReceived = 0;
 static jrawMonitorID eventsReceivedMtx = 0;
@@ -65,7 +65,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
   /* perform testing */
   {
-    jvmtiError* results = NULL;
+    jvmtiError* results = nullptr;
     LOG("Allocate threads array: %d threads\n", THREADS_COUNT);
     check_jvmti_status(jni, jvmti->Allocate((THREADS_COUNT * sizeof(jthread)),
                                             (unsigned char**)&threads), "");
@@ -98,7 +98,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     eventsReceived = 0;
     LOG("Enable event: %s\n", "THREAD_END");
-    enable_events_notifications(jvmti, jni,JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL);
+    enable_events_notifications(jvmti, jni,JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr);
 
     LOG("Let threads to run and finish\n");
     if (!agent_resume_sync())
@@ -136,7 +136,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     LOG("Disable event: %s\n", "THREAD_END");
-    enable_events_notifications(jvmti, jni, JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL);
+    enable_events_notifications(jvmti, jni, JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr);
 
     LOG("Wait for thread to finish\n");
     if (!agent_wait_for_sync(timeout))
@@ -144,7 +144,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     LOG("Delete threads references\n");
     for (int i = 0; i < THREADS_COUNT; i++) {
-      if (threads[i] != NULL)
+      if (threads[i] != nullptr)
         jni->DeleteGlobalRef(threads[i]);
     }
 
@@ -164,13 +164,13 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 static int find_threads_by_name(jvmtiEnv* jvmti, JNIEnv* jni,
                             const char name[], int foundCount, jthread foundThreads[]) {
   jint count = 0;
-  jthread* threads = NULL;
+  jthread* threads = nullptr;
 
   size_t len = strlen(name);
   int found = 0;
 
   for (int i = 0; i < foundCount; i++) {
-    foundThreads[i] = NULL;
+    foundThreads[i] = nullptr;
   }
 
   check_jvmti_status(jni, jvmti->GetAllThreads(&count, &threads), "Error in GetAllThreads");
@@ -180,7 +180,7 @@ static int find_threads_by_name(jvmtiEnv* jvmti, JNIEnv* jni,
     jvmtiThreadInfo info;
 
     check_jvmti_status(jni, jvmti->GetThreadInfo(threads[i], &info), "");
-    if (info.name != NULL && strncmp(name, info.name, len) == 0) {
+    if (info.name != nullptr && strncmp(name, info.name, len) == 0) {
       LOG("  ... found thread #%d: %p (%s)\n", found, threads[i], info.name);
       if (found < foundCount)
         foundThreads[found] = threads[i];
@@ -203,7 +203,7 @@ static int find_threads_by_name(jvmtiEnv* jvmti, JNIEnv* jni,
   LOG("Make global references for threads: %d threads\n", foundCount);
   for (int i = 0; i < foundCount; i++) {
     foundThreads[i] = (jthread) jni->NewGlobalRef(foundThreads[i]);
-    if ( foundThreads[i] == NULL) {
+    if ( foundThreads[i] == nullptr) {
       set_agent_fail_status();
       return JNI_FALSE;
     }
@@ -221,7 +221,7 @@ callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
 
   /* check if event is for tested thread */
   for (int i = 0; i < THREADS_COUNT; i++) {
-    if (thread != NULL && jni->IsSameObject(threads[i], thread)) {
+    if (thread != nullptr && jni->IsSameObject(threads[i], thread)) {
       LOG("  ... received THREAD_END event for thread #%d: %p\n", i, (void*)thread);
       eventsReceived++;
       jvmti->RawMonitorExit(eventsReceivedMtx);
@@ -234,12 +234,12 @@ callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
 
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
-  jvmtiEnv* jvmti = NULL;
+  jvmtiEnv* jvmti = nullptr;
 
   timeout =  60 * 1000;
 
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -273,7 +273,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   }
 
   /* register agent proc and arg */
-  if (!set_agent_proc(agentProc, NULL)) {
+  if (!set_agent_proc(agentProc, nullptr)) {
     return JNI_ERR;
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThread/suspendthrd01/libsuspendthrd01.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThread/suspendthrd01/libsuspendthrd01.cpp
index 0df18a09f2d..300a479d4ce 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThread/suspendthrd01/libsuspendthrd01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThread/suspendthrd01/libsuspendthrd01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -50,7 +50,7 @@ agentProc(jvmtiEnv *jvmti, JNIEnv *jni, void *arg) {
   {
     LOG("Find thread: %s\n", THREAD_NAME);
     jthread tested_thread = find_thread_by_name(jvmti, jni, THREAD_NAME);
-    if (tested_thread == NULL) {
+    if (tested_thread == nullptr) {
       return;
     }
     LOG("  ... found thread: %p\n", (void *) tested_thread);
@@ -97,12 +97,12 @@ agentProc(jvmtiEnv *jvmti, JNIEnv *jni, void *arg) {
 
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
-  jvmtiEnv *jvmti = NULL;
+  jvmtiEnv *jvmti = nullptr;
 
   timeout = 60 * 1000;
 
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -122,7 +122,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   }
 
   /* register agent proc and arg */
-  if (!set_agent_proc(agentProc, NULL)) {
+  if (!set_agent_proc(agentProc, nullptr)) {
     return JNI_ERR;
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThread/suspendthrd02/libsuspendthrd02.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThread/suspendthrd02/libsuspendthrd02.cpp
index 9f3e59e6a88..9ab8e053a51 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThread/suspendthrd02/libsuspendthrd02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThread/suspendthrd02/libsuspendthrd02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -46,7 +46,7 @@ static jvmtiEvent eventsList[EVENTS_COUNT] = {
 };
 
 static volatile int eventsReceived = 0;
-static jthread testedThread = NULL;
+static jthread testedThread = nullptr;
 
 /** Agent algorithm. */
 static void JNICALL
@@ -61,14 +61,14 @@ agentProc(jvmtiEnv *jvmti, JNIEnv *jni, void *arg) {
   {
     LOG("Find thread: %s\n", THREAD_NAME);
     testedThread = find_thread_by_name(jvmti, jni, THREAD_NAME);
-    if (testedThread == NULL) {
+    if (testedThread == nullptr) {
       return;
     }
     LOG("  ... found thread: %p\n", (void *) testedThread);
 
     eventsReceived = 0;
     LOG("Enable event: %s\n", "THREAD_END");
-    enable_events_notifications(jvmti, jni, JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL);
+    enable_events_notifications(jvmti, jni, JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr);
 
     LOG("Suspend thread: %p\n", (void *) testedThread);
     err = jvmti->SuspendThread(testedThread);
@@ -96,7 +96,7 @@ agentProc(jvmtiEnv *jvmti, JNIEnv *jni, void *arg) {
     }
 
     LOG("Disable event: %s\n", "THREAD_END");
-    enable_events_notifications(jvmti, jni, JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL);
+    enable_events_notifications(jvmti, jni, JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr);
 
     LOG("Resume thread: %p\n", (void *) testedThread);
     err = jvmti->ResumeThread(testedThread);
@@ -122,7 +122,7 @@ agentProc(jvmtiEnv *jvmti, JNIEnv *jni, void *arg) {
 JNIEXPORT void JNICALL
 callbackThreadEnd(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread) {
   /* check if event is for tested thread */
-  if (thread != NULL && jni->IsSameObject(testedThread, thread)) {
+  if (thread != nullptr && jni->IsSameObject(testedThread, thread)) {
     LOG("  ... received THREAD_END event for tested thread: %p\n", (void *) thread);
     eventsReceived++;
   } else {
@@ -132,12 +132,12 @@ callbackThreadEnd(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread) {
 
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
-  jvmtiEnv *jvmti = NULL;
+  jvmtiEnv *jvmti = nullptr;
 
   timeout = 60 * 1000;
 
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -168,7 +168,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
   /* register agent proc and arg */
-  if (!set_agent_proc(agentProc, NULL)) {
+  if (!set_agent_proc(agentProc, nullptr)) {
     return JNI_ERR;
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThreadList/suspendthrdlst01/libsuspendthrdlst01.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThreadList/suspendthrdlst01/libsuspendthrdlst01.cpp
index 19bb8e0cadb..30fb104beff 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThreadList/suspendthrdlst01/libsuspendthrdlst01.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThreadList/suspendthrdlst01/libsuspendthrdlst01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -54,8 +54,8 @@ agentProc(jvmtiEnv *jvmti, JNIEnv *jni, void *arg) {
 
   /* perform testing */
   {
-    jthread *threads = NULL;
-    jvmtiError *results = NULL;
+    jthread *threads = nullptr;
+    jvmtiError *results = nullptr;
 
     LOG("Allocate threads array: %d threads\n", THREADS_COUNT);
     check_jvmti_status(jni, jvmti->Allocate((THREADS_COUNT * sizeof(jthread)),
@@ -120,7 +120,7 @@ agentProc(jvmtiEnv *jvmti, JNIEnv *jni, void *arg) {
 
     LOG("Delete threads references\n");
     for (int i = 0; i < THREADS_COUNT; i++) {
-      if (threads[i] != NULL)
+      if (threads[i] != nullptr)
         jni->DeleteGlobalRef(threads[i]);
     }
 
@@ -141,13 +141,13 @@ agentProc(jvmtiEnv *jvmti, JNIEnv *jni, void *arg) {
 /** Find threads whose name starts with specified name prefix. */
 static int find_threads_by_name(jvmtiEnv *jvmti, JNIEnv *jni, const char *name, int found_count, jthread *found_threads) {
   jint count = 0;
-  jthread *threads = NULL;
+  jthread *threads = nullptr;
 
   size_t len = strlen(name);
   int found = 0;
 
   for (int i = 0; i < found_count; i++) {
-    found_threads[i] = NULL;
+    found_threads[i] = nullptr;
   }
 
   check_jvmti_status(jni, jvmti->GetAllThreads(&count, &threads), "Error in GetAllThreads");
@@ -158,7 +158,7 @@ static int find_threads_by_name(jvmtiEnv *jvmti, JNIEnv *jni, const char *name,
 
     check_jvmti_status(jni, jvmti->GetThreadInfo(threads[i], &info), "");
 
-    if (info.name != NULL && strncmp(name, info.name, len) == 0) {
+    if (info.name != nullptr && strncmp(name, info.name, len) == 0) {
       LOG("  ... found thread #%d: %p (%s)\n", found, threads[i], info.name);
       if (found < found_count)
         found_threads[found] = threads[i];
@@ -182,7 +182,7 @@ static int find_threads_by_name(jvmtiEnv *jvmti, JNIEnv *jni, const char *name,
   LOG("Make global references for threads: %d threads\n", found_count);
   for (int i = 0; i < found_count; i++) {
     found_threads[i] = (jthread) jni->NewGlobalRef(found_threads[i]);
-    if (found_threads[i] == NULL) {
+    if (found_threads[i] == nullptr) {
       set_agent_fail_status();
       return JNI_FALSE;
     }
@@ -194,12 +194,12 @@ static int find_threads_by_name(jvmtiEnv *jvmti, JNIEnv *jni, const char *name,
 
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
-  jvmtiEnv *jvmti = NULL;
+  jvmtiEnv *jvmti = nullptr;
 
   timeout = 60 * 1000;
 
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -216,7 +216,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
   /* register agent proc and arg */
-  if (!set_agent_proc(agentProc, NULL)) {
+  if (!set_agent_proc(agentProc, nullptr)) {
     return JNI_ERR;
   }
 
diff --git a/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThreadList/suspendthrdlst02/libsuspendthrdlst02.cpp b/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThreadList/suspendthrdlst02/libsuspendthrdlst02.cpp
index 5fb6c80af98..2ccc96c2596 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThreadList/suspendthrdlst02/libsuspendthrdlst02.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/thread/SuspendThreadList/suspendthrdlst02/libsuspendthrdlst02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,7 +49,7 @@ static jvmtiEvent eventsList[EVENTS_COUNT] = {
     JVMTI_EVENT_THREAD_END
 };
 
-static jthread* threads = NULL;
+static jthread* threads = nullptr;
 
 static volatile int eventsReceived = 0;
 
@@ -66,7 +66,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
   /* perform testing */
   {
-    jvmtiError* results = NULL;
+    jvmtiError* results = nullptr;
 
     LOG("Allocate threads array: %d threads\n", THREADS_COUNT);
     check_jvmti_status(jni, jvmti->Allocate((THREADS_COUNT * sizeof(jthread)),
@@ -100,7 +100,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     eventsReceived = 0;
     LOG("Enable event: %s\n", "THREAD_END");
-    enable_events_notifications(jvmti, jni, JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL);
+    enable_events_notifications(jvmti, jni, JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr);
 
     LOG("Let threads to run and finish\n");
     if (!agent_resume_sync())
@@ -121,7 +121,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     LOG("Disable event: %s\n", "THREAD_END");
-    enable_events_notifications(jvmti, jni,JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL);
+    enable_events_notifications(jvmti, jni,JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr);
 
     LOG("Resume threads list\n");
     err = jvmti->ResumeThreadList(THREADS_COUNT, threads, results);
@@ -137,7 +137,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     LOG("Delete threads references\n");
     for (int i = 0; i < THREADS_COUNT; i++) {
-      if (threads[i] != NULL) {
+      if (threads[i] != nullptr) {
         jni->DeleteGlobalRef(threads[i]);
       }
     }
@@ -159,12 +159,12 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 static int find_threads_by_name(jvmtiEnv* jvmti, JNIEnv* jni,
                             const char name[], int foundCount, jthread foundThreads[]) {
   jint count = 0;
-  jthread* threads = NULL;
+  jthread* threads = nullptr;
   size_t len = strlen(name);
   int found = 0;
 
   for (int i = 0; i < foundCount; i++) {
-    foundThreads[i] = NULL;
+    foundThreads[i] = nullptr;
   }
 
   check_jvmti_status(jni, jvmti->GetAllThreads(&count, &threads), "");
@@ -174,7 +174,7 @@ static int find_threads_by_name(jvmtiEnv* jvmti, JNIEnv* jni,
     jvmtiThreadInfo info;
 
     check_jvmti_status(jni, jvmti->GetThreadInfo(threads[i], &info), "");
-    if (info.name != NULL && strncmp(name, info.name, len) == 0) {
+    if (info.name != nullptr && strncmp(name, info.name, len) == 0) {
       LOG("  ... found thread #%d: %p (%s)\n", found, threads[i], info.name);
       if (found < foundCount) {
         foundThreads[found] = threads[i];
@@ -198,7 +198,7 @@ static int find_threads_by_name(jvmtiEnv* jvmti, JNIEnv* jni,
   LOG("Make global references for threads: %d threads\n", foundCount);
   for (int i = 0; i < foundCount; i++) {
     foundThreads[i] = (jthread) jni->NewGlobalRef(foundThreads[i]);
-    if (foundThreads[i] == NULL) {
+    if (foundThreads[i] == nullptr) {
       set_agent_fail_status();
       return JNI_FALSE;
     }
@@ -213,7 +213,7 @@ JNIEXPORT void JNICALL
 callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
   /* check if event is for tested thread */
   for (int i = 0; i < THREADS_COUNT; i++) {
-    if (thread != NULL && jni->IsSameObject(threads[i], thread)) {
+    if (thread != nullptr && jni->IsSameObject(threads[i], thread)) {
       LOG("  ... received THREAD_END event for thread #%d: %p\n", i, (void*)thread);
       eventsReceived++;
       return;
@@ -224,12 +224,12 @@ callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
 
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
-  jvmtiEnv* jvmti = NULL;
+  jvmtiEnv* jvmti = nullptr;
 
   timeout =  60 * 1000;
 
   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_9);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -261,7 +261,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   }
 
   /* register agent proc and arg */
-  if (!set_agent_proc(agentProc, NULL)) {
+  if (!set_agent_proc(agentProc, nullptr)) {
     return JNI_ERR;
   }
   return JNI_OK;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/BreakpointInYieldTest/libBreakpointInYieldTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/BreakpointInYieldTest/libBreakpointInYieldTest.cpp
index 01b1f2f93dc..aa9f3bbd52a 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/BreakpointInYieldTest/libBreakpointInYieldTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/BreakpointInYieldTest/libBreakpointInYieldTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,8 +27,8 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
-static jrawMonitorID event_mon = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jrawMonitorID event_mon = nullptr;
 static int method_entry_count = 0;
 static int method_exit_count = 0;
 static int breakpoint_count = 0;
@@ -63,7 +63,7 @@ set_breakpoint(JNIEnv *jni, jclass klass, const char *mname)
   jlocation location = (jlocation)0L;
   jvmtiError err;
 
-  if (method == NULL) {
+  if (method == nullptr) {
     jni->FatalError("Error in set_breakpoint: not found method");
   }
   err = jvmti->SetBreakpoint(method, location);
@@ -131,13 +131,13 @@ VirtualThreadMount(jvmtiEnv *jvmti, ...) {
   if (done) {
     return; // defence against JVMTI_ERROR_WRONG_PHASE failures
   }
-  jmethodID method = NULL;
+  jmethodID method = nullptr;
   jlocation loc = 0L;
   jvmtiError err;
 
   va_list ap;
-  JNIEnv* jni = NULL;
-  jthread thread = NULL;
+  JNIEnv* jni = nullptr;
+  jthread thread = nullptr;
 
   va_start(ap, jvmti);
   jni = va_arg(ap, JNIEnv*);
@@ -162,13 +162,13 @@ VirtualThreadUnmount(jvmtiEnv *jvmti, ...) {
   if (done) {
     return; // defence against JVMTI_ERROR_WRONG_PHASE failures
   }
-  jmethodID method = NULL;
+  jmethodID method = nullptr;
   jlocation loc = 0L;
   jvmtiError err;
 
   va_list ap;
-  JNIEnv* jni = NULL;
-  jthread thread = NULL;
+  JNIEnv* jni = nullptr;
+  jthread thread = nullptr;
 
   va_start(ap, jvmti);
   jni = va_arg(ap, JNIEnv*);
@@ -239,24 +239,24 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("error in JVMTI SetEventNotificationMode: %d\n", err);
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("error in JVMTI SetEventNotificationMode: %d\n", err);
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_MOUNT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_MOUNT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("error in JVMTI SetEventNotificationMode: %d\n", err);
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_UNMOUNT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_UNMOUNT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("error in JVMTI SetEventNotificationMode: %d\n", err);
     return JNI_ERR;
@@ -276,16 +276,16 @@ Java_BreakpointInYieldTest_enableEvents(JNIEnv *jni, jclass klass, jthread threa
 
   LOG("enableEvents: started\n");
 
-  jclass k1 = find_class(jvmti, jni, NULL, "Ljava/lang/VirtualThread;");
-  jclass k2 = find_class(jvmti, jni, NULL, "Ljdk/internal/vm/Continuation;");
-  if (k1 == NULL || k2 == NULL) {
+  jclass k1 = find_class(jvmti, jni, nullptr, "Ljava/lang/VirtualThread;");
+  jclass k2 = find_class(jvmti, jni, nullptr, "Ljdk/internal/vm/Continuation;");
+  if (k1 == nullptr || k2 == nullptr) {
     jni->FatalError("Did not find one of the classes by name: VirtualThread or Continuation");
   }
   set_breakpoint(jni, k1, "run");
   set_breakpoint(jni, k2, "yield");
 
   // Enable Breakpoint events globally
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
   check_jvmti_status(jni, err, "enableEvents: error in JVMTI SetEventNotificationMode: enable BREAKPOINT");
 
   LOG("enableEvents: finished\n");
@@ -297,19 +297,19 @@ Java_BreakpointInYieldTest_check(JNIEnv *jni, jclass cls) {
   jvmtiError err;
   done = true; // defence against JVMTI_ERROR_WRONG_PHASE failures
 
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_THREAD_START, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_THREAD_START, nullptr);
   check_jvmti_status(jni, err, "check: error in JVMTI SetEventNotificationMode: disable THREAD_START");
 
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, nullptr);
   check_jvmti_status(jni, err, "check: error in JVMTI SetEventNotificationMode: disable VIRTUAL_THREAD_START");
 
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, EXT_EVENT_VIRTUAL_THREAD_MOUNT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, EXT_EVENT_VIRTUAL_THREAD_MOUNT, nullptr);
   check_jvmti_status(jni, err, "check: error in JVMTI SetEventNotificationMode: disable VIRTUAL_THREAD_MOUNT");
 
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, EXT_EVENT_VIRTUAL_THREAD_UNMOUNT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, EXT_EVENT_VIRTUAL_THREAD_UNMOUNT, nullptr);
   check_jvmti_status(jni, err, "check: error in JVMTI SetEventNotificationMode: disable VIRTUAL_THREAD_UNMOUNT");
 
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
   check_jvmti_status(jni, err, "check: error in JVMTI SetEventNotificationMode: disable BREAKPOINT");
 
   LOG("\n");
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/ContFramePopTest/libContFramePopTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/ContFramePopTest/libContFramePopTest.cpp
index 191d47585e9..1840b6ccac7 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/ContFramePopTest/libContFramePopTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/ContFramePopTest/libContFramePopTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,9 +29,9 @@ extern "C" {
 
 #define MAX_FRAME_COUNT 20
 
-static jvmtiEnv *jvmti = NULL;
-static jthread exp_thread = NULL;
-static jrawMonitorID event_mon = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jthread exp_thread = nullptr;
+static jrawMonitorID event_mon = nullptr;
 static int method_entry_count = 0;
 static int method_exit_count = 0;
 static int frame_pop_count = 0;
@@ -40,11 +40,11 @@ static void
 print_frame_event_info(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread, jmethodID method, const char* event_name) {
   char* tname = get_thread_name(jvmti, jni, thread);
   char* cname = get_method_class_name(jvmti, jni, method);
-  char* mname = NULL;
-  char* msign = NULL;
+  char* mname = nullptr;
+  char* msign = nullptr;
   jvmtiError err;
 
-  err = jvmti->GetMethodName(method, &mname, &msign, NULL);
+  err = jvmti->GetMethodName(method, &mname, &msign, nullptr);
   check_jvmti_status(jni, err, "event handler: error in JVMTI GetMethodName call");
 
   if (strcmp(event_name, "MethodEntry") == 0) {
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/ContStackDepthTest/libContStackDepthTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/ContStackDepthTest/libContStackDepthTest.cpp
index f0b6fcaa254..9bafe3bd5d0 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/ContStackDepthTest/libContStackDepthTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/ContStackDepthTest/libContStackDepthTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,9 +28,9 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
-static jthread exp_thread = NULL;
-static jrawMonitorID event_mon = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jthread exp_thread = nullptr;
+static jrawMonitorID event_mon = nullptr;
 static int breakpoint_count = 0;
 static int frame_pop_count = 0;
 static int method_entry_count = 0;
@@ -42,11 +42,11 @@ print_frame_event_info(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread, jmethodID m
                        const char* event_name, int event_count) {
   char* tname = get_thread_name(jvmti, jni, thread);
   char* cname = get_method_class_name(jvmti, jni, method);
-  char* mname = NULL;
-  char* msign = NULL;
+  char* mname = nullptr;
+  char* msign = nullptr;
   jvmtiError err;
 
-  err = jvmti->GetMethodName(method, &mname, &msign, NULL);
+  err = jvmti->GetMethodName(method, &mname, &msign, nullptr);
   check_jvmti_status(jni, err, "event handler: error in JVMTI GetMethodName call");
 
   LOG("\n%s event #%d: thread: %s, method: %s: %s%s\n",
@@ -181,10 +181,10 @@ FramePop(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread,
   print_frame_event_info(jvmti, jni, thread, method,
                          "FramePop", ++frame_pop_count);
 
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, nullptr);
   check_jvmti_status(jni, err, "FramePop: error in JVMTI SetEventNotificationMode: disable SINGLE_STEP");
 
-  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_FRAME_POP, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_FRAME_POP, nullptr);
   check_jvmti_status(jni, err, "FramePop: error in JVMTI SetEventNotificationMode: disable FRAME_POP");
 
   deallocate(jvmti, jni, (void*)mname);
@@ -236,8 +236,8 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
 JNIEXPORT void JNICALL
 Java_ContStackDepthTest_enableEvents(JNIEnv *jni, jclass klass, jthread thread) {
   jint method_count = 0;
-  jmethodID* methods = NULL;
-  jmethodID method = NULL;
+  jmethodID* methods = nullptr;
+  jmethodID method = nullptr;
   jlocation location = (jlocation)0L;
   jvmtiError err;
 
@@ -259,7 +259,7 @@ Java_ContStackDepthTest_enableEvents(JNIEnv *jni, jclass klass, jthread thread)
     }
     deallocate(jvmti, jni, (void*)mname);
   }
-  if (method == NULL) {
+  if (method == nullptr) {
     jni->FatalError("Error in enableEvents: not found method fibTest()");
   }
 
@@ -267,7 +267,7 @@ Java_ContStackDepthTest_enableEvents(JNIEnv *jni, jclass klass, jthread thread)
   check_jvmti_status(jni, err, "enableEvents: error in JVMTI SetBreakpoint");
 
   // Enable Breakpoint events globally
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
   check_jvmti_status(jni, err, "enableEvents: error in JVMTI SetEventNotificationMode: enable BREAKPOINT");
 
   LOG("enableEvents: finished\n");
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/ContYieldBreakPointTest/libContYieldBreakPointTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/ContYieldBreakPointTest/libContYieldBreakPointTest.cpp
index b4f3da42e4a..e8ac3886461 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/ContYieldBreakPointTest/libContYieldBreakPointTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/ContYieldBreakPointTest/libContYieldBreakPointTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,9 +28,9 @@
 extern "C" {
 
 
-static jvmtiEnv *jvmti = NULL;
-static jthread exp_thread = NULL;
-static jrawMonitorID event_mon = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jthread exp_thread = nullptr;
+static jrawMonitorID event_mon = nullptr;
 static int breakpoint_count = 0;
 static int single_step_count = 0;
 
@@ -39,11 +39,11 @@ print_frame_event_info(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread, jmethodID m
                        const char* event_name, int event_count) {
   char* tname = get_thread_name(jvmti, jni, thread);
   char* cname = get_method_class_name(jvmti, jni, method);
-  char* mname = NULL;
-  char* msign = NULL;
+  char* mname = nullptr;
+  char* msign = nullptr;
   jvmtiError err;
 
-  err = jvmti->GetMethodName(method, &mname, &msign, NULL);
+  err = jvmti->GetMethodName(method, &mname, &msign, nullptr);
   check_jvmti_status(jni, err, "event handler: error in JVMTI GetMethodName call");
 
   LOG("\n%s event #%d: thread: %s, method: %s: %s%s\n",
@@ -150,8 +150,8 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
 JNIEXPORT void JNICALL
 Java_ContYieldBreakPointTest_enableEvents(JNIEnv *jni, jclass klass, jthread thread, jclass contKlass) {
   jint method_count = 0;
-  jmethodID* methods = NULL;
-  jmethodID method = NULL;
+  jmethodID* methods = nullptr;
+  jmethodID method = nullptr;
   jlocation location = (jlocation)0L;
   jvmtiError err;
 
@@ -172,7 +172,7 @@ Java_ContYieldBreakPointTest_enableEvents(JNIEnv *jni, jclass klass, jthread thr
     }
     deallocate(jvmti, jni, (void*)mname);
   }
-  if (method == NULL) {
+  if (method == nullptr) {
     jni->FatalError("Error in enableEvents: not found method fibTest()");
   }
 
@@ -180,7 +180,7 @@ Java_ContYieldBreakPointTest_enableEvents(JNIEnv *jni, jclass klass, jthread thr
   check_jvmti_status(jni, err, "enableEvents: error in JVMTI SetBreakpoint");
 
   // Enable Breakpoint events globally
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
   check_jvmti_status(jni, err, "enableEvents: error in JVMTI SetEventNotificationMode: enable BREAKPOINT");
 
   LOG("enableEvents: finished\n");
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/ContinuationTest/libContinuationTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/ContinuationTest/libContinuationTest.cpp
index c2bc14887b0..81cc1368ad8 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/ContinuationTest/libContinuationTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/ContinuationTest/libContinuationTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -30,9 +30,9 @@ extern "C" {
 #define MAX_FRAME_COUNT 20
 #define FRAMES_TO_NOTIFY_POP 7
 
-static jvmtiEnv *jvmti = NULL;
-static jthread exp_thread = NULL;
-static jrawMonitorID event_mon = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jthread exp_thread = nullptr;
+static jrawMonitorID event_mon = nullptr;
 static int method_entry_count = 0;
 static int frame_pop_count = 0;
 
@@ -40,13 +40,13 @@ static void
 print_frame_event_info(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread, jmethodID method, const char* event_name) {
   char* tname = get_thread_name(jvmti, jni, thread);
   char* cname = get_method_class_name(jvmti, jni, method);
-  char* mname = NULL;
-  char* msign = NULL;
+  char* mname = nullptr;
+  char* msign = nullptr;
   jboolean is_virtual = jni->IsVirtualThread(thread);
   const char* virt =  is_virtual ? "virtual" : "carrier";
   jvmtiError err;
 
-  err = jvmti->GetMethodName(method, &mname, &msign, NULL);
+  err = jvmti->GetMethodName(method, &mname, &msign, nullptr);
   check_jvmti_status(jni, err, "event handler: error in JVMTI GetMethodName call");
 
   if (strcmp(event_name, "MethodEntry") == 0) {
@@ -78,7 +78,7 @@ MethodEntry(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread, jmethodID method) {
     // Request FramePop notifications for all continuation frames.
     // They all are expected to be cleared as a part of yield protocol.
     for (jint depth = 0; depth < FRAMES_TO_NOTIFY_POP; depth++) {
-      jmethodID frame_method = NULL;
+      jmethodID frame_method = nullptr;
       jlocation location = 0LL;
 
       err = jvmti->NotifyFramePop(thread, depth);
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/ForceEarlyReturnTest/libForceEarlyReturnTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/ForceEarlyReturnTest/libForceEarlyReturnTest.cpp
index 86cdf781f7f..4407c5d074d 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/ForceEarlyReturnTest/libForceEarlyReturnTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/ForceEarlyReturnTest/libForceEarlyReturnTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,9 +28,9 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
-static jmethodID mid_B = NULL;
-static jrawMonitorID monitor = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jmethodID mid_B = nullptr;
+static jrawMonitorID monitor = nullptr;
 static volatile bool bp_sync_reached = false;
 
 static void JNICALL
@@ -55,7 +55,7 @@ Breakpoint(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread,
   check_jvmti_status(jni, err, "Breakpoint: Failed in JVMTI GetLocalInt");
 
   if (force_return != 0) {
-    jobject ret_obj = NULL;
+    jobject ret_obj = nullptr;
 
     err = jvmti->ClearBreakpoint(mid_B, 0);
     check_jvmti_status(jni, err, "Breakpoint: Failed in JVMTI ClearBreakpoint");
@@ -79,7 +79,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
   LOG("Agent init\n");
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Agent init: Failed in GetEnv!\n");
     return JNI_ERR;
   }
@@ -124,17 +124,17 @@ Java_ForceEarlyReturnTest_prepareAgent(JNIEnv *jni, jclass cls, jclass task_claz
 
   LOG("Main: prepareAgent started\n");
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     fatal(jni, "prepareAgent: Failed as JVMTI client was not properly loaded!\n");
   }
   mid_B = jni->GetStaticMethodID(task_clazz, "B", "(ZLjava/lang/String;)Ljava/lang/String;");
-  if (mid_B == NULL) {
+  if (mid_B == nullptr) {
     fatal(jni, "prepareAgent: Failed to find Method ID for method: TestTask.B()\n");
   }
   err = jvmti->SetBreakpoint(mid_B, 0); // location: 0
   check_jvmti_status(jni, err, "prepareAgent: Failed in JVMTI SetBreakpoint");
 
-  set_event_notification_mode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  set_event_notification_mode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
 
   LOG("Main: prepareAgent finished\n");
 }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/GetSetLocalTest/libGetSetLocalTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/GetSetLocalTest/libGetSetLocalTest.cpp
index c127e9fff9b..20b2edb1e9d 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/GetSetLocalTest/libGetSetLocalTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/GetSetLocalTest/libGetSetLocalTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -51,7 +51,7 @@ typedef struct Values {
 } Values;
 
 static const int MAX_EVENTS_TO_PROCESS = 20;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static volatile jboolean completed = JNI_FALSE;
 
 static void
@@ -60,7 +60,7 @@ set_breakpoint(JNIEnv *jni, jclass klass, const char *mname, jlocation location)
   jmethodID method = find_method(jvmti, jni, klass, mname);
   jvmtiError err;
 
-  if (method == NULL) {
+  if (method == nullptr) {
     LOG("set_breakpoint: Failed to find method %s()\n", mname);
     fatal(jni, "set_breakpoint: not found method");
   }
@@ -88,10 +88,10 @@ find_method_depth(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread, const char *mna
 
   for (int depth = 0; depth < count; depth++) {
     jmethodID method = frames[depth].method;
-    char* name = NULL;
-    char* sign = NULL;
+    char* name = nullptr;
+    char* sign = nullptr;
 
-    err = jvmti->GetMethodName(method, &name, &sign, NULL);
+    err = jvmti->GetMethodName(method, &name, &sign, nullptr);
     if (err == JVMTI_ERROR_WRONG_PHASE || err == JVMTI_ERROR_THREAD_NOT_ALIVE) {
       return -1; // VM or target thread completed its work
     }
@@ -107,15 +107,15 @@ find_method_depth(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread, const char *mna
 static void
 test_GetLocal(jvmtiEnv *jvmti, JNIEnv *jni, jthread cthread, jthread vthread,
               int depth, int frame_count, Values *exp_values) {
-  jobject msg = NULL;
-  jobject tt = NULL;
+  jobject msg = nullptr;
+  jobject tt = nullptr;
   jint ii = 0;
   jlong ll = 0L;
   jfloat ff = 0.0;
   jdouble dd = 0.0;
   jvmtiError err;
 
-  LOG("test_GetLocal: mounted: %d depth: %d fcount: %d\n", cthread != NULL, depth, frame_count);
+  LOG("test_GetLocal: mounted: %d depth: %d fcount: %d\n", cthread != nullptr, depth, frame_count);
 
   int dep = find_method_depth(jvmti, jni, vthread, "producer");
   if (dep == -1) {
@@ -126,7 +126,7 @@ test_GetLocal(jvmtiEnv *jvmti, JNIEnv *jni, jthread cthread, jthread vthread,
   }
 
   // #0: Test JVMTI GetLocalInstance function for carrier thread
-  if (cthread != NULL) {
+  if (cthread != nullptr) {
     suspend_thread(jvmti, jni, cthread);
 
     err = jvmti->GetLocalInstance(cthread, 3, &msg);
@@ -165,18 +165,18 @@ test_GetLocal(jvmtiEnv *jvmti, JNIEnv *jni, jthread cthread, jthread vthread,
                " to return JVMTI_ERROR_INVALID_SLOT or JVMTI_ERROR_TYPE_MISMATCH");
   }
 
-  // #5: Test JVMTI GetLocalObject function with NULL value_ptr
-  err = jvmti->GetLocalObject(vthread, depth, SlotString, NULL);
+  // #5: Test JVMTI GetLocalObject function with nullptr value_ptr
+  err = jvmti->GetLocalObject(vthread, depth, SlotString, nullptr);
   if (err != JVMTI_ERROR_NULL_POINTER) {
-    LOG("JVMTI GetLocalObject with NULL value_ptr returned error: %d\n", err);
-    fatal(jni, "JVMTI GetLocalObject with NULL value_ptr failed to return JVMTI_ERROR_NULL_POINTER");
+    LOG("JVMTI GetLocalObject with null value_ptr returned error: %d\n", err);
+    fatal(jni, "JVMTI GetLocalObject with null value_ptr failed to return JVMTI_ERROR_NULL_POINTER");
   }
 
   // #6: Test JVMTI GetLocal<Type> functions with a good vthread
   err = jvmti->GetLocalObject(vthread, depth, SlotString, &msg);
   check_jvmti_status(jni, err, "error in JVMTI GetLocalObject with good vthread");
 
-  const char* str = jni->GetStringUTFChars((jstring)msg, NULL);
+  const char* str = jni->GetStringUTFChars((jstring)msg, nullptr);
   LOG("    local String value at slot %d: %s\n", SlotString, str);
   const char* exp_str = "msg: ...";
   if (strncmp(str, exp_str, 5) != 0) {
@@ -189,7 +189,7 @@ test_GetLocal(jvmtiEnv *jvmti, JNIEnv *jni, jthread cthread, jthread vthread,
   check_jvmti_status(jni, err, "error in JVMTI GetLocalObject with good vthread");
 
   LOG("    local Thread value at slot %d: %p\n", SlotThread, (void*)tt);
-  if (exp_values->tt != NULL && !jni->IsSameObject(tt, exp_values->tt)) {
+  if (exp_values->tt != nullptr && !jni->IsSameObject(tt, exp_values->tt)) {
     LOG("    Failed: Expected local Thread value: %p, got: %p\n", exp_values->tt, tt);
     fatal(jni, "JVMTI GetLocalObject returned unexpected local Thread value");
   }
@@ -239,7 +239,7 @@ test_SetLocal(jvmtiEnv *jvmti, JNIEnv *jni, jthread cthread, jthread vthread,
               int depth, int frame_count, Values *values, bool at_event) {
   jvmtiError err;
 
-  LOG("test_SetLocal: mounted: %d depth: %d fcount: %d\n", cthread != NULL, depth, frame_count);
+  LOG("test_SetLocal: mounted: %d depth: %d fcount: %d\n", cthread != nullptr, depth, frame_count);
 
   // #1: Test JVMTI SetLocalObject function with negative frame depth
   err = jvmti->SetLocalObject(vthread, -1, SlotString, values->tt);
@@ -257,7 +257,7 @@ test_SetLocal(jvmtiEnv *jvmti, JNIEnv *jni, jthread cthread, jthread vthread,
 
   // #3: Test JVMTI SetLocalObject function with invalid slot -1
   err = jvmti->SetLocalObject(vthread, depth, SlotInvalid0, values->tt);
-  if (depth > 0 || cthread == NULL) {
+  if (depth > 0 || cthread == nullptr) {
     // JVMTI_ERROR_OPAQUE_FRAME can be returned for unmouted vthread or depth > 0
     if (err != JVMTI_ERROR_OPAQUE_FRAME) {
       LOG("JVMTI SetLocalObject for unmounted vthread or depth > 0 failed to return JVMTI_ERROR_OPAQUE_FRAME: %d\n", err);
@@ -271,14 +271,14 @@ test_SetLocal(jvmtiEnv *jvmti, JNIEnv *jni, jthread cthread, jthread vthread,
 
   // #4: Test JVMTI SetLocalObject function with unaligned slot 4
   err = jvmti->SetLocalObject(vthread, depth, SlotUnaligned, values->tt);
-  if (depth > 0 || cthread == NULL) {
+  if (depth > 0 || cthread == nullptr) {
     // JVMTI_ERROR_OPAQUE_FRAME can be returned for unmouted vthread or depth > 0
     if (err != JVMTI_ERROR_OPAQUE_FRAME) {
       LOG("JVMTI SetLocalObject for unmounted vthread or depth > 0 failed to return JVMTI_ERROR_OPAQUE_FRAME: %d\n", err);
       fatal(jni, "JVMTI SetLocalObject for unmounted vthread or depth > 0 failed to return JVMTI_ERROR_OPAQUE_FRAME");
     }
   }
-  else if (cthread != NULL && err != JVMTI_ERROR_INVALID_SLOT && err != JVMTI_ERROR_TYPE_MISMATCH) {
+  else if (cthread != nullptr && err != JVMTI_ERROR_INVALID_SLOT && err != JVMTI_ERROR_TYPE_MISMATCH) {
     LOG("JVMTI SetLocalObject with unaligned slot 4 returned error: %d\n", err);
     fatal(jni, "JVMTI SetLocalObject with unaligned slot 4 failed"
                " to return JVMTI_ERROR_INVALID_SLOT or JVMTI_ERROR_TYPE_MISMATCH");
@@ -286,7 +286,7 @@ test_SetLocal(jvmtiEnv *jvmti, JNIEnv *jni, jthread cthread, jthread vthread,
 
   // #6: Test JVMTI SetLocal<Type> functions with a good vthread
   err = jvmti->SetLocalObject(vthread, depth, SlotThread, values->tt);
-  if (depth > 0 || cthread == NULL) {
+  if (depth > 0 || cthread == nullptr) {
     if (err != JVMTI_ERROR_OPAQUE_FRAME) {
       LOG("JVMTI SetLocalObject for unmounted vthread or depth > 0 failed to return JVMTI_ERROR_OPAQUE_FRAME: %d\n", err);
       fatal(jni, "JVMTI SetLocalObject for unmounted vthread pr depth > 0failed to return JVMTI_ERROR_OPAQUE_FRAME");
@@ -314,8 +314,8 @@ test_SetLocal(jvmtiEnv *jvmti, JNIEnv *jni, jthread cthread, jthread vthread,
 
 static void
 test_GetSetLocal(jvmtiEnv *jvmti, JNIEnv* jni, jthread vthread, int depth, int frame_count, bool at_event) {
-  Values values0 = { NULL, NULL, 1, 2L, (jfloat)3.2F, (jdouble)4.500000047683716 };
-  Values values1 = { NULL, NULL, 2, 3L, (jfloat)4.2F, (jdouble)5.500000047683716 };
+  Values values0 = { nullptr, nullptr, 1, 2L, (jfloat)3.2F, (jdouble)4.500000047683716 };
+  Values values1 = { nullptr, nullptr, 2, 3L, (jfloat)4.2F, (jdouble)5.500000047683716 };
   jthread cthread = get_carrier_thread(jvmti, jni, vthread);
 
   values0.tt = vthread;
@@ -329,7 +329,7 @@ test_GetSetLocal(jvmtiEnv *jvmti, JNIEnv* jni, jthread vthread, int depth, int f
   if (!success) {
     goto End; // skip testing for compiled frame that can't be deoptimized
   }
-  if (depth > 0 || cthread == NULL) {
+  if (depth > 0 || cthread == nullptr) {
     // No values are expected to be set by SetLocal above as
     // unmounted virtual thread case is not supported.
     // So, we expect local values to remain the same.
@@ -368,8 +368,8 @@ Breakpoint(jvmtiEnv *jvmti, JNIEnv* jni, jthread vthread,
     test_GetSetLocal(jvmti, jni, vthread, depth, frame_count, true /* at_event */);
 
     // vthread passed to callback has to refer to current thread,
-    // so we can also test with NULL in place of vthread.
-    test_GetSetLocal(jvmti, jni, NULL, depth, frame_count, true /* at_event */);
+    // so we can also test with nullptr in place of vthread.
+    test_GetSetLocal(jvmti, jni, nullptr, depth, frame_count, true /* at_event */);
   }
   deallocate(jvmti, jni, (void*)mname);
   deallocate(jvmti, jni, (void*)tname);
@@ -439,7 +439,7 @@ Java_GetSetLocalTest_testSuspendedVirtualThreads(JNIEnv *jni, jclass klass, jthr
 
   // Test each of these cases only once: unmounted, positive depth, frame count 0.
   while (iter++ < 50 && (!seen_depth_0 || !seen_depth_positive || !seen_unmounted)) {
-    jmethodID method = NULL;
+    jmethodID method = nullptr;
     jlocation location = 0;
 
     sleep_ms(1);
@@ -460,7 +460,7 @@ Java_GetSetLocalTest_testSuspendedVirtualThreads(JNIEnv *jni, jclass klass, jthr
     }
     bool case_0 = !seen_depth_0 && depth == 0 && (int)location >= 30;
     bool case_1 = !seen_depth_positive && depth > 0 && (int)location >= 30;
-    bool case_2 = !seen_unmounted && depth >= 0 && cthread == NULL;
+    bool case_2 = !seen_unmounted && depth >= 0 && cthread == nullptr;
 
     if (case_0) {
       LOG("testSuspendedVirtualThreads: DEPTH == 0\n");
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/InterruptThreadTest/libInterruptThreadTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/InterruptThreadTest/libInterruptThreadTest.cpp
index f601aa15e3f..6be49bfb456 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/InterruptThreadTest/libInterruptThreadTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/InterruptThreadTest/libInterruptThreadTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,7 +29,7 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 static void JNICALL
 agent_proc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/MethodExitTest/libMethodExitTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/MethodExitTest/libMethodExitTest.cpp
index 9676d583206..fb6b0bab587 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/MethodExitTest/libMethodExitTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/MethodExitTest/libMethodExitTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,9 +27,9 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
-static jthread exp_thread = NULL;
-static jrawMonitorID event_mon = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jthread exp_thread = nullptr;
+static jrawMonitorID event_mon = nullptr;
 static int vthread_mounted_count = 0;
 static int vthread_unmounted_count = 0;
 static int breakpoint_count = 0;
@@ -41,9 +41,9 @@ static jboolean received_method_exit_event = JNI_FALSE;
 static jboolean passed = JNI_TRUE;
 static bool done = false;
 
-static jmethodID *test_methods = NULL;
+static jmethodID *test_methods = nullptr;
 jint test_method_count = 0;
-jclass test_class = NULL;
+jclass test_class = nullptr;
 
 static void
 print_frame_event_info(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread, jmethodID method,
@@ -79,7 +79,7 @@ set_or_clear_breakpoint(JNIEnv *jni, jboolean set, const char *methodName,
                      jclass klass, jmethodID methods[], int method_count)
 {
   jlocation location = (jlocation)0L;
-  jmethodID method = NULL;
+  jmethodID method = nullptr;
   jvmtiError err;
 
   // Find the jmethodID of the specified method
@@ -93,7 +93,7 @@ set_or_clear_breakpoint(JNIEnv *jni, jboolean set, const char *methodName,
     }
     deallocate(jvmti, jni, (void*)mname);
   }
-  if (method == NULL) {
+  if (method == nullptr) {
       LOG("setupBreakpoint: not found method %s() to %s a breakpoint\n",
              methodName, set ? "set" : "clear");
       jni->FatalError("Error in setupBreakpoint: not found method");
@@ -131,7 +131,7 @@ breakpoint_hit1(jvmtiEnv *jvmti, JNIEnv* jni,
                 jthread thread, jthread cthread,
                 jboolean is_virtual, char* mname) {
   char* tname = get_thread_name(jvmti, jni, cthread);
-  jthread vthread = NULL;
+  jthread vthread = nullptr;
   jvmtiError err;
 
   // Test GetVirtualThread for carrier thread.
@@ -161,10 +161,10 @@ breakpoint_hit1(jvmtiEnv *jvmti, JNIEnv* jni,
     LOG("GetThreadLocalStorage for carrier thread returned value %p as expected\n\n", tls_data);
   }
   {
-    jmethodID method = NULL;
+    jmethodID method = nullptr;
     jlocation loc = 0L;
-    char* mname1 = NULL;
-    char* cname1 = NULL;
+    char* mname1 = nullptr;
+    char* cname1 = nullptr;
 
     err = jvmti->GetFrameLocation(cthread, 0, &method, &loc);
     check_jvmti_status(jni, err, "Breakpoint: error in JVMTI GetFrameLocation");
@@ -252,7 +252,7 @@ breakpoint_hit3(jvmtiEnv *jvmti, JNIEnv* jni,
 
   // Disable breakpoint events.
   clear_breakpoint(jni, "brkpt", test_class, test_methods, test_method_count);
-  set_event_notification_mode(jvmti, jni, JVMTI_DISABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  set_event_notification_mode(jvmti, jni, JVMTI_DISABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
 
   // Disable METHOD_EXIT events on the vthread.
   LOG("Hit #3: Breakpoint: %s: disabling MethodExit events on virtual thread: %p\n", mname, (void*)thread);
@@ -279,7 +279,7 @@ Breakpoint(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread,
   if (done) {
     return; // avoid failures with JVMTI_ERROR_WRONG_PHASE
   }
-  jthread cthread = NULL;
+  jthread cthread = nullptr;
   char* mname = get_method_name(jvmti, jni, method);
   jboolean is_virtual = jni->IsVirtualThread(thread);
 
@@ -347,7 +347,7 @@ MethodExit(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread, jmethodID method,
   }
 
   // print_frame_event_info(jvmti, jni, thread, method, "MethodExit", method_exit_count);
-  if (strstr(mname, "brkpt") != NULL) { // event IS in the "brkpt" method
+  if (strstr(mname, "brkpt") != nullptr) { // event IS in the "brkpt" method
     LOG("Hit #%d: MethodExit #%d: method: %s on thread: %p\n",
            brkptBreakpointHit, method_exit_count, mname, (void*)thread);
     received_method_exit_event = JNI_TRUE; // set it for brkpt method only if brkptBreakpointHit > 1
@@ -433,15 +433,15 @@ VirtualThreadMount(jvmtiEnv *jvmti, ...) {
   if (done) {
     return; // avoid failures with JVMTI_ERROR_WRONG_PHASE
   }
-  jmethodID method = NULL;
+  jmethodID method = nullptr;
   jlocation loc = 0L;
-  char* mname = NULL;
-  char* cname = NULL;
+  char* mname = nullptr;
+  char* cname = nullptr;
   jvmtiError err;
 
   va_list ap;
-  JNIEnv* jni = NULL;
-  jthread thread = NULL;
+  JNIEnv* jni = nullptr;
+  jthread thread = nullptr;
 
   va_start(ap, jvmti);
   jni = va_arg(ap, JNIEnv*);
@@ -478,15 +478,15 @@ VirtualThreadUnmount(jvmtiEnv *jvmti, ...) {
   if (done) {
     return; // avoid failures with JVMTI_ERROR_WRONG_PHASE
   }
-  jmethodID method = NULL;
+  jmethodID method = nullptr;
   jlocation loc = 0L;
-  char* mname = NULL;
-  char* cname = NULL;
+  char* mname = nullptr;
+  char* cname = nullptr;
   jvmtiError err;
 
   va_list ap;
-  JNIEnv* jni = NULL;
-  jthread thread = NULL;
+  JNIEnv* jni = nullptr;
+  jthread thread = nullptr;
 
   va_start(ap, jvmti);
   jni = va_arg(ap, JNIEnv*);
@@ -562,9 +562,9 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
     LOG("Agent_OnLoad: Error in JVMTI SetEventCallbacks: %d\n", err);
     return JNI_ERR;
   }
-  set_event_notification_mode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, NULL);
-  set_event_notification_mode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, NULL);
-  set_event_notification_mode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, NULL);
+  set_event_notification_mode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, nullptr);
+  set_event_notification_mode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, nullptr);
+  set_event_notification_mode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, nullptr);
 
   event_mon = create_raw_monitor(jvmti, "Events Monitor");
 
@@ -585,7 +585,7 @@ Java_MethodExitTest_enableEvents(JNIEnv *jni, jclass klass, jthread thread, jcla
   set_breakpoint(jni, "brkpt", testKlass, test_methods, test_method_count);
 
   // Enable Breakpoint events globally
-  set_event_notification_mode(jvmti, jni, JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  set_event_notification_mode(jvmti, jni, JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
 
   LOG("enableEvents: finished\n");
 }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/NullAsCurrentThreadTest/libNullAsCurrentThreadTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/NullAsCurrentThreadTest/libNullAsCurrentThreadTest.cpp
index 140375d4cb5..82c51dfed75 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/NullAsCurrentThreadTest/libNullAsCurrentThreadTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/NullAsCurrentThreadTest/libNullAsCurrentThreadTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,7 +28,7 @@
 extern "C" {
 
 static const jint MAX_FRAME_CNT = 30;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static int vt_support_enabled = 0;
 static jboolean failed_status = JNI_FALSE;
 
@@ -49,16 +49,16 @@ checkStackTraces(jvmtiEnv* jvmti, JNIEnv* jni, jvmtiFrameInfo* frames0, jvmtiFra
   for (int idx = 0; idx < cnt; idx++) {
     jmethodID method0 = frames0[idx].method;
     jmethodID method1 = frames1[idx].method;
-    char* name0 = NULL;
-    char* name1 = NULL;
-    char* sign0 = NULL;
-    char* sign1 = NULL;
+    char* name0 = nullptr;
+    char* name1 = nullptr;
+    char* sign0 = nullptr;
+    char* sign1 = nullptr;
 
-    err = jvmti->GetMethodName(method0, &name0, &sign0, NULL);
+    err = jvmti->GetMethodName(method0, &name0, &sign0, nullptr);
     check_jvmti_status(jni, err, "GetMethodName");
 
     if (method0 != method1) {
-      err = jvmti->GetMethodName(method1, &name1, &sign1, NULL);
+      err = jvmti->GetMethodName(method1, &name1, &sign1, nullptr);
       check_jvmti_status(jni, err, "GetMethodName");
 
       failed_status = JNI_TRUE;
@@ -80,13 +80,13 @@ testGetThreadInfo(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
   jvmtiThreadInfo inf0;
   jvmtiThreadInfo inf1;
 
-  err = jvmti->GetThreadInfo(NULL, &inf0);
+  err = jvmti->GetThreadInfo(nullptr, &inf0);
   check(jni, "GetThreadInfo", err);
 
   err = jvmti->GetThreadInfo(thread, &inf1);
   check(jni, "GetThreadInfo", err);
 
-  const char* name = (inf0.name == NULL) ? "<Unnamed thread>" : inf0.name;
+  const char* name = (inf0.name == nullptr) ? "<Unnamed thread>" : inf0.name;
   LOG("Agent: GetThreadInfo: current thread: %s\n", name);
 
   if (strcmp(inf0.name, inf1.name) != 0) {
@@ -121,7 +121,7 @@ testGetThreadState(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
   jint state0 = 0;
   jint state1 = 0;
 
-  err = jvmti->GetThreadState(NULL, &state0);
+  err = jvmti->GetThreadState(nullptr, &state0);
   check_jvmti_status(jni, err, "GetThreadState");
 
   err = jvmti->GetThreadState(thread, &state1);
@@ -145,7 +145,7 @@ testGetFrameCount(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
   err = jvmti->GetFrameCount(thread, &count0);
   check_jvmti_status(jni, err,"GetFrameCount");
 
-  err = jvmti->GetFrameCount(NULL, &count1);
+  err = jvmti->GetFrameCount(nullptr, &count1);
   check_jvmti_status(jni, err,"GetFrameCount");
 
   if (count0 != count1) {
@@ -163,24 +163,24 @@ testGetFrameLocation(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
   const jint DEPTH = 1;
   jlocation loc0 = 0;
   jlocation loc1 = 0;
-  jmethodID method0 = NULL;
-  jmethodID method1 = NULL;
-  char* name0 = NULL;
-  char* name1 = NULL;
-  char* sign0 = NULL;
-  char* sign1 = NULL;
+  jmethodID method0 = nullptr;
+  jmethodID method1 = nullptr;
+  char* name0 = nullptr;
+  char* name1 = nullptr;
+  char* sign0 = nullptr;
+  char* sign1 = nullptr;
 
-  err = jvmti->GetFrameLocation(NULL, DEPTH, &method0, &loc0);
+  err = jvmti->GetFrameLocation(nullptr, DEPTH, &method0, &loc0);
   check_jvmti_status(jni, err, "GetFrameLocation");
 
   err = jvmti->GetFrameLocation(thread, DEPTH, &method1, &loc1);
   check_jvmti_status(jni, err, "GetFrameLocation");
 
-  err = jvmti->GetMethodName(method0, &name0, &sign0, NULL);
+  err = jvmti->GetMethodName(method0, &name0, &sign0, nullptr);
   check_jvmti_status(jni, err, "GetMethodName");
 
   if (method0 != method1) {
-    err = jvmti->GetMethodName(method1, &name1, &sign1, NULL);
+    err = jvmti->GetMethodName(method1, &name1, &sign1, nullptr);
     check_jvmti_status(jni, err, "GetMethodName");
 
     failed_status = JNI_TRUE;
@@ -207,7 +207,7 @@ testGetStackTrace(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
   memset(frames0, 0, sizeof(frames0));
   memset(frames1, 0, sizeof(frames1));
 
-  err = jvmti->GetStackTrace(NULL, 0, MAX_FRAME_CNT, frames0, &count0);
+  err = jvmti->GetStackTrace(nullptr, 0, MAX_FRAME_CNT, frames0, &count0);
   check_jvmti_status(jni, err, "GetStackTrace");
 
   err = jvmti->GetStackTrace(thread, 0, MAX_FRAME_CNT, frames1, &count1);
@@ -226,8 +226,8 @@ testGetOwnedMonitorInfo(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
   jvmtiError err;
   jint count0 = 0;
   jint count1 = 0;
-  jobject* monitors0 = NULL;
-  jobject* monitors1 = NULL;
+  jobject* monitors0 = nullptr;
+  jobject* monitors1 = nullptr;
 
   err = jvmti->GetOwnedMonitorInfo(thread, &count0, &monitors0);
   check_jvmti_status(jni, err, "GetOwnedMonitorInfo");
@@ -263,10 +263,10 @@ testGetOwnedMonitorStackDepthInfo(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread)
   jvmtiError err;
   jint count0 = 0;
   jint count1 = 0;
-  jvmtiMonitorStackDepthInfo* inf0 = NULL;
-  jvmtiMonitorStackDepthInfo* inf1 = NULL;
+  jvmtiMonitorStackDepthInfo* inf0 = nullptr;
+  jvmtiMonitorStackDepthInfo* inf1 = nullptr;
 
-  err = jvmti->GetOwnedMonitorStackDepthInfo(NULL, &count0, &inf0);
+  err = jvmti->GetOwnedMonitorStackDepthInfo(nullptr, &count0, &inf0);
   check_jvmti_status(jni, err, "GetOwnedMonitorStackDepthInfo");
 
   err = jvmti->GetOwnedMonitorStackDepthInfo(thread, &count1, &inf1);
@@ -302,10 +302,10 @@ testGetOwnedMonitorStackDepthInfo(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread)
 static void
 testGetCurrentContendedMonitor(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
   jvmtiError err;
-  jobject monitor0 = NULL;
-  jobject monitor1 = NULL;
+  jobject monitor0 = nullptr;
+  jobject monitor1 = nullptr;
 
-  err = jvmti->GetCurrentContendedMonitor(NULL, &monitor0);
+  err = jvmti->GetCurrentContendedMonitor(nullptr, &monitor0);
   check_jvmti_status(jni, err, "GetCurrentContendedMonitor");
 
   err = jvmti->GetCurrentContendedMonitor(thread, &monitor1);
@@ -321,17 +321,17 @@ testGetCurrentContendedMonitor(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
 }
 
 /*
- * Execute JVMTI functions with NULL jthread and check the result is correct.
+ * Execute JVMTI functions with nullptr jthread and check the result is correct.
  */
 JNIEXPORT void JNICALL
 Java_NullAsCurrentThreadTest_testJvmtiFunctions(JNIEnv *jni, jclass cls) {
   jvmtiError err;
-  jthread cur_thr = NULL;
+  jthread cur_thr = nullptr;
 
   err = jvmti->GetCurrentThread(&cur_thr);
   check(jni, "GetCurrentThread", err);
 
-  LOG("Testing JMTI functions accepting NULL jthread as current thread\n");
+  LOG("Testing JMTI functions accepting null jthread as current thread\n");
 
   testGetThreadInfo(jvmti, jni, cur_thr);
   testGetThreadState(jvmti, jni, cur_thr);
@@ -395,7 +395,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
     if (err != JVMTI_ERROR_NONE) {
       LOG("Agent_OnLoad: error in JVMTI SetEventCallbacks: %d\n", err);
     }
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_MOUNT, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_MOUNT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       LOG("Agent_OnLoad: error in JVMTI SetEventNotificationMode: %d\n", err);
     }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/PinnedTaskTest/libPinnedTaskTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/PinnedTaskTest/libPinnedTaskTest.cpp
index f7f740ae9e1..d50d1ab4b8b 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/PinnedTaskTest/libPinnedTaskTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/PinnedTaskTest/libPinnedTaskTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,7 +26,7 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 static void JNICALL
 agent_proc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/PopFrameTest/libPopFrameTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/PopFrameTest/libPopFrameTest.cpp
index 20e4b940649..327b7d1cb2a 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/PopFrameTest/libPopFrameTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/PopFrameTest/libPopFrameTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -69,7 +69,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
   LOG("Agent init\n");
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Agent init: Failed in GetEnv!\n");
     return JNI_ERR;
   }
@@ -114,19 +114,19 @@ Java_PopFrameTest_prepareAgent(JNIEnv *jni, jclass cls, jclass task_clazz, jbool
 
   LOG("Main: prepareAgent started\n");
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     fatal(jni, "prepareAgent: Failed as JVMTI client was not properly loaded!\n");
   }
   do_pop_frame = do_pop;
 
   mid_B = jni->GetStaticMethodID(task_clazz, "B", "()V");
-  if (mid_B == NULL) {
+  if (mid_B == nullptr) {
     fatal(jni, "prepareAgent: Failed to find Method ID for method: TestTask.B()\n");
   }
   err = jvmti->SetBreakpoint(mid_B, 0);
   check_jvmti_status(jni, err, "prepareAgent: Failed in JVMTI SetBreakpoint");
 
-  set_event_notification_mode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  set_event_notification_mode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
 
   LOG("Main: prepareAgent finished\n");
 }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/RawMonitorTest/libRawMonitorTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/RawMonitorTest/libRawMonitorTest.cpp
index 89015fe4bcb..1e7c49af7a9 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/RawMonitorTest/libRawMonitorTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/RawMonitorTest/libRawMonitorTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,7 +29,7 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jrawMonitorID monitor;
 
 JNIEXPORT void JNICALL
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/SelfSuspendDisablerTest/libSelfSuspendDisablerTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/SelfSuspendDisablerTest/libSelfSuspendDisablerTest.cpp
index fdb8110aa57..74a1a3efc0d 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/SelfSuspendDisablerTest/libSelfSuspendDisablerTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/SelfSuspendDisablerTest/libSelfSuspendDisablerTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,7 +25,7 @@
 #include "jvmti.h"
 #include "jvmti_common.h"
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 extern "C" {
 
@@ -50,12 +50,12 @@ Java_SelfSuspendDisablerTest_isSuspended(JNIEnv* jni, jclass cls, jthread thread
 
 JNIEXPORT void JNICALL
 Java_SelfSuspendDisablerTest_suspendAllVirtualThreads(JNIEnv* jni, jclass cls) {
-  check_jvmti_status(jni, jvmti->SuspendAllVirtualThreads(0, NULL), "Error in SuspendAllVirtualThreads");
+  check_jvmti_status(jni, jvmti->SuspendAllVirtualThreads(0, nullptr), "Error in SuspendAllVirtualThreads");
 }
 
 JNIEXPORT void JNICALL
 Java_SelfSuspendDisablerTest_resumeAllVirtualThreads(JNIEnv* jni, jclass cls) {
-  check_jvmti_status(jni, jvmti->ResumeAllVirtualThreads(0, NULL), "Error in ResumeAllVirtualThreads");
+  check_jvmti_status(jni, jvmti->ResumeAllVirtualThreads(0, nullptr), "Error in ResumeAllVirtualThreads");
 }
 
 JNIEXPORT jint JNICALL
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/StopThreadTest/libStopThreadTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/StopThreadTest/libStopThreadTest.cpp
index 9cb9bc4c5a4..ade0e7fb67c 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/StopThreadTest/libStopThreadTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/StopThreadTest/libStopThreadTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,10 +28,10 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
-static jmethodID mid_B = NULL;
-static jobject exception_obj = NULL;
-static jrawMonitorID monitor = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jmethodID mid_B = nullptr;
+static jobject exception_obj = nullptr;
+static jrawMonitorID monitor = nullptr;
 static volatile bool bp_sync_reached = false;
 
 static void JNICALL
@@ -73,7 +73,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
   LOG("Agent init\n");
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Agent init: Failed in GetEnv!\n");
     return JNI_ERR;
   }
@@ -118,21 +118,21 @@ Java_StopThreadTest_prepareAgent(JNIEnv *jni, jclass cls, jclass task_clazz, job
 
   LOG("Main: prepareAgent started\n");
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     fatal(jni, "prepareAgent: Failed as JVMTI client was not properly loaded!\n");
   }
   exception_obj = jni->NewGlobalRef(exc_obj);
-  if (exception_obj == NULL) {
+  if (exception_obj == nullptr) {
     fatal(jni, "prepareAgent: Failed in JNI NewGlobalRef\n");
   }
   mid_B = jni->GetStaticMethodID(task_clazz, "B", "()V");
-  if (mid_B == NULL) {
+  if (mid_B == nullptr) {
     fatal(jni, "prepareAgent: Failed to find Method ID for method: TestTask.B()\n");
   }
   err = jvmti->SetBreakpoint(mid_B, 0);
   check_jvmti_status(jni, err, "prepareAgent: Failed in JVMTI SetBreakpoint");
 
-  set_event_notification_mode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  set_event_notification_mode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
 
   LOG("Main: prepareAgent finished\n");
 }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResume1/libSuspendResume1.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResume1/libSuspendResume1.cpp
index 78f1922f546..9854008c142 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResume1/libSuspendResume1.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResume1/libSuspendResume1.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,8 +35,8 @@ extern "C" {
 static const char* CTHREAD_NAME_START = "ForkJoinPool";
 static const int CTHREAD_NAME_START_LEN = (int)strlen("ForkJoinPool");
 
-static jvmtiEnv *jvmti = NULL;
-static jrawMonitorID agent_event_lock = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jrawMonitorID agent_event_lock = nullptr;
 static jthread tested_vthreads[VTHREAD_CNT];
 static int vthread_no = 0;
 
@@ -48,7 +48,7 @@ test_get_stack_trace(JNIEnv *jni, jthread thread) {
 
 static void
 test_get_thread_list_stack_traces(JNIEnv *jni, bool is_virt, jint thread_cnt, jthread* thread_list) {
-  jvmtiStackInfo* stack_info_arr = NULL;
+  jvmtiStackInfo* stack_info_arr = nullptr;
 
   LOG("## Agent: test_get_thread_list_stack_traces started: is virtual: %d, count: %d\n\n",
          is_virt, thread_cnt);
@@ -70,9 +70,9 @@ static void
 test_get_frame_location(JNIEnv* jni, jthread thread, char* tname) {
   const jint DEPTH = 1;
   jlocation loc = 0;
-  jmethodID method = NULL;
-  char* name = NULL;
-  char* sign = NULL;
+  jmethodID method = nullptr;
+  char* name = nullptr;
+  char* sign = nullptr;
   jboolean is_virtual = jni->IsVirtualThread(thread);
 
   jvmtiError err = jvmti->GetFrameLocation(thread, DEPTH, &method, &loc);
@@ -84,7 +84,7 @@ test_get_frame_location(JNIEnv* jni, jthread thread, char* tname) {
     }
     return;
   }
-  err = jvmti->GetMethodName(method, &name, &sign, NULL);
+  err = jvmti->GetMethodName(method, &name, &sign, nullptr);
   check_jvmti_status(jni, err, "test_get_frame_location: error in JVMTI GetMethodName");
 
   LOG("Agent: GetFrameLocation: frame for current thread %s: method: %s%s, loc: %lld\n",
@@ -93,7 +93,7 @@ test_get_frame_location(JNIEnv* jni, jthread thread, char* tname) {
 
 static jint
 get_cthreads(JNIEnv* jni, jthread** cthreads_p) {
-  jthread* tested_cthreads = NULL;
+  jthread* tested_cthreads = nullptr;
   jint all_cnt = 0;
   jint ct_cnt = 0;
 
@@ -313,7 +313,7 @@ test_jvmti_functions_for_threads(JNIEnv* jni, bool is_virt, jint thread_cnt, jth
 
 JNIEXPORT void JNICALL
 Java_SuspendResume1_TestSuspendResume(JNIEnv* jni, jclass cls) {
-  jthread* tested_cthreads = NULL;
+  jthread* tested_cthreads = nullptr;
   jint cthread_cnt = 0;
 
   LOG("\n## TestSuspendResume: Test carrier threads\n");
@@ -395,7 +395,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   }
 
   err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                                        JVMTI_EVENT_VIRTUAL_THREAD_START, NULL);
+                                        JVMTI_EVENT_VIRTUAL_THREAD_START, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Agent init: error in JVMTI SetEventNotificationMode: %s (%d)\n",
            TranslateError(err), err);
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResume2/libSuspendResume2.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResume2/libSuspendResume2.cpp
index 56faa994be5..97cae4f0f0c 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResume2/libSuspendResume2.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResume2/libSuspendResume2.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,16 +35,16 @@ extern "C" {
 static const char* CTHREAD_NAME_START = "ForkJoinPool";
 static const int CTHREAD_NAME_START_LEN = (int)strlen("ForkJoinPool");
 
-static jvmtiEnv *jvmti = NULL;
-static jrawMonitorID agent_event_lock = NULL;
-static volatile jthread agent_thread = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jrawMonitorID agent_event_lock = nullptr;
+static volatile jthread agent_thread = nullptr;
 static jthread tested_vthreads[VTHREAD_CNT];
 static int vthread_no = 0;
 
 
 static jint
 get_cthreads(JNIEnv* jni, jthread** cthreads_p) {
-  jthread* tested_cthreads = NULL;
+  jthread* tested_cthreads = nullptr;
   jint all_cnt = 0;
   jint ct_cnt = 0;
 
@@ -106,7 +106,7 @@ test_vthread_suspend_all(JNIEnv* jni, const jthread* thread_list, int suspend_ma
   LOG("\n## Agent: test_vthread_suspend_all started\n");
 
   const jint EXCLUDE_CNT = 2;
-  jthread exclude_list[EXCLUDE_CNT] = { NULL, NULL };
+  jthread exclude_list[EXCLUDE_CNT] = { nullptr, nullptr };
   for (int idx = 0; idx < EXCLUDE_CNT; idx++) {
     exclude_list[idx] = thread_list[idx];
   }
@@ -138,7 +138,7 @@ test_vthread_resume_all(JNIEnv* jni, const jthread* thread_list, int suspend_mas
   LOG("\n## Agent: test_vthread_resume_all started\n");
 
   const jint EXCLUDE_CNT = 2;
-  jthread exclude_list[EXCLUDE_CNT] = { NULL, NULL };
+  jthread exclude_list[EXCLUDE_CNT] = { nullptr, nullptr };
   for (int idx = 0; idx < EXCLUDE_CNT; idx++) {
     exclude_list[idx] = thread_list[idx];
   }
@@ -224,7 +224,7 @@ check_threads_resumed_state(JNIEnv* jni, const jthread* thread_list, int thread_
 
 JNIEXPORT void JNICALL
 Java_SuspendResume2_TestSuspendResume(JNIEnv* jni, jclass cls) {
-  jthread* tested_cthreads = NULL;
+  jthread* tested_cthreads = nullptr;
 
   LOG("\n## TestSuspendResume: started\n");
 
@@ -310,7 +310,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   }
 
   err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                                        JVMTI_EVENT_VIRTUAL_THREAD_START, NULL);
+                                        JVMTI_EVENT_VIRTUAL_THREAD_START, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Agent init: error in JVMTI SetEventNotificationMode: %s (%d)\n",
            TranslateError(err), err);
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResumeAll/libSuspendResumeAll.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResumeAll/libSuspendResumeAll.cpp
index 7270d237d74..4aef71c8737 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResumeAll/libSuspendResumeAll.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendResumeAll/libSuspendResumeAll.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,21 +35,21 @@ extern "C" {
 static const char* CTHREAD_NAME_START = "ForkJoinPool";
 static const int CTHREAD_NAME_START_LEN = (int)strlen("ForkJoinPool");
 
-static jvmtiEnv *jvmti = NULL;
-static jrawMonitorID agent_event_lock = NULL;
-static volatile jthread agent_thread = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jrawMonitorID agent_event_lock = nullptr;
+static volatile jthread agent_thread = nullptr;
 static jthread tested_vthreads[VTHREAD_CNT];
 static int vthread_no = 0;
 
-static jmethodID *test_methods = NULL;
+static jmethodID *test_methods = nullptr;
 jint test_method_count = 0;
-jclass test_class = NULL;
+jclass test_class = nullptr;
 
 static void
 set_or_clear_breakpoint(JNIEnv *jni, jboolean set, const char *methodName,
                      jclass klass, jmethodID methods[], int method_count) {
   jlocation location = (jlocation)0L;
-  jmethodID method = NULL;
+  jmethodID method = nullptr;
   jvmtiError err;
 
   // Find the jmethodID of the specified method
@@ -63,7 +63,7 @@ set_or_clear_breakpoint(JNIEnv *jni, jboolean set, const char *methodName,
     }
     deallocate(jvmti, jni, (void*)mname);
   }
-  if (method == NULL) {
+  if (method == nullptr) {
      LOG("setupBreakpoint: not found method %s() to %s a breakpoint\n",
              methodName, set ? "set" : "clear");
       jni->FatalError("Error in setupBreakpoint: not found method");
@@ -109,7 +109,7 @@ Java_SuspendResumeAll_setBreakpoint(JNIEnv *jni, jclass klass, jclass testKlass)
 
 static jint
 get_cthreads(JNIEnv* jni, jthread** cthreads_p) {
-  jthread* tested_cthreads = NULL;
+  jthread* tested_cthreads = nullptr;
   jint all_cnt = 0;
   jint ct_cnt = 0;
 
@@ -171,7 +171,7 @@ test_vthread_suspend_all(JNIEnv* jni, const jthread* thread_list, int suspend_ma
   LOG("\n## Agent: test_vthread_suspend_all started\n");
 
   const jint EXCLUDE_CNT = 2;
-  jthread exclude_list[EXCLUDE_CNT] = { NULL, NULL };
+  jthread exclude_list[EXCLUDE_CNT] = { nullptr, nullptr };
   for (int idx = 0; idx < EXCLUDE_CNT; idx++) {
     exclude_list[idx] = thread_list[idx];
   }
@@ -204,7 +204,7 @@ test_vthread_resume_all(JNIEnv* jni, const jthread* thread_list, int suspend_mas
   LOG("\n## Agent: test_vthread_resume_all started\n");
 
   const jint EXCLUDE_CNT = 2;
-  jthread exclude_list[EXCLUDE_CNT] = { NULL, NULL };
+  jthread exclude_list[EXCLUDE_CNT] = { nullptr, nullptr };
   for (int idx = 0; idx < EXCLUDE_CNT; idx++) {
     exclude_list[idx] = thread_list[idx];
     // Enable Breakpoint events on excluded thread
@@ -264,7 +264,7 @@ check_threads_resumed_state(JNIEnv* jni, const jthread* thread_list, int thread_
 
 JNIEXPORT void JNICALL
 Java_SuspendResumeAll_TestSuspendResume(JNIEnv* jni, jclass cls) {
-  jthread* tested_cthreads = NULL;
+  jthread* tested_cthreads = nullptr;
   jint cthread_cnt = get_cthreads(jni, &tested_cthreads);
 
   LOG("\n## TestSuspendResume: started\n");
@@ -368,7 +368,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   }
 
   err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                                        JVMTI_EVENT_VIRTUAL_THREAD_START, NULL);
+                                        JVMTI_EVENT_VIRTUAL_THREAD_START, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("Agent init: error in JVMTI SetEventNotificationMode: %s (%d)\n",
            TranslateError(err), err);
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/ThreadListStackTracesTest/libThreadListStackTracesTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/ThreadListStackTracesTest/libThreadListStackTracesTest.cpp
index 7441343ac40..3edb2871cc2 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/ThreadListStackTracesTest/libThreadListStackTracesTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/ThreadListStackTracesTest/libThreadListStackTracesTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 
 JNIEXPORT jint JNICALL
 Java_ThreadListStackTracesTest_getStateSingle(JNIEnv* jni, jclass clazz, jthread vthread) {
-  jvmtiStackInfo* info = NULL;
+  jvmtiStackInfo* info = nullptr;
 
   jvmtiError err = jvmti->GetThreadListStackTraces(1, &vthread, MAX_FRAME_COUNT, &info);
   check_jvmti_status(jni, err, "getStateSingle: error in JVMTI GetThreadListStackTraces");
@@ -45,7 +45,7 @@ Java_ThreadListStackTracesTest_getStateSingle(JNIEnv* jni, jclass clazz, jthread
 JNIEXPORT jint JNICALL
 Java_ThreadListStackTracesTest_getStateMultiple(JNIEnv* jni, jclass clazz, jthread vhread, jthread other) {
   jthread threads[2] = { vhread, other };
-  jvmtiStackInfo* info = NULL;
+  jvmtiStackInfo* info = nullptr;
 
   jvmtiError err = jvmti->GetThreadListStackTraces(2, threads, MAX_FRAME_COUNT, &info);
   check_jvmti_status(jni, err, "getStateMultiple: error in JVMTI GetThreadListStackTraces");
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/ThreadStateTest/libThreadStateTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/ThreadStateTest/libThreadStateTest.cpp
index 895a2ba198e..c07b0924cfe 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/ThreadStateTest/libThreadStateTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/ThreadStateTest/libThreadStateTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -87,7 +87,7 @@ JNIEXPORT void JNICALL
 Java_ThreadStateTest_testGetThreadListStackTraces(JNIEnv* jni, jclass klass, jthread vthread) {
   jthread cthread = get_carrier_thread(jvmti, jni, vthread);
   jthread threads[2] = { cthread, vthread };
-  jvmtiStackInfo* stackInfo = NULL;
+  jvmtiStackInfo* stackInfo = nullptr;
 
   jvmtiError err = jvmti->GetThreadListStackTraces(2, threads, MAX_FRAME_COUNT, &stackInfo);
   check_jvmti_status(jni, err, "testGetThreadState: error in JVMTI GetThreadListStackTraces");
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/ToggleNotifyJvmtiTest/libToggleNotifyJvmtiTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/ToggleNotifyJvmtiTest/libToggleNotifyJvmtiTest.cpp
index 1cf4a06592c..9ecece684ab 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/ToggleNotifyJvmtiTest/libToggleNotifyJvmtiTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/ToggleNotifyJvmtiTest/libToggleNotifyJvmtiTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,13 +34,13 @@ static volatile int vthread_ended_cnt = 0;
 static volatile int thread_started_cnt = 0;
 static volatile int thread_ended_cnt = 0;
 
-static jrawMonitorID agent_lock = NULL;
+static jrawMonitorID agent_lock = nullptr;
 static volatile jboolean agent_started = JNI_FALSE;
 
 static void check_and_print_thread_names(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread,
                                          bool is_virtual, const char* msg) {
-  jthread cthread = NULL;
-  jthread vthread = NULL;
+  jthread cthread = nullptr;
+  jthread vthread = nullptr;
 
   if (is_virtual) {
     vthread = thread;
@@ -52,7 +52,7 @@ static void check_and_print_thread_names(jvmtiEnv *jvmti, JNIEnv* jni, jthread t
     cthread = thread;
   }
   char* ctname = get_thread_name(jvmti, jni, cthread);
-  char* vtname = vthread == NULL ? NULL : get_thread_name(jvmti, jni, vthread);
+  char* vtname = vthread == nullptr ? nullptr : get_thread_name(jvmti, jni, vthread);
 
   LOG("Event: %s virtual: %d ct: %s vt: %s\n", msg, is_virtual, ctname, vtname);
 
@@ -158,22 +158,22 @@ jint agent_init(JavaVM *jvm, char *options, void *reserved) {
       LOG("Agent init: error in JVMTI AddCapabilities: %s (%d)\n", TranslateError(err), err);
       return JNI_ERR;
     }
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       LOG("Agent init: error in JVMTI SetEventNotificationMode: %s (%d)\n", TranslateError(err), err);
       return JNI_ERR;
     }
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_END, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_END, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       LOG("Agent init: error in JVMTI SetEventNotificationMode: %s (%d)\n", TranslateError(err), err);
       return JNI_ERR;
     }
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       LOG("Agent init: error in JVMTI SetEventNotificationMode: %s (%d)\n", TranslateError(err), err);
       return JNI_ERR;
     }
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_END, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_END, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       LOG("Agent init: error in JVMTI SetEventNotificationMode: %s (%d)\n", TranslateError(err), err);
       return JNI_ERR;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadMonitorTest/libVThreadMonitorTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadMonitorTest/libVThreadMonitorTest.cpp
index 72be78078bb..c05404658fe 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadMonitorTest/libVThreadMonitorTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadMonitorTest/libVThreadMonitorTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,13 +35,13 @@ extern "C" {
 #define TEST_CLASS_0 "MonitorClass0"
 #define TEST_CLASS_2 "MonitorClass2"
 
-static jvmtiEnv *jvmti = NULL;
-static jrawMonitorID agent_monitor = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jrawMonitorID agent_monitor = nullptr;
 static volatile bool was_lock0_contended = false;
 static volatile bool was_lock2_contended = false;
 static volatile jint status = STATUS_PASSED;
-static volatile jclass test_class_0 = NULL;
-static volatile jclass test_class_2 = NULL;
+static volatile jclass test_class_0 = nullptr;
+static volatile jclass test_class_2 = nullptr;
 
 static jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved);
 
@@ -60,7 +60,7 @@ static void ShowErrorMessage(jvmtiEnv *jvmti, jvmtiError errCode,
 }
 
 static jboolean CheckLockObject0(JNIEnv *jni, jobject monitor) {
-  if (test_class_0 == NULL) {
+  if (test_class_0 == nullptr) {
     // JNI_OnLoad has not been called yet, so can't possibly be an instance of TEST_CLASS_0.
     return JNI_FALSE;
   }
@@ -68,7 +68,7 @@ static jboolean CheckLockObject0(JNIEnv *jni, jobject monitor) {
 }
 
 static jboolean CheckLockObject2(JNIEnv *jni, jobject monitor) {
-  if (test_class_2 == NULL) {
+  if (test_class_2 == nullptr) {
     // JNI_OnLoad has not been called yet, so can't possibly be an instance of TEST_CLASS_2.
     return JNI_FALSE;
   }
@@ -98,7 +98,7 @@ check_contended_monitor(jvmtiEnv *jvmti, JNIEnv *jni, const char* func,
       jni->IsSameObject(monitor2, contended_monitor) == JNI_FALSE) {
     LOG("FAIL: is_vt: %d: unexpected monitor from GetCurrentContendedMonitor\n", is_vt);
     LOG("stack trace of current thread:\n");
-    print_stack_trace(jvmti, jni, NULL);
+    print_stack_trace(jvmti, jni, nullptr);
     LOG("stack trace of target thread:\n");
     print_stack_trace(jvmti, jni, thread);
     status = STATUS_FAILED;
@@ -123,7 +123,7 @@ check_owned_monitor(jvmtiEnv *jvmti, JNIEnv *jni, const char* func,
   jvmtiError err;
   jint state = 0;
   jint mcount = -1;
-  jobject *owned_monitors = NULL;
+  jobject *owned_monitors = nullptr;
 
   err = jvmti->GetOwnedMonitorInfo(thread, &mcount, &owned_monitors);
   if (err != JVMTI_ERROR_NONE) {
@@ -182,9 +182,9 @@ MonitorContendedEnter(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread, jobject mon
   char* ctname = get_thread_name(jvmti, jni, cthread);
 
   check_contended_monitor(jvmti, jni, "MonitorContendedEnter",
-                          vthread, vtname, JNI_TRUE, monitor, NULL);
+                          vthread, vtname, JNI_TRUE, monitor, nullptr);
   check_contended_monitor(jvmti, jni, "MonitorContendedEnter",
-                          cthread,  ctname, JNI_FALSE, NULL, NULL);
+                          cthread,  ctname, JNI_FALSE, nullptr, nullptr);
   check_owned_monitor(jvmti, jni, "MonitorContendedEnter",
                       vthread, vtname, JNI_TRUE, monitor);
   check_owned_monitor(jvmti, jni, "MonitorContendedEnter",
@@ -204,9 +204,9 @@ MonitorContendedEntered(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread, jobject m
   char* ctname = get_thread_name(jvmti, jni, cthread);
 
   check_contended_monitor(jvmti, jni, "MonitorContendedEntered",
-                          vthread, vtname, JNI_TRUE, NULL, NULL);
+                          vthread, vtname, JNI_TRUE, nullptr, nullptr);
   check_contended_monitor(jvmti, jni, "MonitorContendedEntered",
-                          cthread, ctname, JNI_FALSE, NULL, NULL);
+                          cthread, ctname, JNI_FALSE, nullptr, nullptr);
 
   deallocate(jvmti, jni, (void*)vtname);
   deallocate(jvmti, jni, (void*)ctname);
@@ -226,7 +226,7 @@ static
 jclass find_test_class(JNIEnv *jni, const char* cname) {
   jclass k = jni->FindClass(cname);
 
-  if (k == NULL) {
+  if (k == nullptr) {
     LOG("Error: Could not find class %s!\n", cname);
   } else {
     k = (jclass)jni->NewGlobalRef(k);
@@ -240,7 +240,7 @@ JNI_OnLoad(JavaVM *jvm, void *reserved) {
   JNIEnv *jni;
 
   res = jvm->GetEnv((void **)&jni, JNI_VERSION_9);
-  if (res != JNI_OK || jni == NULL) {
+  if (res != JNI_OK || jni == nullptr) {
     LOG("Error: GetEnv call failed(%d)!\n", res);
     return JNI_ERR;
   }
@@ -248,7 +248,7 @@ JNI_OnLoad(JavaVM *jvm, void *reserved) {
   test_class_0 = find_test_class(jni, TEST_CLASS_0);
   test_class_2 = find_test_class(jni, TEST_CLASS_2);
 
-  if (test_class_0 == NULL || test_class_2 == NULL) {
+  if (test_class_0 == nullptr || test_class_2 == nullptr) {
     return JNI_ERR;
   }
   return JNI_VERSION_9;
@@ -264,7 +264,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   LOG("Agent_OnLoad started\n");
 
   res = jvm->GetEnv((void **)&jvmti, JVMTI_VERSION);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Error: wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -315,14 +315,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   }
 
   err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                                        JVMTI_EVENT_MONITOR_CONTENDED_ENTER, NULL);
+                                        JVMTI_EVENT_MONITOR_CONTENDED_ENTER, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     ShowErrorMessage(jvmti, err, "Agent_OnLoad",
                      "error in JVMTI SetEventNotificationMode #1");
     return JNI_ERR;
   }
   err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                                        JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, NULL);
+                                        JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     ShowErrorMessage(jvmti, err, "Agent_OnLoad",
                      "error in JVMTI SetEventNotificationMode #2");
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadNotifyFramePopTest/libVThreadNotifyFramePopTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadNotifyFramePopTest/libVThreadNotifyFramePopTest.cpp
index 55803e5abf5..d5254293ab1 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadNotifyFramePopTest/libVThreadNotifyFramePopTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadNotifyFramePopTest/libVThreadNotifyFramePopTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,32 +29,32 @@ extern "C" {
 
 #define MAX_FRAME_COUNT 20
 
-static jvmtiEnv *jvmti = NULL;
-static jrawMonitorID event_mon = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jrawMonitorID event_mon = nullptr;
 static int breakpoint_count = 0;
 static int frame_pop_count = 0;
 static int brkptBreakpointHit = 0;
 static jboolean received_frame_pop_event = JNI_FALSE;
 static jboolean passed = JNI_TRUE;
 
-static jmethodID *test_methods = NULL;
+static jmethodID *test_methods = nullptr;
 jint test_method_count = 0;
-jclass test_class = NULL;
+jclass test_class = nullptr;
 
-static jmethodID *url_methods = NULL;
+static jmethodID *url_methods = nullptr;
 jint url_method_count = 0;
-jclass url_class = NULL;
+jclass url_class = nullptr;
 
 static void
 print_frame_event_info(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread, jmethodID method,
                        const char* event_name, int event_count) {
   char* tname = get_thread_name(jvmti, jni, thread);
   char* cname = get_method_class_name(jvmti, jni, method);
-  char* mname = NULL;
-  char* msign = NULL;
+  char* mname = nullptr;
+  char* msign = nullptr;
   jvmtiError err;
 
-  err = jvmti->GetMethodName(method, &mname, &msign, NULL);
+  err = jvmti->GetMethodName(method, &mname, &msign, nullptr);
   check_jvmti_status(jni, err, "event handler: error in JVMTI GetMethodName call");
 
  LOG("%s #%d: thread: %s, method: %s.%s%s\n",
@@ -84,7 +84,7 @@ static void
 set_or_clear_breakpoint(JNIEnv *jni, jboolean set, const char *methodName,
                      jclass klass, jmethodID methods[], int method_count) {
   jlocation location = (jlocation)0L;
-  jmethodID method = NULL;
+  jmethodID method = nullptr;
   jvmtiError err;
 
   // Find the jmethodID of the specified method
@@ -98,7 +98,7 @@ set_or_clear_breakpoint(JNIEnv *jni, jboolean set, const char *methodName,
     }
     deallocate(jvmti, jni, (void*)mname);
   }
-  if (method == NULL) {
+  if (method == nullptr) {
      LOG("setupBreakpoint: not found method %s() to %s a breakpoint\n",
              methodName, set ? "set" : "clear");
       jni->FatalError("Error in setupBreakpoint: not found method");
@@ -237,7 +237,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
    LOG("Agent_OnLoad: Error in JVMTI SetEventCallbacks: %d\n", err);
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, nullptr);
   if (err != JVMTI_ERROR_NONE) {
    LOG("error in JVMTI SetEventNotificationMode: %d\n", err);
   }
@@ -268,7 +268,7 @@ Java_VThreadNotifyFramePopTest_enableEvents(JNIEnv *jni, jclass klass, jthread t
   set_breakpoint(jni, "openStream", urlKlass, url_methods, url_method_count);
 
   // Enable Breakpoint events globally
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
   check_jvmti_status(jni, err, "enableEvents: error in JVMTI SetEventNotificationMode: enable BREAKPOINT");
 
  LOG("enableEvents: finished\n");
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadTest/libVThreadTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadTest/libVThreadTest.cpp
index 32037f79f53..701797bcfc2 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadTest/libVThreadTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadTest/libVThreadTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,8 +36,8 @@ typedef struct Tinfo {
 } Tinfo;
 
 static const int MAX_EVENTS_TO_PROCESS = 20;
-static jvmtiEnv *jvmti = NULL;
-static jrawMonitorID events_monitor = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jrawMonitorID events_monitor = nullptr;
 static Tinfo tinfo[MAX_WORKER_THREADS];
 
 static int vthread_mount_count = 0;
@@ -46,13 +46,13 @@ static jboolean passed = JNI_TRUE;
 
 static Tinfo*
 find_tinfo(JNIEnv* jni, const char* tname) {
-  Tinfo* inf = NULL;
+  Tinfo* inf = nullptr;
   int idx = 0;
 
   // Find slot with named worker thread or empty slot
   for (; idx < MAX_WORKER_THREADS; idx++) {
     inf = &tinfo[idx];
-    if (inf->tname == NULL) {
+    if (inf->tname == nullptr) {
       inf->tname = (char*)malloc(strlen(tname) + 1);
       strcpy(inf->tname, tname);
       break;
@@ -78,10 +78,10 @@ find_method_depth(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread, const char *mna
 
   for (int depth = 0; depth < count; depth++) {
     jmethodID method = frames[depth].method;
-    char* name = NULL;
-    char* sign = NULL;
+    char* name = nullptr;
+    char* sign = nullptr;
 
-    err = jvmti->GetMethodName(method, &name, &sign, NULL);
+    err = jvmti->GetMethodName(method, &name, &sign, nullptr);
     check_jvmti_status(jni, err, "find_method_depth: error in JVMTI GetMethodName");
 
     if (strcmp(name, mname) == 0) {
@@ -102,7 +102,7 @@ print_vthread_event_info(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jthread v
     inf->just_scheduled = JNI_TRUE;
   }
   else {
-    if (inf->tname == NULL && strcmp(event_name, "VirtualThreadEnd") != 0) {
+    if (inf->tname == nullptr && strcmp(event_name, "VirtualThreadEnd") != 0) {
       fatal(jni, "VThread event: worker thread not found!");
     }
     if (strcmp(event_name, "VirtualThreadUnmount") == 0) {
@@ -117,19 +117,19 @@ print_vthread_event_info(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jthread v
 
 static void
 test_GetVirtualThread(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jthread vthread, const char *event_name) {
-  jobject thread_vthread = NULL;
+  jobject thread_vthread = nullptr;
   jvmtiError err;
 
   LOG("\ntest_GetVirtualThread: event: %s\n", event_name);
 
-  // #1: Test JVMTI GetVirtualThread extension function NULL thread (current)
-  err = GetVirtualThread(jvmti, jni, NULL, &thread_vthread);
-  check_jvmti_status(jni, err, "event handler: error in JVMTI GetVirtualThread with NULL thread (current)");
+  // #1: Test JVMTI GetVirtualThread extension function nullptr thread (current)
+  err = GetVirtualThread(jvmti, jni, nullptr, &thread_vthread);
+  check_jvmti_status(jni, err, "event handler: error in JVMTI GetVirtualThread with null thread (current)");
 
-  if (thread_vthread == NULL) {
-    fatal(jni, "event handler: JVMTI GetVirtualThread with NULL thread (current) failed to return non-NULL vthread");
+  if (thread_vthread == nullptr) {
+    fatal(jni, "event handler: JVMTI GetVirtualThread with nullptr thread (current) failed to return non-null vthread");
   }
-  LOG("JVMTI GetVirtualThread with NULL thread (current) returned non-NULL vthread as expected\n");
+  LOG("JVMTI GetVirtualThread with nullptr thread (current) returned non-null vthread as expected\n");
 
   // #2: Test JVMTI GetVirtualThread extension function with a bad thread
   err = GetVirtualThread(jvmti, jni, vthread, &thread_vthread);
@@ -141,21 +141,21 @@ test_GetVirtualThread(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jthread vthr
   err = GetVirtualThread(jvmti, jni,thread, &thread_vthread);
   check_jvmti_status(jni, err, "event handler: error in JVMTI GetVirtualThread");
 
-  if (thread_vthread == NULL) {
-    fatal(jni, "event handler: JVMTI GetVirtualThread with good thread failed to return non-NULL vthread");
+  if (thread_vthread == nullptr) {
+    fatal(jni, "event handler: JVMTI GetVirtualThread with good thread failed to return non-null vthread");
   }
-  LOG("JVMTI GetVirtualThread with good thread returned non-NULL vthread as expected\n");
+  LOG("JVMTI GetVirtualThread with good thread returned non-null vthread as expected\n");
 }
 
 static void
 test_GetCarrierThread(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jthread vthread, const char *event_name) {
-  jthread vthread_thread = NULL;
+  jthread vthread_thread = nullptr;
   jvmtiError err;
 
   LOG("\ntest_GetCarrierThread: event: %s\n", event_name);
 
-  // #1: Test JVMTI GetCarrierThread extension function with NULL vthread
-  err = GetCarrierThread(jvmti, jni, NULL, &vthread_thread);
+  // #1: Test JVMTI GetCarrierThread extension function with nullptr vthread
+  err = GetCarrierThread(jvmti, jni, nullptr, &vthread_thread);
   check_jvmti_status(jni, err, "event handler: error in JVMTI GetCarrierThread");
 
   // #2: Test JVMTI GetCarrierThread extension function with a bad vthread
@@ -168,10 +168,10 @@ test_GetCarrierThread(jvmtiEnv *jvmti, JNIEnv *jni, jthread thread, jthread vthr
   err = GetCarrierThread(jvmti, jni, vthread, &vthread_thread);
   check_jvmti_status(jni, err, "event handler: error in JVMTI GetCarrierThread");
 
-  if (vthread_thread == NULL) {
-    fatal(jni, "event handler: JVMTI GetCarrierThread with good vthread failed to return non-NULL carrier thread");
+  if (vthread_thread == nullptr) {
+    fatal(jni, "event handler: JVMTI GetCarrierThread with good vthread failed to return non-null carrier thread");
   }
-  LOG("JVMTI GetCarrierThread with good vthread returned non-NULL carrier thread as expected\n");
+  LOG("JVMTI GetCarrierThread with good vthread returned non-null carrier thread as expected\n");
 }
 
 static void
@@ -180,7 +180,7 @@ test_GetThreadInfo(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread, const char *ev
   jvmtiThreadInfo thr_info;
   jvmtiThreadGroupInfo ginfo;
   jint class_count = -1;
-  jclass* classes = NULL;
+  jclass* classes = nullptr;
   jboolean found = JNI_FALSE;
 
   LOG("test_GetThreadInfo: started\n");
@@ -207,11 +207,11 @@ test_GetThreadInfo(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread, const char *ev
 
   // #4: Test the thr_info.context_class_loader has the VThreadTest class
   for (int idx = 0; idx < class_count; idx++) {
-    char* sign = NULL;
-    err = jvmti->GetClassSignature(classes[idx], &sign, NULL);
+    char* sign = nullptr;
+    err = jvmti->GetClassSignature(classes[idx], &sign, nullptr);
     check_jvmti_status(jni, err, "event handler: error in JVMTI GetClassSignature");
 
-    if (strstr(sign, "VThreadTest") != NULL) {
+    if (strstr(sign, "VThreadTest") != nullptr) {
       found = JNI_TRUE;
       break;
     }
@@ -228,11 +228,11 @@ test_GetFrameCount(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread, const char *ev
   jint frame_count = -1;
   jvmtiError err;
 
-  // #1: Test JVMTI GetFrameCount function with NULL count_ptr pointer
-  err = jvmti->GetFrameCount(vthread, NULL);
+  // #1: Test JVMTI GetFrameCount function with nullptr count_ptr pointer
+  err = jvmti->GetFrameCount(vthread, nullptr);
   if (err != JVMTI_ERROR_NULL_POINTER) {
-    LOG("JVMTI GetFrameCount with NULL count_ptr returned error: %d\n", err);
-    fatal(jni, "event handler: JVMTI GetFrameCount with NULL count_ptr pointer failed to return JVMTI_ERROR_NULL_POINTER");
+    LOG("JVMTI GetFrameCount with null count_ptr returned error: %d\n", err);
+    fatal(jni, "event handler: JVMTI GetFrameCount with null count_ptr pointer failed to return JVMTI_ERROR_NULL_POINTER");
   }
 
   // #2: Test JVMTI GetFrameCount function with a good vthread
@@ -249,7 +249,7 @@ test_GetFrameCount(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread, const char *ev
 
 static void
 test_GetFrameLocation(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread, const char *event_name, jint frame_count) {
-  jmethodID method = NULL;
+  jmethodID method = nullptr;
   jlocation location = -1;
   jvmtiError err;
 
@@ -260,18 +260,18 @@ test_GetFrameLocation(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread, const char
     fatal(jni, "event handler: JVMTI GetFrameLocation with negative frame depth failed to return JVMTI_ERROR_ILLEGAL_ARGUMENT");
   }
 
-  // #2: Test JVMTI GetFrameLocation function with NULL method_ptr
-  err = jvmti->GetFrameLocation(vthread, 0, NULL, &location);
+  // #2: Test JVMTI GetFrameLocation function with nullptr method_ptr
+  err = jvmti->GetFrameLocation(vthread, 0, nullptr, &location);
   if (err != JVMTI_ERROR_NULL_POINTER) {
-    LOG("JVMTI GetFrameLocation with NULL method_ptr returned error: %d\n", err);
-    fatal(jni, "event handler: JVMTI GetFrameLocation with NULL method_ptr failed to return JVMTI_ERROR_NULL_POINTER");
+    LOG("JVMTI GetFrameLocation with null method_ptr returned error: %d\n", err);
+    fatal(jni, "event handler: JVMTI GetFrameLocation with null method_ptr failed to return JVMTI_ERROR_NULL_POINTER");
   }
 
-  // #3: Test JVMTI GetFrameLocation function with NULL location_ptr
-  err = jvmti->GetFrameLocation(vthread, 0, &method, NULL);
+  // #3: Test JVMTI GetFrameLocation function with nullptr location_ptr
+  err = jvmti->GetFrameLocation(vthread, 0, &method, nullptr);
   if (err != JVMTI_ERROR_NULL_POINTER) {
-    LOG("JVMTI GetFrameCount with NULL location_ptr returned error: %d\n", err);
-    fatal(jni, "event handler: JVMTI GetFrameLocation with NULL location_ptr failed to return JVMTI_ERROR_NULL_POINTER");
+    LOG("JVMTI GetFrameCount with null location_ptr returned error: %d\n", err);
+    fatal(jni, "event handler: JVMTI GetFrameLocation with null location_ptr failed to return JVMTI_ERROR_NULL_POINTER");
   }
 
   // #4: Test JVMTI GetFrameLocation function with a good vthread
@@ -304,7 +304,7 @@ static void
 test_GetStackTrace(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread, const char *event_name, jint frame_count) {
   jvmtiFrameInfo frames[MAX_FRAME_COUNT];
   jint count = -1;
-  jmethodID method = NULL;
+  jmethodID method = nullptr;
   jvmtiError err;
 
   LOG("\n");
@@ -328,18 +328,18 @@ test_GetStackTrace(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread, const char *ev
     fatal(jni, "event handler: JVMTI GetStackTrace with negative max_frame_count failed to return JVMTI_ERROR_ILLEGAL_ARGUMENT");
   }
 
-  // #3: Test JVMTI GetStackTrace function with NULL frame_buffer pointer
-  err = jvmti->GetStackTrace(vthread, 0, MAX_FRAME_COUNT, NULL, &count);
+  // #3: Test JVMTI GetStackTrace function with nullptr frame_buffer pointer
+  err = jvmti->GetStackTrace(vthread, 0, MAX_FRAME_COUNT, nullptr, &count);
   if (err != JVMTI_ERROR_NULL_POINTER) {
-    LOG("JVMTI GetStackTrace with NULL frame_buffer pointer returned error: %d\n", err);
-    fatal(jni, "event handler: JVMTI GetStackTrace witt NULL frame_buffer pointer failed to return JVMTI_ERROR_NULL_POINTER");
+    LOG("JVMTI GetStackTrace with null frame_buffer pointer returned error: %d\n", err);
+    fatal(jni, "event handler: JVMTI GetStackTrace witt null frame_buffer pointer failed to return JVMTI_ERROR_NULL_POINTER");
   }
 
-  // #4: Test JVMTI GetStackTrace function with NULL count_ptr pointer
-  err = jvmti->GetStackTrace(vthread, 0, MAX_FRAME_COUNT, frames, NULL);
+  // #4: Test JVMTI GetStackTrace function with nullptr count_ptr pointer
+  err = jvmti->GetStackTrace(vthread, 0, MAX_FRAME_COUNT, frames, nullptr);
   if (err != JVMTI_ERROR_NULL_POINTER) {
-    LOG("JVMTI GetStackTrace with NULL count_ptr pointer returned error: %d\n", err);
-    fatal(jni, "event handler: JVMTI GetStackTrace witt NULL count_ptr pointer failed to return JVMTI_ERROR_NULL_POINTER");
+    LOG("JVMTI GetStackTrace with null count_ptr pointer returned error: %d\n", err);
+    fatal(jni, "event handler: JVMTI GetStackTrace witt null count_ptr pointer failed to return JVMTI_ERROR_NULL_POINTER");
   }
 
   // #5: Test JVMTI GetStackTrace function with a good vthread
@@ -364,8 +364,8 @@ enum Slots { SlotInvalid0 = -1, SlotObj = 0, SlotInt = 1, SlotLong = 2, SlotUnal
 
 static void
 test_GetLocal(jvmtiEnv *jvmti, JNIEnv *jni, jthread cthread, jthread vthread, const char *event_name, jint frame_count) {
-  jmethodID method = NULL;
-  jobject obj = NULL;
+  jmethodID method = nullptr;
+  jobject obj = nullptr;
   jint ii = 0;
   jlong ll = 0L;
   jfloat ff = 0.0;
@@ -423,18 +423,18 @@ test_GetLocal(jvmtiEnv *jvmti, JNIEnv *jni, jthread cthread, jthread vthread, co
                " to return JVMTI_ERROR_INVALID_SLOT or JVMTI_ERROR_TYPE_MISMATCH");
   }
 
-  // #5: Test JVMTI GetLocalObject function with NULL value_ptr
-  err = jvmti->GetLocalObject(vthread, depth, SlotObj, NULL);
+  // #5: Test JVMTI GetLocalObject function with null value_ptr
+  err = jvmti->GetLocalObject(vthread, depth, SlotObj, nullptr);
   if (err != JVMTI_ERROR_NULL_POINTER) {
-    LOG("JVMTI GetLocalObject with NULL method_ptr returned error: %d\n", err);
-    fatal(jni, "JVMTI GetLocalObject with NULL method_ptr failed to return JVMTI_ERROR_NULL_POINTER");
+    LOG("JVMTI GetLocalObject with null method_ptr returned error: %d\n", err);
+    fatal(jni, "JVMTI GetLocalObject with null method_ptr failed to return JVMTI_ERROR_NULL_POINTER");
   }
 
   // #6: Test JVMTI GetLocal<Type> functions with a good vthread
   err = jvmti->GetLocalObject(vthread, depth, SlotObj, &obj);
   check_jvmti_status(jni, err, "event handler: error in JVMTI GetLocalObject with good vthread");
 
-  const char* str = jni->GetStringUTFChars((jstring)obj, NULL);
+  const char* str = jni->GetStringUTFChars((jstring)obj, nullptr);
   LOG("    local String value at slot %d: %s\n", SlotObj, str);
   const char* exp_str = "msg: ...";
   if (strncmp(str, exp_str, 5) != 0) {
@@ -500,7 +500,7 @@ processVThreadEvent(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread, const char *e
   deallocate(jvmti, jni, (void*)tname);
 
   if (strcmp(event_name, "VirtualThreadEnd") == 0) {
-    return; // skip further testing as GetVirtualThread can return NULL
+    return; // skip further testing as GetVirtualThread can return nullptr
   }
 
   test_GetVirtualThread(jvmti, jni, cthread, vthread, event_name);
@@ -532,8 +532,8 @@ VirtualThreadEnd(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread) {
 static void JNICALL
 VirtualThreadMount(jvmtiEnv *jvmti, ...) {
   va_list ap;
-  JNIEnv* jni = NULL;
-  jthread thread = NULL;
+  JNIEnv* jni = nullptr;
+  jthread thread = nullptr;
 
   va_start(ap, jvmti);
   jni = va_arg(ap, JNIEnv*);
@@ -549,8 +549,8 @@ VirtualThreadMount(jvmtiEnv *jvmti, ...) {
 static void JNICALL
 VirtualThreadUnmount(jvmtiEnv *jvmti, ...) {
   va_list ap;
-  JNIEnv* jni = NULL;
-  jthread thread = NULL;
+  JNIEnv* jni = nullptr;
+  jthread thread = nullptr;
 
   va_start(ap, jvmti);
   jni = va_arg(ap, JNIEnv*);
@@ -608,25 +608,25 @@ Agent_OnLoad(JavaVM *jvm, char *options,
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("error in JVMTI SetEventNotificationMode: %d\n", err);
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_END, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_END, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("error in JVMTI SetEventNotificationMode: %d\n", err);
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_MOUNT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_MOUNT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("error in JVMTI SetEventNotificationMode: %d\n", err);
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_UNMOUNT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_UNMOUNT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("error in JVMTI SetEventNotificationMode: %d\n", err);
     return JNI_ERR;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadUnsupportedTest/libVThreadUnsupportedTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadUnsupportedTest/libVThreadUnsupportedTest.cpp
index 14698b6e528..5b299a46f48 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadUnsupportedTest/libVThreadUnsupportedTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadUnsupportedTest/libVThreadUnsupportedTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,7 +29,7 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 static std::atomic<bool> is_completed_test_in_event;
 
@@ -68,7 +68,7 @@ test_unsupported_jvmti_functions(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread)
   jvmtiError err;
   jboolean is_vthread;
   jvmtiCapabilities caps;
-  void* local_storage_data = NULL;
+  void* local_storage_data = nullptr;
   jlong nanos;
 
   LOG("test_unsupported_jvmti_functions: started\n");
@@ -98,7 +98,7 @@ test_unsupported_jvmti_functions(jvmtiEnv *jvmti, JNIEnv *jni, jthread vthread)
     check_jvmti_error_unsupported_operation(jni, "GetCurrentThreadCpuTime", err);
   }
 
-  err = jvmti->RunAgentThread(vthread, agent_proc, (const void*)NULL, JVMTI_THREAD_NORM_PRIORITY);
+  err = jvmti->RunAgentThread(vthread, agent_proc, nullptr, JVMTI_THREAD_NORM_PRIORITY);
   check_jvmti_error_unsupported_operation(jni, "RunAgentThread", err);
 
   LOG("test_unsupported_jvmti_functions: finished\n");
@@ -121,8 +121,8 @@ Java_VThreadUnsupportedTest_testJvmtiFunctionsInJNICall(JNIEnv *jni, jobject obj
 static void JNICALL
 VirtualThreadMount(jvmtiEnv *jvmti, ...) {
   va_list ap;
-  JNIEnv* jni = NULL;
-  jthread thread = NULL;
+  JNIEnv* jni = nullptr;
+  jthread thread = nullptr;
 
   va_start(ap, jvmti);
   jni = va_arg(ap, JNIEnv*);
@@ -175,7 +175,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_MOUNT, NULL);
+  err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_MOUNT, nullptr);
   if (err != JVMTI_ERROR_NONE) {
     LOG("error in JVMTI SetEventNotificationMode: %d\n", err);
     return JNI_ERR;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/VirtualStackTraceTest/libVirtualStackTraceTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/VirtualStackTraceTest/libVirtualStackTraceTest.cpp
index eb387a1f8dc..744e75ac29f 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/VirtualStackTraceTest/libVirtualStackTraceTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/VirtualStackTraceTest/libVirtualStackTraceTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,21 +40,21 @@ Java_VirtualStackTraceTest_getStackTrace(JNIEnv* jni, jclass clazz) {
   jobject visibleFrames[MAX_COUNT];
   jvmtiFrameInfo frameInfo[MAX_COUNT];
 
-  err = jvmti->GetStackTrace(NULL, 0, MAX_COUNT, frameInfo, &count);
+  err = jvmti->GetStackTrace(nullptr, 0, MAX_COUNT, frameInfo, &count);
   check_jvmti_status(jni, err, "event handler: error in JVMTI GetStackTrace call");
 
   for (int idx = 0; idx < count; idx++) {
-    jclass declaringClass = NULL;
-    char *clasSignature = NULL;
-    char *methodName = NULL;
+    jclass declaringClass = nullptr;
+    char *clasSignature = nullptr;
+    char *methodName = nullptr;
 
     err = jvmti->GetMethodDeclaringClass(frameInfo[idx].method, &declaringClass);
     check_jvmti_status(jni, err, "event handler: error in JVMTI GetMethodDeclaringClass call");
 
-    err = jvmti->GetClassSignature(declaringClass, &clasSignature, NULL);
+    err = jvmti->GetClassSignature(declaringClass, &clasSignature, nullptr);
     check_jvmti_status(jni, err, "event handler: error in JVMTI GetClassSignature call");
 
-    err = jvmti->GetMethodName(frameInfo[idx].method, &methodName, NULL, NULL);
+    err = jvmti->GetMethodName(frameInfo[idx].method, &methodName, nullptr, nullptr);
     check_jvmti_status(jni, err, "event handler: error in JVMTI GetMethodName call");
 
     if (strchr(clasSignature, '.')) {
@@ -66,11 +66,11 @@ Java_VirtualStackTraceTest_getStackTrace(JNIEnv* jni, jclass clazz) {
     jvmti->Deallocate(reinterpret_cast<unsigned char*>(methodName));
     jvmti->Deallocate(reinterpret_cast<unsigned char*>(clasSignature));
   }
-  jobjectArray methodNames = jni->NewObjectArray(count - skipped, jni->FindClass("java/lang/String"), NULL);
+  jobjectArray methodNames = jni->NewObjectArray(count - skipped, jni->FindClass("java/lang/String"), nullptr);
   for (int idx = 0; idx < count - skipped; idx++) {
     jni->SetObjectArrayElement(methodNames, idx, visibleFrames[idx]);
   }
-  print_stack_trace(jvmti, jni, NULL);
+  print_stack_trace(jvmti, jni, nullptr);
 
   return methodNames;
 }
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/VirtualThreadStartTest/libVirtualThreadStartTest.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/VirtualThreadStartTest/libVirtualThreadStartTest.cpp
index b4eefa992ef..262712dfb0c 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/VirtualThreadStartTest/libVirtualThreadStartTest.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/VirtualThreadStartTest/libVirtualThreadStartTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -30,7 +30,7 @@ extern "C" {
 
 static jvmtiEnv *jvmti;
 static int started_thread_cnt = 0;
-static jrawMonitorID agent_event_lock = NULL;
+static jrawMonitorID agent_event_lock = nullptr;
 static const char* TESTED_TNAME_START = "Tested-VT";
 static const size_t TESTED_TNAME_START_LEN = strlen(TESTED_TNAME_START);
 static bool can_support_vt_enabled = false;
@@ -40,7 +40,7 @@ void JNICALL ThreadStart(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread) {
 
   RawMonitorLocker agent_start_locker(jvmti, jni, agent_event_lock);
 
-  if (tname != NULL && strncmp(tname, TESTED_TNAME_START, TESTED_TNAME_START_LEN) == 0) {
+  if (tname != nullptr && strncmp(tname, TESTED_TNAME_START, TESTED_TNAME_START_LEN) == 0) {
     jboolean is_virtual = jni->IsVirtualThread(thread);
     if (!is_virtual) {
       fatal(jni, "Failed: tested thread expected to be virtual");
@@ -59,7 +59,7 @@ void JNICALL VirtualThreadStart(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread) {
 
   RawMonitorLocker agent_start_locker(jvmti, jni, agent_event_lock);
 
-  if (tname != NULL && strncmp(tname, TESTED_TNAME_START, TESTED_TNAME_START_LEN) == 0) {
+  if (tname != nullptr && strncmp(tname, TESTED_TNAME_START, TESTED_TNAME_START_LEN) == 0) {
     jboolean is_virtual = jni->IsVirtualThread(thread);
     if (!is_virtual) {
       fatal(jni, "Failed: tested thread expected to be virtual");
@@ -101,7 +101,7 @@ jint agent_init(JavaVM *jvm, char *options, void *reserved) {
   callbacks.ThreadStart = &ThreadStart;
   callbacks.VirtualThreadStart = &VirtualThreadStart;
 
-  if (options != NULL && strcmp(options, "can_support_virtual_threads") == 0) {
+  if (options != nullptr && strcmp(options, "can_support_virtual_threads") == 0) {
     can_support_vt_enabled = true;
     caps.can_support_virtual_threads = 1;
 
@@ -110,13 +110,13 @@ jint agent_init(JavaVM *jvm, char *options, void *reserved) {
       LOG("Agent init: error in JVMTI AddCapabilities: %s (%d)\n", TranslateError(err), err);
       return JNI_ERR;
     }
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_START, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       LOG("Agent init: error in JVMTI SetEventNotificationMode: %s (%d)\n", TranslateError(err), err);
       return JNI_ERR;
     }
   } else {
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       LOG("Agent init: error in JVMTI SetEventNotificationMode: %s (%d)\n", TranslateError(err), err);
       return JNI_ERR;
diff --git a/test/hotspot/jtreg/serviceability/jvmti/vthread/WaitNotifySuspendedVThreadTest/libWaitNotifySuspendedVThread.cpp b/test/hotspot/jtreg/serviceability/jvmti/vthread/WaitNotifySuspendedVThreadTest/libWaitNotifySuspendedVThread.cpp
index e6ad883944a..44b931c0ff9 100644
--- a/test/hotspot/jtreg/serviceability/jvmti/vthread/WaitNotifySuspendedVThreadTest/libWaitNotifySuspendedVThread.cpp
+++ b/test/hotspot/jtreg/serviceability/jvmti/vthread/WaitNotifySuspendedVThreadTest/libWaitNotifySuspendedVThread.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,7 +39,7 @@ set_breakpoint(JNIEnv *jni, jclass klass, const char *mname) {
   jmethodID method = find_method(jvmti_env, jni, klass, mname);
   jvmtiError err;
 
-  if (method == NULL) {
+  if (method == nullptr) {
     jni->FatalError("Error in set_breakpoint: not found method");
   }
   err = jvmti_env->SetBreakpoint(method, location);
@@ -56,7 +56,7 @@ Java_WaitNotifySuspendedVThreadTask_setBreakpoint(JNIEnv *jni, jclass klass) {
   set_breakpoint(jni, klass, "methBreakpoint");
 
   // Enable Breakpoint events globally
-  err = jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+  err = jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
   check_jvmti_status(jni, err, "enableEvents: error in JVMTI SetEventNotificationMode: enable BREAKPOINT");
 
   LOG("setBreakpoint: finished\n");
@@ -137,7 +137,7 @@ Breakpoint(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread,
 
 JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
-  jvmtiEnv * jvmti = NULL;
+  jvmtiEnv * jvmti = nullptr;
 
   jvmtiEventCallbacks callbacks;
   jvmtiCapabilities caps;
@@ -145,7 +145,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
   jint res;
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     LOG("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
diff --git a/test/hotspot/jtreg/serviceability/monitoring/ThreadInfo/GetLockOwnerName/libGetLockOwnerName.cpp b/test/hotspot/jtreg/serviceability/monitoring/ThreadInfo/GetLockOwnerName/libGetLockOwnerName.cpp
index ee4fb5c6d8a..cc377667093 100644
--- a/test/hotspot/jtreg/serviceability/monitoring/ThreadInfo/GetLockOwnerName/libGetLockOwnerName.cpp
+++ b/test/hotspot/jtreg/serviceability/monitoring/ThreadInfo/GetLockOwnerName/libGetLockOwnerName.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,7 +26,7 @@
 
 extern "C" {
 
-static jvmtiEnv* jvmti = NULL;
+static jvmtiEnv* jvmti = nullptr;
 
 #define LOG(...) \
   do { \
@@ -53,7 +53,7 @@ Java_GetLockOwnerName_wait4ContendedEnter(JNIEnv *jni, jclass cls, jthread thr)
       if (err != JVMTI_ERROR_NONE) {
         return err;
       }
-      if (monitor_ptr != NULL) {
+      if (monitor_ptr != nullptr) {
         break;
       }
     }
diff --git a/test/hotspot/jtreg/testlibrary/jvmti/libJvmtiUtils.cpp b/test/hotspot/jtreg/testlibrary/jvmti/libJvmtiUtils.cpp
index 0e7f1eba383..28afafda3a7 100644
--- a/test/hotspot/jtreg/testlibrary/jvmti/libJvmtiUtils.cpp
+++ b/test/hotspot/jtreg/testlibrary/jvmti/libJvmtiUtils.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,7 +27,7 @@
 
 extern "C" {
 
-static jvmtiEnv* jvmti = NULL;
+static jvmtiEnv* jvmti = nullptr;
 
 JNIEXPORT jint JNICALL
 Java_jvmti_JVMTIUtils_init(JNIEnv *jni, jclass cls) {
diff --git a/test/hotspot/jtreg/vmTestbase/gc/g1/unloading/libdefine.cpp b/test/hotspot/jtreg/vmTestbase/gc/g1/unloading/libdefine.cpp
index 157ea1f92a7..e1b16107e12 100644
--- a/test/hotspot/jtreg/vmTestbase/gc/g1/unloading/libdefine.cpp
+++ b/test/hotspot/jtreg/vmTestbase/gc/g1/unloading/libdefine.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -44,14 +44,14 @@ extern "C" {
 JNIEXPORT jclass JNICALL Java_gc_g1_unloading_classloaders_JNIClassloader_loadThroughJNI0 (JNIEnv * env,
                                          jclass clazz, jstring className, jobject classLoader, jbyteArray bytecode) {
 
-  const char * classNameChar = env->GetStringUTFChars(className, NULL);
-  jbyte * arrayContent = env->GetByteArrayElements(bytecode, NULL);
+  const char * classNameChar = env->GetStringUTFChars(className, nullptr);
+  jbyte * arrayContent = env->GetByteArrayElements(bytecode, nullptr);
   jsize bytecodeLength = env->GetArrayLength(bytecode);
   jclass returnValue = env->DefineClass(classNameChar, classLoader, arrayContent, bytecodeLength);
   env->ReleaseByteArrayElements(bytecode, arrayContent, JNI_ABORT);
   env->ReleaseStringUTFChars(className, classNameChar);
   if (!returnValue) {
-    printf("ERROR: DefineClass call returned NULL by some reason. Classloading failed.\n");
+    printf("ERROR: DefineClass call returned null by some reason. Classloading failed.\n");
   }
 
   return returnValue;
@@ -101,7 +101,7 @@ JNIEXPORT jint JNICALL  Java_gc_g1_unloading_loading_ClassLoadingHelper_makeRede
     classDef.klass = redefCls;
     classDef.class_byte_count =
         env->GetArrayLength(classBytes);
-    jbyte * class_bytes = env->GetByteArrayElements(classBytes, NULL);
+    jbyte * class_bytes = env->GetByteArrayElements(classBytes, nullptr);
     classDef.class_bytes = (unsigned char *)class_bytes;
 
     if (fl == 2) {
@@ -167,7 +167,7 @@ JNIEXPORT void JNICALL Java_gc_g1_unloading_keepref_JNILocalRefHolder_holdWithJN
     objectToKeepField = env->GetFieldID(clazz, "objectToKeep", "Ljava/lang/Object;");
     objectToKeep = env->GetObjectField(thisObject, objectToKeepField);
     localRef = env->NewLocalRef(objectToKeep);
-    env->SetObjectField(thisObject, objectToKeepField, NULL);
+    env->SetObjectField(thisObject, objectToKeepField, nullptr);
 
     objectClazz = env->FindClass("Ljava/lang/Object;");
     waitMethod = env->GetMethodID(objectClazz, "wait", "()V");
diff --git a/test/hotspot/jtreg/vmTestbase/gc/gctests/nativeGC03/libnativeGC03.cpp b/test/hotspot/jtreg/vmTestbase/gc/gctests/nativeGC03/libnativeGC03.cpp
index e8520a1ad4f..2c97863db5a 100644
--- a/test/hotspot/jtreg/vmTestbase/gc/gctests/nativeGC03/libnativeGC03.cpp
+++ b/test/hotspot/jtreg/vmTestbase/gc/gctests/nativeGC03/libnativeGC03.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ Java_gc_gctests_nativeGC03_nativeGC03_nativeMethod03
         /*Trash all the linked lists */
         while (count < 10) {
                 while (i < len) {
-                        env->SetObjectArrayElement(listHolder, i, NULL);
+                        env->SetObjectArrayElement(listHolder, i, nullptr);
                         i++;
                 }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent00.cpp
index 932d44e6727..5d819851e4b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -37,7 +37,7 @@ JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM *vm, char *optionsString, void *res
     // can't use NSK_DISPLAY since needed for nsk_ functions initialization isn't done here
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     printf("%s: initialization was done\n", AGENT_NAME);
@@ -46,7 +46,7 @@ JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM *vm, char *optionsString, void *res
     if (!NSK_VERIFY(nsk_aod_agentLoaded(jni, AGENT_NAME)))
         return JNI_ERR;
 
-    if (optionsString == NULL) {
+    if (optionsString == nullptr) {
         success = 0;
         printf("%s: ERROR: unexpected null options\n", AGENT_NAME);
         fflush(stdout);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent01.cpp b/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent01.cpp
index 04949f4d861..d2c5f13cd34 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent01.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM *vm, char *optionsString, void *res
     // can't use NSK_DISPLAY since needed for nsk_ functions initialization isn't done here
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     printf("%s: initialization was done\n", AGENT_NAME);
@@ -49,7 +49,7 @@ JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM *vm, char *optionsString, void *res
     if (!NSK_VERIFY(nsk_aod_agentLoaded(jni, AGENT_NAME)))
         return JNI_ERR;
 
-    if (optionsString == NULL) {
+    if (optionsString == nullptr) {
         success = 0;
         printf("%s: ERROR: unexpected null options\n", AGENT_NAME);
         fflush(stdout);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent02.cpp b/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent02.cpp
index b93f3ba03c0..257511c60f3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent02.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@ JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM *vm, char *optionsString, void *res
     // can't use NSK_DISPLAY since needed for nsk_ functions initialization isn't done here
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     printf("%s: initialization was done\n", AGENT_NAME);
@@ -51,7 +51,7 @@ JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM *vm, char *optionsString, void *res
     if (!NSK_VERIFY(nsk_aod_agentLoaded(jni, AGENT_NAME)))
         return JNI_ERR;
 
-    if (optionsString == NULL) {
+    if (optionsString == nullptr) {
         success = 0;
         printf("%s: ERROR: unexpected null options\n", AGENT_NAME);
         fflush(stdout);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent03.cpp b/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent03.cpp
index 029057cc4b9..66bbc6a990a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent03.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine07/agent03.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,7 +39,7 @@ JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM *vm, char *optionsString, void *res
     JNIEnv* jni;
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     // can't use NSK_DISPLAY since needed for nsk_ functions initialization isn't done here
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine09/agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine09/agent00.cpp
index c63187191d9..e7e6452603f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine09/agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/aod/VirtualMachine/VirtualMachine09/agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -44,18 +44,18 @@ JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *vm, char *optionsString, void *reser
 }
 
 JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved) {
-    JNIEnv* jni = NULL;
-    Options* options = NULL;
+    JNIEnv* jni = nullptr;
+    Options* options = nullptr;
     const char* agentName;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     NSK_DISPLAY1("%s: initialization was done\n", agentName);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AddCapabilities/addcaps001/addcaps001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AddCapabilities/addcaps001/addcaps001.cpp
index 86626181ea3..65ff008a046 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AddCapabilities/addcaps001/addcaps001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AddCapabilities/addcaps001/addcaps001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -268,7 +268,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     success = checkCapabilities(jvmti, &initCaps, "VM_DEATH callback");
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -295,7 +295,7 @@ JNIEXPORT jint JNI_OnLoad_addcaps001(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -303,7 +303,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -318,7 +318,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Testcase #0: Add empty capabilities list in Agent_OnLoad()\n");
@@ -333,7 +333,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AddCapabilities/addcaps002/addcaps002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AddCapabilities/addcaps002/addcaps002.cpp
index 54b85588f5c..5853d3db13e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AddCapabilities/addcaps002/addcaps002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AddCapabilities/addcaps002/addcaps002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -287,7 +287,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     success = checkCapabilities(jvmti, &initCaps, "VM_DEATH callback");
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -314,7 +314,7 @@ JNIEXPORT jint JNI_OnLoad_addcaps002(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -322,7 +322,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -337,7 +337,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&initCaps, 0, sizeof(jvmtiCapabilities));
@@ -356,7 +356,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AddCapabilities/addcaps003/addcaps003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AddCapabilities/addcaps003/addcaps003.cpp
index 0f5476edc1d..742d50aaf8e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AddCapabilities/addcaps003/addcaps003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AddCapabilities/addcaps003/addcaps003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -136,7 +136,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     success = checkCapabilities(jvmti, &initCaps, "VM_DEATH callback");
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -163,7 +163,7 @@ JNIEXPORT jint JNI_OnLoad_addcaps003(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -171,7 +171,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -186,7 +186,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&initCaps, 0, sizeof(jvmtiCapabilities));
@@ -205,7 +205,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Agent_OnLoad/agentonload001/agentonload001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Agent_OnLoad/agentonload001/agentonload001.cpp
index 1aa6e1b6679..b74de21db4e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Agent_OnLoad/agentonload001/agentonload001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Agent_OnLoad/agentonload001/agentonload001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -67,13 +67,13 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY1("    options:  \"%s\"\n", nsk_null_string(options));
     NSK_DISPLAY1("    reserved: 0x%p\n", (void*)jvm);
 
-    if (jvm == NULL) {
-        NSK_COMPLAIN1("First parameter 'vm' in JVM_OnLoad() is NULL: 0x%p\n", (void*)jvm);
+    if (jvm == nullptr) {
+        NSK_COMPLAIN1("First parameter 'vm' in JVM_OnLoad() is null: 0x%p\n", (void*)jvm);
         status = STATUS_FAILED;
     }
 
-    if (options == NULL) {
-        NSK_COMPLAIN1("Second parameter 'options' in JVM_OnLoad() is NULL: 0x%p\n", (void*)options);
+    if (options == nullptr) {
+        NSK_COMPLAIN1("Second parameter 'options' in JVM_OnLoad() is null: 0x%p\n", (void*)options);
         status = STATUS_FAILED;
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Agent_OnLoad/agentonload002/agentonload002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Agent_OnLoad/agentonload002/agentonload002.cpp
index d591cac18a5..abec073b2f8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Agent_OnLoad/agentonload002/agentonload002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Agent_OnLoad/agentonload002/agentonload002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,8 +48,8 @@ JNIEXPORT jint JNI_OnLoad_agentonload002(JavaVM *jvm, char *options, void *reser
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
-    if (options == NULL) {
-        printf("# ERROR: Second parameter 'options' in JVM_OnLoad() is NULL: 0x%p\n",
+    if (options == nullptr) {
+        printf("# ERROR: Second parameter 'options' in JVM_OnLoad() is null: 0x%p\n",
                     (void*)options);
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Agent_OnLoad/agentonload003/agentonload003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Agent_OnLoad/agentonload003/agentonload003.cpp
index 9aa1c4a0e58..271bf79be5b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Agent_OnLoad/agentonload003/agentonload003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Agent_OnLoad/agentonload003/agentonload003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,8 +48,8 @@ JNIEXPORT jint JNI_OnLoad_agentonload003(JavaVM *jvm, char *options, void *reser
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
-    if (options == NULL) {
-        printf("# ERROR: Second parameter 'options' in JVM_OnLoad() is NULL: 0x%p\n",
+    if (options == nullptr) {
+        printf("# ERROR: Second parameter 'options' in JVM_OnLoad() is null: 0x%p\n",
                     (void*)options);
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Allocate/alloc001/alloc001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Allocate/alloc001/alloc001.cpp
index d2df97bdea9..77402be9a4d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Allocate/alloc001/alloc001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Allocate/alloc001/alloc001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ extern "C" {
 // limit virtual memory (this usually happens on mac).
 #define MAX_CHUNK_COUNT 8 * 1024
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 
 #ifdef STATIC_BUILD
@@ -59,7 +59,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -71,17 +71,17 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_Allocate_alloc001_Test_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     size_t size;
-    void *prev = NULL;
+    void *prev = nullptr;
     void **mem;
     int memCount = 1;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     printf(">>> Null pointer check ...\n");
-    err = jvmti->Allocate((jlong)1, NULL);
+    err = jvmti->Allocate((jlong)1, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER, got: %s\n",
                TranslateError(err));
@@ -135,7 +135,7 @@ Java_nsk_jvmti_Allocate_alloc001_Test_check(JNIEnv *env, jclass cls) {
     printf(">>> ... done (%dMb)\n", memCount);
 
     printf(">>> Deallocation ...\n");
-    while (prev != NULL) {
+    while (prev != nullptr) {
         mem = (void**) prev;
         prev = *mem;
         err = jvmti->Deallocate((unsigned char *)mem);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach002/attach002Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach002/attach002Agent00.cpp
index de5229e6b6e..53283bd74ad 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach002/attach002Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach002/attach002Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,7 +45,7 @@ extern "C" {
 // class name in the ClassFileLoadHook callback
 #define REDEFINED_CLASS_NAME_INTERNAL "nsk/jvmti/AttachOnDemand/attach002/ClassToRedefine"
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 static volatile jboolean agentGotCapabilities = JNI_FALSE;
@@ -152,13 +152,13 @@ void JNICALL classFileLoadHoockHandler(
         jint * new_class_data_len,
         unsigned char** new_class_data) {
 
-    if (name != NULL) {
+    if (name != nullptr) {
         NSK_DISPLAY2("%s: ClassFileLoadHook event received for class '%s'\n", agentName, name);
         if (!strcmp(name, REDEFINED_CLASS_NAME_INTERNAL)) {
             classFileLoadHookReceived++;
         }
     } else {
-        NSK_DISPLAY1("%s: ClassFileLoadHook event received for class with NULL name\n", agentName);
+        NSK_DISPLAY1("%s: ClassFileLoadHook event received for class with null name\n", agentName);
     }
 }
 
@@ -177,21 +177,21 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
 {
     jvmtiEventCallbacks eventCallbacks;
     jvmtiCapabilities caps;
-    jvmtiEnv* jvmti = NULL;
-    JNIEnv* jni = NULL;
+    jvmtiEnv* jvmti = nullptr;
+    JNIEnv* jni = nullptr;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return NSK_FALSE;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     registerNativeMethods(jni);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach002a/attach002aAgent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach002a/attach002aAgent00.cpp
index ccc022edd1f..0ff97a05b20 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach002a/attach002aAgent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach002a/attach002aAgent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ extern "C" {
 #define REDEFINED_CLASS_NAME "Ljava/lang/InterruptedException;"
 #define REDEFINED_CLASS_FILE_NAME "java/lang/InterruptedException"
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 static jvmtiEvent testEvents[] = { JVMTI_EVENT_VM_OBJECT_ALLOC };
@@ -89,21 +89,21 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
 {
     jvmtiEventCallbacks eventCallbacks;
     jvmtiCapabilities caps;
-    jvmtiEnv* jvmti = NULL;
-    JNIEnv* jni = NULL;
+    jvmtiEnv* jvmti = nullptr;
+    JNIEnv* jni = nullptr;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return NSK_FALSE;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach008/attach008Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach008/attach008Agent00.cpp
index c1e9bce3ee3..b65c1cd6d9f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach008/attach008Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach008/attach008Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ extern "C" {
 
 #define THREAD_GENERATING_EVENTS_NAME "ThreadGeneratingEvents"
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 static jvmtiEvent testEvents[] = { JVMTI_EVENT_MONITOR_CONTENDED_ENTER, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED };
@@ -107,21 +107,21 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
 {
     jvmtiEventCallbacks eventCallbacks;
     jvmtiCapabilities caps;
-    jvmtiEnv* jvmti = NULL;
-    JNIEnv* jni = NULL;
+    jvmtiEnv* jvmti = nullptr;
+    JNIEnv* jni = nullptr;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return NSK_FALSE;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach009/attach009Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach009/attach009Agent00.cpp
index 3256b62582f..62afb281ba2 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach009/attach009Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach009/attach009Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ extern "C" {
  *  - receive ClassLoad event for class LastLoadedClass and finish work
  */
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 #define FIRST_LOADED_CLASS  "Lnsk/jvmti/AttachOnDemand/attach009/FirstLoadedClass;"
@@ -129,17 +129,17 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
     JNIEnv* jni;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return NSK_FALSE;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     memset(&eventCallbacks,0, sizeof(eventCallbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach012/attach012Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach012/attach012Agent00.cpp
index 64ab7c0974b..05ee3d82ac5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach012/attach012Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach012/attach012Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,23 +49,23 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
 #endif
 {
     jvmtiEnv* jvmti;
-    JNIEnv* jni = NULL;
-    Options* options = NULL;
+    JNIEnv* jni = nullptr;
+    Options* options = nullptr;
     const char* agentName;
     jvmtiCapabilities caps;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return NSK_FALSE;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->GetPotentialCapabilities(&caps))) {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach014/attach014Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach014/attach014Agent00.cpp
index ce3fa29a4e2..4575d4d7bfb 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach014/attach014Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach014/attach014Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,7 +39,7 @@ extern "C" {
  *  - agent receives ClassLoad event for this class, calls DisposeEnvironment and finishes work
  */
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 void JNICALL
@@ -88,21 +88,21 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
 #endif
 {
     jvmtiEventCallbacks eventCallbacks;
-    jvmtiEnv* jvmti = NULL;
-    JNIEnv* jni = NULL;
+    jvmtiEnv* jvmti = nullptr;
+    JNIEnv* jni = nullptr;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return NSK_FALSE;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     memset(&eventCallbacks,0, sizeof(eventCallbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach015/attach015Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach015/attach015Agent00.cpp
index a28c912880c..c96519aecf2 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach015/attach015Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach015/attach015Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ extern "C" {
 #define CLASS_NAME1 "Lnsk/jvmti/AttachOnDemand/attach015/ClassToLoad1;"
 #define CLASS_NAME2 "Lnsk/jvmti/AttachOnDemand/attach015/ClassToLoad2;"
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 static int receivedEventsCount = 0;
@@ -81,21 +81,21 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
 #endif
 {
     jvmtiEventCallbacks eventCallbacks;
-    jvmtiEnv* jvmti = NULL;
-    JNIEnv* jni = NULL;
+    jvmtiEnv* jvmti = nullptr;
+    JNIEnv* jni = nullptr;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return NSK_FALSE;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     memset(&eventCallbacks,0, sizeof(eventCallbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach015/attach015Agent01.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach015/attach015Agent01.cpp
index 78527c41cc8..eb42625c140 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach015/attach015Agent01.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach015/attach015Agent01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ extern "C" {
 #define CLASS_NAME1 "Lnsk/jvmti/AttachOnDemand/attach015/ClassToLoad1;"
 #define CLASS_NAME2 "Lnsk/jvmti/AttachOnDemand/attach015/ClassToLoad2;"
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 static int receivedEventsCount = 0;
@@ -81,21 +81,21 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
 #endif
 {
     jvmtiEventCallbacks eventCallbacks;
-    jvmtiEnv* jvmti = NULL;
-    JNIEnv* jni = NULL;
+    jvmtiEnv* jvmti = nullptr;
+    JNIEnv* jni = nullptr;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     memset(&eventCallbacks,0, sizeof(eventCallbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/attach020Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/attach020Agent00.cpp
index 0a229c858a2..7552e2bb936 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/attach020Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/attach020Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,7 +41,7 @@ extern "C" {
  *
  */
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 static jvmtiEvent testEvents[] = { JVMTI_EVENT_GARBAGE_COLLECTION_START, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH };
@@ -116,10 +116,10 @@ int startAuxiliaryThread(jvmtiEnv* jvmti, JNIEnv* jni) {
     jthread thread;
 
     thread = nsk_jvmti_aod_createThread(jni);
-    if (!NSK_VERIFY(thread != NULL))
+    if (!NSK_VERIFY(thread != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->RunAgentThread(thread, auxiliaryThreadFunction, NULL, JVMTI_THREAD_NORM_PRIORITY))) {
+    if (!NSK_JVMTI_VERIFY(jvmti->RunAgentThread(thread, auxiliaryThreadFunction, nullptr, JVMTI_THREAD_NORM_PRIORITY))) {
         return NSK_FALSE;
     }
 
@@ -147,17 +147,17 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
     JNIEnv* jni;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("GCFinishMonitor", &gcFinishMonitor))) {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/attach021Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/attach021Agent00.cpp
index 9a921d36a6f..cae9a35c8ee 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/attach021Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/attach021Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,7 +48,7 @@ extern "C" {
 
 static jvmtiEnv* jvmti;
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 // agent should set success status from objectFreeHandler
@@ -74,7 +74,7 @@ Java_nsk_jvmti_AttachOnDemand_attach021_attach021Target_shutdownAgent(JNIEnv * j
        for any pending ObjectFree events. */
     if (jvmti->SetEventNotificationMode(JVMTI_DISABLE,
                                         JVMTI_EVENT_OBJECT_FREE,
-                                        NULL) != JVMTI_ERROR_NONE) {
+                                        nullptr) != JVMTI_ERROR_NONE) {
         success = 0;
     }
 
@@ -127,17 +127,17 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
     JNIEnv* jni;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     registerNativeMethods(jni);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/attach022Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/attach022Agent00.cpp
index dfece015378..422cfa01356 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/attach022Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/attach022Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define OBJECTS_FOR_ALLOCATION_TEST_CLASS_NAME "Lnsk/jvmti/AttachOnDemand/attach022/ClassForAllocationEventsTest;"
 
 static jvmtiEnv* jvmti;
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 static jvmtiEvent testEvents[] = { JVMTI_EVENT_OBJECT_FREE, JVMTI_EVENT_VM_OBJECT_ALLOC };
@@ -174,17 +174,17 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
     JNIEnv* jni;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     registerNativeMethods(jni);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach037/attach037Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach037/attach037Agent00.cpp
index c7e22cdd3f0..798c1a77bc1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach037/attach037Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach037/attach037Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ extern "C" {
 
 #define THREAD_GENERATING_EVENTS_NAME "ThreadGeneratingEvents"
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 static jvmtiEvent testEvents[] = { JVMTI_EVENT_MONITOR_WAIT, JVMTI_EVENT_MONITOR_WAITED };
@@ -110,17 +110,17 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
     JNIEnv* jni;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach038/attach038Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach038/attach038Agent00.cpp
index d2f0767a9a4..6e66ecde85f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach038/attach038Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach038/attach038Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ extern "C" {
 
 #define THREAD_GENERATING_EVENTS_NAME "ThreadGeneratingEvents"
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 static jvmtiEvent testEvents[] = { JVMTI_EVENT_THREAD_START, JVMTI_EVENT_THREAD_END };
@@ -106,17 +106,17 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
     JNIEnv* jni;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     memset(&eventCallbacks,0, sizeof(eventCallbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach039/attach039Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach039/attach039Agent00.cpp
index 7fcea1fac3b..d1ca8919c40 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach039/attach039Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach039/attach039Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ extern "C" {
 
 #define STARTED_THREAD_NAME "ThreadStartedByAgent"
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 static jvmtiEvent testEvents[] = { JVMTI_EVENT_THREAD_START, JVMTI_EVENT_THREAD_END };
@@ -52,7 +52,7 @@ volatile int threadWasExecuted = 0;
 void JNICALL startedThreadFunction(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     char threadName[MAX_STRING_LENGTH];
 
-    if (!nsk_jvmti_aod_getThreadName(jvmti, NULL, threadName)) {
+    if (!nsk_jvmti_aod_getThreadName(jvmti, nullptr, threadName)) {
         nsk_jvmti_aod_disableEventsAndFinish(agentName, testEvents, testEventsNumber, 0, jvmti, jni);
         return;
     }
@@ -66,10 +66,10 @@ int startNewThread(jvmtiEnv* jvmti, JNIEnv* jni) {
     jthread thread;
 
     thread = nsk_jvmti_aod_createThreadWithName(jni, STARTED_THREAD_NAME);
-    if (!NSK_VERIFY(thread != NULL))
+    if (!NSK_VERIFY(thread != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->RunAgentThread(thread, startedThreadFunction, NULL, JVMTI_THREAD_NORM_PRIORITY))) {
+    if (!NSK_JVMTI_VERIFY(jvmti->RunAgentThread(thread, startedThreadFunction, nullptr, JVMTI_THREAD_NORM_PRIORITY))) {
         return NSK_FALSE;
     }
 
@@ -142,17 +142,17 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
     JNIEnv* jni;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     memset(&eventCallbacks,0, sizeof(eventCallbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach040/attach040Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach040/attach040Agent00.cpp
index b5ec2fbf809..d4ee65131c5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach040/attach040Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach040/attach040Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -47,7 +47,7 @@ static jrawMonitorID threadsCounterMonitor;
 
 static volatile int testThreadsCounter = 0;
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 void JNICALL threadStartHandler(jvmtiEnv *jvmti,
@@ -134,17 +134,17 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
     JNIEnv* jni;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("threadsCounterMonitor", &threadsCounterMonitor))) {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach041/attach041Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach041/attach041Agent00.cpp
index 6934868d6d3..e2aeb3c8dbe 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach041/attach041Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach041/attach041Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,14 +40,14 @@ extern "C" {
 
 #define STARTED_TEST_THREAD_NAME "attach041-TestThread"
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 int tryFindThread(jvmtiEnv *jvmti, jthreadGroup group, const char* threadNameToFind) {
     jint threadsCount = 0;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint groupsCount = 0;
-    jthreadGroup* groups = NULL;
+    jthreadGroup* groups = nullptr;
     jvmtiThreadGroupInfo groupInfo;
     int i;
     char threadGroupName[MAX_STRING_LENGTH];
@@ -160,17 +160,17 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
     JNIEnv* jni;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     memset(&eventCallbacks,0, sizeof(eventCallbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach042/attach042Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach042/attach042Agent00.cpp
index 0edaf1107ad..262fd40fd26 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach042/attach042Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach042/attach042Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ extern "C" {
 
 #define STARTED_TEST_THREAD_NAME "attach042-TestThread"
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 void JNICALL threadStartHandler(jvmtiEnv *jvmti,
@@ -58,7 +58,7 @@ void JNICALL threadStartHandler(jvmtiEnv *jvmti,
     if (!strcmp(startedThreadName, STARTED_TEST_THREAD_NAME)) {
         int success = 1;
         jint threadsCount = 0;
-        jthread* threads = NULL;
+        jthread* threads = nullptr;
         int i;
         int startedThreadWasFound = 0;
 
@@ -124,17 +124,17 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
     JNIEnv* jni;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     memset(&eventCallbacks,0, sizeof(eventCallbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent00.cpp
index a196150bc81..593f880330d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -37,7 +37,7 @@ extern "C" {
 
 #define EXPECTED_EVENTS_NUMBER 500
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 static jrawMonitorID eventsCounterMonitor;
@@ -98,17 +98,17 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
     JNIEnv* jni;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("attach045-agent00-eventsCounterMonitor", &eventsCounterMonitor))) {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent01.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent01.cpp
index a7ce1343d9e..a3957d5b2ce 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent01.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent01.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -37,7 +37,7 @@ extern "C" {
 
 #define EXPECTED_EVENTS_NUMBER 500
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 static jrawMonitorID eventsCounterMonitor;
@@ -109,17 +109,17 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
     JNIEnv* jni;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("attach045-agent01-eventsCounterMonitor", &eventsCounterMonitor))) {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent02.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent02.cpp
index f2f05136e6d..a4e08c526f2 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent02.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent02.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ extern "C" {
 
 #define EXPECTED_EVENTS_NUMBER 200
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 static jvmtiEvent testEvents[] = { JVMTI_EVENT_THREAD_START, JVMTI_EVENT_THREAD_END };
@@ -129,17 +129,17 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
     JNIEnv* jni;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("attach045-agent02-eventsCounterMonitor", &eventsCounterMonitor))) {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent03.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent03.cpp
index 65bd1604681..7cb7362289d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent03.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach045/attach045Agent03.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -37,7 +37,7 @@ extern "C" {
 
 #define EXPECTED_EVENTS_NUMBER 500
 
-static Options* options = NULL;
+static Options* options = nullptr;
 static const char* agentName;
 
 static jvmtiEvent testEvents[] = { JVMTI_EVENT_VM_OBJECT_ALLOC };
@@ -119,17 +119,17 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
     JNIEnv* jni;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("attach045-agent03-eventsCounterMonitor", &eventsCounterMonitor))) {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach046/attach046Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach046/attach046Agent00.cpp
index 0c1e03cf5f0..df01f06eac5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach046/attach046Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach046/attach046Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,7 +52,7 @@ void JNICALL  classLoadHandler(
     Options* options;
 
     options = nsk_jvmti_aod_getMultiagentsOptions(jvmti);
-    if (!NSK_VERIFY(options != NULL)) {
+    if (!NSK_VERIFY(options != nullptr)) {
         NSK_COMPLAIN0("Failed to get agents's options\n");
         nsk_jvmti_aod_disableEvent(jvmti, JVMTI_EVENT_CLASS_LOAD);
         // can't call nsk_aod_agentFinished because of without options can't get agent's name
@@ -96,23 +96,23 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
 {
     jvmtiEventCallbacks eventCallbacks;
     jvmtiCapabilities caps;
-    jvmtiEnv* jvmti = NULL;
-    JNIEnv* jni = NULL;
+    jvmtiEnv* jvmti = nullptr;
+    JNIEnv* jni = nullptr;
     Options* options;
     const char* agentName;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return NSK_FALSE;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach050/attach050Agent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach050/attach050Agent00.cpp
index 6a7ceeb4c48..beaca490a34 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach050/attach050Agent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach050/attach050Agent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -54,22 +54,22 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
 #endif
 {
     jvmtiEnv* jvmti;
-    JNIEnv* jni = NULL;
-    Options* options = NULL;
+    JNIEnv* jni = nullptr;
+    Options* options = nullptr;
     const char* agentName;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("%s: initialization was done\n", agentName);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/sharedAgents/simpleAgent00.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/sharedAgents/simpleAgent00.cpp
index d24922f2bfe..8f0f986f05d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/sharedAgents/simpleAgent00.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/sharedAgents/simpleAgent00.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -50,22 +50,22 @@ Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
 #endif
 {
     jvmtiEnv* jvmti;
-    JNIEnv* jni = NULL;
-    Options* options = NULL;
+    JNIEnv* jni = nullptr;
+    Options* options = nullptr;
     const char* agentName;
 
     options = (Options*) nsk_aod_createOptions(optionsString);
-    if (!NSK_VERIFY(options != NULL))
+    if (!NSK_VERIFY(options != nullptr))
         return JNI_ERR;
 
     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 
     jni = (JNIEnv*) nsk_aod_createJNIEnv(vm);
-    if (jni == NULL)
+    if (jni == nullptr)
         return JNI_ERR;
 
     jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("%s: initialization was done\n", agentName);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk001/classfloadhk001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk001/classfloadhk001.cpp
index ef6c10fc9fc..e204e5aedf5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk001/classfloadhk001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk001/classfloadhk001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,7 +41,7 @@ extern "C" {
 const char* CLASS_NAME = "nsk/jvmti/ClassFileLoadHook/classfloadhk001";
 
 static jint result = STATUS_FAILED;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 
 /** callback functions **/
@@ -51,7 +51,7 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *env, jclass class_beeing_redefine
         jint class_data_len, const unsigned char* class_data,
         jint *new_class_data_len, unsigned char** new_class_data) {
 
-    if (name != NULL && (strcmp(name, CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, CLASS_NAME) == 0)) {
         NSK_DISPLAY1("CHECK PASSED: ClassFileLoadHook event received for the class \"%s\" as expected\n",
             name);
         result = PASSED;
@@ -87,7 +87,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY0("setting event callbacks ...\n");
@@ -97,7 +97,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     NSK_DISPLAY0("setting event callbacks done\nenabling ClassFileLoadHook event ...\n");
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling ClassFileLoadHook event done\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk002/classfloadhk002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk002/classfloadhk002.cpp
index 520563f459f..976a53cc1c8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk002/classfloadhk002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk002/classfloadhk002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,7 +41,7 @@ static jlong timeout = 0;
 #define BYTECODE_FIELD_SIG    "[B"
 #define ORIG_BYTECODE_FIELD_NAME  "origClassBytes"
 
-static unsigned char* origClassBytes = NULL;
+static unsigned char* origClassBytes = nullptr;
 static jint origClassSize = 0;
 
 static volatile int eventsCount = 0;
@@ -59,8 +59,8 @@ static int checkBytecode(const char kind[], jint size, const unsigned char bytes
         nsk_printHexBytes("   ", 16, size, bytes);
     }
 
-    if (bytes == NULL) {
-        NSK_COMPLAIN2("Unexpected NULL pointer to %s bytecode in CLASS_FILE_LOAD_HOOK: 0x%p\n",
+    if (bytes == nullptr) {
+        NSK_COMPLAIN2("Unexpected null pointer to %s bytecode in CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                             kind, (void*)bytes);
         return NSK_FALSE;
     }
@@ -115,14 +115,14 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
                                     const char fieldName[], const char fieldSig[],
                                     jint* size, unsigned char* *bytes) {
 
-    jfieldID fieldID = NULL;
-    jbyteArray array = NULL;
+    jfieldID fieldID = nullptr;
+    jbyteArray array = nullptr;
     jbyte* elements;
     int i;
 
     NSK_DISPLAY1("Find static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (fieldID =
-            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != NULL)) {
+            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -130,7 +130,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     NSK_DISPLAY1("Get classfile bytes array from static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (array = (jbyteArray)
-            jni->GetStaticObjectField(cls, fieldID)) != NULL)) {
+            jni->GetStaticObjectField(cls, fieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -144,7 +144,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     {
         jboolean isCopy;
-        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != NULL)) {
+        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != nullptr)) {
             nsk_jvmti_setFailStatus();
         return NSK_FALSE;
         }
@@ -182,11 +182,11 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     {
         NSK_DISPLAY0(">>> Obtain original bytecode of tested class\n");
         {
-            jclass debugeeClass = NULL;
+            jclass debugeeClass = nullptr;
 
             NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
             if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-                    jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+                    jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -204,7 +204,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             jvmtiEvent event = JVMTI_EVENT_CLASS_FILE_LOAD_HOOK;
 
             NSK_DISPLAY1("Enable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
                 return;
             NSK_DISPLAY0("  ... event enabled\n");
 
@@ -216,7 +216,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
                 return;
 
             NSK_DISPLAY1("Disable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL))) {
+            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr))) {
                 NSK_DISPLAY0("  ... event disabled\n");
             }
 
@@ -261,13 +261,13 @@ callbackClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *env,
                         nsk_null_string(name), (void*)loader, (void*)class_being_redefined,
                         (void*)class_data, (int)class_data_len);
 
-    if (name != NULL && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
         NSK_DISPLAY1("SUCCESS! CLASS_FILE_LOAD_HOOK for tested class: %s\n", TESTED_CLASS_NAME);
         eventsCount++;
 
         NSK_DISPLAY1("Check class_being_redefined: 0x%p\n", (void*)class_being_redefined);
-        if (class_being_redefined != NULL) {
-            NSK_COMPLAIN1("Unexpected not NULL class_being_redefined in CLASS_FILE_LOAD_HOOK: 0x%p\n",
+        if (class_being_redefined != nullptr) {
+            NSK_COMPLAIN1("Unexpected not null class_being_redefined in CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                     (void*)class_being_redefined);
             nsk_jvmti_setFailStatus();
         }
@@ -294,7 +294,7 @@ JNIEXPORT jint JNI_OnLoad_classfloadhk002(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -304,7 +304,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("Add required capability: %s\n", "can_generate_eraly_class_hook_events");
@@ -333,7 +333,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("  ... set\n");
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk003/classfloadhk003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk003/classfloadhk003.cpp
index b9a11398753..d254e93b833 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk003/classfloadhk003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk003/classfloadhk003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,9 +45,9 @@ static jlong timeout = 0;
 #define BYTECODE_FIELD_SIG      "[B"
 #define ORIG_BYTECODE_FIELD_NAME  "origClassBytes"
 
-static jobject classLoader = NULL;
+static jobject classLoader = nullptr;
 static jint origClassSize = 0;
-static unsigned char* origClassBytes = NULL;
+static unsigned char* origClassBytes = nullptr;
 
 static volatile int eventsCount = 0;
 
@@ -64,8 +64,8 @@ static int checkBytecode(const char kind[], jint size, const unsigned char bytes
         nsk_printHexBytes("   ", 16, size, bytes);
     }
 
-    if (bytes == NULL) {
-        NSK_COMPLAIN2("Unexpected NULL pointer to %s bytecode in CLASS_FILE_LOAD_HOOK: 0x%p\n",
+    if (bytes == nullptr) {
+        NSK_COMPLAIN2("Unexpected null pointer to %s bytecode in CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                             kind, (void*)bytes);
         return NSK_FALSE;
     }
@@ -120,14 +120,14 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
                                     const char fieldName[], const char fieldSig[],
                                     jint* size, unsigned char* *bytes) {
 
-    jfieldID fieldID = NULL;
-    jbyteArray array = NULL;
+    jfieldID fieldID = nullptr;
+    jbyteArray array = nullptr;
     jbyte* elements;
     int i;
 
     NSK_DISPLAY1("Find static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (fieldID =
-            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != NULL)) {
+            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -135,7 +135,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     NSK_DISPLAY1("Get classfile bytes array from static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (array = (jbyteArray)
-            jni->GetStaticObjectField(cls, fieldID)) != NULL)) {
+            jni->GetStaticObjectField(cls, fieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -149,7 +149,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     {
         jboolean isCopy;
-        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != NULL)) {
+        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != nullptr)) {
             nsk_jvmti_setFailStatus();
         return NSK_FALSE;
         }
@@ -178,28 +178,28 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 static jobject getObject(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
                                     const char fieldName[], const char fieldSig[]) {
 
-    jfieldID fieldID = NULL;
-    jobject obj = NULL;
+    jfieldID fieldID = nullptr;
+    jobject obj = nullptr;
 
     NSK_DISPLAY1("Find static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (fieldID =
-            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != NULL)) {
+            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got fieldID: 0x%p\n", (void*)fieldID);
 
     NSK_DISPLAY1("Get object from static field: %s\n", fieldName);
-    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetStaticObjectField(cls, fieldID)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetStaticObjectField(cls, fieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got object: 0x%p\n", (void*)obj);
 
     NSK_DISPLAY1("Make global reference to object: 0x%p\n", obj);
-    if (!NSK_JNI_VERIFY(jni, (obj = jni->NewGlobalRef(obj)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (obj = jni->NewGlobalRef(obj)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got global ref: 0x%p\n", (void*)obj);
 
@@ -218,12 +218,12 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     /* perform testing */
     {
         {
-            jclass debugeeClass = NULL;
+            jclass debugeeClass = nullptr;
 
             NSK_DISPLAY0(">>> Obtain debuggee class\n");
             NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
             if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-                    jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+                    jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -232,7 +232,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             NSK_DISPLAY0(">>> Obtain classloader of tested class\n");
             if (!NSK_VERIFY((classLoader =
                     getObject(jvmti, jni, debugeeClass, CLASSLOADER_FIELD_NAME,
-                                                        TESTED_CLASSLOADER_SIG)) != NULL))
+                                                        TESTED_CLASSLOADER_SIG)) != nullptr))
                 return;
 
             NSK_DISPLAY0(">>> Obtain original bytecode of tested class\n");
@@ -248,7 +248,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             jvmtiEvent event = JVMTI_EVENT_CLASS_FILE_LOAD_HOOK;
 
             NSK_DISPLAY1("Enable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
                 return;
             NSK_DISPLAY0("  ... event enabled\n");
 
@@ -260,7 +260,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
                 return;
 
             NSK_DISPLAY1("Disable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL))) {
+            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr))) {
                 NSK_DISPLAY0("  ... event disabled\n");
             }
 
@@ -308,20 +308,20 @@ callbackClassFileLoadHook(jvmtiEnv *jvmti, JNIEnv *jni,
                         nsk_null_string(name), (void*)loader, (void*)class_being_redefined,
                         (void*)class_data, (int)class_data_len);
 
-    if (name != NULL && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
         NSK_DISPLAY1("SUCCESS! CLASS_FILE_LOAD_HOOK for tested class: %s\n", TESTED_CLASS_NAME);
         eventsCount++;
 
         NSK_DISPLAY1("Check class_being_redefined: 0x%p\n", (void*)class_being_redefined);
-        if (class_being_redefined != NULL) {
-            NSK_COMPLAIN1("Unexpected not NULL class_being_redefined in CLASS_FILE_LOAD_HOOK: 0x%p\n",
+        if (class_being_redefined != nullptr) {
+            NSK_COMPLAIN1("Unexpected not null class_being_redefined in CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                     (void*)class_being_redefined);
             nsk_jvmti_setFailStatus();
         }
 
         NSK_DISPLAY1("Check classloader: 0x%p\n", (void*)loader);
-        if (loader == NULL) {
-            NSK_COMPLAIN1("Unexpected NULL classloader in CLASS_FILE_LOAD_HOOK: 0x%p\n",
+        if (loader == nullptr) {
+            NSK_COMPLAIN1("Unexpected null classloader in CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                     (void*)loader);
             nsk_jvmti_setFailStatus();
         } else if (!jni->IsSameObject(loader, classLoader)) {
@@ -354,7 +354,7 @@ JNIEXPORT jint JNI_OnLoad_classfloadhk003(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -364,7 +364,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("Add required capability: %s\n", "can_generate_eraly_class_hook_events");
@@ -393,7 +393,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("  ... set\n");
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk004/classfloadhk004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk004/classfloadhk004.cpp
index 7fe5d9b89d1..e587e45c1da 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk004/classfloadhk004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk004/classfloadhk004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -43,7 +43,7 @@ static jlong timeout = 0;
 #define NEW_BYTECODE_FIELD_NAME  "newClassBytes"
 
 static jint newClassSize = 0;
-static unsigned char* newClassBytes = NULL;
+static unsigned char* newClassBytes = nullptr;
 
 static volatile int eventsCount = 0;
 
@@ -54,14 +54,14 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
                                     const char fieldName[], const char fieldSig[],
                                     jint* size, unsigned char* *bytes) {
 
-    jfieldID fieldID = NULL;
-    jbyteArray array = NULL;
+    jfieldID fieldID = nullptr;
+    jbyteArray array = nullptr;
     jbyte* elements;
     int i;
 
     NSK_DISPLAY1("Find static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (fieldID =
-            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != NULL)) {
+            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -69,7 +69,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     NSK_DISPLAY1("Get classfile bytes array from static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (array = (jbyteArray)
-            jni->GetStaticObjectField(cls, fieldID)) != NULL)) {
+            jni->GetStaticObjectField(cls, fieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -83,7 +83,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     {
         jboolean isCopy;
-        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != NULL)) {
+        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != nullptr)) {
             nsk_jvmti_setFailStatus();
         return NSK_FALSE;
         }
@@ -121,11 +121,11 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     {
         NSK_DISPLAY0(">>> Obtain classloader and instrumented bytecode of tested class\n");
         {
-            jclass debugeeClass = NULL;
+            jclass debugeeClass = nullptr;
 
             NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
             if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-                    jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+                    jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -143,7 +143,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             jvmtiEvent event = JVMTI_EVENT_CLASS_FILE_LOAD_HOOK;
 
             NSK_DISPLAY1("Enable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
                 return;
             NSK_DISPLAY0("  ... event enabled\n");
 
@@ -155,7 +155,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
                 return;
 
             NSK_DISPLAY1("Disable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL))) {
+            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr))) {
                 NSK_DISPLAY0("  ... event disabled\n");
             }
 
@@ -196,7 +196,7 @@ callbackClassFileLoadHook(jvmtiEnv *jvmti, JNIEnv *jni,
                         nsk_null_string(name), (void*)loader, (void*)class_being_redefined,
                         (void*)class_data, (int)class_data_len);
 
-    if (name != NULL && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
         NSK_DISPLAY1("SUCCESS! CLASS_FILE_LOAD_HOOK for tested class: %s\n", TESTED_CLASS_NAME);
         eventsCount++;
 
@@ -207,20 +207,20 @@ callbackClassFileLoadHook(jvmtiEnv *jvmti, JNIEnv *jni,
         }
 
         NSK_DISPLAY1("Check pointer to new_class_data_len: 0x%p\n", (void*)new_class_data_len);
-        if (new_class_data_len == NULL) {
-            NSK_COMPLAIN1("NULL new_class_data_len pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
+        if (new_class_data_len == nullptr) {
+            NSK_COMPLAIN1("null new_class_data_len pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                     (void*)new_class_data_len);
             nsk_jvmti_setFailStatus();
         }
 
         NSK_DISPLAY1("Check pointer to new_class_data: 0x%p\n", (void*)new_class_data);
-        if (new_class_data == NULL) {
-            NSK_COMPLAIN1("NULL new_class_data pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
+        if (new_class_data == nullptr) {
+            NSK_COMPLAIN1("null new_class_data pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                     (void*)new_class_data);
             nsk_jvmti_setFailStatus();
         }
 
-        if (new_class_data_len != NULL && new_class_data != NULL) {
+        if (new_class_data_len != nullptr && new_class_data != nullptr) {
             NSK_DISPLAY2("Replace with new bytecode: 0x%p:%d\n",
                                         (void*)newClassBytes, (int)newClassSize);
             if (nsk_getVerboseMode()) {
@@ -248,7 +248,7 @@ JNIEXPORT jint JNI_OnLoad_classfloadhk004(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -258,7 +258,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("Add required capability: %s\n", "can_generate_eraly_class_hook_events");
@@ -287,7 +287,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("  ... set\n");
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk005/classfloadhk005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk005/classfloadhk005.cpp
index 937d8d4a3e2..112f0dda0e9 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk005/classfloadhk005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk005/classfloadhk005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -43,7 +43,7 @@ static jlong timeout = 0;
 #define NEW_BYTECODE_FIELD_NAME  "newClassBytes"
 
 static jint newClassSize = 0;
-static unsigned char* newClassBytes = NULL;
+static unsigned char* newClassBytes = nullptr;
 
 static volatile int eventsCount = 0;
 
@@ -60,8 +60,8 @@ static int checkBytecode(const char kind[], jint size, const unsigned char bytes
         nsk_printHexBytes("   ", 16, size, bytes);
     }
 
-    if (bytes == NULL) {
-        NSK_COMPLAIN2("Unexpected NULL pointer to %s bytecode in CLASS_FILE_LOAD_HOOK: 0x%p\n",
+    if (bytes == nullptr) {
+        NSK_COMPLAIN2("Unexpected null pointer to %s bytecode in CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                             kind, (void*)bytes);
         return NSK_FALSE;
     }
@@ -116,14 +116,14 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
                                     const char fieldName[], const char fieldSig[],
                                     jint* size, unsigned char* *bytes) {
 
-    jfieldID fieldID = NULL;
-    jbyteArray array = NULL;
+    jfieldID fieldID = nullptr;
+    jbyteArray array = nullptr;
     jbyte* elements;
     int i;
 
     NSK_DISPLAY1("Find static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (fieldID =
-            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != NULL)) {
+            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -131,7 +131,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     NSK_DISPLAY1("Get classfile bytes array from static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (array = (jbyteArray)
-            jni->GetStaticObjectField(cls, fieldID)) != NULL)) {
+            jni->GetStaticObjectField(cls, fieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -145,7 +145,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     {
         jboolean isCopy;
-        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != NULL)) {
+        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != nullptr)) {
             nsk_jvmti_setFailStatus();
         return NSK_FALSE;
         }
@@ -183,11 +183,11 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     {
         NSK_DISPLAY0(">>> Obtain classloader and instrumented bytecode of tested class\n");
         {
-            jclass debugeeClass = NULL;
+            jclass debugeeClass = nullptr;
 
             NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
             if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-                    jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+                    jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -205,7 +205,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             jvmtiEvent event = JVMTI_EVENT_CLASS_FILE_LOAD_HOOK;
 
             NSK_DISPLAY1("Enable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
                 return;
             NSK_DISPLAY0("  ... event enabled\n");
 
@@ -217,7 +217,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
                 return;
 
             NSK_DISPLAY1("Disable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL))) {
+            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr))) {
                 NSK_DISPLAY0("  ... event disabled\n");
             }
 
@@ -258,7 +258,7 @@ callbackClassFileLoadHook(jvmtiEnv *jvmti, JNIEnv *jni,
                         nsk_null_string(name), (void*)loader, (void*)class_being_redefined,
                         (void*)class_data, (int)class_data_len);
 
-    if (name != NULL && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
         NSK_DISPLAY1("SUCCESS! CLASS_FILE_LOAD_HOOK for tested class: %s\n", TESTED_CLASS_NAME);
         eventsCount++;
 
@@ -269,20 +269,20 @@ callbackClassFileLoadHook(jvmtiEnv *jvmti, JNIEnv *jni,
         }
 
         NSK_DISPLAY1("Check pointer to new_class_data_len: 0x%p\n", (void*)new_class_data_len);
-        if (new_class_data_len == NULL) {
-            NSK_COMPLAIN1("NULL new_class_data_len pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
+        if (new_class_data_len == nullptr) {
+            NSK_COMPLAIN1("null new_class_data_len pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                     (void*)new_class_data_len);
             nsk_jvmti_setFailStatus();
         }
 
         NSK_DISPLAY1("Check pointer to new_class_data: 0x%p\n", (void*)new_class_data);
-        if (new_class_data == NULL) {
-            NSK_COMPLAIN1("NULL new_class_data pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
+        if (new_class_data == nullptr) {
+            NSK_COMPLAIN1("null new_class_data pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                     (void*)new_class_data);
             nsk_jvmti_setFailStatus();
         }
 
-        if (new_class_data_len != NULL && new_class_data != NULL) {
+        if (new_class_data_len != nullptr && new_class_data != nullptr) {
             NSK_DISPLAY2("Replace with instrumented bytecode: 0x%p:%d\n",
                                                 (void*)newClassBytes, (int)newClassSize);
             if (nsk_getVerboseMode()) {
@@ -310,7 +310,7 @@ JNIEXPORT jint JNI_OnLoad_classfloadhk005(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -320,7 +320,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("Add required capability: %s\n", "can_generate_eraly_class_hook_events");
@@ -349,7 +349,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("  ... set\n");
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk006/classfloadhk006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk006/classfloadhk006.cpp
index 41d48e5a484..31414b4ed90 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk006/classfloadhk006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk006/classfloadhk006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,10 +45,10 @@ static jlong timeout = 0;
 #define TESTED_CLASS_FIELD_NAME "testedClass"
 #define TESTED_CLASS_FIELD_SIG  "Ljava/lang/Class;"
 
-static jclass testedClass = NULL;
+static jclass testedClass = nullptr;
 
 static jint redefClassSize = 0;
-static unsigned char* redefClassBytes = NULL;
+static unsigned char* redefClassBytes = nullptr;
 
 static volatile int eventsCount = 0;
 
@@ -65,8 +65,8 @@ static int checkBytecode(const char kind[], jint size, const unsigned char bytes
         nsk_printHexBytes("   ", 16, size, bytes);
     }
 
-    if (bytes == NULL) {
-        NSK_COMPLAIN2("Unexpected NULL pointer to %s bytecode in CLASS_FILE_LOAD_HOOK: 0x%p\n",
+    if (bytes == nullptr) {
+        NSK_COMPLAIN2("Unexpected null pointer to %s bytecode in CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                             kind, (void*)bytes);
         return NSK_FALSE;
     }
@@ -121,14 +121,14 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
                                     const char fieldName[], const char fieldSig[],
                                     jint* size, unsigned char* *bytes) {
 
-    jfieldID fieldID = NULL;
-    jbyteArray array = NULL;
+    jfieldID fieldID = nullptr;
+    jbyteArray array = nullptr;
     jbyte* elements;
     int i;
 
     NSK_DISPLAY1("Find static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (fieldID =
-            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != NULL)) {
+            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -136,7 +136,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     NSK_DISPLAY1("Get classfile bytes array from static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (array = (jbyteArray)
-            jni->GetStaticObjectField(cls, fieldID)) != NULL)) {
+            jni->GetStaticObjectField(cls, fieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -150,7 +150,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     {
         jboolean isCopy;
-        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != NULL)) {
+        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != nullptr)) {
             nsk_jvmti_setFailStatus();
         return NSK_FALSE;
         }
@@ -179,28 +179,28 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 static jobject getObject(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
                                     const char fieldName[], const char fieldSig[]) {
 
-    jfieldID fieldID = NULL;
-    jobject obj = NULL;
+    jfieldID fieldID = nullptr;
+    jobject obj = nullptr;
 
     NSK_DISPLAY1("Find static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (fieldID =
-            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != NULL)) {
+            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got fieldID: 0x%p\n", (void*)fieldID);
 
     NSK_DISPLAY1("Get object from static field: %s\n", fieldName);
-    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetStaticObjectField(cls, fieldID)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetStaticObjectField(cls, fieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got object: 0x%p\n", (void*)obj);
 
     NSK_DISPLAY1("Make global reference to object: 0x%p\n", obj);
-    if (!NSK_JNI_VERIFY(jni, (obj = jni->NewGlobalRef(obj)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (obj = jni->NewGlobalRef(obj)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got global ref: 0x%p\n", (void*)obj);
 
@@ -238,12 +238,12 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     /* perform testing */
     {
         {
-            jclass debugeeClass = NULL;
+            jclass debugeeClass = nullptr;
 
             NSK_DISPLAY0(">>> Obtain debuggee class\n");
             NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
             if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-                    jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+                    jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -252,7 +252,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             NSK_DISPLAY0(">>> Obtain tested class object\n");
             if (!NSK_VERIFY((testedClass = (jclass)
                     getObject(jvmti, jni, debugeeClass, TESTED_CLASS_FIELD_NAME,
-                                                        TESTED_CLASS_FIELD_SIG)) != NULL))
+                                                        TESTED_CLASS_FIELD_SIG)) != nullptr))
                 return;
 
             NSK_DISPLAY0(">>> Obtain redefined bytecode of tested class\n");
@@ -275,7 +275,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             jvmtiEvent event = JVMTI_EVENT_CLASS_FILE_LOAD_HOOK;
 
             NSK_DISPLAY1("Enable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
                 return;
             NSK_DISPLAY0("  ... event enabled\n");
 
@@ -283,7 +283,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
                                                         redefClassSize, redefClassBytes));
 
             NSK_DISPLAY1("Disable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL))) {
+            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr))) {
                 NSK_DISPLAY0("  ... event disabled\n");
             }
 
@@ -330,13 +330,13 @@ callbackClassFileLoadHook(jvmtiEnv *jvmti, JNIEnv *jni,
                         nsk_null_string(name), (void*)loader, (void*)class_being_redefined,
                         (void*)class_data, (int)class_data_len);
 
-    if (name != NULL && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
         NSK_DISPLAY1("SUCCESS! CLASS_FILE_LOAD_HOOK for tested class: %s\n", TESTED_CLASS_NAME);
         eventsCount++;
 
         NSK_DISPLAY1("Check class_being_redefined: 0x%p\n", (void*)class_being_redefined);
-        if (class_being_redefined == NULL) {
-            NSK_COMPLAIN1("Unexpected NULL class_being_redefined in CLASS_FILE_LOAD_HOOK: 0x%p\n",
+        if (class_being_redefined == nullptr) {
+            NSK_COMPLAIN1("Unexpected null class_being_redefined in CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                     (void*)class_being_redefined);
             nsk_jvmti_setFailStatus();
         } else if (!jni->IsSameObject(class_being_redefined, testedClass)) {
@@ -369,7 +369,7 @@ JNIEXPORT jint JNI_OnLoad_classfloadhk006(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -379,7 +379,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("Add required capabilities: %s\n", "can_generate_eraly_class_hook_events, can_redefine_classes");
@@ -409,7 +409,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("  ... set\n");
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk007/classfloadhk007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk007/classfloadhk007.cpp
index 8c1f686361a..7107ccfdf41 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk007/classfloadhk007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk007/classfloadhk007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,11 +48,11 @@ static jlong timeout = 0;
 #define TESTED_CLASS_FIELD_NAME "testedClass"
 #define TESTED_CLASS_FIELD_SIG  "Ljava/lang/Class;"
 
-static jobject classLoader = NULL;
-static jclass testedClass = NULL;
+static jobject classLoader = nullptr;
+static jclass testedClass = nullptr;
 
 static jint redefClassSize = 0;
-static unsigned char* redefClassBytes = NULL;
+static unsigned char* redefClassBytes = nullptr;
 
 static volatile int eventsCount = 0;
 
@@ -69,8 +69,8 @@ static int checkBytecode(const char kind[], jint size, const unsigned char bytes
         nsk_printHexBytes("   ", 16, size, bytes);
     }
 
-    if (bytes == NULL) {
-        NSK_COMPLAIN2("Unexpected NULL pointer to %s bytecode in CLASS_FILE_LOAD_HOOK: 0x%p\n",
+    if (bytes == nullptr) {
+        NSK_COMPLAIN2("Unexpected null pointer to %s bytecode in CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                             kind, (void*)bytes);
         return NSK_FALSE;
     }
@@ -125,14 +125,14 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
                                     const char fieldName[], const char fieldSig[],
                                     jint* size, unsigned char* *bytes) {
 
-    jfieldID fieldID = NULL;
-    jbyteArray array = NULL;
+    jfieldID fieldID = nullptr;
+    jbyteArray array = nullptr;
     jbyte* elements;
     int i;
 
     NSK_DISPLAY1("Find static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (fieldID =
-            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != NULL)) {
+            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -140,7 +140,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     NSK_DISPLAY1("Get classfile bytes array from static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (array = (jbyteArray)
-            jni->GetStaticObjectField(cls, fieldID)) != NULL)) {
+            jni->GetStaticObjectField(cls, fieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -154,7 +154,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     {
         jboolean isCopy;
-        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != NULL)) {
+        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != nullptr)) {
             nsk_jvmti_setFailStatus();
         return NSK_FALSE;
         }
@@ -183,28 +183,28 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 static jobject getObject(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
                                     const char fieldName[], const char fieldSig[]) {
 
-    jfieldID fieldID = NULL;
-    jobject obj = NULL;
+    jfieldID fieldID = nullptr;
+    jobject obj = nullptr;
 
     NSK_DISPLAY1("Find static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (fieldID =
-            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != NULL)) {
+            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got fieldID: 0x%p\n", (void*)fieldID);
 
     NSK_DISPLAY1("Get object from static field: %s\n", fieldName);
-    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetStaticObjectField(cls, fieldID)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetStaticObjectField(cls, fieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got object: 0x%p\n", (void*)obj);
 
     NSK_DISPLAY1("Make global reference to object: 0x%p\n", obj);
-    if (!NSK_JNI_VERIFY(jni, (obj = jni->NewGlobalRef(obj)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (obj = jni->NewGlobalRef(obj)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got global ref: 0x%p\n", (void*)obj);
 
@@ -242,12 +242,12 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     /* perform testing */
     {
         {
-            jclass debugeeClass = NULL;
+            jclass debugeeClass = nullptr;
 
             NSK_DISPLAY0(">>> Obtain debuggee class\n");
             NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
             if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-                    jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+                    jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -256,13 +256,13 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             NSK_DISPLAY0(">>> Obtain tested class object\n");
             if (!NSK_VERIFY((testedClass = (jclass)
                     getObject(jvmti, jni, debugeeClass, TESTED_CLASS_FIELD_NAME,
-                                                        TESTED_CLASS_FIELD_SIG)) != NULL))
+                                                        TESTED_CLASS_FIELD_SIG)) != nullptr))
                 return;
 
             NSK_DISPLAY0(">>> Obtain classloader object\n");
             if (!NSK_VERIFY((classLoader =
                     getObject(jvmti, jni, debugeeClass, CLASSLOADER_FIELD_NAME,
-                                                        TESTED_CLASSLOADER_SIG)) != NULL))
+                                                        TESTED_CLASSLOADER_SIG)) != nullptr))
                 return;
 
             NSK_DISPLAY0(">>> Obtain redefined bytecode of tested class\n");
@@ -285,7 +285,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             jvmtiEvent event = JVMTI_EVENT_CLASS_FILE_LOAD_HOOK;
 
             NSK_DISPLAY1("Enable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
                 return;
             NSK_DISPLAY0("  ... event enabled\n");
 
@@ -293,7 +293,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
                                                         redefClassSize, redefClassBytes));
 
             NSK_DISPLAY1("Disable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL))) {
+            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr))) {
                 NSK_DISPLAY0("  ... event disabled\n");
             }
 
@@ -343,13 +343,13 @@ callbackClassFileLoadHook(jvmtiEnv *jvmti, JNIEnv *jni,
                         nsk_null_string(name), (void*)loader, (void*)class_being_redefined,
                         (void*)class_data, (int)class_data_len);
 
-    if (name != NULL && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
         NSK_DISPLAY1("SUCCESS! CLASS_FILE_LOAD_HOOK for tested class: %s\n", TESTED_CLASS_NAME);
         eventsCount++;
 
         NSK_DISPLAY1("Check classloader: 0x%p\n", (void*)loader);
-        if (loader == NULL) {
-            NSK_COMPLAIN1("Unexpected NULL classloader in CLASS_FILE_LOAD_HOOK: 0x%p\n",
+        if (loader == nullptr) {
+            NSK_COMPLAIN1("Unexpected null classloader in CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                     (void*)loader);
             nsk_jvmti_setFailStatus();
         } else if (!jni->IsSameObject(loader, classLoader)) {
@@ -361,8 +361,8 @@ callbackClassFileLoadHook(jvmtiEnv *jvmti, JNIEnv *jni,
         }
 
         NSK_DISPLAY1("Check class_being_redefined: 0x%p\n", (void*)class_being_redefined);
-        if (class_being_redefined == NULL) {
-            NSK_COMPLAIN1("Unexpected NULL class_being_redefined in CLASS_FILE_LOAD_HOOK: 0x%p\n",
+        if (class_being_redefined == nullptr) {
+            NSK_COMPLAIN1("Unexpected null class_being_redefined in CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                     (void*)class_being_redefined);
             nsk_jvmti_setFailStatus();
         } else if (!jni->IsSameObject(class_being_redefined, testedClass)) {
@@ -395,7 +395,7 @@ JNIEXPORT jint JNI_OnLoad_classfloadhk007(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -405,7 +405,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("Add required capabilities: %s\n", "can_generate_eraly_class_hook_events, can_redefine_classes");
@@ -435,7 +435,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("  ... set\n");
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk008/classfloadhk008.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk008/classfloadhk008.cpp
index 7f18912194d..01ea3da04a6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk008/classfloadhk008.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk008/classfloadhk008.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -46,13 +46,13 @@ static jlong timeout = 0;
 #define TESTED_CLASS_FIELD_NAME "testedClass"
 #define TESTED_CLASS_FIELD_SIG  "Ljava/lang/Class;"
 
-static jclass testedClass = NULL;
+static jclass testedClass = nullptr;
 
 static jint redefClassSize = 0;
-static unsigned char* redefClassBytes = NULL;
+static unsigned char* redefClassBytes = nullptr;
 
 static jint newClassSize = 0;
-static unsigned char* newClassBytes = NULL;
+static unsigned char* newClassBytes = nullptr;
 
 static volatile int eventsCount = 0;
 
@@ -63,14 +63,14 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
                                     const char fieldName[], const char fieldSig[],
                                     jint* size, unsigned char* *bytes) {
 
-    jfieldID fieldID = NULL;
-    jbyteArray array = NULL;
+    jfieldID fieldID = nullptr;
+    jbyteArray array = nullptr;
     jbyte* elements;
     int i;
 
     NSK_DISPLAY1("Find static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (fieldID =
-            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != NULL)) {
+            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -78,7 +78,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     NSK_DISPLAY1("Get classfile bytes array from static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (array = (jbyteArray)
-            jni->GetStaticObjectField(cls, fieldID)) != NULL)) {
+            jni->GetStaticObjectField(cls, fieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -92,7 +92,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     {
         jboolean isCopy;
-        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != NULL)) {
+        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != nullptr)) {
             nsk_jvmti_setFailStatus();
         return NSK_FALSE;
         }
@@ -121,28 +121,28 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 static jobject getObject(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
                                     const char fieldName[], const char fieldSig[]) {
 
-    jfieldID fieldID = NULL;
-    jobject obj = NULL;
+    jfieldID fieldID = nullptr;
+    jobject obj = nullptr;
 
     NSK_DISPLAY1("Find static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (fieldID =
-            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != NULL)) {
+            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got fieldID: 0x%p\n", (void*)fieldID);
 
     NSK_DISPLAY1("Get object from static field: %s\n", fieldName);
-    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetStaticObjectField(cls, fieldID)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetStaticObjectField(cls, fieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got object: 0x%p\n", (void*)obj);
 
     NSK_DISPLAY1("Make global reference to object: 0x%p\n", obj);
-    if (!NSK_JNI_VERIFY(jni, (obj = jni->NewGlobalRef(obj)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (obj = jni->NewGlobalRef(obj)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got global ref: 0x%p\n", (void*)obj);
 
@@ -180,12 +180,12 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     /* perform testing */
     {
         {
-            jclass debugeeClass = NULL;
+            jclass debugeeClass = nullptr;
 
             NSK_DISPLAY0(">>> Obtain debuggee class\n");
             NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
             if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-                    jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+                    jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -194,7 +194,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             NSK_DISPLAY0(">>> Obtain tested class object\n");
             if (!NSK_VERIFY((testedClass = (jclass)
                     getObject(jvmti, jni, debugeeClass, TESTED_CLASS_FIELD_NAME,
-                                                        TESTED_CLASS_FIELD_SIG)) != NULL))
+                                                        TESTED_CLASS_FIELD_SIG)) != nullptr))
                 return;
 
             NSK_DISPLAY0(">>> Obtain redefined bytecode of tested class\n");
@@ -224,7 +224,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             jvmtiEvent event = JVMTI_EVENT_CLASS_FILE_LOAD_HOOK;
 
             NSK_DISPLAY1("Enable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
                 return;
             NSK_DISPLAY0("  ... event enabled\n");
 
@@ -232,7 +232,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
                                                         redefClassSize, redefClassBytes));
 
             NSK_DISPLAY1("Disable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL))) {
+            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr))) {
                 NSK_DISPLAY0("  ... event disabled\n");
             }
 
@@ -279,7 +279,7 @@ callbackClassFileLoadHook(jvmtiEnv *jvmti, JNIEnv *jni,
                         nsk_null_string(name), (void*)loader, (void*)class_being_redefined,
                         (void*)class_data, (int)class_data_len);
 
-    if (name != NULL && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
         NSK_DISPLAY1("SUCCESS! CLASS_FILE_LOAD_HOOK for tested class: %s\n", TESTED_CLASS_NAME);
         eventsCount++;
 
@@ -290,20 +290,20 @@ callbackClassFileLoadHook(jvmtiEnv *jvmti, JNIEnv *jni,
         }
 
         NSK_DISPLAY1("Check pointer to new_class_data_len: 0x%p\n", (void*)new_class_data_len);
-        if (new_class_data_len == NULL) {
-            NSK_COMPLAIN1("NULL new_class_data_len pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
+        if (new_class_data_len == nullptr) {
+            NSK_COMPLAIN1("null new_class_data_len pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                     (void*)new_class_data_len);
             nsk_jvmti_setFailStatus();
         }
 
         NSK_DISPLAY1("Check pointer to new_class_data: 0x%p\n", (void*)new_class_data);
-        if (new_class_data == NULL) {
-            NSK_COMPLAIN1("NULL new_class_data pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
+        if (new_class_data == nullptr) {
+            NSK_COMPLAIN1("null new_class_data pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                     (void*)new_class_data);
             nsk_jvmti_setFailStatus();
         }
 
-        if (new_class_data_len != NULL && new_class_data != NULL) {
+        if (new_class_data_len != nullptr && new_class_data != nullptr) {
             NSK_DISPLAY2("Replace with new instrumented bytecode: 0x%p:%d\n",
                                         (void*)newClassBytes, (int)newClassSize);
             if (nsk_getVerboseMode()) {
@@ -331,7 +331,7 @@ JNIEXPORT jint JNI_OnLoad_classfloadhk008(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -341,7 +341,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("Add required capabilities: %s\n", "can_generate_eraly_class_hook_events, can_redefine_classes");
@@ -371,7 +371,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("  ... set\n");
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk009/classfloadhk009.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk009/classfloadhk009.cpp
index e4a2067772c..296c10cb84a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk009/classfloadhk009.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClassFileLoadHook/classfloadhk009/classfloadhk009.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -46,13 +46,13 @@ static jlong timeout = 0;
 #define TESTED_CLASS_FIELD_NAME "testedClass"
 #define TESTED_CLASS_FIELD_SIG  "Ljava/lang/Class;"
 
-static jclass testedClass = NULL;
+static jclass testedClass = nullptr;
 
 static jint redefClassSize = 0;
-static unsigned char* redefClassBytes = NULL;
+static unsigned char* redefClassBytes = nullptr;
 
 static jint newClassSize = 0;
-static unsigned char* newClassBytes = NULL;
+static unsigned char* newClassBytes = nullptr;
 
 static volatile int eventsCount = 0;
 
@@ -63,14 +63,14 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
                                     const char fieldName[], const char fieldSig[],
                                     jint* size, unsigned char* *bytes) {
 
-    jfieldID fieldID = NULL;
-    jbyteArray array = NULL;
+    jfieldID fieldID = nullptr;
+    jbyteArray array = nullptr;
     jbyte* elements;
     int i;
 
     NSK_DISPLAY1("Find static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (fieldID =
-            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != NULL)) {
+            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -78,7 +78,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     NSK_DISPLAY1("Get classfile bytes array from static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (array = (jbyteArray)
-            jni->GetStaticObjectField(cls, fieldID)) != NULL)) {
+            jni->GetStaticObjectField(cls, fieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -92,7 +92,7 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 
     {
         jboolean isCopy;
-        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != NULL)) {
+        if (!NSK_JNI_VERIFY(jni, (elements = jni->GetByteArrayElements(array, &isCopy)) != nullptr)) {
             nsk_jvmti_setFailStatus();
         return NSK_FALSE;
         }
@@ -121,28 +121,28 @@ static int getBytecode(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
 static jobject getObject(jvmtiEnv* jvmti, JNIEnv* jni, jclass cls,
                                     const char fieldName[], const char fieldSig[]) {
 
-    jfieldID fieldID = NULL;
-    jobject obj = NULL;
+    jfieldID fieldID = nullptr;
+    jobject obj = nullptr;
 
     NSK_DISPLAY1("Find static field: %s\n", fieldName);
     if (!NSK_JNI_VERIFY(jni, (fieldID =
-            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != NULL)) {
+            jni->GetStaticFieldID(cls, fieldName, fieldSig)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got fieldID: 0x%p\n", (void*)fieldID);
 
     NSK_DISPLAY1("Get object from static field: %s\n", fieldName);
-    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetStaticObjectField(cls, fieldID)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetStaticObjectField(cls, fieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got object: 0x%p\n", (void*)obj);
 
     NSK_DISPLAY1("Make global reference to object: 0x%p\n", obj);
-    if (!NSK_JNI_VERIFY(jni, (obj = jni->NewGlobalRef(obj)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (obj = jni->NewGlobalRef(obj)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
     NSK_DISPLAY1("  ... got global ref: 0x%p\n", (void*)obj);
 
@@ -180,12 +180,12 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     /* perform testing */
     {
         {
-            jclass debugeeClass = NULL;
+            jclass debugeeClass = nullptr;
 
             NSK_DISPLAY0(">>> Obtain debuggee class\n");
             NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
             if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-                    jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+                    jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -194,7 +194,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             NSK_DISPLAY0(">>> Obtain tested class object\n");
             if (!NSK_VERIFY((testedClass = (jclass)
                     getObject(jvmti, jni, debugeeClass, TESTED_CLASS_FIELD_NAME,
-                                                        TESTED_CLASS_FIELD_SIG)) != NULL))
+                                                        TESTED_CLASS_FIELD_SIG)) != nullptr))
                 return;
 
             NSK_DISPLAY0(">>> Obtain redefined bytecode of tested class\n");
@@ -224,7 +224,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             jvmtiEvent event = JVMTI_EVENT_CLASS_FILE_LOAD_HOOK;
 
             NSK_DISPLAY1("Enable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
                 return;
             NSK_DISPLAY0("  ... event enabled\n");
 
@@ -232,7 +232,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
                                                         redefClassSize, redefClassBytes));
 
             NSK_DISPLAY1("Disable event: %s\n", "CLASS_FILE_LOAD_HOOK");
-            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL))) {
+            if (NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr))) {
                 NSK_DISPLAY0("  ... event disabled\n");
             }
 
@@ -279,7 +279,7 @@ callbackClassFileLoadHook(jvmtiEnv *jvmti, JNIEnv *jni,
                         nsk_null_string(name), (void*)loader, (void*)class_being_redefined,
                         (void*)class_data, (int)class_data_len);
 
-    if (name != NULL && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, TESTED_CLASS_NAME) == 0)) {
         NSK_DISPLAY1("SUCCESS! CLASS_FILE_LOAD_HOOK for tested class: %s\n", TESTED_CLASS_NAME);
         eventsCount++;
 
@@ -290,20 +290,20 @@ callbackClassFileLoadHook(jvmtiEnv *jvmti, JNIEnv *jni,
         }
 
         NSK_DISPLAY1("Check pointer to new_class_data_len: 0x%p\n", (void*)new_class_data_len);
-        if (new_class_data_len == NULL) {
-            NSK_COMPLAIN1("NULL new_class_data_len pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
+        if (new_class_data_len == nullptr) {
+            NSK_COMPLAIN1("null new_class_data_len pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                     (void*)new_class_data_len);
             nsk_jvmti_setFailStatus();
         }
 
         NSK_DISPLAY1("Check pointer to new_class_data: 0x%p\n", (void*)new_class_data);
-        if (new_class_data == NULL) {
-            NSK_COMPLAIN1("NULL new_class_data pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
+        if (new_class_data == nullptr) {
+            NSK_COMPLAIN1("null new_class_data pointer passed to CLASS_FILE_LOAD_HOOK: 0x%p\n",
                                                     (void*)new_class_data);
             nsk_jvmti_setFailStatus();
         }
 
-        if (new_class_data_len != NULL && new_class_data != NULL) {
+        if (new_class_data_len != nullptr && new_class_data != nullptr) {
             NSK_DISPLAY2("Replace with new instrumented bytecode: 0x%p:%d\n",
                                         (void*)newClassBytes, (int)newClassSize);
             if (nsk_getVerboseMode()) {
@@ -331,7 +331,7 @@ JNIEXPORT jint JNI_OnLoad_classfloadhk009(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -341,7 +341,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("Add required capabilities: %s\n", "can_generate_eraly_class_hook_events, can_redefine_classes");
@@ -371,7 +371,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("  ... set\n");
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearBreakpoint/clrbrk001/clrbrk001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearBreakpoint/clrbrk001/clrbrk001.cpp
index 07540af5bf0..cae177d2537 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearBreakpoint/clrbrk001/clrbrk001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearBreakpoint/clrbrk001/clrbrk001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
@@ -62,12 +62,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -102,7 +102,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
             return JNI_ERR;
         }
         err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_BREAKPOINT, NULL);
+            JVMTI_EVENT_BREAKPOINT, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                    TranslateError(err), err);
@@ -118,7 +118,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 JNIEXPORT void JNICALL
 Java_nsk_jvmti_ClearBreakpoint_clrbrk001_getReady(JNIEnv *env, jclass cls, jint i) {
     mid = env->GetStaticMethodID(cls, "trial", "(I)I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find method \"trial(I)I\"\n");
         result = STATUS_FAILED;
     } else {
@@ -129,7 +129,7 @@ Java_nsk_jvmti_ClearBreakpoint_clrbrk001_getReady(JNIEnv *env, jclass cls, jint
 JNIEXPORT void JNICALL Java_nsk_jvmti_ClearBreakpoint_clrbrk001_setBP(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return;
     }
@@ -138,7 +138,7 @@ JNIEXPORT void JNICALL Java_nsk_jvmti_ClearBreakpoint_clrbrk001_setBP(JNIEnv *en
         return;
     }
 
-    if (mid == NULL) {
+    if (mid == nullptr) {
         return;
     }
 
@@ -153,7 +153,7 @@ JNIEXPORT void JNICALL Java_nsk_jvmti_ClearBreakpoint_clrbrk001_setBP(JNIEnv *en
 JNIEXPORT void JNICALL Java_nsk_jvmti_ClearBreakpoint_clrbrk001_clearBP(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return;
     }
@@ -162,7 +162,7 @@ JNIEXPORT void JNICALL Java_nsk_jvmti_ClearBreakpoint_clrbrk001_clearBP(JNIEnv *
         return;
     }
 
-    if (mid == NULL) {
+    if (mid == nullptr) {
         return;
     }
 
@@ -176,7 +176,7 @@ JNIEXPORT void JNICALL Java_nsk_jvmti_ClearBreakpoint_clrbrk001_clearBP(JNIEnv *
 
 JNIEXPORT jint JNICALL
 Java_nsk_jvmti_ClearBreakpoint_clrbrk001_check(JNIEnv *env, jclass cls) {
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearBreakpoint/clrbrk002/clrbrk002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearBreakpoint/clrbrk002/clrbrk002.cpp
index 79fde2ad9f2..e61a953186d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearBreakpoint/clrbrk002/clrbrk002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearBreakpoint/clrbrk002/clrbrk002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -98,7 +98,7 @@ Java_nsk_jvmti_ClearBreakpoint_clrbrk002_check(JNIEnv *env, jclass cls) {
     jlocation start;
     jlocation end;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -108,7 +108,7 @@ Java_nsk_jvmti_ClearBreakpoint_clrbrk002_check(JNIEnv *env, jclass cls) {
     }
 
     mid = env->GetStaticMethodID(cls, "run", "([Ljava/lang/String;Ljava/io/PrintStream;)I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find method run\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearBreakpoint/clrbrk005/clrbrk005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearBreakpoint/clrbrk005/clrbrk005.cpp
index f431e14ef10..d845833d94b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearBreakpoint/clrbrk005/clrbrk005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearBreakpoint/clrbrk005/clrbrk005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -96,7 +96,7 @@ Java_nsk_jvmti_ClearBreakpoint_clrbrk005_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jmethodID mid;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -114,7 +114,7 @@ Java_nsk_jvmti_ClearBreakpoint_clrbrk005_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid method check ...\n");
     }
-    err = jvmti->ClearBreakpoint(NULL, 0);
+    err = jvmti->ClearBreakpoint(nullptr, 0);
     if (err != JVMTI_ERROR_INVALID_METHODID) {
         printf("Error expected: JVMTI_ERROR_INVALID_METHODID,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldAccessWatch/clrfldw001/clrfldw001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldAccessWatch/clrfldw001/clrfldw001.cpp
index b40cf1e70fa..09561cd971b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldAccessWatch/clrfldw001/clrfldw001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldAccessWatch/clrfldw001/clrfldw001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,14 +45,14 @@ static jvmtiEnv *jvmti;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
-static jfieldID thrown_fid = NULL;
+static jfieldID thrown_fid = nullptr;
 static field fields[] = {
-    { "nsk/jvmti/ClearFieldAccessWatch/clrfldw001", "fld0", "I", 0, NULL },
-    { "nsk/jvmti/ClearFieldAccessWatch/clrfldw001", "fld1", "I", 1, NULL },
+    { "nsk/jvmti/ClearFieldAccessWatch/clrfldw001", "fld0", "I", 0, nullptr },
+    { "nsk/jvmti/ClearFieldAccessWatch/clrfldw001", "fld1", "I", 1, nullptr },
     { "nsk/jvmti/ClearFieldAccessWatch/clrfldw001", "fld2",
-      "Lnsk/jvmti/ClearFieldAccessWatch/clrfldw001a;", 0, NULL },
-    { "nsk/jvmti/ClearFieldAccessWatch/clrfldw001a", "fld3", "[I", 0, NULL },
-    { "nsk/jvmti/ClearFieldAccessWatch/clrfldw001b", "fld4", "F", 0, NULL },
+      "Lnsk/jvmti/ClearFieldAccessWatch/clrfldw001a;", 0, nullptr },
+    { "nsk/jvmti/ClearFieldAccessWatch/clrfldw001a", "fld3", "[I", 0, nullptr },
+    { "nsk/jvmti/ClearFieldAccessWatch/clrfldw001b", "fld4", "F", 0, nullptr },
 };
 
 void switchWatch(JNIEnv *env, jint ind, jboolean on) {
@@ -62,7 +62,7 @@ void switchWatch(JNIEnv *env, jint ind, jboolean on) {
     const char *msg;
 
     cls = env->FindClass(fld.klass);
-    if (fld.fid == NULL) {
+    if (fld.fid == nullptr) {
         if (fld.stat) {
             fields[ind].fid = env->GetStaticFieldID(cls, fld.name, fld.sig);
         } else {
@@ -109,7 +109,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -145,7 +145,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
 
         err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                JVMTI_EVENT_FIELD_ACCESS, NULL);
+                JVMTI_EVENT_FIELD_ACCESS, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to enable JVMTI_EVENT_FIELD_ACCESS: %s (%d)\n",
                    TranslateError(err), err);
@@ -182,7 +182,7 @@ JNIEXPORT void JNICALL
 Java_nsk_jvmti_ClearFieldAccessWatch_clrfldw001_check(JNIEnv *env,
         jclass cls, jint fld_ind, jboolean flag) {
     if (caps.can_generate_field_access_events) {
-        if (flag == JNI_FALSE && thrown_fid != NULL) {
+        if (flag == JNI_FALSE && thrown_fid != nullptr) {
             result = STATUS_FAILED;
             printf("(Field %d) FIELD_ACCESS event without access watch set\n",
                    fld_ind);
@@ -191,7 +191,7 @@ Java_nsk_jvmti_ClearFieldAccessWatch_clrfldw001_check(JNIEnv *env,
             printf("(Field %d) thrown field ID expected: 0x%p, got: 0x%p\n",
                    fld_ind, fields[fld_ind].fid, thrown_fid);
         }
-        thrown_fid = NULL;
+        thrown_fid = nullptr;
     }
 }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldAccessWatch/clrfldw002/clrfldw002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldAccessWatch/clrfldw002/clrfldw002.cpp
index 889c2781623..4ae421245ee 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldAccessWatch/clrfldw002/clrfldw002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldAccessWatch/clrfldw002/clrfldw002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -59,7 +59,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -96,7 +96,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
 
         err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                JVMTI_EVENT_FIELD_ACCESS, NULL);
+                JVMTI_EVENT_FIELD_ACCESS, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to enable JVMTI_EVENT_FIELD_ACCESS: %s (%d)\n",
                    TranslateError(err), err);
@@ -125,14 +125,14 @@ Java_nsk_jvmti_ClearFieldAccessWatch_clrfldw002_check(JNIEnv *env, jclass cls) {
                    TranslateError(err), err);
         }
     } else {
-        err = jvmti->ClearFieldAccessWatch(NULL, fid2);
+        err = jvmti->ClearFieldAccessWatch(nullptr, fid2);
         if (err != JVMTI_ERROR_INVALID_CLASS) {
             result = STATUS_FAILED;
             printf("Failed to return JVMTI_ERROR_INVALID_CLASS: %s (%d)\n",
                    TranslateError(err), err);
         }
 
-        err = jvmti->ClearFieldAccessWatch(cls, NULL);
+        err = jvmti->ClearFieldAccessWatch(cls, nullptr);
         if (err != JVMTI_ERROR_INVALID_FIELDID) {
             result = STATUS_FAILED;
             printf("Failed to return INVALID_FIELDID: %s (%d)\n",
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldModificationWatch/clrfmodw001/clrfmodw001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldModificationWatch/clrfmodw001/clrfmodw001.cpp
index 46e0dffa21c..eaf686e623e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldModificationWatch/clrfmodw001/clrfmodw001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldModificationWatch/clrfmodw001/clrfmodw001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,14 +45,14 @@ static jvmtiEnv *jvmti;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
-static jfieldID thrown_fid = NULL;
+static jfieldID thrown_fid = nullptr;
 static field fields[] = {
-    { "nsk/jvmti/ClearFieldModificationWatch/clrfmodw001", "fld0", "I", 0, NULL },
-    { "nsk/jvmti/ClearFieldModificationWatch/clrfmodw001", "fld1", "I", 1, NULL },
+    { "nsk/jvmti/ClearFieldModificationWatch/clrfmodw001", "fld0", "I", 0, nullptr },
+    { "nsk/jvmti/ClearFieldModificationWatch/clrfmodw001", "fld1", "I", 1, nullptr },
     { "nsk/jvmti/ClearFieldModificationWatch/clrfmodw001", "fld2",
-      "Lnsk/jvmti/ClearFieldModificationWatch/clrfmodw001a;", 0, NULL },
-    { "nsk/jvmti/ClearFieldModificationWatch/clrfmodw001a", "fld3", "[I", 0, NULL },
-    { "nsk/jvmti/ClearFieldModificationWatch/clrfmodw001b", "fld4", "F", 0, NULL },
+      "Lnsk/jvmti/ClearFieldModificationWatch/clrfmodw001a;", 0, nullptr },
+    { "nsk/jvmti/ClearFieldModificationWatch/clrfmodw001a", "fld3", "[I", 0, nullptr },
+    { "nsk/jvmti/ClearFieldModificationWatch/clrfmodw001b", "fld4", "F", 0, nullptr },
 };
 
 void switchWatch(JNIEnv *env, jint ind, jboolean on) {
@@ -62,7 +62,7 @@ void switchWatch(JNIEnv *env, jint ind, jboolean on) {
     const char *msg;
 
     cls = env->FindClass(fld.klass);
-    if (fld.fid == NULL) {
+    if (fld.fid == nullptr) {
         if (fld.stat) {
             fields[ind].fid = env->GetStaticFieldID(cls, fld.name, fld.sig);
         } else {
@@ -109,7 +109,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -145,7 +145,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
 
         err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                JVMTI_EVENT_FIELD_MODIFICATION, NULL);
+                JVMTI_EVENT_FIELD_MODIFICATION, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to enable JVMTI_EVENT_FIELD_MODIFICATION: %s (%d)\n",
                    TranslateError(err), err);
@@ -175,7 +175,7 @@ JNIEXPORT void JNICALL Java_nsk_jvmti_ClearFieldModificationWatch_clrfmodw001_to
 JNIEXPORT void JNICALL
 Java_nsk_jvmti_ClearFieldModificationWatch_clrfmodw001_check(JNIEnv *env, jclass cls, jint fld_ind, jboolean flag) {
     if (caps.can_generate_field_modification_events) {
-        if (flag == JNI_FALSE && thrown_fid != NULL) {
+        if (flag == JNI_FALSE && thrown_fid != nullptr) {
             result = STATUS_FAILED;
             printf("(Field %d) ", fld_ind);
             printf("FieldModification event without modification watch set\n");
@@ -184,7 +184,7 @@ Java_nsk_jvmti_ClearFieldModificationWatch_clrfmodw001_check(JNIEnv *env, jclass
             printf("(Field %d) thrown field ID expected: 0x%p, got: 0x%p\n",
                    fld_ind, fields[fld_ind].fid, thrown_fid);
         }
-        thrown_fid = NULL;
+        thrown_fid = nullptr;
     }
 }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldModificationWatch/clrfmodw002/clrfmodw002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldModificationWatch/clrfmodw002/clrfmodw002.cpp
index 127653e5010..329e8c32a2c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldModificationWatch/clrfmodw002/clrfmodw002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ClearFieldModificationWatch/clrfmodw002/clrfmodw002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -60,7 +60,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -96,7 +96,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
 
         err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                JVMTI_EVENT_FIELD_MODIFICATION, NULL);
+                JVMTI_EVENT_FIELD_MODIFICATION, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to enable JVMTI_EVENT_FIELD_MODIFICATION: %s (%d)\n",
                    TranslateError(err), err);
@@ -127,14 +127,14 @@ Java_nsk_jvmti_ClearFieldModificationWatch_clrfmodw002_check(JNIEnv *env,
                    TranslateError(err), err);
         }
     } else {
-        err = jvmti->ClearFieldModificationWatch(NULL, fid2);
+        err = jvmti->ClearFieldModificationWatch(nullptr, fid2);
         if (err != JVMTI_ERROR_INVALID_CLASS) {
             result = STATUS_FAILED;
             printf("Failed to return JVMTI_ERROR_INVALID_CLASS: %s (%d)\n",
                    TranslateError(err), err);
         }
 
-        err = jvmti->ClearFieldModificationWatch(cls, NULL);
+        err = jvmti->ClearFieldModificationWatch(cls, nullptr);
         if (err != JVMTI_ERROR_INVALID_FIELDID) {
             result = STATUS_FAILED;
             printf("Failed to return INVALID_FIELDID: %s (%d)\n",
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CompiledMethodLoad/compmethload001/compmethload001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CompiledMethodLoad/compmethload001/compmethload001.cpp
index a75546f9bdd..f70ded6238a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CompiledMethodLoad/compmethload001/compmethload001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CompiledMethodLoad/compmethload001/compmethload001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,7 +36,7 @@ extern "C" {
 #define PASSED 0
 
 static volatile jint result = PASSED;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -113,7 +113,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capability to generate compiled method events */
@@ -137,9 +137,9 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     NSK_DISPLAY0("setting event callbacks done\nenabling VMInit, CompiledMethodLoad event ...\n");
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr)))
         return JNI_ERR;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CompiledMethodUnload/compmethunload001/compmethunload001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CompiledMethodUnload/compmethunload001/compmethunload001.cpp
index 7b048a2202f..e3b50a0474e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CompiledMethodUnload/compmethunload001/compmethunload001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CompiledMethodUnload/compmethunload001/compmethunload001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ extern "C" {
 static volatile jint result = PASSED;
 static volatile int compunload = 0;
 static volatile int class_unloaded = 0;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -88,7 +88,7 @@ CompiledMethodUnload(jvmtiEnv *jvmti_env, jmethodID method,
 
     NSK_DISPLAY0("CompiledMethodUnload event received\n");
     // Check for the case that the class has been unloaded
-    err = jvmti_env->GetMethodName(method, &name, &sig, NULL);
+    err = jvmti_env->GetMethodName(method, &name, &sig, nullptr);
     if (err == JVMTI_ERROR_NONE) {
         NSK_DISPLAY3("for: \tmethod: name=\"%s\" signature=\"%s\"\n\tnative address=0x%p\n",
           name, sig, code_addr);
@@ -157,7 +157,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capability to generate compiled method events */
@@ -182,11 +182,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     NSK_DISPLAY0("setting event callbacks done\nenabling JVMTI events ...\n");
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr)))
         return JNI_ERR;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, nullptr)))
         return JNI_ERR;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_UNLOAD, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_UNLOAD, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CreateRawMonitor/crrawmon001/crrawmon001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CreateRawMonitor/crrawmon001/crrawmon001.cpp
index 4e8af24dc49..d2a0073b2ae 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CreateRawMonitor/crrawmon001/crrawmon001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CreateRawMonitor/crrawmon001/crrawmon001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define RAW_MONITORS_NUMBER 1024
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -57,7 +57,7 @@ void JNICALL VMInit(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thr) {
             printf("(CreateRawMonitor#%d) unexpected error: %s (%d)\n",
                    i, TranslateError(err), err);
             result = STATUS_FAILED;
-        } else if (monitors[i] == NULL) {
+        } else if (monitors[i] == nullptr) {
             printf("(CreateRawMonitor#%d) jrawMonitorID is null\n", i);
             result = STATUS_FAILED;
         }
@@ -79,12 +79,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -98,7 +98,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_VM_INIT, NULL);
+            JVMTI_EVENT_VM_INIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable JVMTI_EVENT_VM_INIT: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CreateRawMonitor/crrawmon002/crrawmon002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CreateRawMonitor/crrawmon002/crrawmon002.cpp
index 65edf664342..12519a57c2a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CreateRawMonitor/crrawmon002/crrawmon002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CreateRawMonitor/crrawmon002/crrawmon002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED  0
 #define STATUS_FAILED  2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_crrawmon002(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -69,7 +69,7 @@ Java_nsk_jvmti_CreateRawMonitor_crrawmon002_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jrawMonitorID monitor;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -77,7 +77,7 @@ Java_nsk_jvmti_CreateRawMonitor_crrawmon002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> name null pointer check ...\n");
     }
-    err = jvmti->CreateRawMonitor(NULL, &monitor);
+    err = jvmti->CreateRawMonitor(nullptr, &monitor);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER, got: %s\n",
                TranslateError(err));
@@ -87,7 +87,7 @@ Java_nsk_jvmti_CreateRawMonitor_crrawmon002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> monitorPtr null pointer check ...\n");
     }
-    err = jvmti->CreateRawMonitor("dummy", NULL);
+    err = jvmti->CreateRawMonitor("dummy", nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER, got: %s\n",
                TranslateError(err));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DataDumpRequest/datadumpreq001/datadumpreq001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DataDumpRequest/datadumpreq001/datadumpreq001.cpp
index 61994f9b6a6..5a8843e6e38 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DataDumpRequest/datadumpreq001/datadumpreq001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DataDumpRequest/datadumpreq001/datadumpreq001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ extern "C" {
 #define PASSED 0
 
 static jint result = STATUS_FAILED;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jboolean eventReceived = JNI_FALSE;
 
@@ -106,7 +106,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL)) {
+    if (!NSK_VERIFY(jvmti != nullptr)) {
         return JNI_ERR;
     }
 
@@ -122,7 +122,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     NSK_DISPLAY0("setting event callbacks done\nenabling JVMTI events ...\n");
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_DATA_DUMP_REQUEST, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_DATA_DUMP_REQUEST, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Deallocate/dealloc001/dealloc001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Deallocate/dealloc001/dealloc001.cpp
index 3aac4d41b95..82ea6825b63 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Deallocate/dealloc001/dealloc001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/Deallocate/dealloc001/dealloc001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED  0
 #define STATUS_FAILED  2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_dealloc001(JavaVM *jvm, char *options, void *reserved)
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -68,7 +68,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_Deallocate_dealloc001_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -76,7 +76,7 @@ Java_nsk_jvmti_Deallocate_dealloc001_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> Null pointer check ...\n");
     }
-    err = jvmti->Deallocate(NULL);
+    err = jvmti->Deallocate(nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Error expected: JVMTI_ERROR_NONE, got: %s\n",
                TranslateError(err));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DestroyRawMonitor/drrawmon001/drrawmon001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DestroyRawMonitor/drrawmon001/drrawmon001.cpp
index 35f2e6557f2..341da0a65b3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DestroyRawMonitor/drrawmon001/drrawmon001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DestroyRawMonitor/drrawmon001/drrawmon001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define RAW_MONITORS_NUMBER 1024
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -58,7 +58,7 @@ void JNICALL VMInit(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thr) {
                    i, TranslateError(err), err);
             result = STATUS_FAILED;
             return;
-        } else if (monitors[i] == NULL) {
+        } else if (monitors[i] == nullptr) {
             printf("(CreateRawMonitor#%d) jrawMonitorID is null\n", i);
             result = STATUS_FAILED;
             return;
@@ -94,12 +94,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -113,7 +113,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_VM_INIT, NULL);
+            JVMTI_EVENT_VM_INIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable JVMTI_EVENT_VM_INIT: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DestroyRawMonitor/drrawmon003/drrawmon003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DestroyRawMonitor/drrawmon003/drrawmon003.cpp
index 451be8b3bc8..22765b973d8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DestroyRawMonitor/drrawmon003/drrawmon003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DestroyRawMonitor/drrawmon003/drrawmon003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jboolean printdump = JNI_FALSE;
 
 #ifdef STATIC_BUILD
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_drrawmon003(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -69,7 +69,7 @@ Java_nsk_jvmti_DestroyRawMonitor_drrawmon003_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jrawMonitorID monitor;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DestroyRawMonitor/drrawmon004/drrawmon004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DestroyRawMonitor/drrawmon004/drrawmon004.cpp
index 18e322e2438..154e98fe12f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DestroyRawMonitor/drrawmon004/drrawmon004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DestroyRawMonitor/drrawmon004/drrawmon004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_drrawmon004(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -68,7 +68,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_DestroyRawMonitor_drrawmon004_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -77,7 +77,7 @@ Java_nsk_jvmti_DestroyRawMonitor_drrawmon004_check(JNIEnv *env, jclass cls) {
         printf(">>> invalid monitor check ...\n");
     }
 
-    err = jvmti->DestroyRawMonitor(NULL);
+    err = jvmti->DestroyRawMonitor(nullptr);
     if (err != JVMTI_ERROR_INVALID_MONITOR) {
         printf("Error expected: JVMTI_ERROR_INVALID_MONITOR,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DisposeEnvironment/disposeenv001/disposeenv001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DisposeEnvironment/disposeenv001/disposeenv001.cpp
index 43dc539ab3f..b652a8259dd 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DisposeEnvironment/disposeenv001/disposeenv001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DisposeEnvironment/disposeenv001/disposeenv001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -44,13 +44,13 @@ JNIEXPORT jint JNI_OnLoad_disposeenv001(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Testcase #1: Dispose JVMTI environment in Agent_OnLoad()\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DisposeEnvironment/disposeenv002/disposeenv002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DisposeEnvironment/disposeenv002/disposeenv002.cpp
index c804a2ca64c..220243ae1a2 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DisposeEnvironment/disposeenv002/disposeenv002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DisposeEnvironment/disposeenv002/disposeenv002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,7 +45,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
 
     NSK_DISPLAY0("Disable VM_DEATH event in VM_DEATH callback\n");
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_VM_DEATH, NULL))) {
+            jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_VM_DEATH, nullptr))) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -79,13 +79,13 @@ JNIEXPORT jint JNI_OnLoad_disposeenv002(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -99,7 +99,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
         NSK_DISPLAY0("Enable VM_DEATH event in JVM_OnLoad()\n");
         if (!NSK_JVMTI_VERIFY(
-                jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL))) {
+                jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr))) {
             return JNI_ERR;
         }
         NSK_DISPLAY0("  ... enabled\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DynamicCodeGenerated/dyncodgen001/dyncodgen001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DynamicCodeGenerated/dyncodgen001/dyncodgen001.cpp
index 9de2b542633..676fd762a7a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DynamicCodeGenerated/dyncodgen001/dyncodgen001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/DynamicCodeGenerated/dyncodgen001/dyncodgen001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -99,7 +99,7 @@ JNIEXPORT jint JNI_OnLoad_dyncodgen001(JavaVM *jvm, char *options, void *reserve
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
 
     /* init framework and parse options */
@@ -111,7 +111,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
@@ -121,11 +121,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* enable DynamicCodeGenerated event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_DYNAMIC_CODE_GENERATED, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_DYNAMIC_CODE_GENERATED, nullptr)))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ForceEarlyReturn/ForceEarlyReturn001/ForceEarlyReturn001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ForceEarlyReturn/ForceEarlyReturn001/ForceEarlyReturn001.cpp
index c3eed7356cc..29df3168b9b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ForceEarlyReturn/ForceEarlyReturn001/ForceEarlyReturn001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ForceEarlyReturn/ForceEarlyReturn001/ForceEarlyReturn001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -31,7 +31,7 @@ extern "C" {
 
 /* ============================================================================= */
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 
@@ -178,7 +178,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
 {
     jvmtiCapabilities caps;
 
-    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != NULL))
+    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->GetCapabilities(&caps)))
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ForceGarbageCollection/forcegc001/forcegc001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ForceGarbageCollection/forcegc001/forcegc001.cpp
index d7d1d712550..eb956244fe5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ForceGarbageCollection/forcegc001/forcegc001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ForceGarbageCollection/forcegc001/forcegc001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -72,7 +72,7 @@ JNIEXPORT jint JNI_OnLoad_forcegc001(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -80,10 +80,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ForceGarbageCollection/forcegc002/forcegc002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ForceGarbageCollection/forcegc002/forcegc002.cpp
index a069c099e50..5332beb8397 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ForceGarbageCollection/forcegc002/forcegc002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ForceGarbageCollection/forcegc002/forcegc002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -50,7 +50,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
         events = 0;
         NSK_DISPLAY0("Enable event GarbageCollectionStart\n");
-        if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+        if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
             return;
 
         NSK_DISPLAY0("Call ForceGarbageCollection()\n");
@@ -60,7 +60,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         }
 
         NSK_DISPLAY0("Disable event GarbageCollectionStart\n");
-        if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL)))
+        if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr)))
             return;
 
         NSK_DISPLAY0("Check if expected events received\n");
@@ -98,7 +98,7 @@ JNIEXPORT jint JNI_OnLoad_forcegc002(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -106,7 +106,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -125,7 +125,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
             return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001/gcfinish001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001/gcfinish001.cpp
index e247fbdbd00..819aa9189aa 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001/gcfinish001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001/gcfinish001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ extern "C" {
 
 #define MEM_SIZE 1024
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -194,7 +194,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capability to generate compiled method events */
@@ -218,9 +218,9 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     NSK_DISPLAY0("setting event callbacks done\nenabling JVMTI events ...\n");
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr)))
         return JNI_ERR;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001/gcstart001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001/gcstart001.cpp
index d9dab1b0c7d..ff8e837f277 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001/gcstart001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001/gcstart001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,7 +39,7 @@ extern "C" {
 static volatile jint result = PASSED;
 static volatile int gcstart = 0;
 static volatile int gcfinish = 0;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -114,7 +114,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capability to generate compiled method events */
@@ -139,11 +139,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     NSK_DISPLAY0("setting event callbacks done\nenabling JVMTI events ...\n");
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr)))
         return JNI_ERR;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, nullptr)))
         return JNI_ERR;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002/gcstart002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002/gcstart002.cpp
index fb9d69ddd08..ba134f06ed8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002/gcstart002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002/gcstart002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ extern "C" {
 
 #define MEM_SIZE 1024
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -195,7 +195,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capability to generate compiled method events */
@@ -219,9 +219,9 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     NSK_DISPLAY0("setting event callbacks done\nenabling JVMTI events ...\n");
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr)))
         return JNI_ERR;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GenerateEvents/genevents001/genevents001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GenerateEvents/genevents001/genevents001.cpp
index f208bcdfb42..02228b3021a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GenerateEvents/genevents001/genevents001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GenerateEvents/genevents001/genevents001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -94,7 +94,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         }
 
         NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-        if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL)) {
+        if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr)) {
             nsk_jvmti_setFailStatus();
         }
 
@@ -108,7 +108,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         }
 
         NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-        if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL)) {
+        if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr)) {
             nsk_jvmti_setFailStatus();
         }
 
@@ -174,7 +174,7 @@ JNIEXPORT jint JNI_OnLoad_genevents001(JavaVM *jvm, char *options, void *reserve
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -182,10 +182,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* add required capabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetArgumentsSize/argsize001/argsize001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetArgumentsSize/argsize001/argsize001.cpp
index 38b2612cab8..25d72ff3ba6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetArgumentsSize/argsize001/argsize001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetArgumentsSize/argsize001/argsize001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,12 +32,12 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 
 void chk(JNIEnv *env, jclass cl, const char *name, const char *sig, int stat, int size) {
     jvmtiError err;
-    jmethodID mid = NULL;
+    jmethodID mid = nullptr;
     jint ret_size;
 
     if (stat) {
@@ -45,7 +45,7 @@ void chk(JNIEnv *env, jclass cl, const char *name, const char *sig, int stat, in
     } else {
         mid = env->GetMethodID(cl, name, sig);
     }
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Name = %s, sig = %s: mid = 0\n", name, sig);
     }
     err = jvmti->GetArgumentsSize(mid, &ret_size);
@@ -76,7 +76,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetArgumentsSize/argsize002/argsize002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetArgumentsSize/argsize002/argsize002.cpp
index 5fd7c0d2d04..f2d9f76e219 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetArgumentsSize/argsize002/argsize002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetArgumentsSize/argsize002/argsize002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_argsize002(JavaVM *jvm, char *options, void *reserved)
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,13 +70,13 @@ Java_nsk_jvmti_GetArgumentsSize_argsize002_check(JNIEnv *env, jclass cls) {
     jmethodID mid;
     jint size;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     mid = env->GetMethodID(cls, "<init>", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID for \"<init>\"!\n");
         return STATUS_FAILED;
     }
@@ -84,7 +84,7 @@ Java_nsk_jvmti_GetArgumentsSize_argsize002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid method check ...\n");
     }
-    err = jvmti->GetArgumentsSize(NULL, &size);
+    err = jvmti->GetArgumentsSize(nullptr, &size);
     if (err != JVMTI_ERROR_INVALID_METHODID) {
         printf("Error expected: JVMTI_ERROR_INVALID_METHODID,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -94,7 +94,7 @@ Java_nsk_jvmti_GetArgumentsSize_argsize002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->GetArgumentsSize(mid, NULL);
+    err = jvmti->GetArgumentsSize(mid, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -102,7 +102,7 @@ Java_nsk_jvmti_GetArgumentsSize_argsize002_check(JNIEnv *env, jclass cls) {
     }
 
     mid = env->GetStaticMethodID(cls, "check", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID for \"check\"!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetAvailableProcessors/getavailproc001/getavailproc001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetAvailableProcessors/getavailproc001/getavailproc001.cpp
index 28d4ad2a91a..f374cef29ae 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetAvailableProcessors/getavailproc001/getavailproc001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetAvailableProcessors/getavailproc001/getavailproc001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -112,7 +112,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     success = checkProcessors(jvmti, "VM_DEATH callback");
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -139,7 +139,7 @@ JNIEXPORT jint JNI_OnLoad_getavailproc001(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -147,7 +147,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -162,7 +162,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Testcase #1: Check available processors in Agent_OnLoad()\n");
@@ -171,7 +171,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetBytecodes/bytecodes001/bytecodes001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetBytecodes/bytecodes001/bytecodes001.cpp
index ee476a7ce33..b0971242418 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetBytecodes/bytecodes001/bytecodes001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetBytecodes/bytecodes001/bytecodes001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,7 +41,7 @@ typedef struct {
     unsigned char *codes;
 } info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -70,12 +70,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -117,12 +117,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
 void checkMeth(JNIEnv *env, jclass cl, int meth_ind) {
     jvmtiError err;
-    jmethodID mid = NULL;
+    jmethodID mid = nullptr;
     jint count = -1;
-    unsigned char *codes = NULL;
+    unsigned char *codes = nullptr;
     int i;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -135,7 +135,7 @@ void checkMeth(JNIEnv *env, jclass cl, int meth_ind) {
         mid = env->GetMethodID(cl,
             meth_tab[meth_ind].name, meth_tab[meth_ind].sig);
     }
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("\"%s%s\": cannot get method ID!\n",
             meth_tab[meth_ind].name, meth_tab[meth_ind].sig);
         result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetBytecodes/bytecodes002/bytecodes002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetBytecodes/bytecodes002/bytecodes002.cpp
index ad5e5eeacd2..63a0a3c866a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetBytecodes/bytecodes002/bytecodes002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetBytecodes/bytecodes002/bytecodes002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -105,13 +105,13 @@ Java_nsk_jvmti_GetBytecodes_bytecodes002_check(JNIEnv *env, jclass cls) {
     jint bytecodeCount;
     unsigned char *bytecodes;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     mid = env->GetMethodID(cls, "<init>", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID for \"<init>\"!\n");
         return STATUS_FAILED;
     }
@@ -119,7 +119,7 @@ Java_nsk_jvmti_GetBytecodes_bytecodes002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid method check ...\n");
     }
-    err = jvmti->GetBytecodes(NULL, &bytecodeCount, &bytecodes);
+    err = jvmti->GetBytecodes(nullptr, &bytecodeCount, &bytecodes);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY && !caps.can_get_bytecodes) {
         /* It is OK */
     } else if (err != JVMTI_ERROR_INVALID_METHODID) {
@@ -131,7 +131,7 @@ Java_nsk_jvmti_GetBytecodes_bytecodes002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (bytecodeCountPtr) null pointer check ...\n");
     }
-    err = jvmti->GetBytecodes(mid, NULL, &bytecodes);
+    err = jvmti->GetBytecodes(mid, nullptr, &bytecodes);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY && !caps.can_get_bytecodes) {
         /* It is OK */
     } else if (err != JVMTI_ERROR_NULL_POINTER) {
@@ -143,7 +143,7 @@ Java_nsk_jvmti_GetBytecodes_bytecodes002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (bytecodesPtr) null pointer check ...\n");
     }
-    err = jvmti->GetBytecodes(mid, &bytecodeCount, NULL);
+    err = jvmti->GetBytecodes(mid, &bytecodeCount, nullptr);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY && !caps.can_get_bytecodes) {
         /* It is OK */
     } else if (err != JVMTI_ERROR_NULL_POINTER) {
@@ -153,7 +153,7 @@ Java_nsk_jvmti_GetBytecodes_bytecodes002_check(JNIEnv *env, jclass cls) {
     }
 
     mid = env->GetStaticMethodID(cls, "check", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID for \"check\"!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetBytecodes/bytecodes003/bytecodes003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetBytecodes/bytecodes003/bytecodes003.cpp
index bd8c2e25abe..4d7ed6978de 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetBytecodes/bytecodes003/bytecodes003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetBytecodes/bytecodes003/bytecodes003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -46,7 +46,7 @@ typedef struct {
     int length;
 } opcode_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
@@ -324,8 +324,8 @@ void JNICALL ClassPrepare(jvmtiEnv *jvmti_env, JNIEnv *env,
     unsigned char *bytecodes;
     jint i;
 
-    sig = NULL;
-    err = jvmti_env->GetClassSignature(cls, &sig, NULL);
+    sig = nullptr;
+    err = jvmti_env->GetClassSignature(cls, &sig, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("(GetClassSignature#%d) unexpected error: %s (%d)\n",
                eventsCount, TranslateError(err), err);
@@ -347,15 +347,15 @@ void JNICALL ClassPrepare(jvmtiEnv *jvmti_env, JNIEnv *env,
     }
 
     for (i = 0; i < mcount; i++) {
-        if (methods[i] == NULL) {
+        if (methods[i] == nullptr) {
             if (printdump == JNI_TRUE) {
                 printf(" null");
             }
         } else {
-            name = NULL;
-            msig = NULL;
-            bytecodes = NULL;
-            err = jvmti_env->GetMethodName(methods[i], &name, &msig, NULL);
+            name = nullptr;
+            msig = nullptr;
+            bytecodes = nullptr;
+            err = jvmti_env->GetMethodName(methods[i], &name, &msig, nullptr);
             if (err != JVMTI_ERROR_NONE) {
                 printf("(GetMethodName) unexpected error: %s (%d)\n",
                        TranslateError(err), err);
@@ -397,22 +397,22 @@ void JNICALL ClassPrepare(jvmtiEnv *jvmti_env, JNIEnv *env,
                     }
                 }
             }
-            if (name != NULL) {
+            if (name != nullptr) {
                 jvmti_env->Deallocate((unsigned char *)name);
             }
-            if (msig != NULL) {
+            if (msig != nullptr) {
                 jvmti_env->Deallocate((unsigned char *)msig);
             }
-            if (bytecodes != NULL) {
+            if (bytecodes != nullptr) {
                 jvmti_env->Deallocate(bytecodes);
             }
         }
     }
 
-    if (methods != NULL) {
+    if (methods != nullptr) {
         jvmti_env->Deallocate((unsigned char *)methods);
     }
-    if (sig != NULL) {
+    if (sig != nullptr) {
         jvmti_env->Deallocate((unsigned char *)sig);
     }
     eventsCount++;
@@ -433,12 +433,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -488,7 +488,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
 
         err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                JVMTI_EVENT_CLASS_PREPARE, NULL);
+                JVMTI_EVENT_CLASS_PREPARE, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to enable ClassPrepare: %s (%d)\n",
                    TranslateError(err), err);
@@ -505,14 +505,14 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_GetBytecodes_bytecodes003_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     if (caps.can_get_bytecodes) {
         err = jvmti->SetEventNotificationMode(JVMTI_DISABLE,
-                JVMTI_EVENT_CLASS_PREPARE, NULL);
+                JVMTI_EVENT_CLASS_PREPARE, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to disable JVMTI_EVENT_CLASS_PREPARE: %s (%d)\n",
                    TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCapabilities/getcaps001/getcaps001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCapabilities/getcaps001/getcaps001.cpp
index 33057c64901..74adc9187a8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCapabilities/getcaps001/getcaps001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCapabilities/getcaps001/getcaps001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getcaps001(JavaVM *jvm, char *options, void *reserved)
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -68,7 +68,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_GetCapabilities_getcaps001_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -76,7 +76,7 @@ Java_nsk_jvmti_GetCapabilities_getcaps001_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->GetCapabilities(NULL);
+    err = jvmti->GetCapabilities(nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCapabilities/getcaps002/getcaps002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCapabilities/getcaps002/getcaps002.cpp
index d3ddec8ad80..90bab14b567 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCapabilities/getcaps002/getcaps002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCapabilities/getcaps002/getcaps002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -252,7 +252,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     success = checkCapabilities(jvmti, "VM_DEATH callback");
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -279,7 +279,7 @@ JNIEXPORT jint JNI_OnLoad_getcaps002(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -287,7 +287,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -302,7 +302,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Testcase #1: Check capabilities in Agent_OnLoad()\n");
@@ -311,7 +311,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassFields/getclfld005/getclfld005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassFields/getclfld005/getclfld005.cpp
index 38264eaa61a..cd178863545 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassFields/getclfld005/getclfld005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassFields/getclfld005/getclfld005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getclfld005(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,7 +70,7 @@ Java_nsk_jvmti_GetClassFields_getclfld005_check(JNIEnv *env, jclass cls) {
     jint fcount;
     jfieldID *fields;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -78,7 +78,7 @@ Java_nsk_jvmti_GetClassFields_getclfld005_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid class check ...\n");
     }
-    err = jvmti->GetClassFields(NULL, &fcount, &fields);
+    err = jvmti->GetClassFields(nullptr, &fcount, &fields);
     if (err != JVMTI_ERROR_INVALID_CLASS) {
         printf("Error expected: JVMTI_ERROR_INVALID_CLASS,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -88,7 +88,7 @@ Java_nsk_jvmti_GetClassFields_getclfld005_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (fieldCountPtr) null pointer check ...\n");
     }
-    err = jvmti->GetClassFields(cls, NULL, &fields);
+    err = jvmti->GetClassFields(cls, nullptr, &fields);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("(fieldCountPtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -98,7 +98,7 @@ Java_nsk_jvmti_GetClassFields_getclfld005_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (fieldsPtr) null pointer check ...\n");
     }
-    err = jvmti->GetClassFields(cls, &fcount, NULL);
+    err = jvmti->GetClassFields(cls, &fcount, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("(fieldsPtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassFields/getclfld006/getclfld006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassFields/getclfld006/getclfld006.cpp
index aace1a93e3c..1c786d84908 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassFields/getclfld006/getclfld006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassFields/getclfld006/getclfld006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getclfld006(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,7 +70,7 @@ Java_nsk_jvmti_GetClassFields_getclfld006_check(JNIEnv *env, jclass cls, jint i,
     jint fcount;
     jfieldID *fields;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassFields/getclfld007/getclfld007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassFields/getclfld007/getclfld007.cpp
index 93da371fd54..c3f5a53daa5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassFields/getclfld007/getclfld007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassFields/getclfld007/getclfld007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,16 +33,16 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 
 
 // compares 'value' with jobject_arr[index]
 static bool equals_str(JNIEnv *env, const char *value, jobjectArray jobject_arr, jint index) {
     jstring jstr = (jstring)env->GetObjectArrayElement(jobject_arr, index);
-    const char* utf = env->GetStringUTFChars(jstr, NULL);
+    const char* utf = env->GetStringUTFChars(jstr, nullptr);
     bool res = false;
-    if (utf != NULL) {
+    if (utf != nullptr) {
         res = strcmp(value, utf) == 0;
         env->ReleaseStringUTFChars(jstr, utf);
     } else {
@@ -68,7 +68,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -84,7 +84,7 @@ Java_nsk_jvmti_GetClassFields_getclfld007_check(JNIEnv *env, jclass cls, jclass
     char *name, *sig;
     int j;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         fflush(0);
         result = STATUS_FAILED;
@@ -109,12 +109,12 @@ Java_nsk_jvmti_GetClassFields_getclfld007_check(JNIEnv *env, jclass cls, jclass
         result = STATUS_FAILED;
     }
     for (j = 0; j < fcount; j++) {
-        if (fields[j] == NULL) {
+        if (fields[j] == nullptr) {
             printf("(%d) fieldID = null\n", j);
             result = STATUS_FAILED;
             continue;
         }
-        err = jvmti->GetFieldName(clazz, fields[j], &name, &sig, NULL);
+        err = jvmti->GetFieldName(clazz, fields[j], &name, &sig, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("(GetFieldName#%d) unexpected error: %s (%d)\n",
                    j, TranslateError(err), err);
@@ -123,7 +123,7 @@ Java_nsk_jvmti_GetClassFields_getclfld007_check(JNIEnv *env, jclass cls, jclass
         }
         printf(">>>   [%d]: %s, sig = \"%s\"\n", j, name, sig);
         if ((j < field_count) &&
-               (name == NULL || sig == NULL ||
+               (name == nullptr || sig == nullptr ||
                 !equals_str(env, name, fieldArr, j * 2) ||
                 !equals_str(env, sig, fieldArr, j * 2 + 1))) {
             printf("(%d) wrong field: \"%s%s\"", j, name, sig);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoader/getclsldr001/getclsldr001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoader/getclsldr001/getclsldr001.cpp
index f337c203ba7..9d2d8a449d3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoader/getclsldr001/getclsldr001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoader/getclsldr001/getclsldr001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getclsldr001(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -69,7 +69,7 @@ Java_nsk_jvmti_GetClassLoader_getclsldr001_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jobject classloader;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -77,7 +77,7 @@ Java_nsk_jvmti_GetClassLoader_getclsldr001_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid class check ...\n");
     }
-    err = jvmti->GetClassLoader(NULL, &classloader);
+    err = jvmti->GetClassLoader(nullptr, &classloader);
     if (err != JVMTI_ERROR_INVALID_CLASS) {
         printf("Error expected: JVMTI_ERROR_INVALID_CLASS,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -87,7 +87,7 @@ Java_nsk_jvmti_GetClassLoader_getclsldr001_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->GetClassLoader(cls, NULL);
+    err = jvmti->GetClassLoader(cls, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoader/getclsldr002/getclsldr002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoader/getclsldr002/getclsldr002.cpp
index 04d473fc7c3..968158cc087 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoader/getclsldr002/getclsldr002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoader/getclsldr002/getclsldr002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getclsldr002(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -71,7 +71,7 @@ Java_nsk_jvmti_GetClassLoader_getclsldr002_check(JNIEnv *env,
     jobject classloader;
     char *sig, *generic;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -97,8 +97,8 @@ Java_nsk_jvmti_GetClassLoader_getclsldr002_check(JNIEnv *env,
         printf(">>> %d: %s\n", i, sig);
     }
 
-    if (classloader != NULL) {
-        printf("(%d:%s) class loader is not NULL: 0x%p\n",
+    if (classloader != nullptr) {
+        printf("(%d:%s) class loader is not null: 0x%p\n",
                i, sig, classloader);
         result = STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoader/getclsldr003/getclsldr003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoader/getclsldr003/getclsldr003.cpp
index d003074a629..3bd7008a32d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoader/getclsldr003/getclsldr003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoader/getclsldr003/getclsldr003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getclsldr003(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -71,7 +71,7 @@ Java_nsk_jvmti_GetClassLoader_getclsldr003_check(JNIEnv *env,
     jobject classloader;
     char *sig, *generic;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoaderClasses/clsldrclss001/clsldrclss001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoaderClasses/clsldrclss001/clsldrclss001.cpp
index afe7952ab20..af3a2e0b162 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoaderClasses/clsldrclss001/clsldrclss001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoaderClasses/clsldrclss001/clsldrclss001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_clsldrclss001(JavaVM *jvm, char *options, void *reserv
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -71,7 +71,7 @@ Java_nsk_jvmti_GetClassLoaderClasses_clsldrclss001_check(JNIEnv *env, jclass cls
     jclass *classes;
     jint classCount;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -87,7 +87,7 @@ Java_nsk_jvmti_GetClassLoaderClasses_clsldrclss001_check(JNIEnv *env, jclass cls
     if (printdump == JNI_TRUE) {
         printf(">>> (initiatingLoader) null pointer check ...\n");
     }
-    err = jvmti->GetClassLoaderClasses(NULL, &classCount, &classes);
+    err = jvmti->GetClassLoaderClasses(nullptr, &classCount, &classes);
     if (err == JVMTI_ERROR_NULL_POINTER) {
         printf("Expected: the classes initiated by the bootstrap loader,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -97,7 +97,7 @@ Java_nsk_jvmti_GetClassLoaderClasses_clsldrclss001_check(JNIEnv *env, jclass cls
     if (printdump == JNI_TRUE) {
         printf(">>> (classCountPtr) null pointer check ...\n");
     }
-    err = jvmti->GetClassLoaderClasses(classloader, NULL, &classes);
+    err = jvmti->GetClassLoaderClasses(classloader, nullptr, &classes);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -107,7 +107,7 @@ Java_nsk_jvmti_GetClassLoaderClasses_clsldrclss001_check(JNIEnv *env, jclass cls
     if (printdump == JNI_TRUE) {
         printf(">>> (classesPtr) null pointer check ...\n");
     }
-    err = jvmti->GetClassLoaderClasses(classloader, &classCount, NULL);
+    err = jvmti->GetClassLoaderClasses(classloader, &classCount, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoaderClasses/clsldrclss002/clsldrclss002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoaderClasses/clsldrclss002/clsldrclss002.cpp
index 65116a118a3..f389a9d56e1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoaderClasses/clsldrclss002/clsldrclss002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassLoaderClasses/clsldrclss002/clsldrclss002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,9 +35,9 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jobject testedClassLoader = NULL;
-static jclass testedClass = NULL;
-static jfieldID testedFieldID = NULL;
+static jobject testedClassLoader = nullptr;
+static jclass testedClass = nullptr;
+static jfieldID testedFieldID = nullptr;
 
 static const char* CLASS_SIG =
     "Lnsk/jvmti/GetClassLoaderClasses/clsldrclss002;";
@@ -58,15 +58,15 @@ static int prepare(JNIEnv* jni) {
     NSK_DISPLAY0("Obtain tested object from a static field of debugee class\n");
 
     NSK_DISPLAY1("Find class: %s\n", CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (testedClass = jni->FindClass(CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = jni->FindClass(CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass) jni->NewGlobalRef(testedClass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass) jni->NewGlobalRef(testedClass)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY2("Find field: %s:%s\n", FIELD_NAME, FIELD_SIGNATURE);
     if (!NSK_JNI_VERIFY(jni, (testedFieldID =
-            jni->GetStaticFieldID(testedClass, FIELD_NAME, FIELD_SIGNATURE)) != NULL))
+            jni->GetStaticFieldID(testedClass, FIELD_NAME, FIELD_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -82,15 +82,15 @@ static int lookup(jvmtiEnv* jvmti,
         if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(classes[i], &signature, &generic)))
             break;
 
-        if (signature != NULL && strcmp(signature, exp_sig) == 0) {
+        if (signature != nullptr && strcmp(signature, exp_sig) == 0) {
             NSK_DISPLAY1("Expected class found: %s\n", exp_sig);
             found = NSK_TRUE;
         }
 
-        if (signature != NULL)
+        if (signature != nullptr)
             jvmti->Deallocate((unsigned char*)signature);
 
-        if (generic != NULL)
+        if (generic != nullptr)
             jvmti->Deallocate((unsigned char*)generic);
     }
 
@@ -115,7 +115,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     NSK_DISPLAY0("Testcase #1: check on default classloader\n");
     if (!NSK_JNI_VERIFY(jni, (testedClassLoader =
-            jni->GetStaticObjectField(testedClass, testedFieldID)) != NULL)) {
+            jni->GetStaticObjectField(testedClass, testedFieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -127,7 +127,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         nsk_jvmti_setFailStatus();
         return;
     }
-    if (!NSK_VERIFY(classes != NULL)) {
+    if (!NSK_VERIFY(classes != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -136,7 +136,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         nsk_jvmti_setFailStatus();
         return;
     }
-    if (classes != NULL)
+    if (classes != nullptr)
         jvmti->Deallocate((unsigned char*)classes);
 
     if (!nsk_jvmti_resumeSync())
@@ -146,7 +146,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     NSK_DISPLAY0("Testcase #2: check on custom classloader\n");
     if (!NSK_JNI_VERIFY(jni, (testedClassLoader =
-            jni->GetStaticObjectField(testedClass, testedFieldID)) != NULL)) {
+            jni->GetStaticObjectField(testedClass, testedFieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -158,7 +158,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         nsk_jvmti_setFailStatus();
         return;
     }
-    if (!NSK_VERIFY(classes != NULL)) {
+    if (!NSK_VERIFY(classes != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -174,7 +174,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_COMPLAIN1("Cannot find class in the list: %s\n", CLASS_SIG_E);
         nsk_jvmti_setFailStatus();
     }
-    if (classes != NULL)
+    if (classes != nullptr)
         jvmti->Deallocate((unsigned char*)classes);
 
     NSK_TRACE(jni->DeleteGlobalRef(testedClass));
@@ -198,7 +198,7 @@ JNIEXPORT jint JNI_OnLoad_clsldrclss002(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     NSK_DISPLAY0("Agent_OnLoad\n");
 
@@ -208,10 +208,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassMethods/getclmthd005/getclmthd005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassMethods/getclmthd005/getclmthd005.cpp
index ec8da62bb60..5a39a2bf549 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassMethods/getclmthd005/getclmthd005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassMethods/getclmthd005/getclmthd005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getclmthd005(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,7 +70,7 @@ Java_nsk_jvmti_GetClassMethods_getclmthd005_check(JNIEnv *env, jclass cls) {
     jint mcount;
     jmethodID *methods;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -78,7 +78,7 @@ Java_nsk_jvmti_GetClassMethods_getclmthd005_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid class check ...\n");
     }
-    err = jvmti->GetClassMethods(NULL, &mcount, &methods);
+    err = jvmti->GetClassMethods(nullptr, &mcount, &methods);
     if (err != JVMTI_ERROR_INVALID_CLASS) {
         printf("Error expected: JVMTI_ERROR_INVALID_CLASS,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -88,7 +88,7 @@ Java_nsk_jvmti_GetClassMethods_getclmthd005_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (methodCountPtr) null pointer check ...\n");
     }
-    err = jvmti->GetClassMethods(cls, NULL, &methods);
+    err = jvmti->GetClassMethods(cls, nullptr, &methods);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("(methodCountPtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -98,7 +98,7 @@ Java_nsk_jvmti_GetClassMethods_getclmthd005_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (methodsPtr) null pointer check ...\n");
     }
-    err = jvmti->GetClassMethods(cls, &mcount, NULL);
+    err = jvmti->GetClassMethods(cls, &mcount, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("(methodsPtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassMethods/getclmthd006/getclmthd006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassMethods/getclmthd006/getclmthd006.cpp
index 03d1152454c..3435c915a48 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassMethods/getclmthd006/getclmthd006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassMethods/getclmthd006/getclmthd006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getclmthd006(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,7 +70,7 @@ Java_nsk_jvmti_GetClassMethods_getclmthd006_check(JNIEnv *env, jclass cls, jint
     jint mcount;
     jmethodID *methods;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassMethods/getclmthd007/getclmthd007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassMethods/getclmthd007/getclmthd007.cpp
index 031f11d03ed..e5e75b5d9b1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassMethods/getclmthd007/getclmthd007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassMethods/getclmthd007/getclmthd007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -44,7 +44,7 @@ typedef struct {
     meth_info *meths;
 } class_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -124,12 +124,12 @@ JNIEXPORT jint JNI_OnLoad_getclmthd007(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -147,7 +147,7 @@ Java_nsk_jvmti_GetClassMethods_getclmthd007_check(JNIEnv *env,
     int j, k;
 
     int failed = JNI_FALSE; // enable debugging on failure
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -173,7 +173,7 @@ Java_nsk_jvmti_GetClassMethods_getclmthd007_check(JNIEnv *env,
         printf(">>> %s:\n", classes[i].name);
     }
     for (k = 0; k < mcount; k++) {
-        if (methods[k] == NULL) {
+        if (methods[k] == nullptr) {
             printf("(%d:%d) methodID = null\n", i, k);
             result = STATUS_FAILED;
         } else if (printdump == JNI_TRUE || failed == JNI_TRUE) {
@@ -187,7 +187,7 @@ Java_nsk_jvmti_GetClassMethods_getclmthd007_check(JNIEnv *env,
     for (j = 0; j < classes[i].mcount; j++) {
         /* search the returned table for each expected entry */
         for (k = 0; k < mcount; k++) {
-            if (methods[k] != NULL) {
+            if (methods[k] != nullptr) {
                 err = jvmti->GetMethodName(methods[k],
                     &name, &sig, &generic);
                 if (err != JVMTI_ERROR_NONE) {
@@ -195,7 +195,7 @@ Java_nsk_jvmti_GetClassMethods_getclmthd007_check(JNIEnv *env,
                            i, k, TranslateError(err), err);
                     result = STATUS_FAILED;
                 } else {
-                    if (name != NULL && sig != NULL &&
+                    if (name != nullptr && sig != nullptr &&
                         strcmp(name, classes[i].meths[j].name) == 0 &&
                         strcmp(sig, classes[i].meths[j].sig) == 0) break;
                 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf004/getclmdf004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf004/getclmdf004.cpp
index da09f1c5f2c..f929d466d9c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf004/getclmdf004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf004/getclmdf004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getclmdf004(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -69,7 +69,7 @@ Java_nsk_jvmti_GetClassModifiers_getclmdf004_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jint modifiers;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -77,7 +77,7 @@ Java_nsk_jvmti_GetClassModifiers_getclmdf004_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid class check ...\n");
     }
-    err = jvmti->GetClassModifiers(NULL, &modifiers);
+    err = jvmti->GetClassModifiers(nullptr, &modifiers);
     if (err != JVMTI_ERROR_INVALID_CLASS) {
         printf("Error expected: JVMTI_ERROR_INVALID_CLASS,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -87,7 +87,7 @@ Java_nsk_jvmti_GetClassModifiers_getclmdf004_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->GetClassModifiers(cls, NULL);
+    err = jvmti->GetClassModifiers(cls, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf005/getclmdf005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf005/getclmdf005.cpp
index 7a83d1dbd72..8cdaff36314 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf005/getclmdf005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf005/getclmdf005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,7 +39,7 @@ extern "C" {
 #define ACC_FINAL       0x0010
 #define ACC_INTERFACE   0x0200
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -57,12 +57,12 @@ JNIEXPORT jint JNI_OnLoad_getclmdf005(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -75,7 +75,7 @@ Java_nsk_jvmti_GetClassModifiers_getclmdf005_check(JNIEnv *env, jclass cls, jint
     jvmtiError err;
     jint modifiers;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf006/getclmdf006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf006/getclmdf006.cpp
index d13e51d5a5d..14d7a0b2e29 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf006/getclmdf006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf006/getclmdf006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@ extern "C" {
 #define ACC_INTERFACE   0x0200
 #define ACC_ABSTRACT    0x0400
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -60,12 +60,12 @@ JNIEXPORT jint JNI_OnLoad_getclmdf006(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -90,7 +90,7 @@ Java_nsk_jvmti_GetClassModifiers_getclmdf006_check(JNIEnv *env, jclass cls, jcla
     jvmtiError err;
     jint modifiers;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf007/getclmdf007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf007/getclmdf007.cpp
index f6742e15cd7..5315c795dba 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf007/getclmdf007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassModifiers/getclmdf007/getclmdf007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@ extern "C" {
 #define ACC_INTERFACE   0x0200
 #define ACC_ABSTRACT    0x0400
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -60,12 +60,12 @@ JNIEXPORT jint JNI_OnLoad_getclmdf007(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -91,7 +91,7 @@ Java_nsk_jvmti_GetClassModifiers_getclmdf007_check(JNIEnv *env, jclass cls, jint
     jint ArrayModifiers;
     jint ComponentModifiers;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassSignature/getclsig004/getclsig004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassSignature/getclsig004/getclsig004.cpp
index 782a331729b..d01bf625873 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassSignature/getclsig004/getclsig004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassSignature/getclsig004/getclsig004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static const char *sigs[] = {
@@ -63,12 +63,12 @@ JNIEXPORT jint JNI_OnLoad_getclsig004(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -82,7 +82,7 @@ Java_nsk_jvmti_GetClassSignature_getclsig004_check(JNIEnv *env,
     jvmtiError err;
     char *sig, *generic;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassSignature/getclsig005/getclsig005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassSignature/getclsig005/getclsig005.cpp
index 149ab655a72..919bd50b940 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassSignature/getclsig005/getclsig005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassSignature/getclsig005/getclsig005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define CLASS_SIGNATURE "Lnsk/jvmti/GetClassSignature/getclsig005;"
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -52,12 +52,12 @@ JNIEXPORT jint JNI_OnLoad_getclsig005(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,7 +70,7 @@ Java_nsk_jvmti_GetClassSignature_getclsig005_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     char *sig, *generic;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -78,7 +78,7 @@ Java_nsk_jvmti_GetClassSignature_getclsig005_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid class check ...\n");
     }
-    err = jvmti->GetClassSignature(NULL, &sig, &generic);
+    err = jvmti->GetClassSignature(nullptr, &sig, &generic);
     if (err != JVMTI_ERROR_INVALID_CLASS) {
         printf("Error expected: JVMTI_ERROR_INVALID_CLASS,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -88,7 +88,7 @@ Java_nsk_jvmti_GetClassSignature_getclsig005_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (signature_ptr) null pointer check ...\n");
     }
-    err = jvmti->GetClassSignature(cls, NULL, &generic);
+    err = jvmti->GetClassSignature(cls, nullptr, &generic);
     if (err != JVMTI_ERROR_NONE) {
         printf("(signature_ptr) unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -102,7 +102,7 @@ Java_nsk_jvmti_GetClassSignature_getclsig005_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (generic_ptr) null pointer check ...\n");
     }
-    err = jvmti->GetClassSignature(cls, &sig, NULL);
+    err = jvmti->GetClassSignature(cls, &sig, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("(generic_ptr) unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -111,7 +111,7 @@ Java_nsk_jvmti_GetClassSignature_getclsig005_check(JNIEnv *env, jclass cls) {
         if (printdump == JNI_TRUE) {
             printf(">>> sig = \"%s\"\n", sig);
         }
-        if (sig == NULL || strcmp(sig, CLASS_SIGNATURE) != 0) {
+        if (sig == nullptr || strcmp(sig, CLASS_SIGNATURE) != 0) {
             printf("Wrong class sig: \"%s\", expected: \"%s\"\n",
                    CLASS_SIGNATURE, sig);
             result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassSignature/getclsig006/getclsig006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassSignature/getclsig006/getclsig006.cpp
index acd3ed52578..56b79a1cdf1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassSignature/getclsig006/getclsig006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassSignature/getclsig006/getclsig006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ extern "C" {
 
 /* expected class signatures are below */
 static const char *class_sig[][CLS_NUM] = {
-    { "getclsig006", "Lnsk/jvmti/GetClassSignature/getclsig006;", "NULL" },
+    { "getclsig006", "Lnsk/jvmti/GetClassSignature/getclsig006;", "null" },
     { "getclsig006b", "Lnsk/jvmti/GetClassSignature/getclsig006b;",
       "<L:Ljava/lang/String;>Ljava/lang/Object;" },
     { "getclsig006c", "Lnsk/jvmti/GetClassSignature/getclsig006c;",
@@ -51,7 +51,7 @@ static const char *class_sig[][CLS_NUM] = {
       "<E:Lnsk/jvmti/GetClassSignature/getclsig006e;:Lnsk/jvmti/GetClassSignature/getclsig006if;>Ljava/lang/Object;" }
 };
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 static int checkSig(JNIEnv *jni_env, jclass testedCls, int idx) {
     int totRes = PASSED;
@@ -67,7 +67,7 @@ static int checkSig(JNIEnv *jni_env, jclass testedCls, int idx) {
             class_sig[idx][0]);
 
         if (strcmp(class_sig[idx][1], sign) != 0 ||
-                strcmp(class_sig[idx][2], (gen_sign == NULL) ? "NULL" : gen_sign) != 0) {
+                strcmp(class_sig[idx][2], (gen_sign == nullptr) ? "null" : gen_sign) != 0) {
             NSK_COMPLAIN5(
                 "TEST FAILED: class: \"%s\" has\n"
                 "\tsignature: \"%s\"\n"
@@ -75,19 +75,19 @@ static int checkSig(JNIEnv *jni_env, jclass testedCls, int idx) {
                 "\tExpected: \"%s\"\n"
                 "\t\"%s\"\n\n",
                 class_sig[idx][0],
-                sign, (gen_sign == NULL) ? "NULL" : gen_sign,
+                sign, (gen_sign == nullptr) ? "null" : gen_sign,
                 class_sig[idx][1], class_sig[idx][2]);
             totRes = STATUS_FAILED;
         }
         else
             NSK_DISPLAY2("CHECK PASSED: signature: \"%s\",\n\tgeneric signature: \"%s\"\n",
-                sign, (gen_sign == NULL) ? "NULL" : gen_sign);
+                sign, (gen_sign == nullptr) ? "null" : gen_sign);
 
         NSK_DISPLAY0("Deallocating the signature array\n");
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*) sign))) {
             totRes = STATUS_FAILED;
         }
-        if (gen_sign != NULL)
+        if (gen_sign != nullptr)
             if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*) gen_sign))) {
                 totRes = STATUS_FAILED;
             }
@@ -105,7 +105,7 @@ Java_nsk_jvmti_GetClassSignature_getclsig006_check(
     jclass testedCls;
 
     for (i=0; i<CLS_NUM; i++) {
-        if (!NSK_JNI_VERIFY(jni, (testedCls = jni->FindClass(class_sig[i][1])) != NULL)) {
+        if (!NSK_JNI_VERIFY(jni, (testedCls = jni->FindClass(class_sig[i][1])) != nullptr)) {
             NSK_COMPLAIN1("TEST FAILURE: unable to find class \"%s\"\n\n",
                 class_sig[i][0]);
             res = STATUS_FAILED;
@@ -137,7 +137,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassStatus/getclstat005/getclstat005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassStatus/getclstat005/getclstat005.cpp
index f348991f670..7bc57e7082b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassStatus/getclstat005/getclstat005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassStatus/getclstat005/getclstat005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getclstat005(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -69,7 +69,7 @@ Java_nsk_jvmti_GetClassStatus_getclstat005_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jint status;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -77,7 +77,7 @@ Java_nsk_jvmti_GetClassStatus_getclstat005_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid class check ...\n");
     }
-    err = jvmti->GetClassStatus(NULL, &status);
+    err = jvmti->GetClassStatus(nullptr, &status);
     if (err != JVMTI_ERROR_INVALID_CLASS) {
         printf("Error expected: JVMTI_ERROR_INVALID_CLASS,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -87,7 +87,7 @@ Java_nsk_jvmti_GetClassStatus_getclstat005_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->GetClassStatus(cls, NULL);
+    err = jvmti->GetClassStatus(cls, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassStatus/getclstat006/getclstat006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassStatus/getclstat006/getclstat006.cpp
index 8f8a5d38820..72fb949f9b0 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassStatus/getclstat006/getclstat006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassStatus/getclstat006/getclstat006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ typedef struct {
     const char *name;
 } bit_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static bit_info bits[] = {
@@ -60,12 +60,12 @@ JNIEXPORT jint JNI_OnLoad_getclstat006(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -78,7 +78,7 @@ Java_nsk_jvmti_GetClassStatus_getclstat006_check(JNIEnv *env, jclass cls, jint i
     jvmtiError err;
     jint status;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassStatus/getclstat007/getclstat007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassStatus/getclstat007/getclstat007.cpp
index ed1ce5ace77..4daaed64594 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassStatus/getclstat007/getclstat007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassStatus/getclstat007/getclstat007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getclstat007(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,7 +70,7 @@ Java_nsk_jvmti_GetClassStatus_getclstat007_check(JNIEnv *env, jclass cls,
     jvmtiError err;
     jint status;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCurrentThreadCpuTime/curthrcputime001/curthrcputime001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCurrentThreadCpuTime/curthrcputime001/curthrcputime001.cpp
index 3e7fcdd1b17..b883c0b682f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCurrentThreadCpuTime/curthrcputime001/curthrcputime001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCurrentThreadCpuTime/curthrcputime001/curthrcputime001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -80,7 +80,7 @@ static int checkCpuTime(jvmtiEnv* jvmti, jthread thread, julong* time,
                             where, julong_to_string(*time, buf));
     }
 
-    if (prevTime != NULL) {
+    if (prevTime != nullptr) {
         julong diff = *time - *prevTime;
 
         NSK_DISPLAY1("Compare with previous time: %s\n",
@@ -147,7 +147,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     NSK_DISPLAY0(">>> Testcase #2: Check initial cpu time in agent thread\n");
     {
-        if (!checkCpuTime(jvmti, testAgentThread, &prevAgentThreadTime, NULL, "agent thread")) {
+        if (!checkCpuTime(jvmti, testAgentThread, &prevAgentThreadTime, nullptr, "agent thread")) {
             nsk_jvmti_setFailStatus();
         }
     }
@@ -157,7 +157,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         runIterations(iterations);
 
         NSK_DISPLAY1("Enable thread events: %d events\n", THREAD_EVENTS_COUNT);
-        if (nsk_jvmti_enableEvents(JVMTI_ENABLE, THREAD_EVENTS_COUNT, threadEvents, NULL)) {
+        if (nsk_jvmti_enableEvents(JVMTI_ENABLE, THREAD_EVENTS_COUNT, threadEvents, nullptr)) {
             NSK_DISPLAY0("  ... enabled\n");
         }
 
@@ -184,7 +184,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             return;
 
         NSK_DISPLAY1("Disable thread events: %d events\n", THREAD_EVENTS_COUNT);
-        if (nsk_jvmti_enableEvents(JVMTI_DISABLE, THREAD_EVENTS_COUNT, threadEvents, NULL)) {
+        if (nsk_jvmti_enableEvents(JVMTI_DISABLE, THREAD_EVENTS_COUNT, threadEvents, nullptr)) {
             NSK_DISPLAY0("  ... disabled\n");
         }
     }
@@ -214,7 +214,7 @@ callbackVMInit(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
     NSK_DISPLAY0(">>> Testcase #1: Check initial cpu time in VM_INIT callback\n");
     {
         julong time = 0;
-        if (!checkCpuTime(jvmti, thread, &time, NULL, "VM_INIT callback")) {
+        if (!checkCpuTime(jvmti, thread, &time, nullptr, "VM_INIT callback")) {
             nsk_jvmti_setFailStatus();
         }
     }
@@ -230,14 +230,14 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     NSK_DISPLAY0(">>> Testcase #7: Check initial cpu time in VM_DEATH callback\n");
     {
         julong time = 0;
-        if (!checkCpuTime(jvmti, NULL, &time, NULL, "VM_DEATH callback")) {
+        if (!checkCpuTime(jvmti, nullptr, &time, nullptr, "VM_DEATH callback")) {
             success = NSK_FALSE;
             nsk_jvmti_setFailStatus();
         }
     }
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -266,9 +266,9 @@ callbackThreadStart(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
         NSK_DISPLAY1("    <THREAD_START> for thread: %s\n", nsk_null_string(threadInfo.name));
     }
 
-    if (threadInfo.name != NULL && strcmp(threadInfo.name, TESTED_THREAD_NAME) == 0) {
+    if (threadInfo.name != nullptr && strcmp(threadInfo.name, TESTED_THREAD_NAME) == 0) {
         NSK_DISPLAY0(">>> Testcase #3: Check initial cpu time in THREAD_START callback\n");
-        if (!checkCpuTime(jvmti, thread, &prevTestedThreadTime, NULL, "THREAD_START callback")) {
+        if (!checkCpuTime(jvmti, thread, &prevTestedThreadTime, nullptr, "THREAD_START callback")) {
             nsk_jvmti_setFailStatus();
         }
     }
@@ -289,7 +289,7 @@ callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
         NSK_DISPLAY1("    <THREAD_END>   for thread: %s\n", nsk_null_string(threadInfo.name));
     }
 
-    if (threadInfo.name != NULL && strcmp(threadInfo.name, TESTED_THREAD_NAME) == 0) {
+    if (threadInfo.name != nullptr && strcmp(threadInfo.name, TESTED_THREAD_NAME) == 0) {
         julong time = 0;
         NSK_DISPLAY0(">>> Testcase #5: Check final cpu time in THREAD_END callback\n");
         if (!checkCpuTime(jvmti, thread, &time, &prevTestedThreadTime, "THREAD_END callback")) {
@@ -313,7 +313,7 @@ JNIEXPORT jint JNI_OnLoad_curthrcputime001(JavaVM *jvm, char *options, void *res
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -325,7 +325,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("Add required capability: %s\n", "can_get_current_thread_cpu_time");
@@ -355,11 +355,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
     NSK_DISPLAY0("  ... callbacks set\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCurrentThreadCpuTimerInfo/curthrtimerinfo001/curthrtimerinfo001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCurrentThreadCpuTimerInfo/curthrtimerinfo001/curthrtimerinfo001.cpp
index cf22a491b08..2efa96fb584 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCurrentThreadCpuTimerInfo/curthrtimerinfo001/curthrtimerinfo001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetCurrentThreadCpuTimerInfo/curthrtimerinfo001/curthrtimerinfo001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -76,7 +76,7 @@ static int checkTimerInfo(jvmtiEnv* jvmti, jvmtiTimerInfo* info,
     NSK_DISPLAY1("    may_skip_forward:  %d\n", (int)info->may_skip_forward);
     NSK_DISPLAY1("    may_skip_backward: %d\n", (int)info->may_skip_backward);
 
-    if (initInfo != NULL) {
+    if (initInfo != nullptr) {
         NSK_DISPLAY0("Compare with initial timer info\n");
         if (info->max_value != initInfo->max_value) {
             NSK_COMPLAIN4("In %s GetCurrentThreadCpuTimerInfo() returned different info:\n"
@@ -132,7 +132,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     NSK_DISPLAY0(">>> Testcases #3,4: Check timer info in thread events\n");
     {
         NSK_DISPLAY1("Enable thread events: %d events\n", THREAD_EVENTS_COUNT);
-        if (nsk_jvmti_enableEvents(JVMTI_ENABLE, THREAD_EVENTS_COUNT, threadEvents, NULL)) {
+        if (nsk_jvmti_enableEvents(JVMTI_ENABLE, THREAD_EVENTS_COUNT, threadEvents, nullptr)) {
             NSK_DISPLAY0("  ... enabled\n");
         }
 
@@ -143,7 +143,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             return;
 
         NSK_DISPLAY1("Disable thread events: %d events\n", THREAD_EVENTS_COUNT);
-        if (nsk_jvmti_enableEvents(JVMTI_DISABLE, THREAD_EVENTS_COUNT, threadEvents, NULL)) {
+        if (nsk_jvmti_enableEvents(JVMTI_DISABLE, THREAD_EVENTS_COUNT, threadEvents, nullptr)) {
             NSK_DISPLAY0("  ... disabled\n");
         }
     }
@@ -163,7 +163,7 @@ callbackVMInit(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
 
     NSK_DISPLAY0(">>> Testcase #1: Check initial timer info in VM_INIT callback\n");
     {
-        if (!checkTimerInfo(jvmti, &initInfo, NULL, "VM_INIT callback")) {
+        if (!checkTimerInfo(jvmti, &initInfo, nullptr, "VM_INIT callback")) {
             nsk_jvmti_setFailStatus();
         }
     }
@@ -183,7 +183,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     }
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -242,7 +242,7 @@ JNIEXPORT jint JNI_OnLoad_curthrtimerinfo001(JavaVM *jvm, char *options, void *r
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -250,7 +250,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("Add required capability: %s\n", "can_get_current_thread_cpu_time");
@@ -282,11 +282,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
     NSK_DISPLAY0("  ... callbacks set\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetEnv/GetEnv001/GetEnv001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetEnv/GetEnv001/GetEnv001.cpp
index 0a6ba80bf70..3959c846492 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetEnv/GetEnv001/GetEnv001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetEnv/GetEnv001/GetEnv001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -87,7 +87,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
         return JNI_ERR;
     }
 
-    if (vm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1) != JNI_OK || jvmti == NULL) {
+    if (vm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1) != JNI_OK || jvmti == nullptr) {
         NSK_COMPLAIN0("JVMTI_VERSION_1_1 isn't supported.");
         return JNI_OK;
     }
@@ -109,7 +109,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
         return JNI_ERR;
 
     // Enable class retransformation
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetEnvironmentLocalStorage/getenvstor001/getenvstor001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetEnvironmentLocalStorage/getenvstor001/getenvstor001.cpp
index c196ea89f1d..34b26debe67 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetEnvironmentLocalStorage/getenvstor001/getenvstor001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetEnvironmentLocalStorage/getenvstor001/getenvstor001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -50,7 +50,7 @@ static jvmtiEvent events[EVENTS_COUNT] = {
  * @returns NSK_FALSE if any error occured.
  */
 static int checkEnvStorage(jvmtiEnv* jvmti, const char where[]) {
-    void* storage = NULL;
+    void* storage = nullptr;
 
     NSK_DISPLAY0("GetEnvironmentLocalStorage() for current JVMTI env\n");
     if (!NSK_JVMTI_VERIFY(jvmti->GetEnvironmentLocalStorage(&storage))) {
@@ -58,8 +58,8 @@ static int checkEnvStorage(jvmtiEnv* jvmti, const char where[]) {
     }
     NSK_DISPLAY1("  ... got storage: 0x%p\n", (void*)storage);
 
-    if (storage != NULL) {
-        NSK_COMPLAIN2("GetEnvironmentLocalStorage() returned NOT NULL storage in %s:\n"
+    if (storage != nullptr) {
+        NSK_COMPLAIN2("GetEnvironmentLocalStorage() returned NOT null storage in %s:\n"
                       "#   storage pointer: 0x%p\n",
                         where, (void*)storage);
         return NSK_FALSE;
@@ -113,7 +113,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     success = checkEnvStorage(jvmti, "VM_DEATH callback");
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -140,7 +140,7 @@ JNIEXPORT jint JNI_OnLoad_getenvstor001(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -148,7 +148,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -163,7 +163,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Testcase #1: Check env storage in JVM_OnLoad()\n");
@@ -172,7 +172,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetErrorName/geterrname001/geterrname001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetErrorName/geterrname001/geterrname001.cpp
index cc0aa8ba792..6f8bcb17b3a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetErrorName/geterrname001/geterrname001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetErrorName/geterrname001/geterrname001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -253,7 +253,7 @@ JNIEXPORT jint JNI_OnLoad_geterrname001(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv *jvmti = NULL;
+    jvmtiEnv *jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
 
     /* init framework and parse options */
@@ -265,7 +265,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* Create data access lock */
@@ -290,16 +290,16 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* enable VMInit event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr)))
         return JNI_ERR;
 
     /* enable ClassFileLoadHook event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetErrorName/geterrname002/geterrname002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetErrorName/geterrname002/geterrname002.cpp
index 05937d62892..9dcf87e7be1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetErrorName/geterrname002/geterrname002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetErrorName/geterrname002/geterrname002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -53,7 +53,7 @@ agentProc(jvmtiEnv *jvmti, JNIEnv* jni, void* arg) {
 
     NSK_DISPLAY0("Testcase #2: check on JVMTI_ERROR_NULL_POINTER\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_NULL_POINTER,
-                               jvmti->GetErrorName(JVMTI_ERROR_NONE, NULL)))
+                               jvmti->GetErrorName(JVMTI_ERROR_NONE, nullptr)))
         nsk_jvmti_setFailStatus();
 
     /* resume debugee after last sync */
@@ -76,7 +76,7 @@ JNIEXPORT jint JNI_OnLoad_geterrname002(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv *jvmti = NULL;
+    jvmtiEnv *jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -89,11 +89,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetExtensionEvents/extevents001/extevents001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetExtensionEvents/extevents001/extevents001.cpp
index 24edbbbd494..bdc033f35cb 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetExtensionEvents/extevents001/extevents001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetExtensionEvents/extevents001/extevents001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -50,7 +50,7 @@ static jlong timeout = 0;
 static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
     int success = NSK_TRUE;
     jint extCount = 0;
-    jvmtiExtensionEventInfo* extList = NULL;
+    jvmtiExtensionEventInfo* extList = nullptr;
     int i;
 
     NSK_DISPLAY0("Get extension events list\n");
@@ -61,8 +61,8 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
     NSK_DISPLAY1("  ... got list:  0x%p\n", (void*)extList);
 
     if (extCount > 0) {
-        if (extList == NULL) {
-            NSK_COMPLAIN3("In %s phase GetExtensionEvents() returned NULL pointer:\n"
+        if (extList == nullptr) {
+            NSK_COMPLAIN3("In %s phase GetExtensionEvents() returned null pointer:\n"
                           "#   extensions pointer: 0x%p\n"
                           "#   extensions count:   %d\n",
                             phase, (void*)extList, (int)extCount);
@@ -80,7 +80,7 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
             NSK_DISPLAY1("    param_count: %d\n", (int)extList[i].param_count);
             NSK_DISPLAY1("    params:      0x%p\n", (void*)extList[i].params);
 
-            if (extList[i].params != NULL) {
+            if (extList[i].params != nullptr) {
                 for (j = 0; j < extList[i].param_count; j++) {
                     NSK_DISPLAY1("      param #%d:\n", j);
                     NSK_DISPLAY1("        name:      \"%s\"\n",
@@ -94,10 +94,10 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
                 }
             }
 
-            if (extList[i].id == NULL
-                    || extList[i].short_description == NULL
-                    || (extList[i].params == NULL && extList[i].param_count > 0)) {
-                NSK_COMPLAIN9("In %s phase GetExtensionEvents() returned event #%d with NULL attribute(s):\n"
+            if (extList[i].id == nullptr
+                    || extList[i].short_description == nullptr
+                    || (extList[i].params == nullptr && extList[i].param_count > 0)) {
+                NSK_COMPLAIN9("In %s phase GetExtensionEvents() returned event #%d with null attribute(s):\n"
                               "#   event_index: %d\n"
                               "#   id:          0x%p (%s)\n"
                               "#   short_desc:  0x%p (%s)\n"
@@ -111,7 +111,7 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
                 success = NSK_FALSE;
             }
 
-            if (extList[i].id != NULL && strlen(extList[i].id) <= 0) {
+            if (extList[i].id != nullptr && strlen(extList[i].id) <= 0) {
                 NSK_COMPLAIN6("In %s phase GetExtensionEvents() returned event #%d with empty id:\n"
                               "#   event_index: %d\n"
                               "#   id:          \"%s\"\n"
@@ -123,7 +123,7 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
                                 nsk_null_string(extList[i].short_description),
                                 (int)extList[i].param_count);
                 success = NSK_FALSE;
-            } else if (strstr(extList[i].id, NAME_PREFIX) == NULL) {
+            } else if (strstr(extList[i].id, NAME_PREFIX) == nullptr) {
                 NSK_COMPLAIN6("In %s phase GetExtensionEvents() returned event #%d with unexpected id:\n"
                               "#   event_index: %d\n"
                               "#   id:          \"%s\"\n"
@@ -137,7 +137,7 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
                 success = NSK_FALSE;
             }
 
-            if (extList[i].short_description != NULL && strlen(extList[i].short_description) <= 0) {
+            if (extList[i].short_description != nullptr && strlen(extList[i].short_description) <= 0) {
                 NSK_COMPLAIN6("In %s phase GetExtensionEvents() returned event #%d with empty desc:\n"
                               "#   event_index: %d\n"
                               "#   id:          \"%s\"\n"
@@ -151,9 +151,9 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
                 success = NSK_FALSE;
             }
 
-            if (extList[i].param_count > 0 && extList[i].params != NULL) {
+            if (extList[i].param_count > 0 && extList[i].params != nullptr) {
                 for (j = 0; j < extList[i].param_count; j++) {
-                    if (extList[i].params[j].name == NULL
+                    if (extList[i].params[j].name == nullptr
                             || strlen(extList[i].params[j].name) <= 0) {
                         NSK_COMPLAIN9("In %s phase GetExtensionEvents() returned event #%d with empty desc:\n"
                                       "#   event_index: %d\n"
@@ -262,7 +262,7 @@ JNIEXPORT jint JNI_OnLoad_extevents001(JavaVM *jvm, char *options, void *reserve
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -270,7 +270,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Testcase #1: Check extension events in OnLoad phase\n");
@@ -280,7 +280,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetExtensionFunctions/extfuncs001/extfuncs001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetExtensionFunctions/extfuncs001/extfuncs001.cpp
index 60f573c2b71..015313e7b2b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetExtensionFunctions/extfuncs001/extfuncs001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetExtensionFunctions/extfuncs001/extfuncs001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,7 +49,7 @@ static jlong timeout = 0;
 static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
     int success = NSK_TRUE;
     jint extCount = 0;
-    jvmtiExtensionFunctionInfo* extList = NULL;
+    jvmtiExtensionFunctionInfo* extList = nullptr;
     int i;
 
     NSK_DISPLAY0("Get extension functions list\n");
@@ -60,8 +60,8 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
     NSK_DISPLAY1("  ... got list:  0x%p\n", (void*)extList);
 
     if (extCount > 0) {
-        if (extList == NULL) {
-            NSK_COMPLAIN3("In %s phase GetExtensionFunctions() returned NULL pointer:\n"
+        if (extList == nullptr) {
+            NSK_COMPLAIN3("In %s phase GetExtensionFunctions() returned null pointer:\n"
                           "#   extensions pointer: 0x%p\n"
                           "#   extensions count:   %d\n",
                             phase, (void*)extList, (int)extCount);
@@ -79,7 +79,7 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
             NSK_DISPLAY1("    param_count: %d\n", (int)extList[i].param_count);
             NSK_DISPLAY1("    params:      0x%p\n", (void*)extList[i].params);
 
-            if (extList[i].params != NULL) {
+            if (extList[i].params != nullptr) {
                 for (j = 0; j < extList[i].param_count; j++) {
                     NSK_DISPLAY1("      param #%d:\n", j);
                     NSK_DISPLAY1("        name:      \"%s\"\n",
@@ -96,19 +96,19 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
             NSK_DISPLAY1("    error_count: %d\n", (int)extList[i].error_count);
             NSK_DISPLAY1("    errors:      0x%p\n", (void*)extList[i].errors);
 
-            if (extList[i].errors != NULL) {
+            if (extList[i].errors != nullptr) {
                 for (j = 0; j < extList[i].error_count; j++) {
                     NSK_DISPLAY2("      error #%d: %d\n",
                                             j, (int)extList[i].errors[j]);
                 }
             }
 
-            if (extList[i].func == NULL
-                    || extList[i].id == NULL
-                    || extList[i].short_description == NULL
-                    || (extList[i].params == NULL && extList[i].param_count > 0)
-                    || (extList[i].errors == NULL && extList[i].error_count > 0)) {
-                NSK_COMPLAIN9("In %s phase GetExtensionFunctions() returned function #%d with NULL attribute(s):\n"
+            if (extList[i].func == nullptr
+                    || extList[i].id == nullptr
+                    || extList[i].short_description == nullptr
+                    || (extList[i].params == nullptr && extList[i].param_count > 0)
+                    || (extList[i].errors == nullptr && extList[i].error_count > 0)) {
+                NSK_COMPLAIN9("In %s phase GetExtensionFunctions() returned function #%d with null attribute(s):\n"
                               "#   func:        0x%p\n"
                               "#   id:          0x%p (%s)\n"
                               "#   short_desc:  0x%p (%s)\n"
@@ -122,7 +122,7 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
                 success = NSK_FALSE;
             }
 
-            if (extList[i].id != NULL && strlen(extList[i].id) <= 0) {
+            if (extList[i].id != nullptr && strlen(extList[i].id) <= 0) {
                 NSK_COMPLAIN6("In %s phase GetExtensionFunctions() returned function #%d with empty id:\n"
                               "#   func:        0x%p\n"
                               "#   id:          \"%s\"\n"
@@ -134,7 +134,7 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
                                 nsk_null_string(extList[i].short_description),
                                 (int)extList[i].param_count);
                 success = NSK_FALSE;
-            } else if (strstr(extList[i].id, NAME_PREFIX) == NULL) {
+            } else if (strstr(extList[i].id, NAME_PREFIX) == nullptr) {
                 NSK_COMPLAIN6("In %s phase GetExtensionFunctions() returned function #%d with unexpected id:\n"
                               "#   func:        0x%p\n"
                               "#   id:          \"%s\"\n"
@@ -148,7 +148,7 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
                 success = NSK_FALSE;
             }
 
-            if (extList[i].short_description != NULL && strlen(extList[i].short_description) <= 0) {
+            if (extList[i].short_description != nullptr && strlen(extList[i].short_description) <= 0) {
                 NSK_COMPLAIN6("In %s phase GetExtensionFunctions() returned function #%d with empty desc:\n"
                               "#   func:        0x%p\n"
                               "#   id:          \"%s\"\n"
@@ -162,9 +162,9 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
                 success = NSK_FALSE;
             }
 
-            if (extList[i].param_count > 0 && extList[i].params != NULL) {
+            if (extList[i].param_count > 0 && extList[i].params != nullptr) {
                 for (j = 0; j < extList[i].param_count; j++) {
-                    if (extList[i].params[j].name == NULL
+                    if (extList[i].params[j].name == nullptr
                             || strlen(extList[i].params[j].name) <= 0) {
                         NSK_COMPLAIN9("In %s phase GetExtensionFunctions() returned function #%d with empty desc:\n"
                                       "#   func:        0x%p\n"
@@ -273,7 +273,7 @@ JNIEXPORT jint JNI_OnLoad_extfuncs001(JavaVM *jvm, char *options, void *reserved
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -281,7 +281,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Testcase #1: Check extension functions in OnLoad phase\n");
@@ -291,7 +291,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldDeclaringClass/getfldecl001/getfldecl001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldDeclaringClass/getfldecl001/getfldecl001.cpp
index 9c1e9b050c9..695d6758f24 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldDeclaringClass/getfldecl001/getfldecl001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldDeclaringClass/getfldecl001/getfldecl001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static const char* fields[] = { "x", "y", "z" };
@@ -52,12 +52,12 @@ JNIEXPORT jint JNI_OnLoad_getfldecl001(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -73,7 +73,7 @@ Java_nsk_jvmti_GetFieldDeclaringClass_getfldecl001_check(JNIEnv *env,
     jclass declaringClass;
     char *sig, *generic;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -84,7 +84,7 @@ Java_nsk_jvmti_GetFieldDeclaringClass_getfldecl001_check(JNIEnv *env,
     } else {
         fid = env->GetFieldID(cls1, fields[i], "I");
     }
-    if (fid == NULL) {
+    if (fid == nullptr) {
         printf("(%d) cannot get field ID for %s:\"I\"\n", i, fields[i]);
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldDeclaringClass/getfldecl002/getfldecl002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldDeclaringClass/getfldecl002/getfldecl002.cpp
index 10ba137744c..aac0cbe4d66 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldDeclaringClass/getfldecl002/getfldecl002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldDeclaringClass/getfldecl002/getfldecl002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static const char* fields[] = { "const1", "fld", "xx" };
@@ -52,12 +52,12 @@ JNIEXPORT jint JNI_OnLoad_getfldecl002(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -73,7 +73,7 @@ Java_nsk_jvmti_GetFieldDeclaringClass_getfldecl002_check(JNIEnv *env,
     jclass declaringClass;
     char *sig, *generic;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -84,7 +84,7 @@ Java_nsk_jvmti_GetFieldDeclaringClass_getfldecl002_check(JNIEnv *env,
     } else {
         fid = env->GetFieldID(cls1, fields[i], "I");
     }
-    if (fid == NULL) {
+    if (fid == nullptr) {
         printf("(%d) cannot get field ID for %s:\"I\"\n", i, fields[i]);
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldDeclaringClass/getfldecl004/getfldecl004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldDeclaringClass/getfldecl004/getfldecl004.cpp
index 1661a4dc28e..66bfdd8ce2f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldDeclaringClass/getfldecl004/getfldecl004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldDeclaringClass/getfldecl004/getfldecl004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,7 +39,7 @@ typedef struct {
     jboolean is_static;
 } field_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static field_info fields[] = {
@@ -71,12 +71,12 @@ JNIEXPORT jint JNI_OnLoad_getfldecl004(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -92,7 +92,7 @@ Java_nsk_jvmti_GetFieldDeclaringClass_getfldecl004_check(JNIEnv *env,
     jclass declaringClass;
     char *sig, *generic;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -103,7 +103,7 @@ Java_nsk_jvmti_GetFieldDeclaringClass_getfldecl004_check(JNIEnv *env,
     } else {
         fid = env->GetFieldID(cls1, fields[i].name, fields[i].sig);
     }
-    if (fid == NULL) {
+    if (fid == nullptr) {
         printf("(%d) cannot get field ID for %s:\"%s\"\n",
                i, fields[i].name, fields[i].sig);
         result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldModifiers/getfldmdf003/getfldmdf003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldModifiers/getfldmdf003/getfldmdf003.cpp
index e112f59ab60..f763138923d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldModifiers/getfldmdf003/getfldmdf003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldModifiers/getfldmdf003/getfldmdf003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getfldmdf003(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,13 +70,13 @@ Java_nsk_jvmti_GetFieldModifiers_getfldmdf003_check(JNIEnv *env, jclass cls) {
     jfieldID fid;
     jint modifiers;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     fid = env->GetFieldID(cls, "fld", "I");
-    if (fid == NULL) {
+    if (fid == nullptr) {
         printf("Cannot get field ID!\n");
         return STATUS_FAILED;
     }
@@ -84,7 +84,7 @@ Java_nsk_jvmti_GetFieldModifiers_getfldmdf003_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid class check ...\n");
     }
-    err = jvmti->GetFieldModifiers(NULL, fid, &modifiers);
+    err = jvmti->GetFieldModifiers(nullptr, fid, &modifiers);
     if (err != JVMTI_ERROR_INVALID_CLASS) {
         printf("Error expected: JVMTI_ERROR_INVALID_CLASS,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -94,7 +94,7 @@ Java_nsk_jvmti_GetFieldModifiers_getfldmdf003_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid field check ...\n");
     }
-    err = jvmti->GetFieldModifiers(cls, NULL, &modifiers);
+    err = jvmti->GetFieldModifiers(cls, nullptr, &modifiers);
     if (err != JVMTI_ERROR_INVALID_FIELDID) {
         printf("Error expected: JVMTI_ERROR_INVALID_FIELDID,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -104,7 +104,7 @@ Java_nsk_jvmti_GetFieldModifiers_getfldmdf003_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->GetFieldModifiers(cls, fid, NULL);
+    err = jvmti->GetFieldModifiers(cls, fid, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("(namePtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldModifiers/getfldmdf004/getfldmdf004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldModifiers/getfldmdf004/getfldmdf004.cpp
index ab10f30398e..72fc33280e5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldModifiers/getfldmdf004/getfldmdf004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldModifiers/getfldmdf004/getfldmdf004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -51,7 +51,7 @@ typedef struct {
     jboolean is_static;
 } field_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static field_info fields[] = {
@@ -120,12 +120,12 @@ JNIEXPORT jint JNI_OnLoad_getfldmdf004(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -155,7 +155,7 @@ Java_nsk_jvmti_GetFieldModifiers_getfldmdf004_check(JNIEnv *env,
     jfieldID fid;
     jint modifiers;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -166,7 +166,7 @@ Java_nsk_jvmti_GetFieldModifiers_getfldmdf004_check(JNIEnv *env,
     } else {
         fid = env->GetFieldID(cls, fields[i].name, fields[i].sig);
     }
-    if (fid == NULL) {
+    if (fid == nullptr) {
         printf("(%d) cannot get field ID for %s:\"%s\"\n",
                i, fields[i].name, fields[i].sig);
         result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldName/getfldnm003/getfldnm003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldName/getfldnm003/getfldnm003.cpp
index 643f0ce376d..c1121a55259 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldName/getfldnm003/getfldnm003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldName/getfldnm003/getfldnm003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getfldnm003(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,13 +70,13 @@ Java_nsk_jvmti_GetFieldName_getfldnm003_check(JNIEnv *env, jclass cls) {
     jfieldID field;
     char *name, *sig, *generic;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     field = env->GetFieldID(cls, "fld", "I");
-    if (field == NULL) {
+    if (field == nullptr) {
         printf("Cannot get field ID!\n");
         return STATUS_FAILED;
     }
@@ -84,7 +84,7 @@ Java_nsk_jvmti_GetFieldName_getfldnm003_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid class check ...\n");
     }
-    err = jvmti->GetFieldName(NULL, field, &name, &sig, &generic);
+    err = jvmti->GetFieldName(nullptr, field, &name, &sig, &generic);
     if (err != JVMTI_ERROR_INVALID_CLASS) {
         printf("Error expected: JVMTI_ERROR_INVALID_CLASS,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -94,7 +94,7 @@ Java_nsk_jvmti_GetFieldName_getfldnm003_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid field check ...\n");
     }
-    err = jvmti->GetFieldName(cls, NULL, &name, &sig, &generic);
+    err = jvmti->GetFieldName(cls, nullptr, &name, &sig, &generic);
     if (err != JVMTI_ERROR_INVALID_FIELDID) {
         printf("Error expected: JVMTI_ERROR_INVALID_FIELDID,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -104,7 +104,7 @@ Java_nsk_jvmti_GetFieldName_getfldnm003_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (namePtr) null pointer check ...\n");
     }
-    err = jvmti->GetFieldName(cls, field, NULL, &sig, &generic);
+    err = jvmti->GetFieldName(cls, field, nullptr, &sig, &generic);
     if (err != JVMTI_ERROR_NONE) {
         printf("(name_ptr) unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -113,7 +113,7 @@ Java_nsk_jvmti_GetFieldName_getfldnm003_check(JNIEnv *env, jclass cls) {
         if (printdump == JNI_TRUE) {
             printf(">>> sig = \"%s\", generic = \"%s\"\n", sig, generic);
         }
-        if (sig == NULL || strcmp(sig, "I") != 0) {
+        if (sig == nullptr || strcmp(sig, "I") != 0) {
             printf("Wrong field sig: \"%s\", expected: \"I\"\n", sig);
             result = STATUS_FAILED;
         }
@@ -122,7 +122,7 @@ Java_nsk_jvmti_GetFieldName_getfldnm003_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (signature_ptr) null pointer check ...\n");
     }
-    err = jvmti->GetFieldName(cls, field, &name, NULL, &generic);
+    err = jvmti->GetFieldName(cls, field, &name, nullptr, &generic);
     if (err != JVMTI_ERROR_NONE) {
         printf("(signaturePtr) unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -131,7 +131,7 @@ Java_nsk_jvmti_GetFieldName_getfldnm003_check(JNIEnv *env, jclass cls) {
         if (printdump == JNI_TRUE) {
             printf(">>> name = \"%s\", generic = \"%s\"\n", name, generic);
         }
-        if (name == NULL || strcmp(name, "fld") != 0) {
+        if (name == nullptr || strcmp(name, "fld") != 0) {
             printf("Wrong field name: \"%s\", expected: \"fld\"\n", name);
             result = STATUS_FAILED;
         }
@@ -140,7 +140,7 @@ Java_nsk_jvmti_GetFieldName_getfldnm003_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (generic_ptr) null pointer check ...\n");
     }
-    err = jvmti->GetFieldName(cls, field, &name, &sig, NULL);
+    err = jvmti->GetFieldName(cls, field, &name, &sig, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("(signaturePtr) unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -149,11 +149,11 @@ Java_nsk_jvmti_GetFieldName_getfldnm003_check(JNIEnv *env, jclass cls) {
         if (printdump == JNI_TRUE) {
             printf(">>> name = \"%s\", sig = \"%s\"\n", name, sig);
         }
-        if (name == NULL || strcmp(name, "fld") != 0) {
+        if (name == nullptr || strcmp(name, "fld") != 0) {
             printf("Wrong field name: \"%s\", expected: \"fld\"\n", name);
             result = STATUS_FAILED;
         }
-        if (sig == NULL || strcmp(sig, "I") != 0) {
+        if (sig == nullptr || strcmp(sig, "I") != 0) {
             printf("Wrong field sig: \"%s\", expected: \"I\"\n", sig);
             result = STATUS_FAILED;
         }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldName/getfldnm004/getfldnm004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldName/getfldnm004/getfldnm004.cpp
index 5cb6eca8ddf..f748f6600c0 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldName/getfldnm004/getfldnm004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldName/getfldnm004/getfldnm004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ typedef struct {
     jboolean is_static;
 } field_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static field_info fields[] = {
@@ -81,12 +81,12 @@ JNIEXPORT jint JNI_OnLoad_getfldnm004(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -102,7 +102,7 @@ Java_nsk_jvmti_GetFieldName_getfldnm004_check(JNIEnv *env,
     char *name, *sig, *generic;
     size_t i;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -115,7 +115,7 @@ Java_nsk_jvmti_GetFieldName_getfldnm004_check(JNIEnv *env,
             fid = env->GetFieldID(
                 clazz, fields[i].name, fields[i].sig);
         }
-        if (fid == NULL) {
+        if (fid == nullptr) {
             printf("(%" PRIuPTR ") cannot get field ID for %s:\"%s\"\n",
                    i, fields[i].name, fields[i].sig);
             result = STATUS_FAILED;
@@ -131,12 +131,12 @@ Java_nsk_jvmti_GetFieldName_getfldnm004_check(JNIEnv *env,
         if (printdump == JNI_TRUE) {
             printf(">>> %" PRIuPTR " -- %s:\"%s\"\n", i, name, sig);
         }
-        if (name == NULL || strcmp(name, fields[i].name) != 0) {
+        if (name == nullptr || strcmp(name, fields[i].name) != 0) {
             printf("(%" PRIuPTR ") wrong field name: \"%s\"", i, name);
             printf(", expected: \"%s\"\n", fields[i].name);
             result = STATUS_FAILED;
         }
-        if (sig == NULL || strcmp(sig, fields[i].sig) != 0) {
+        if (sig == nullptr || strcmp(sig, fields[i].sig) != 0) {
             printf("(%" PRIuPTR ") wrong field sig: \"%s\"", i, sig);
             printf(", expected: \"%s\"\n", fields[i].sig);
             result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldName/getfldnm005/getfldnm005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldName/getfldnm005/getfldnm005.cpp
index 87332b15447..65508b38baf 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldName/getfldnm005/getfldnm005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetFieldName/getfldnm005/getfldnm005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,7 +41,7 @@ extern "C" {
 /* expected field signatures are below */
 static const char *fld_sig[][FLDS_NUM] = {
     { "_getfldnm005St", "static",
-      "Lnsk/jvmti/GetFieldName/getfldnm005;", "NULL" },
+      "Lnsk/jvmti/GetFieldName/getfldnm005;", "null" },
 
     { "_getfldnm005b", "instance",
       "Lnsk/jvmti/GetFieldName/getfldnm005b;",
@@ -59,10 +59,10 @@ static const char *fld_sig[][FLDS_NUM] = {
 
     { "_getfldnm005e", "instance",
       "Lnsk/jvmti/GetFieldName/getfldnm005e;",
-      "NULL" },
+      "null" },
     { "_getfldnm005eSt", "static",
       "Lnsk/jvmti/GetFieldName/getfldnm005e;",
-      "NULL" },
+      "null" },
 
     { "_getfldnm005if", "instance",
       "Lnsk/jvmti/GetFieldName/getfldnm005if;",
@@ -80,10 +80,10 @@ static const char *fld_sig[][FLDS_NUM] = {
 
     { "_getfldnm005gArr", "instance",
       "[Lnsk/jvmti/GetFieldName/getfldnm005g;",
-      "NULL" }
+      "null" }
 };
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 static int checkSig(JNIEnv *jni_env, jclass testedCls,
         jfieldID testedFld, int instance, int idx) {
@@ -101,7 +101,7 @@ static int checkSig(JNIEnv *jni_env, jclass testedCls,
             name);
 
         if (strcmp(fld_sig[idx][2], sign) != 0 ||
-                strcmp(fld_sig[idx][3], (gen_sign == NULL) ? "NULL" : gen_sign) != 0) {
+                strcmp(fld_sig[idx][3], (gen_sign == nullptr) ? "null" : gen_sign) != 0) {
             NSK_COMPLAIN6(
                 "TEST FAILED: %s field \"%s\" has\n"
                 "\tsignature: \"%s\"\n"
@@ -110,20 +110,20 @@ static int checkSig(JNIEnv *jni_env, jclass testedCls,
                 "\t\t\"%s\"\n\n",
                (instance == 0) ? "instance" : "static",
                 fld_sig[idx][0],
-                sign, (gen_sign == NULL) ? "NULL" : gen_sign,
+                sign, (gen_sign == nullptr) ? "null" : gen_sign,
                 fld_sig[idx][2], fld_sig[idx][3]);
             totRes = STATUS_FAILED;
         }
         else
             NSK_DISPLAY2("CHECK PASSED: signature: \"%s\",\n\tgeneric signature: \"%s\"\n",
-                sign, (gen_sign == NULL) ? "NULL" : gen_sign);
+                sign, (gen_sign == nullptr) ? "null" : gen_sign);
 
         NSK_DISPLAY0("Deallocating name & signature arrays\n");
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*) name)))
             totRes = STATUS_FAILED;
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*) sign)))
             totRes = STATUS_FAILED;
-        if (gen_sign != NULL)
+        if (gen_sign != nullptr)
             if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*) gen_sign)))
                 totRes = STATUS_FAILED;
     }
@@ -135,7 +135,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_GetFieldName_getfldnm005_check(
         JNIEnv *jni, jobject obj) {
     int res = PASSED, i, instance;
-    jfieldID testedFld = NULL;
+    jfieldID testedFld = nullptr;
     jclass objCls = jni->GetObjectClass(obj);
 
     for (i=0; i<FLDS_NUM; i++) {
@@ -145,7 +145,7 @@ Java_nsk_jvmti_GetFieldName_getfldnm005_check(
             (instance == 0) ? "instance" : "static",
              fld_sig[i][0]);
         if (instance == 0) {
-            if (!NSK_JNI_VERIFY(jni, (testedFld = jni->GetFieldID(objCls, fld_sig[i][0], fld_sig[i][2])) != NULL)) {
+            if (!NSK_JNI_VERIFY(jni, (testedFld = jni->GetFieldID(objCls, fld_sig[i][0], fld_sig[i][2])) != nullptr)) {
                 NSK_COMPLAIN1("TEST FAILERE: unable to get field ID for \"%s\"\n\n",
                     fld_sig[i][0]);
                 res = STATUS_FAILED;
@@ -153,7 +153,7 @@ Java_nsk_jvmti_GetFieldName_getfldnm005_check(
             }
         }
         else
-            if (!NSK_JNI_VERIFY(jni, (testedFld = jni->GetStaticFieldID(objCls, fld_sig[i][0], fld_sig[i][2])) != NULL)) {
+            if (!NSK_JNI_VERIFY(jni, (testedFld = jni->GetStaticFieldID(objCls, fld_sig[i][0], fld_sig[i][2])) != nullptr)) {
                 NSK_COMPLAIN1("TEST FAILERE: unable to get field ID for \"%s\"\n\n",
                     fld_sig[i][0]);
                 res = STATUS_FAILED;
@@ -189,7 +189,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetImplementedInterfaces/getintrf005/getintrf005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetImplementedInterfaces/getintrf005/getintrf005.cpp
index ee7b56923c4..89e743f1b9f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetImplementedInterfaces/getintrf005/getintrf005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetImplementedInterfaces/getintrf005/getintrf005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getintrf005(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,7 +70,7 @@ Java_nsk_jvmti_GetImplementedInterfaces_getintrf005_check(JNIEnv *env, jclass cl
     jint icount;
     jclass *interfaces;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -78,7 +78,7 @@ Java_nsk_jvmti_GetImplementedInterfaces_getintrf005_check(JNIEnv *env, jclass cl
     if (printdump == JNI_TRUE) {
         printf(">>> invalid class check ...\n");
     }
-    err = jvmti->GetImplementedInterfaces(NULL, &icount, &interfaces);
+    err = jvmti->GetImplementedInterfaces(nullptr, &icount, &interfaces);
     if (err != JVMTI_ERROR_INVALID_CLASS) {
         printf("Error expected: JVMTI_ERROR_INVALID_CLASS,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -88,7 +88,7 @@ Java_nsk_jvmti_GetImplementedInterfaces_getintrf005_check(JNIEnv *env, jclass cl
     if (printdump == JNI_TRUE) {
         printf(">>> (interfaceCountPtr) null pointer check ...\n");
     }
-    err = jvmti->GetImplementedInterfaces(cls, NULL, &interfaces);
+    err = jvmti->GetImplementedInterfaces(cls, nullptr, &interfaces);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("(interfaceCountPtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -98,7 +98,7 @@ Java_nsk_jvmti_GetImplementedInterfaces_getintrf005_check(JNIEnv *env, jclass cl
     if (printdump == JNI_TRUE) {
         printf(">>> (interfacesPtr) null pointer check ...\n");
     }
-    err = jvmti->GetImplementedInterfaces(cls, &icount, NULL);
+    err = jvmti->GetImplementedInterfaces(cls, &icount, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("(interfacesPtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetImplementedInterfaces/getintrf006/getintrf006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetImplementedInterfaces/getintrf006/getintrf006.cpp
index 50b4f30383e..6c6b4e060fb 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetImplementedInterfaces/getintrf006/getintrf006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetImplementedInterfaces/getintrf006/getintrf006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getintrf006(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,7 +70,7 @@ Java_nsk_jvmti_GetImplementedInterfaces_getintrf006_check(JNIEnv *env, jclass cl
     jint icount;
     jclass *interfaces;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetImplementedInterfaces/getintrf007/getintrf007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetImplementedInterfaces/getintrf007/getintrf007.cpp
index da6fb2acbc4..5b855f85b9d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetImplementedInterfaces/getintrf007/getintrf007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetImplementedInterfaces/getintrf007/getintrf007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -43,7 +43,7 @@ typedef struct {
     iface_info *ifaces;
 } class_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -68,17 +68,17 @@ static iface_info i9[] = {
 };
 
 static class_info classes[] = {
-    { "InnerClass1", 0, NULL },
-    { "InnerInterface1", 0, NULL },
+    { "InnerClass1", 0, nullptr },
+    { "InnerInterface1", 0, nullptr },
     { "InnerInterface2", 1, i2 },
     { "InnerClass2", 1, i3 },
-    { "OuterClass1", 0, NULL },
-    { "OuterClass2", 0, NULL },
-    { "OuterInterface1", 0, NULL },
+    { "OuterClass1", 0, nullptr },
+    { "OuterClass2", 0, nullptr },
+    { "OuterInterface1", 0, nullptr },
     { "OuterClass3", 1, i7 },
     { "OuterInterface2", 1, i8 },
     { "OuterClass4", 1, i9 },
-    { "OuterClass5", 0, NULL }
+    { "OuterClass5", 0, nullptr }
 };
 
 #ifdef STATIC_BUILD
@@ -95,12 +95,12 @@ JNIEXPORT jint JNI_OnLoad_getintrf007(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -116,7 +116,7 @@ Java_nsk_jvmti_GetImplementedInterfaces_getintrf007_check(JNIEnv *env, jclass cl
     char *sig, *generic;
     int j;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -141,7 +141,7 @@ Java_nsk_jvmti_GetImplementedInterfaces_getintrf007_check(JNIEnv *env, jclass cl
     }
 
     for (j = 0; j < icount; j++) {
-        if (interfaces[j] == NULL) {
+        if (interfaces[j] == nullptr) {
             printf("(%d:%d) null reference\n", i, j);
         } else {
             err = jvmti->GetClassSignature(interfaces[j],
@@ -153,7 +153,7 @@ Java_nsk_jvmti_GetImplementedInterfaces_getintrf007_check(JNIEnv *env, jclass cl
                 if (printdump == JNI_TRUE) {
                     printf(">>>   [%d]: %s\n", j, sig);
                 }
-                if ((j < classes[i].icount) && (sig == NULL ||
+                if ((j < classes[i].icount) && (sig == nullptr ||
                         strcmp(sig, classes[i].ifaces[j].sig) != 0)) {
                     printf("(%d:%d) wrong interface: \"%s\"", i, j, sig);
                     printf(", expected: \"%s\"\n", classes[i].ifaces[j].sig);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJLocationFormat/getjlocfmt001/getjlocfmt001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJLocationFormat/getjlocfmt001/getjlocfmt001.cpp
index b604af51f8a..2725d43068f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJLocationFormat/getjlocfmt001/getjlocfmt001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJLocationFormat/getjlocfmt001/getjlocfmt001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -156,7 +156,7 @@ JNIEXPORT jint JNI_OnLoad_getjlocfmt001(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv *jvmti = NULL;
+    jvmtiEnv *jvmti = nullptr;
     jvmtiJlocationFormat format;
     jvmtiEventCallbacks callbacks;
 
@@ -169,7 +169,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* Create data access lock */
@@ -199,16 +199,16 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* enable VMInit event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr)))
         return JNI_ERR;
 
     /* enable ClassFileLoadHook event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJLocationFormat/getjlocfmt002/getjlocfmt002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJLocationFormat/getjlocfmt002/getjlocfmt002.cpp
index b8125340a95..f13d7f1cf10 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJLocationFormat/getjlocfmt002/getjlocfmt002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJLocationFormat/getjlocfmt002/getjlocfmt002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,8 +45,8 @@ agentProc(jvmtiEnv *jvmti, JNIEnv* jni, void* arg) {
     if (!nsk_jvmti_waitForSync(timeout))
         return;
 
-    NSK_DISPLAY0("Check if GetJLocationFormat(NULL) returns JVMTI_ERROR_NULL_POINTER\n");
-    if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_NULL_POINTER, jvmti->GetJLocationFormat(NULL)))
+    NSK_DISPLAY0("Check if GetJLocationFormat(null) returns JVMTI_ERROR_NULL_POINTER\n");
+    if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_NULL_POINTER, jvmti->GetJLocationFormat(nullptr)))
         nsk_jvmti_setFailStatus();
 
     /* resume debugee after last sync */
@@ -69,7 +69,7 @@ JNIEXPORT jint JNI_OnLoad_getjlocfmt002(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv *jvmti = NULL;
+    jvmtiEnv *jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -82,11 +82,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJNIFunctionTable/getjniftab001/getjniftab001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJNIFunctionTable/getjniftab001/getjniftab001.cpp
index 213daccd426..a1293a0cb5d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJNIFunctionTable/getjniftab001/getjniftab001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJNIFunctionTable/getjniftab001/getjniftab001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,17 +38,17 @@ extern "C" {
 #define STATUS_FAILED  2
 
 static JavaVM *vm;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 static int verbose = 0;
 
 static jint result = PASSED;
 
 /* the original JNI function table */
-static jniNativeInterface *orig_jni_functions = NULL;
+static jniNativeInterface *orig_jni_functions = nullptr;
 
 /* the redirected JNI function table */
-static jniNativeInterface *redir_jni_functions = NULL;
+static jniNativeInterface *redir_jni_functions = nullptr;
 
 /* number of the redirected JNI function calls */
 static volatile int redir_calls = 0;
@@ -120,7 +120,7 @@ static void doRestore(JNIEnv *env) {
 }
 
 static void checkRedir(JNIEnv *env, int exCalls) {
-    jniNativeInterface *tested_jni_functions = NULL;
+    jniNativeInterface *tested_jni_functions = nullptr;
     jvmtiError err;
     jint res;
 
@@ -156,7 +156,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_GetJNIFunctionTable_getjniftab001_check(JNIEnv *env, jobject obj) {
     int exitCode = PASSED;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("(%s,%d): TEST FAILURE: JVMTI client was not properly loaded\n",
             __FILE__, __LINE__);
         return STATUS_FAILED;
@@ -191,14 +191,14 @@ JNIEXPORT jint JNI_OnLoad_getjniftab001(JavaVM *jvm, char *options, void *reserv
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "-verbose") == 0)
+    if (options != nullptr && strcmp(options, "-verbose") == 0)
         verbose = 1;
 
     if (verbose)
         printf("verbose mode on\n");
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("(%s,%d): Failed to call GetEnv\n", __FILE__, __LINE__);
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJNIFunctionTable/getjniftab002/getjniftab002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJNIFunctionTable/getjniftab002/getjniftab002.cpp
index db01fdbe12d..7c564bfa28c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJNIFunctionTable/getjniftab002/getjniftab002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetJNIFunctionTable/getjniftab002/getjniftab002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,8 +33,8 @@ extern "C" {
 #define STATUS_FAILED  2
 
 static JavaVM *vm;
-static jvmtiEnv *jvmti = NULL;
-static jniNativeInterface *orig_jni_functions = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jniNativeInterface *orig_jni_functions = nullptr;
 
 static int verbose = 0;
 static jint result = PASSED;
@@ -46,7 +46,7 @@ void redirect(JNIEnv *env, jvmtiError exError) {
         printf("\ntrying to get the JNI function table expecting the error %s to be returned ...\n",
             TranslateError(exError));
 
-    err = jvmti->GetJNIFunctionTable((exError == JVMTI_ERROR_NULL_POINTER) ? NULL : &orig_jni_functions);
+    err = jvmti->GetJNIFunctionTable((exError == JVMTI_ERROR_NULL_POINTER) ? nullptr : &orig_jni_functions);
     if (err != exError) {
         result = STATUS_FAILED;
         printf("(%s,%d): TEST FAILED: GetJNIFunctionTable() returns %s instead of %s as expected\n",
@@ -61,9 +61,9 @@ void redirect(JNIEnv *env, jvmtiError exError) {
 JNIEXPORT jint JNICALL
 Java_nsk_jvmti_GetJNIFunctionTable_getjniftab002_check(JNIEnv *env, jobject obj) {
     jint err;
-    JNIEnv *nextEnv = NULL;
+    JNIEnv *nextEnv = nullptr;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("(%s,%d): TEST FAILURE: JVMTI client was not properly loaded\n",
             __FILE__, __LINE__);
         return STATUS_FAILED;
@@ -115,14 +115,14 @@ JNIEXPORT jint JNI_OnLoad_getjniftab002(JavaVM *jvm, char *options, void *reserv
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "-verbose") == 0)
+    if (options != nullptr && strcmp(options, "-verbose") == 0)
         verbose = 1;
 
     if (verbose)
         printf("verbose mode on\n");
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("(%s,%d): Failed to call GetEnv\n", __FILE__, __LINE__);
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLineNumberTable/linetab001/linetab001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLineNumberTable/linetab001/linetab001.cpp
index 17884af7497..669374789ec 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLineNumberTable/linetab001/linetab001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLineNumberTable/linetab001/linetab001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -67,8 +67,8 @@ void checkMeth(JNIEnv *env, jclass cl, const char *name, const char *sig,
     } else {
         mid = env->GetMethodID(cl, name, sig);
     }
-    if (mid == NULL) {
-        printf("Name = %s, sig = %s: mid = NULL\n", name, sig);
+    if (mid == nullptr) {
+        printf("Name = %s, sig = %s: mid = null\n", name, sig);
         result = STATUS_FAILED;
         return;
     }
@@ -132,7 +132,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLineNumberTable/linetab002/linetab002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLineNumberTable/linetab002/linetab002.cpp
index a4df264ccbe..ad5984a64d9 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLineNumberTable/linetab002/linetab002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLineNumberTable/linetab002/linetab002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -98,7 +98,7 @@ Java_nsk_jvmti_GetLineNumberTable_linetab002_check(JNIEnv *env, jclass cls) {
     jint entryCount;
     jvmtiLineNumberEntry *table;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -108,7 +108,7 @@ Java_nsk_jvmti_GetLineNumberTable_linetab002_check(JNIEnv *env, jclass cls) {
     }
 
     mid = env->GetMethodID(cls, "<init>", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
@@ -116,7 +116,7 @@ Java_nsk_jvmti_GetLineNumberTable_linetab002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid method check ...\n");
     }
-    err = jvmti->GetLineNumberTable(NULL, &entryCount, &table);
+    err = jvmti->GetLineNumberTable(nullptr, &entryCount, &table);
     if (err != JVMTI_ERROR_INVALID_METHODID) {
         printf("Error expected: JVMTI_ERROR_INVALID_METHODID,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -126,7 +126,7 @@ Java_nsk_jvmti_GetLineNumberTable_linetab002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (entryCountPtr) null pointer check ...\n");
     }
-    err = jvmti->GetLineNumberTable(mid, NULL, &table);
+    err = jvmti->GetLineNumberTable(mid, nullptr, &table);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("(entryCountPtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -136,7 +136,7 @@ Java_nsk_jvmti_GetLineNumberTable_linetab002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (tablePtr) null pointer check ...\n");
     }
-    err = jvmti->GetLineNumberTable(mid, &entryCount, NULL);
+    err = jvmti->GetLineNumberTable(mid, &entryCount, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("(tablePtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLineNumberTable/linetab003/linetab003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLineNumberTable/linetab003/linetab003.cpp
index 26ba35b8472..00468064849 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLineNumberTable/linetab003/linetab003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLineNumberTable/linetab003/linetab003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -99,7 +99,7 @@ Java_nsk_jvmti_GetLineNumberTable_linetab003_check(JNIEnv *env, jclass cls) {
     jvmtiLineNumberEntry *table;
     int i;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -109,7 +109,7 @@ Java_nsk_jvmti_GetLineNumberTable_linetab003_check(JNIEnv *env, jclass cls) {
     }
 
     mid = env->GetMethodID(cls, "meth", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLoadedClasses/loadedclss001/loadedclss001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLoadedClasses/loadedclss001/loadedclss001.cpp
index 12515f15fca..23bd64d6284 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLoadedClasses/loadedclss001/loadedclss001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLoadedClasses/loadedclss001/loadedclss001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_loadedclss001(JavaVM *jvm, char *options, void *reserv
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -69,7 +69,7 @@ Java_nsk_jvmti_GetLoadedClasses_loadedclss001_check(JNIEnv *env, jclass cls) {
     jclass *classes;
     jint classCount;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -77,7 +77,7 @@ Java_nsk_jvmti_GetLoadedClasses_loadedclss001_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (classCountPtr) null pointer check ...\n");
     }
-    err = jvmti->GetLoadedClasses(NULL, &classes);
+    err = jvmti->GetLoadedClasses(nullptr, &classes);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -87,7 +87,7 @@ Java_nsk_jvmti_GetLoadedClasses_loadedclss001_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (classesPtr) null pointer check ...\n");
     }
-    err = jvmti->GetLoadedClasses(&classCount, NULL);
+    err = jvmti->GetLoadedClasses(&classCount, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLoadedClasses/loadedclss002/loadedclss002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLoadedClasses/loadedclss002/loadedclss002.cpp
index 8a65e34cfd4..73e8472c3c4 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLoadedClasses/loadedclss002/loadedclss002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLoadedClasses/loadedclss002/loadedclss002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,9 +35,9 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jobject testedClassLoader = NULL;
-static jclass testedClass = NULL;
-static jfieldID testedFieldID = NULL;
+static jobject testedClassLoader = nullptr;
+static jclass testedClass = nullptr;
+static jfieldID testedFieldID = nullptr;
 
 static const char *CLASS_SIG[] = {
     "Lnsk/jvmti/GetLoadedClasses/loadedclss002;",
@@ -63,15 +63,15 @@ static int lookup(jvmtiEnv* jvmti,
         if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(classes[i], &signature, &generic)))
             break;
 
-        if (signature != NULL && strcmp(signature, exp_sig) == 0) {
+        if (signature != nullptr && strcmp(signature, exp_sig) == 0) {
             NSK_DISPLAY1("Expected class found: %s\n", exp_sig);
             found = NSK_TRUE;
         }
 
-        if (signature != NULL)
+        if (signature != nullptr)
             jvmti->Deallocate((unsigned char*)signature);
 
-        if (generic != NULL)
+        if (generic != nullptr)
             jvmti->Deallocate((unsigned char*)generic);
     }
 
@@ -100,7 +100,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         return;
     }
 
-    if (!NSK_VERIFY(classes != NULL)) {
+    if (!NSK_VERIFY(classes != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -121,7 +121,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         }
     }
 
-    if (classes != NULL)
+    if (classes != nullptr)
         jvmti->Deallocate((unsigned char*)classes);
 
     if (!nsk_jvmti_resumeSync())
@@ -143,7 +143,7 @@ JNIEXPORT jint JNI_OnLoad_loadedclss002(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     NSK_DISPLAY0("Agent_OnLoad\n");
 
@@ -153,10 +153,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariable/getlocal001/getlocal001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariable/getlocal001/getlocal001.cpp
index 42bdfb46cc2..9095312a5b6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariable/getlocal001/getlocal001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariable/getlocal001/getlocal001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -146,7 +146,7 @@ void check2(jvmtiEnv *jvmti_env, jthread thr, jint depth,
 void check3(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thr, jint depth,
         jvmtiLocalVariableEntry *table, jint count, jmethodID mid) {
     jvmtiError err;
-    jobject ob1 = NULL, ob2 = NULL;
+    jobject ob1 = nullptr, ob2 = nullptr;
     jclass cls;
     jfieldID fid;
     jint fldVal = 0;
@@ -171,7 +171,7 @@ void check3(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thr, jint depth,
                 continue;
             }
             fid = env->GetFieldID(cls, "fld", "I");
-            if (fid == NULL) {
+            if (fid == nullptr) {
                 printf("Cannot find ID for \"fld\" field of meth03\n");
                 env->ExceptionClear();
                 result = STATUS_FAILED;
@@ -284,7 +284,7 @@ void JNICALL MethodExit(jvmtiEnv *jvmti_env, JNIEnv *env,
         jthread thr, jmethodID mid,
         jboolean was_poped_by_exception, jvalue return_value) {
     jvmtiError err;
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLocalVariableEntry *table = nullptr;
     jint entryCount = 0;
     int i;
 
@@ -307,7 +307,7 @@ void JNICALL MethodExit(jvmtiEnv *jvmti_env, JNIEnv *env,
                 printf(">>> exit: meth02\n");
             }
             check2(jvmti_env, thr, 0, table, entryCount);
-            mid2 = NULL;
+            mid2 = nullptr;
         } else if (mid == mid3) {
             if (printdump == JNI_TRUE) {
                 printf(">>> exit: meth03\n");
@@ -320,7 +320,7 @@ void JNICALL MethodExit(jvmtiEnv *jvmti_env, JNIEnv *env,
             check4(jvmti_env, thr, 0, table, entryCount);
         }
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (i = 0; i < entryCount; i++) {
             jvmti_env->Deallocate((unsigned char*)table[i].name);
             jvmti_env->Deallocate((unsigned char*)table[i].signature);
@@ -332,7 +332,7 @@ void JNICALL MethodExit(jvmtiEnv *jvmti_env, JNIEnv *env,
 void JNICALL Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *env,
         jthread thr, jmethodID method, jlocation location) {
     jvmtiError err;
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLocalVariableEntry *table = nullptr;
     jint entryCount = 0;
     jmethodID mid;
     jlocation loc;
@@ -376,7 +376,7 @@ void JNICALL Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *env,
         printf("ERROR: didn't know where we got called from");
         result = STATUS_FAILED;
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (i = 0; i < entryCount; i++) {
             jvmti_env->Deallocate((unsigned char*)table[i].name);
             jvmti_env->Deallocate((unsigned char*)table[i].signature);
@@ -400,12 +400,12 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -474,7 +474,7 @@ Java_nsk_jvmti_GetLocalVariable_getlocal001_getMeth(JNIEnv *env, jclass cls,
         result = STATUS_FAILED;
         return;
     }
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_EXIT, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_EXIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable METHOD_EXIT event: %s (%d)\n",
                TranslateError(err), err);
@@ -487,7 +487,7 @@ Java_nsk_jvmti_GetLocalVariable_getlocal001_getMeth(JNIEnv *env, jclass cls,
         return;
     }
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariable/getlocal002/getlocal002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariable/getlocal002/getlocal002.cpp
index 6f6081fe24e..48fac6fc75f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariable/getlocal002/getlocal002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariable/getlocal002/getlocal002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,12 +33,12 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
-static jmethodID mid = NULL;
+static jmethodID mid = nullptr;
 
 void JNICALL MethodExit(jvmtiEnv *jvmti_env, JNIEnv *env,
         jthread thr, jmethodID method,
@@ -52,7 +52,7 @@ void JNICALL MethodExit(jvmtiEnv *jvmti_env, JNIEnv *env,
 
     if (mid == method) {
         err = jvmti->SetEventNotificationMode(JVMTI_DISABLE,
-            JVMTI_EVENT_METHOD_EXIT, NULL);
+            JVMTI_EVENT_METHOD_EXIT, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to disable metod exit event: %s (%d)\n",
                    TranslateError(err), err);
@@ -98,7 +98,7 @@ void JNICALL MethodExit(jvmtiEnv *jvmti_env, JNIEnv *env,
                 if (printdump == JNI_TRUE) {
                     printf(">>> null pointer check ...\n");
                 }
-                err = jvmti->GetLocalFloat(thr, 0, table[i].slot, NULL);
+                err = jvmti->GetLocalFloat(thr, 0, table[i].slot, nullptr);
                 if (err != JVMTI_ERROR_NULL_POINTER) {
                     printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
                     printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -129,12 +129,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -181,7 +181,7 @@ JNIEXPORT void JNICALL
 Java_nsk_jvmti_GetLocalVariable_getlocal002_getMeth(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -191,14 +191,14 @@ Java_nsk_jvmti_GetLocalVariable_getlocal002_getMeth(JNIEnv *env, jclass cls) {
         !caps.can_generate_method_exit_events) return;
 
     mid = env->GetMethodID(cls, "meth01", "()D");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find Method ID for meth01\n");
         result = STATUS_FAILED;
         return;
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_METHOD_EXIT, NULL);
+        JVMTI_EVENT_METHOD_EXIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable metod exit event: %s (%d)\n",
                TranslateError(err), err);
@@ -215,12 +215,12 @@ Java_nsk_jvmti_GetLocalVariable_getlocal002_checkLoc(JNIEnv *env,
     jmethodID mid;
     jint i1;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         return;
     }
 
     mid = env->GetStaticMethodID(cls, "meth02", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find Method ID for meth02\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab001/localtab001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab001/localtab001.cpp
index fcc3e5040ba..bca81f0d9fe 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab001/localtab001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab001/localtab001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,47 +42,47 @@ static jvmtiEnv *jvmti;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jvmtiLocalVariableEntry m1[] = {
-    { 0, 21, (char*) "this", (char*) "Lnsk/jvmti/GetLocalVariableTable/localtab001;", NULL, 0 },
-    { 4, 17, (char*) "l",    (char*) "J", NULL, 1 },
-    { 7, 14, (char*) "f",    (char*) "F", NULL, 2 },
-    { 12, 9, (char*) "d",    (char*) "D", NULL, 3 }
+    { 0, 21, (char*) "this", (char*) "Lnsk/jvmti/GetLocalVariableTable/localtab001;", nullptr, 0 },
+    { 4, 17, (char*) "l",    (char*) "J", nullptr, 1 },
+    { 7, 14, (char*) "f",    (char*) "F", nullptr, 2 },
+    { 12, 9, (char*) "d",    (char*) "D", nullptr, 3 }
 };
 static jvmtiLocalVariableEntry m2[] = {
-    { 0, 32, (char*) "this", (char*) "Lnsk/jvmti/GetLocalVariableTable/localtab001;", NULL, 0 },
-    { 0, 32, (char*) "step", (char*) "I", NULL, 1 },
-    { 2, 29, (char*) "i2",   (char*) "S", NULL, 2 },
-    { 4, 27, (char*) "i3",   (char*) "C", NULL, 3 },
-    { 7, 24, (char*) "i4",   (char*) "B", NULL, 4 },
-    { 10,21, (char*) "i5",   (char*) "Z", NULL, 5 },
-    { 13,18, (char*) "i1",   (char*) "I", NULL, 6 }
+    { 0, 32, (char*) "this", (char*) "Lnsk/jvmti/GetLocalVariableTable/localtab001;", nullptr, 0 },
+    { 0, 32, (char*) "step", (char*) "I", nullptr, 1 },
+    { 2, 29, (char*) "i2",   (char*) "S", nullptr, 2 },
+    { 4, 27, (char*) "i3",   (char*) "C", nullptr, 3 },
+    { 7, 24, (char*) "i4",   (char*) "B", nullptr, 4 },
+    { 10,21, (char*) "i5",   (char*) "Z", nullptr, 5 },
+    { 13,18, (char*) "i1",   (char*) "I", nullptr, 6 }
 };
 static jvmtiLocalVariableEntry m3[] = {
-    { 0, 70, (char*) "ob",  (char*) "Lnsk/jvmti/GetLocalVariableTable/localtab001;", NULL, 0 },
-    { 2, 67, (char*) "ob1", (char*) "Lnsk/jvmti/GetLocalVariableTable/localtab001;", NULL, 1 },
-    { 56,13, (char*) "ob2", (char*) "[I", NULL, 2 },
-    { 61, 0, (char*) "i",   (char*) "I", NULL, 3 },
-    { 64, 5, (char*) "e",   (char*) "Ljava/lang/IndexOutOfBoundsException;", NULL, 4 }
+    { 0, 70, (char*) "ob",  (char*) "Lnsk/jvmti/GetLocalVariableTable/localtab001;", nullptr, 0 },
+    { 2, 67, (char*) "ob1", (char*) "Lnsk/jvmti/GetLocalVariableTable/localtab001;", nullptr, 1 },
+    { 56,13, (char*) "ob2", (char*) "[I", nullptr, 2 },
+    { 61, 0, (char*) "i",   (char*) "I", nullptr, 3 },
+    { 64, 5, (char*) "e",   (char*) "Ljava/lang/IndexOutOfBoundsException;", nullptr, 4 }
 };
 static jvmtiLocalVariableEntry m4[] = {
-    { 0, 33, (char*) "i1", (char*) "I", NULL, 0 },
-    { 0, 33, (char*) "l",  (char*) "J", NULL, 1 },
-    { 0, 33, (char*) "i2", (char*) "S", NULL, 2 },
-    { 0, 33, (char*) "d",  (char*) "D", NULL, 3 },
-    { 0, 33, (char*) "i3", (char*) "C", NULL, 4 },
-    { 0, 33, (char*) "f",  (char*) "F", NULL, 5 },
-    { 0, 33, (char*) "i4", (char*) "B", NULL, 6 },
-    { 0, 33, (char*) "b",  (char*) "Z", NULL, 7 }
+    { 0, 33, (char*) "i1", (char*) "I", nullptr, 0 },
+    { 0, 33, (char*) "l",  (char*) "J", nullptr, 1 },
+    { 0, 33, (char*) "i2", (char*) "S", nullptr, 2 },
+    { 0, 33, (char*) "d",  (char*) "D", nullptr, 3 },
+    { 0, 33, (char*) "i3", (char*) "C", nullptr, 4 },
+    { 0, 33, (char*) "f",  (char*) "F", nullptr, 5 },
+    { 0, 33, (char*) "i4", (char*) "B", nullptr, 6 },
+    { 0, 33, (char*) "b",  (char*) "Z", nullptr, 7 }
 };
 static jvmtiLocalVariableEntry m5[] = {
-    { 0, 6, (char*) "this", (char*) "Lnsk/jvmti/GetLocalVariableTable/localtab001;", NULL, 0 },
-    { 0, 6, (char*) "i",    (char*) "I", NULL, 1 },
-    { 2, 4, (char*) "i12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678", (char*) "I", NULL, 2 }
+    { 0, 6, (char*) "this", (char*) "Lnsk/jvmti/GetLocalVariableTable/localtab001;", nullptr, 0 },
+    { 0, 6, (char*) "i",    (char*) "I", nullptr, 1 },
+    { 2, 4, (char*) "i12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678", (char*) "I", nullptr, 2 }
 };
 static jvmtiLocalVariableEntry m6[] = {
-    { 0, 5, (char*) "this", (char*) "Lnsk/jvmti/GetLocalVariableTable/localtab001;", NULL, 0 },
+    { 0, 5, (char*) "this", (char*) "Lnsk/jvmti/GetLocalVariableTable/localtab001;", nullptr, 0 },
 };
 static info meth_tab[] = {
-    { 0, NULL },
+    { 0, nullptr },
     { 4, m1 },
     { 7, m2 },
     { 5, m3 },
@@ -106,8 +106,8 @@ void checkMeth(JNIEnv *env, jclass cl, const char *name, const char *sig,
     } else {
         mid = env->GetMethodID(cl, name, sig);
     }
-    if (mid == NULL) {
-        printf("Name = %s, sig = %s: mid = NULL\n", name, sig);
+    if (mid == nullptr) {
+        printf("Name = %s, sig = %s: mid = null\n", name, sig);
         result = STATUS_FAILED;
         return;
     }
@@ -194,7 +194,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab002/localtab002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab002/localtab002.cpp
index 10ce5662641..877ed5fe517 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab002/localtab002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab002/localtab002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -98,7 +98,7 @@ Java_nsk_jvmti_GetLocalVariableTable_localtab002_check(JNIEnv *env, jclass cls)
     jint entryCount;
     jvmtiLocalVariableEntry *table;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -106,7 +106,7 @@ Java_nsk_jvmti_GetLocalVariableTable_localtab002_check(JNIEnv *env, jclass cls)
     if (!caps.can_access_local_variables) return result;
 
     mid = env->GetMethodID(cls, "<init>", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID for \"<init>\"!\n");
         return STATUS_FAILED;
     }
@@ -114,7 +114,7 @@ Java_nsk_jvmti_GetLocalVariableTable_localtab002_check(JNIEnv *env, jclass cls)
     if (printdump == JNI_TRUE) {
         printf(">>> invalid method check ...\n");
     }
-    err = jvmti->GetLocalVariableTable(NULL, &entryCount, &table);
+    err = jvmti->GetLocalVariableTable(nullptr, &entryCount, &table);
     if (err != JVMTI_ERROR_INVALID_METHODID) {
         printf("Error expected: JVMTI_ERROR_INVALID_METHODID,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -124,7 +124,7 @@ Java_nsk_jvmti_GetLocalVariableTable_localtab002_check(JNIEnv *env, jclass cls)
     if (printdump == JNI_TRUE) {
         printf(">>> (entryCountPtr) null pointer check ...\n");
     }
-    err = jvmti->GetLocalVariableTable(mid, NULL, &table);
+    err = jvmti->GetLocalVariableTable(mid, nullptr, &table);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -134,7 +134,7 @@ Java_nsk_jvmti_GetLocalVariableTable_localtab002_check(JNIEnv *env, jclass cls)
     if (printdump == JNI_TRUE) {
         printf(">>> (tablePtr) null pointer check ...\n");
     }
-    err = jvmti->GetLocalVariableTable(mid, &entryCount, NULL);
+    err = jvmti->GetLocalVariableTable(mid, &entryCount, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -142,7 +142,7 @@ Java_nsk_jvmti_GetLocalVariableTable_localtab002_check(JNIEnv *env, jclass cls)
     }
 
     mid = env->GetStaticMethodID(cls, "check", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID for \"check\"!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab003/localtab003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab003/localtab003.cpp
index f1763f736ea..00f3498d4d8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab003/localtab003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab003/localtab003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -99,7 +99,7 @@ Java_nsk_jvmti_GetLocalVariableTable_localtab003_check(JNIEnv *env, jclass cls)
     jvmtiLocalVariableEntry *table;
     int i;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -107,7 +107,7 @@ Java_nsk_jvmti_GetLocalVariableTable_localtab003_check(JNIEnv *env, jclass cls)
     if (!caps.can_access_local_variables) return result;
 
     mid = env->GetMethodID(cls, "meth", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab004/localtab004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab004/localtab004.cpp
index 8f25575e04d..2bd35a65392 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab004/localtab004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab004/localtab004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -81,12 +81,12 @@ typedef struct {    /* local variables of a method */
 
 /* list of tested methods */
 static methodInfo methInfo[] = {
-    { 1, (char*) "<init>", (char*) "()V", 6, constr_lv, NULL },
-    { 1, (char*) "finMethod", (char*) "(CJIJ)V", 7, finMeth_lv, NULL },
-    { 0, (char*) "statMethod", (char*) "(III)D", 5, statMeth_lv, NULL }
+    { 1, (char*) "<init>", (char*) "()V", 6, constr_lv, nullptr },
+    { 1, (char*) "finMethod", (char*) "(CJIJ)V", 7, finMeth_lv, nullptr },
+    { 0, (char*) "statMethod", (char*) "(III)D", 5, statMeth_lv, nullptr }
 };
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 
 static int checkAttr(JNIEnv *jni_env, jclass testedCls) {
@@ -102,7 +102,7 @@ static int checkAttr(JNIEnv *jni_env, jclass testedCls) {
             methInfo[i].mid = jni_env->GetMethodID(testedCls, methInfo[i].m_name, methInfo[i].m_sign);
         else                   /* a static method */
             methInfo[i].mid = jni_env->GetStaticMethodID(testedCls, methInfo[i].m_name, methInfo[i].m_sign);
-        if (methInfo[i].mid == NULL) {
+        if (methInfo[i].mid == nullptr) {
             NSK_COMPLAIN3("TEST FAILURE: unable to get the method ID for the %s method \"%s\", signature \"%s\"\n\n",
                 methInfo[i].inst ? "instance" : "static",
                 methInfo[i].m_name, methInfo[i].m_sign);
@@ -196,7 +196,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capability to access local variables */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab005/localtab005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab005/localtab005.cpp
index 3a681654762..0436b7f1d49 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab005/localtab005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetLocalVariableTable/localtab005/localtab005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,35 +45,35 @@ typedef struct {      /* local variable info */
 
 /* expected local variable info are below */
 static localVar constr_lv[] = { /* constructor's local variables */
-    { "this", "Lnsk/jvmti/GetLocalVariableTable/localtab005a;", "NULL" },
+    { "this", "Lnsk/jvmti/GetLocalVariableTable/localtab005a;", "null" },
     { "constr_b", "Lnsk/jvmti/GetLocalVariableTable/localtab005b;",
       "Lnsk/jvmti/GetLocalVariableTable/localtab005b<Ljava/lang/String;>;" },
-    { "constr_i", "I", "NULL" },
+    { "constr_i", "I", "null" },
     { "constr_c", "Lnsk/jvmti/GetLocalVariableTable/localtab005c;",
       "Lnsk/jvmti/GetLocalVariableTable/localtab005c<Ljava/lang/Boolean;Ljava/lang/Integer;>;" },
-    { "constr_f", "F", "NULL" },
-    { "constr_ch", "C", "NULL" },
+    { "constr_f", "F", "null" },
+    { "constr_ch", "C", "null" },
     { "constr_if", "Lnsk/jvmti/GetLocalVariableTable/localtab005if;",
       "Lnsk/jvmti/GetLocalVariableTable/localtab005if<Ljava/lang/Object;>;" }
 };
 
 static localVar insMeth_lv[] = { /* finMethod()'s local variables */
-    { "this", "Lnsk/jvmti/GetLocalVariableTable/localtab005a;", "NULL" },
-    { "ins_c", "C", "NULL" },
-    { "ins_i", "J", "NULL" },
+    { "this", "Lnsk/jvmti/GetLocalVariableTable/localtab005a;", "null" },
+    { "ins_c", "C", "null" },
+    { "ins_i", "J", "null" },
     { "ltab005d", "Lnsk/jvmti/GetLocalVariableTable/localtab005d;",
       "Lnsk/jvmti/GetLocalVariableTable/localtab005d<Ljava/lang/Object;>;" },
-    { "ins_k", "J", "NULL" },
-    { "ins_l", "J", "NULL" },
+    { "ins_k", "J", "null" },
+    { "ins_l", "J", "null" },
     { "ins_g", "Lnsk/jvmti/GetLocalVariableTable/localtab005g;",
       "Lnsk/jvmti/GetLocalVariableTable/localtab005g<Lnsk/jvmti/GetLocalVariableTable/localtab005f;>;" }
 };
 
 static localVar statMeth_lv[] = { /* statMethod()'s local variables */
-    { "stat_x", "I", "NULL" },
-    { "stat_y", "I", "NULL" },
-    { "stat_z", "I", "NULL" },
-    { "stat_j", "D", "NULL" },
+    { "stat_x", "I", "null" },
+    { "stat_y", "I", "null" },
+    { "stat_z", "I", "null" },
+    { "stat_j", "D", "null" },
     { "stat_d", "Lnsk/jvmti/GetLocalVariableTable/localtab005d;",
       "Lnsk/jvmti/GetLocalVariableTable/localtab005d<Ljava/lang/Byte;>;" }
 };
@@ -89,12 +89,12 @@ typedef struct {    /* local variables of a method */
 
 /* list of tested methods */
 static methodInfo methInfo[] = {
-    { 1, (char*) "<init>", (char*) "()V", 7, constr_lv, NULL },
-    { 1, (char*) "insMethod", (char*) "(CJLnsk/jvmti/GetLocalVariableTable/localtab005d;J)V", 7, insMeth_lv, NULL },
-    { 0, (char*) "statMethod", (char*) "(III)D", 5, statMeth_lv, NULL }
+    { 1, (char*) "<init>", (char*) "()V", 7, constr_lv, nullptr },
+    { 1, (char*) "insMethod", (char*) "(CJLnsk/jvmti/GetLocalVariableTable/localtab005d;J)V", 7, insMeth_lv, nullptr },
+    { 0, (char*) "statMethod", (char*) "(III)D", 5, statMeth_lv, nullptr }
 };
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 
 static int checkAttr(JNIEnv *jni_env, jclass testedCls) {
@@ -110,7 +110,7 @@ static int checkAttr(JNIEnv *jni_env, jclass testedCls) {
             methInfo[i].mid = jni_env->GetMethodID(testedCls, methInfo[i].m_name, methInfo[i].m_sign);
         else                   /* a static method */
             methInfo[i].mid = jni_env->GetStaticMethodID(testedCls, methInfo[i].m_name, methInfo[i].m_sign);
-        if (methInfo[i].mid == NULL) {
+        if (methInfo[i].mid == nullptr) {
             NSK_COMPLAIN3("TEST FAILURE: unable to get the method ID for the %s method \"%s\", signature \"%s\"\n\n",
                 methInfo[i].inst ? "instance" : "static",
                 methInfo[i].m_name, methInfo[i].m_sign);
@@ -137,7 +137,7 @@ static int checkAttr(JNIEnv *jni_env, jclass testedCls) {
                     NSK_COMPLAIN4("\t%d) name: \"%s\"\n\tsignature: \"%s\"\n\tgeneric signature: \"%s\"\n",
                         j+1, lv_table[j].name,
                         lv_table[j].signature,
-                       (lv_table[j].generic_signature == NULL) ? "NULL" : lv_table[j].generic_signature);
+                       (lv_table[j].generic_signature == nullptr) ? "null" : lv_table[j].generic_signature);
                 NSK_COMPLAIN0("\n");
 
                 continue;
@@ -155,7 +155,7 @@ static int checkAttr(JNIEnv *jni_env, jclass testedCls) {
                 for (k=0; k<count; k++) {
                     if (strcmp(lv_table[j].name, methInfo[i].vars[k].v_name) == 0) {
                         if ((strcmp(lv_table[j].signature, methInfo[i].vars[k].v_sign) != 0) ||
-                            (strcmp((lv_table[j].generic_signature == NULL) ? "NULL" : lv_table[j].generic_signature,
+                            (strcmp((lv_table[j].generic_signature == nullptr) ? "null" : lv_table[j].generic_signature,
                                 methInfo[i].vars[k].v_gen_sign) != 0)) {
                             NSK_COMPLAIN8(
                                 "TEST FAILED: %s method: \"%s\" \"%s\":\n"
@@ -165,9 +165,9 @@ static int checkAttr(JNIEnv *jni_env, jclass testedCls) {
                                 methInfo[i].inst ? "instance" : "static",
                                 methInfo[i].m_name, methInfo[i].m_sign,
                                 lv_table[j].name, lv_table[j].signature,
-                               (lv_table[j].generic_signature == NULL) ? "NULL" : lv_table[j].generic_signature,
+                               (lv_table[j].generic_signature == nullptr) ? "null" : lv_table[j].generic_signature,
                                 methInfo[i].vars[k].v_sign,
-                               (methInfo[i].vars[k].v_gen_sign == NULL) ? "NULL" : methInfo[i].vars[k].v_gen_sign);
+                               (methInfo[i].vars[k].v_gen_sign == nullptr) ? "null" : methInfo[i].vars[k].v_gen_sign);
                             totRes = STATUS_FAILED;
                             break;
                         }
@@ -175,7 +175,7 @@ static int checkAttr(JNIEnv *jni_env, jclass testedCls) {
                             NSK_DISPLAY3("CHECK PASSED: var: \"%s\",\n\tsignature: \"%s\",\n\tgeneric signature: \"%s\"\n",
                                 lv_table[j].name,
                                 lv_table[j].signature,
-                               (lv_table[j].generic_signature == NULL) ? "NULL" : lv_table[j].generic_signature);
+                               (lv_table[j].generic_signature == nullptr) ? "null" : lv_table[j].generic_signature);
                     }
                 }
             }
@@ -220,7 +220,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capability to access local variables */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMaxLocals/maxloc001/maxloc001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMaxLocals/maxloc001/maxloc001.cpp
index 63e0e98b80d..aa6b4dcb99c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMaxLocals/maxloc001/maxloc001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMaxLocals/maxloc001/maxloc001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,12 +33,12 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 
 void checkMeth(JNIEnv *env, jclass cl, const char *name, const char *sig, int stat, int max_loc) {
     jvmtiError err;
-    jmethodID mid = NULL;
+    jmethodID mid = nullptr;
     jint ret_loc;
 
     if (stat) {
@@ -46,7 +46,7 @@ void checkMeth(JNIEnv *env, jclass cl, const char *name, const char *sig, int st
     } else {
         mid = env->GetMethodID(cl, name, sig);
     }
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Name = %s, sig = %s: mid = 0\n", name, sig);
         result = STATUS_FAILED;
         return;
@@ -77,7 +77,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMaxLocals/maxloc002/maxloc002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMaxLocals/maxloc002/maxloc002.cpp
index 6fbea7d6a5a..81851e1e282 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMaxLocals/maxloc002/maxloc002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMaxLocals/maxloc002/maxloc002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_maxloc002(JavaVM *jvm, char *options, void *reserved)
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,13 +70,13 @@ Java_nsk_jvmti_GetMaxLocals_maxloc002_check(JNIEnv *env, jclass cls) {
     jmethodID mid;
     jint max;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     mid = env->GetMethodID(cls, "<init>", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID for \"<init>\"!\n");
         return STATUS_FAILED;
     }
@@ -84,7 +84,7 @@ Java_nsk_jvmti_GetMaxLocals_maxloc002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid method check ...\n");
     }
-    err = jvmti->GetMaxLocals(NULL, &max);
+    err = jvmti->GetMaxLocals(nullptr, &max);
     if (err != JVMTI_ERROR_INVALID_METHODID) {
         printf("Error expected: JVMTI_ERROR_INVALID_METHODID,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -94,7 +94,7 @@ Java_nsk_jvmti_GetMaxLocals_maxloc002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->GetMaxLocals(mid, NULL);
+    err = jvmti->GetMaxLocals(mid, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -102,7 +102,7 @@ Java_nsk_jvmti_GetMaxLocals_maxloc002_check(JNIEnv *env, jclass cls) {
     }
 
     mid = env->GetStaticMethodID(cls, "check", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID for \"check\"!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodDeclaringClass/declcls001/declcls001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodDeclaringClass/declcls001/declcls001.cpp
index ec3691af227..bfb2441f7dc 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodDeclaringClass/declcls001/declcls001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodDeclaringClass/declcls001/declcls001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,8 +49,8 @@ void checkMeth(JNIEnv *env, const char *cl_name, const char *name, const char *s
     } else {
         mid = env->GetMethodID(cl, name, sig);
     }
-    if (mid == NULL) {
-        printf("%s.%s%s: mid = NULL\n", cl_name, name, sig);
+    if (mid == nullptr) {
+        printf("%s.%s%s: mid = null\n", cl_name, name, sig);
         result = STATUS_FAILED;
         return;
     }
@@ -95,7 +95,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodDeclaringClass/declcls002/declcls002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodDeclaringClass/declcls002/declcls002.cpp
index a923fd4d950..8edd98ab96e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodDeclaringClass/declcls002/declcls002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodDeclaringClass/declcls002/declcls002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_declcls002(JavaVM *jvm, char *options, void *reserved)
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,13 +70,13 @@ Java_nsk_jvmti_GetMethodDeclaringClass_declcls002_check(JNIEnv *env, jclass cls)
     jmethodID mid;
     jclass declaringClass;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     mid = env->GetMethodID(cls, "<init>", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
@@ -84,7 +84,7 @@ Java_nsk_jvmti_GetMethodDeclaringClass_declcls002_check(JNIEnv *env, jclass cls)
     if (printdump == JNI_TRUE) {
         printf(">>> invalid method check ...\n");
     }
-    err = jvmti->GetMethodDeclaringClass(NULL, &declaringClass);
+    err = jvmti->GetMethodDeclaringClass(nullptr, &declaringClass);
     if (err != JVMTI_ERROR_INVALID_METHODID) {
         printf("Error expected: JVMTI_ERROR_INVALID_METHODID,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -94,7 +94,7 @@ Java_nsk_jvmti_GetMethodDeclaringClass_declcls002_check(JNIEnv *env, jclass cls)
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->GetMethodDeclaringClass(mid, NULL);
+    err = jvmti->GetMethodDeclaringClass(mid, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodDeclaringClass/declcls003/declcls003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodDeclaringClass/declcls003/declcls003.cpp
index 8f447709770..ca7bce9eb81 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodDeclaringClass/declcls003/declcls003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodDeclaringClass/declcls003/declcls003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static const char *exp_class_sig = "Ljava/lang/Object;";
@@ -55,8 +55,8 @@ void do_check(JNIEnv *env, const char *name, const char *meth, const char *sig)
 
     cl = env->FindClass(name);
     mid = env->GetMethodID(cl, meth, sig);
-    if (mid == NULL) {
-        printf("%s.%s%s: mid = NULL\n", name, meth, sig);
+    if (mid == nullptr) {
+        printf("%s.%s%s: mid = null\n", name, meth, sig);
         result = STATUS_FAILED;
         return;
     }
@@ -105,12 +105,12 @@ JNIEXPORT jint JNI_OnLoad_declcls003(JavaVM *jvm, char *options, void *reserved)
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodLocation/methloc001/methloc001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodLocation/methloc001/methloc001.cpp
index c8e9cd6c730..53978f36efe 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodLocation/methloc001/methloc001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodLocation/methloc001/methloc001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -59,8 +59,8 @@ void checkMeth(JNIEnv *env, jclass cl, const char *name, const char *sig,
     } else {
         mid = env->GetMethodID(cl, name, sig);
     }
-    if (mid == NULL) {
-        printf("Name = %s, sig = %s: mid = NULL\n", name, sig);
+    if (mid == nullptr) {
+        printf("Name = %s, sig = %s: mid = null\n", name, sig);
         result = STATUS_FAILED;
         return;
     }
@@ -103,7 +103,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodLocation/methloc002/methloc002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodLocation/methloc002/methloc002.cpp
index 858553a7d85..2e596dd7861 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodLocation/methloc002/methloc002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodLocation/methloc002/methloc002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_methloc002(JavaVM *jvm, char *options, void *reserved)
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -71,13 +71,13 @@ Java_nsk_jvmti_GetMethodLocation_methloc002_check(JNIEnv *env, jclass cls) {
     jlocation startLocation;
     jlocation endLocation;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     mid = env->GetMethodID(cls, "<init>", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID for \"<init>\"!\n");
         return STATUS_FAILED;
     }
@@ -85,7 +85,7 @@ Java_nsk_jvmti_GetMethodLocation_methloc002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid method check ...\n");
     }
-    err = jvmti->GetMethodLocation(NULL, &startLocation, &endLocation);
+    err = jvmti->GetMethodLocation(nullptr, &startLocation, &endLocation);
     if (err != JVMTI_ERROR_INVALID_METHODID) {
         printf("Error expected: JVMTI_ERROR_INVALID_METHODID,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -95,7 +95,7 @@ Java_nsk_jvmti_GetMethodLocation_methloc002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (startLocationPtr) null pointer check ...\n");
     }
-    err = jvmti->GetMethodLocation(mid, NULL, &endLocation);
+    err = jvmti->GetMethodLocation(mid, nullptr, &endLocation);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("(startLocationPtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -105,7 +105,7 @@ Java_nsk_jvmti_GetMethodLocation_methloc002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (endLocationPtr) null pointer check ...\n");
     }
-    err = jvmti->GetMethodLocation(mid, &startLocation, NULL);
+    err = jvmti->GetMethodLocation(mid, &startLocation, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("(endLocationPtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -113,7 +113,7 @@ Java_nsk_jvmti_GetMethodLocation_methloc002_check(JNIEnv *env, jclass cls) {
     }
 
     mid = env->GetStaticMethodID(cls, "check", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID for \"check\"!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodModifiers/methmod001/methmod001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodModifiers/methmod001/methmod001.cpp
index 838adc03019..3b44d8daf4c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodModifiers/methmod001/methmod001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodModifiers/methmod001/methmod001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@ extern "C" {
 #define ACC_NATIVE        0x100
 #define ACC_ABSTRACT      0x400
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -70,7 +70,7 @@ void checkMeth(jvmtiEnv *jvmti_env, JNIEnv *env, jclass cl,
     } else {
         mid = env->GetMethodID(cl, name, sig);
     }
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find MethodID for \"%s%s\"\n", name, sig);
         result = STATUS_FAILED;
         return;
@@ -135,12 +135,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -154,7 +154,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_CLASS_LOAD, NULL);
+        JVMTI_EVENT_CLASS_LOAD, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable event JVMTI_EVENT_CLASS_LOAD: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodModifiers/methmod002/methmod002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodModifiers/methmod002/methmod002.cpp
index 5542a3d35fc..02fc2a5ba77 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodModifiers/methmod002/methmod002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodModifiers/methmod002/methmod002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_methmod002(JavaVM *jvm, char *options, void *reserved)
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,13 +70,13 @@ Java_nsk_jvmti_GetMethodModifiers_methmod002_check(JNIEnv *env, jclass cls) {
     jmethodID mid;
     jint modifiers;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     mid = env->GetMethodID(cls, "<init>", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
@@ -84,7 +84,7 @@ Java_nsk_jvmti_GetMethodModifiers_methmod002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid method check ...\n");
     }
-    err = jvmti->GetMethodModifiers(NULL, &modifiers);
+    err = jvmti->GetMethodModifiers(nullptr, &modifiers);
     if (err != JVMTI_ERROR_INVALID_METHODID) {
         printf("Error expected: JVMTI_ERROR_INVALID_METHODID,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -94,7 +94,7 @@ Java_nsk_jvmti_GetMethodModifiers_methmod002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->GetMethodModifiers(mid, NULL);
+    err = jvmti->GetMethodModifiers(mid, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodName/methname001/methname001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodName/methname001/methname001.cpp
index 79c0db9c6af..6c4dcbb889e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodName/methname001/methname001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodName/methname001/methname001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -50,7 +50,7 @@ void checkMeth(jvmtiEnv *jvmti_env, JNIEnv *env, jclass cl,
     } else {
         mid = env->GetMethodID(cl, name, sig);
     }
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find MethodID for \"%s%s\"\n", name, sig);
         result = STATUS_FAILED;
         return;
@@ -115,12 +115,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -134,7 +134,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_CLASS_LOAD, NULL);
+        JVMTI_EVENT_CLASS_LOAD, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable event JVMTI_EVENT_CLASS_LOAD: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodName/methname002/methname002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodName/methname002/methname002.cpp
index 292d5f2b4be..bd503a6ae8c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodName/methname002/methname002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodName/methname002/methname002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_methname002(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,13 +70,13 @@ Java_nsk_jvmti_GetMethodName_methname002_check(JNIEnv *env, jclass cls) {
     jmethodID mid;
     char *name, *sig, *generic;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     mid = env->GetMethodID(cls, "<init>", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
@@ -84,7 +84,7 @@ Java_nsk_jvmti_GetMethodName_methname002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid method check ...\n");
     }
-    err = jvmti->GetMethodName(NULL, &name, &sig, &generic);
+    err = jvmti->GetMethodName(nullptr, &name, &sig, &generic);
     if (err != JVMTI_ERROR_INVALID_METHODID) {
         printf("Error expected: JVMTI_ERROR_INVALID_METHODID,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -94,7 +94,7 @@ Java_nsk_jvmti_GetMethodName_methname002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (namePtr) null pointer check ...\n");
     }
-    err = jvmti->GetMethodName(mid, NULL, &sig, &generic);
+    err = jvmti->GetMethodName(mid, nullptr, &sig, &generic);
     if (err != JVMTI_ERROR_NONE) {
         printf("(namePtr) unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -103,7 +103,7 @@ Java_nsk_jvmti_GetMethodName_methname002_check(JNIEnv *env, jclass cls) {
         if (printdump == JNI_TRUE) {
             printf(">>> sig = \"%s\", generic = \"%s\"\n", sig, generic);
         }
-        if (sig == NULL || strcmp(sig, "()V") != 0) {
+        if (sig == nullptr || strcmp(sig, "()V") != 0) {
             printf("Wrong field sig: \"%s\", expected: \"I\"\n", sig);
             result = STATUS_FAILED;
         }
@@ -112,7 +112,7 @@ Java_nsk_jvmti_GetMethodName_methname002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (signaturePtr) null pointer check ...\n");
     }
-    err = jvmti->GetMethodName(mid, &name, NULL, &generic);
+    err = jvmti->GetMethodName(mid, &name, nullptr, &generic);
     if (err != JVMTI_ERROR_NONE) {
         printf("(signaturePtr) unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -121,7 +121,7 @@ Java_nsk_jvmti_GetMethodName_methname002_check(JNIEnv *env, jclass cls) {
         if (printdump == JNI_TRUE) {
             printf(">>> name = \"%s\", generic = \"%s\"\n", name, generic);
         }
-        if (name == NULL || strcmp(name, "<init>") != 0) {
+        if (name == nullptr || strcmp(name, "<init>") != 0) {
             printf("Wrong field name: \"%s\", expected: \"fld\"\n", name);
             result = STATUS_FAILED;
         }
@@ -130,7 +130,7 @@ Java_nsk_jvmti_GetMethodName_methname002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (genericPtr) null pointer check ...\n");
     }
-    err = jvmti->GetMethodName(mid, &name, &sig, NULL);
+    err = jvmti->GetMethodName(mid, &name, &sig, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("(signaturePtr) unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -139,11 +139,11 @@ Java_nsk_jvmti_GetMethodName_methname002_check(JNIEnv *env, jclass cls) {
         if (printdump == JNI_TRUE) {
             printf(">>> name = \"%s\", sig = \"%s\"\n", name, sig);
         }
-        if (name == NULL || strcmp(name, "<init>") != 0) {
+        if (name == nullptr || strcmp(name, "<init>") != 0) {
             printf("Wrong field name: \"%s\", expected: \"fld\"\n", name);
             result = STATUS_FAILED;
         }
-        if (sig == NULL || strcmp(sig, "()V") != 0) {
+        if (sig == nullptr || strcmp(sig, "()V") != 0) {
             printf("Wrong field sig: \"%s\", expected: \"I\"\n", sig);
             result = STATUS_FAILED;
         }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodName/methname003/methname003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodName/methname003/methname003.cpp
index 669500625f1..a7a3a44022f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodName/methname003/methname003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetMethodName/methname003/methname003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -60,14 +60,14 @@ static const char *meth_sig[][METH_NUM][TOT_NUM] = {
 
     { { "methname003eMeth", "instance",
         "(Lnsk/jvmti/GetMethodName/methname003e;)V",
-        "NULL" },
+        "null" },
      { "methname003eMethSt", "static",
        "(Lnsk/jvmti/GetMethodName/methname003e;)V",
-       "NULL" } },
+       "null" } },
 
     { { "methname003ifMeth", "instance",
         "()I",
-        "NULL" },
+        "null" },
      { "methname003ifMeth2", "instance",
        "(Ljava/lang/Object;)I",
        "<T:Ljava/lang/Object;>(TT;)I" } },
@@ -80,7 +80,7 @@ static const char *meth_sig[][METH_NUM][TOT_NUM] = {
        "<A:Ljava/lang/Byte;B:Ljava/lang/Double;>(TA;TB;)V" } }
 };
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 static int checkSig(JNIEnv *jni_env, jmethodID testedMeth,
         int instance, int clsIdx, int methIdx) {
@@ -98,17 +98,17 @@ static int checkSig(JNIEnv *jni_env, jmethodID testedMeth,
             meth_sig[clsIdx][methIdx][0]);
 
         if (strcmp(meth_sig[clsIdx][methIdx][2], sign) != 0 ||
-                strcmp(meth_sig[clsIdx][methIdx][3], (gen_sign == NULL) ? "NULL" : gen_sign) != 0) {
+                strcmp(meth_sig[clsIdx][methIdx][3], (gen_sign == nullptr) ? "null" : gen_sign) != 0) {
             NSK_COMPLAIN5("TEST FAILED: class: \"%s\" \
 has\n\tsignature: \"%s\"\n\tgeneric signature: \"%s\"\n\n\tExpected: \"%s\"\n\t\t\"%s\"\n\n",
                 meth_sig[clsIdx][methIdx][0],
-                sign, (gen_sign == NULL) ? "NULL" : gen_sign,
+                sign, (gen_sign == nullptr) ? "null" : gen_sign,
                 meth_sig[clsIdx][methIdx][2], meth_sig[clsIdx][methIdx][3]);
             totRes = STATUS_FAILED;
         }
         else
             NSK_DISPLAY2("CHECK PASSED: signature: \"%s\",\n\tgeneric signature: \"%s\"\n",
-                sign, (gen_sign == NULL) ? "NULL" : gen_sign);
+                sign, (gen_sign == nullptr) ? "null" : gen_sign);
 
         NSK_DISPLAY0("Deallocating name & signature arrays\n");
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*) name))) {
@@ -117,7 +117,7 @@ has\n\tsignature: \"%s\"\n\tgeneric signature: \"%s\"\n\n\tExpected: \"%s\"\n\t\
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*) sign))) {
             totRes = STATUS_FAILED;
         }
-        if (gen_sign != NULL)
+        if (gen_sign != nullptr)
             if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*) gen_sign))) {
                 totRes = STATUS_FAILED;
             }
@@ -130,7 +130,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_GetMethodName_methname003_check(
         JNIEnv *jni, jobject obj, jobject testedObj, jint clsIdx) {
     int res = PASSED, i, instance;
-    jmethodID testedMeth = NULL;
+    jmethodID testedMeth = nullptr;
     jclass objCls = jni->GetObjectClass(testedObj);
 
     for (i=0; i<METH_NUM; i++) {
@@ -140,7 +140,7 @@ Java_nsk_jvmti_GetMethodName_methname003_check(
             (instance == 0) ? "instance" : "static",
              meth_sig[clsIdx][i][0]);
         if (instance == 0) {
-            if (!NSK_JNI_VERIFY(jni, (testedMeth = jni->GetMethodID(objCls, meth_sig[clsIdx][i][0], meth_sig[clsIdx][i][2])) != NULL)) {
+            if (!NSK_JNI_VERIFY(jni, (testedMeth = jni->GetMethodID(objCls, meth_sig[clsIdx][i][0], meth_sig[clsIdx][i][2])) != nullptr)) {
                 NSK_COMPLAIN2("TEST FAILERE: unable to get method ID for \"%s\" \"%s\"\n\n",
                     meth_sig[clsIdx][i][0], meth_sig[clsIdx][i][2]);
                 res = STATUS_FAILED;
@@ -148,7 +148,7 @@ Java_nsk_jvmti_GetMethodName_methname003_check(
             }
         }
         else
-            if (!NSK_JNI_VERIFY(jni, (testedMeth = jni->GetStaticMethodID(objCls, meth_sig[clsIdx][i][0], meth_sig[clsIdx][i][2])) != NULL)) {
+            if (!NSK_JNI_VERIFY(jni, (testedMeth = jni->GetStaticMethodID(objCls, meth_sig[clsIdx][i][0], meth_sig[clsIdx][i][2])) != nullptr)) {
                 NSK_COMPLAIN2("TEST FAILERE: unable to get method ID for \"%s\" \"%s\"\n\n",
                     meth_sig[clsIdx][i][0], meth_sig[clsIdx][i][2]);
                 res = STATUS_FAILED;
@@ -184,7 +184,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectHashCode/objhashcode001/objhashcode001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectHashCode/objhashcode001/objhashcode001.cpp
index da85ff4c539..2931d0b0319 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectHashCode/objhashcode001/objhashcode001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectHashCode/objhashcode001/objhashcode001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -51,16 +51,16 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     /* perform testing */
     {
-        jobject testedObject = NULL;
+        jobject testedObject = nullptr;
         jint objectHashCode = 0;
 
         NSK_DISPLAY0(">>> Obtain tested object from a static field of debugee class\n");
         {
-            jclass debugeeClass = NULL;
-            jfieldID objectField = NULL;
+            jclass debugeeClass = nullptr;
+            jfieldID objectField = nullptr;
 
             NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
-            if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+            if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -68,7 +68,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
             NSK_DISPLAY1("Find static field: %s\n", OBJECT_FIELD_NAME);
             if (!NSK_JNI_VERIFY(jni, (objectField =
-                    jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, OBJECT_CLASS_SIG)) != NULL)) {
+                    jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, OBJECT_CLASS_SIG)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -76,14 +76,14 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
             NSK_DISPLAY1("Get object from static field: %s\n", OBJECT_FIELD_NAME);
             if (!NSK_JNI_VERIFY(jni, (testedObject =
-                    jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+                    jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
             NSK_DISPLAY1("  ... got object: %p\n", (void*)testedObject);
 
             NSK_DISPLAY1("Create global reference for object: %p\n", (void*)testedObject);
-            if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewGlobalRef(testedObject)) != NULL)) {
+            if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewGlobalRef(testedObject)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -180,7 +180,7 @@ JNIEXPORT jint JNI_OnLoad_objhashcode001(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -190,11 +190,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage001/objmonusage001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage001/objmonusage001.cpp
index de518c2240f..a02179847f6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage001/objmonusage001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage001/objmonusage001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -117,7 +117,7 @@ Java_nsk_jvmti_GetObjectMonitorUsage_objmonusage001_check(JNIEnv *env,
     }
 
     if (printdump == JNI_TRUE) {
-        if (inf.owner == NULL) {
+        if (inf.owner == nullptr) {
             printf(">>> [%2d]    owner: none (0x0)\n", i);
         } else {
             jvmti->GetThreadInfo(inf.owner, &tinf);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage002/objmonusage002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage002/objmonusage002.cpp
index dda31c173b1..2dd0eaa24f0 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage002/objmonusage002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage002/objmonusage002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -97,7 +97,7 @@ Java_nsk_jvmti_GetObjectMonitorUsage_objmonusage002_check(JNIEnv *env,
     jvmtiError err;
     jvmtiMonitorUsage inf;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -105,7 +105,7 @@ Java_nsk_jvmti_GetObjectMonitorUsage_objmonusage002_check(JNIEnv *env,
     if (printdump == JNI_TRUE) {
         printf(">>> invalid object check ...\n");
     }
-    err = jvmti->GetObjectMonitorUsage(NULL, &inf);
+    err = jvmti->GetObjectMonitorUsage(nullptr, &inf);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY &&
             !caps.can_get_monitor_info) {
         /* Ok, it's expected */
@@ -118,7 +118,7 @@ Java_nsk_jvmti_GetObjectMonitorUsage_objmonusage002_check(JNIEnv *env,
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->GetObjectMonitorUsage(obj, NULL);
+    err = jvmti->GetObjectMonitorUsage(obj, nullptr);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY &&
             !caps.can_get_monitor_info) {
         /* Ok, it's expected */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage003/objmonusage003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage003/objmonusage003.cpp
index b9d8346c879..d696fa08c4f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage003/objmonusage003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage003/objmonusage003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -54,12 +54,12 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -116,7 +116,7 @@ Java_nsk_jvmti_GetObjectMonitorUsage_objmonusage003_check(JNIEnv *env,
     }
 
     if (printdump == JNI_TRUE) {
-        if (inf.owner == NULL) {
+        if (inf.owner == nullptr) {
             printf(">>> [%2d]    owner: none (0x0)\n", count);
         } else {
             err = jvmti->GetThreadInfo(inf.owner, &tinf);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage004/objmonusage004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage004/objmonusage004.cpp
index 34e340e1f65..47be3771376 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage004/objmonusage004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage004/objmonusage004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -54,12 +54,12 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -116,7 +116,7 @@ Java_nsk_jvmti_GetObjectMonitorUsage_objmonusage004_check(JNIEnv *env,
     }
 
     if (printdump == JNI_TRUE) {
-        if (inf.owner == NULL) {
+        if (inf.owner == nullptr) {
             printf(">>> [%2d]    owner: none (0x0)\n", count);
         } else {
             err = jvmti->GetThreadInfo(inf.owner, &tinf);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage005/objmonusage005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage005/objmonusage005.cpp
index 881607b4678..36aed3377ca 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage005/objmonusage005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage005/objmonusage005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 
@@ -53,7 +53,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage006/objmonusage006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage006/objmonusage006.cpp
index 460abfd41c7..2be448e7342 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage006/objmonusage006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage006/objmonusage006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 
@@ -53,7 +53,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectSize/objsize001/objsize001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectSize/objsize001/objsize001.cpp
index 10860792e17..87dfb9c40f7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectSize/objsize001/objsize001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectSize/objsize001/objsize001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,16 +48,16 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         return;
 
     {
-        jobject testedObject = NULL;
+        jobject testedObject = nullptr;
         jlong objectSize = 0;
 
         NSK_DISPLAY0(">>> Obtain tested object from a static field of debugee class\n");
         {
-            jclass debugeeClass = NULL;
-            jfieldID objectField = NULL;
+            jclass debugeeClass = nullptr;
+            jfieldID objectField = nullptr;
 
             NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
-            if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+            if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -65,7 +65,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
             NSK_DISPLAY1("Find static field: %s\n", OBJECT_FIELD_NAME);
             if (!NSK_JNI_VERIFY(jni, (objectField =
-                    jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, OBJECT_CLASS_SIG)) != NULL)) {
+                    jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, OBJECT_CLASS_SIG)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -73,14 +73,14 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
             NSK_DISPLAY1("Get object from static field: %s\n", OBJECT_FIELD_NAME);
             if (!NSK_JNI_VERIFY(jni, (testedObject =
-                    jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+                    jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
             NSK_DISPLAY1("  ... got object: 0x%p\n", (void*)testedObject);
 
             NSK_DISPLAY1("Create global reference for object: 0x%p\n", (void*)testedObject);
-            if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewGlobalRef(testedObject)) != NULL)) {
+            if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewGlobalRef(testedObject)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -180,7 +180,7 @@ JNIEXPORT jint JNI_OnLoad_objsize001(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -188,10 +188,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectsWithTags/objwithtags001/objwithtags001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectsWithTags/objwithtags001/objwithtags001.cpp
index d6ea8445774..c2f4d92e318 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectsWithTags/objwithtags001/objwithtags001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectsWithTags/objwithtags001/objwithtags001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -56,9 +56,9 @@ static int objectsCount = 0;
 /** Obtain tested objects from static field of debugee class. */
 static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int tagsCount, int objectsCount,
                                                 jobject* *objects, jlong* *tags) {
-    jclass debugeeClass = NULL;
-    jfieldID objectField = NULL;
-    jobjectArray arrayObject = NULL;
+    jclass debugeeClass = nullptr;
+    jfieldID objectField = nullptr;
+    jobjectArray arrayObject = nullptr;
     int size = tagsCount * objectsCount;
 
     NSK_DISPLAY2("Allocate memory for lists: %d objects for %d tags\n",
@@ -78,7 +78,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int tagsCount, int obj
     {
         int i, k;
         for (k = 0; k < size; k++) {
-            (*objects)[k] = NULL;
+            (*objects)[k] = nullptr;
         }
 
         for (i = 0; i < tagsCount; i++) {
@@ -87,7 +87,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int tagsCount, int obj
     }
 
     NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -95,7 +95,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int tagsCount, int obj
 
     NSK_DISPLAY1("Find static field: %s\n", OBJECTS_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (objectField =
-            jni->GetStaticFieldID(debugeeClass, OBJECTS_FIELD_NAME, OBJECTS_FIELD_SIG)) != NULL)) {
+            jni->GetStaticFieldID(debugeeClass, OBJECTS_FIELD_NAME, OBJECTS_FIELD_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -103,7 +103,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int tagsCount, int obj
 
     NSK_DISPLAY1("Get objects array from static field: %s\n", OBJECTS_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (arrayObject = (jobjectArray)
-            jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+            jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -121,13 +121,13 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int tagsCount, int obj
         NSK_DISPLAY1("  ... got array length: %d\n", (int)size);
 
         for (k = 0; k < size; k++) {
-            jobject object = NULL;
+            jobject object = nullptr;
 
-            if (!NSK_JNI_VERIFY(jni, (object = jni->GetObjectArrayElement(arrayObject, k)) != NULL)) {
+            if (!NSK_JNI_VERIFY(jni, (object = jni->GetObjectArrayElement(arrayObject, k)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return NSK_FALSE;
             }
-            if (!NSK_JNI_VERIFY(jni, (object = jni->NewGlobalRef(object)) != NULL)) {
+            if (!NSK_JNI_VERIFY(jni, (object = jni->NewGlobalRef(object)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return NSK_FALSE;
             }
@@ -146,12 +146,12 @@ static int releaseTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int tagsCount, int
     int size = tagsCount * objectsCount;
     int k;
 
-    if (objects == NULL)
+    if (objects == nullptr)
         return NSK_TRUE;
 
     NSK_DISPLAY1("Release objects references: %d objects\n", size);
     for (k = 0; k < size; k++) {
-        if (objects[k] != NULL) {
+        if (objects[k] != nullptr) {
             NSK_TRACE(jni->DeleteGlobalRef(objects[k]));
         }
     }
@@ -163,7 +163,7 @@ static int releaseTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int tagsCount, int
         nsk_jvmti_setFailStatus();
     }
 
-    if (tags == NULL)
+    if (tags == nullptr)
         return NSK_FALSE;
 
     NSK_DISPLAY1("Deallocate tags list: 0x%p\n", (void*)tags);
@@ -180,8 +180,8 @@ static int checkTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int tagsCount, int o
                                                 jlong tags[], jobject objects[],
                                                 const char kind[], int expectedCount) {
     jint taggedObjectsCount = 0;
-    jobject* taggedObjectsList = NULL;
-    jlong* taggedObjectsTags = NULL;
+    jobject* taggedObjectsList = nullptr;
+    jlong* taggedObjectsTags = nullptr;
     jlong expectedTag = 0;
     int k;
 
@@ -201,15 +201,15 @@ static int checkTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int tagsCount, int o
         nsk_jvmti_setFailStatus();
     }
 
-    if (taggedObjectsList == NULL && taggedObjectsCount > 0) {
-        NSK_COMPLAIN2("GetObjectsWithTags() returns NULL list of objects %s: 0x%p\n",
+    if (taggedObjectsList == nullptr && taggedObjectsCount > 0) {
+        NSK_COMPLAIN2("GetObjectsWithTags() returns null list of objects %s: 0x%p\n",
                         kind, (void*)taggedObjectsList);
         nsk_jvmti_setFailStatus();
         return NSK_TRUE;
     }
 
-    if (taggedObjectsTags == NULL && taggedObjectsCount > 0) {
-        NSK_COMPLAIN2("GetObjectsWithTags() returns NULL list of tags for objects %s: 0x%p\n",
+    if (taggedObjectsTags == nullptr && taggedObjectsCount > 0) {
+        NSK_COMPLAIN2("GetObjectsWithTags() returns null list of tags for objects %s: 0x%p\n",
                         kind, (void*)taggedObjectsTags);
         nsk_jvmti_setFailStatus();
         return NSK_TRUE;
@@ -223,8 +223,8 @@ static int checkTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int tagsCount, int o
 
         NSK_DISPLAY3("   #%d: object: 0x%p, tag: %ld\n", k, (void*)object, (long)tag);
 
-        if (object == NULL) {
-            NSK_COMPLAIN3("GetObjectsWithTags() returns NULL for object #%d %s: 0x%p\n",
+        if (object == nullptr) {
+            NSK_COMPLAIN3("GetObjectsWithTags() returns null for object #%d %s: 0x%p\n",
                         k, kind, (void*)object);
             nsk_jvmti_setFailStatus();
             continue;
@@ -306,8 +306,8 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     /* perform testing */
     {
         int size = tagsCount * objectsCount;
-        jobject* objects = NULL;
-        jlong* tags = NULL;
+        jobject* objects = nullptr;
+        jlong* tags = nullptr;
 
         NSK_DISPLAY0(">>> Obtain tested objects list from a static field of debugee class\n");
         {
@@ -417,7 +417,7 @@ JNIEXPORT jint JNI_OnLoad_objwithtags001(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -433,7 +433,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add required capabilities */
@@ -448,7 +448,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetOwnedMonitorInfo/ownmoninf001/ownmoninf001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetOwnedMonitorInfo/ownmoninf001/ownmoninf001.cpp
index 3d304530135..e86bf820b34 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetOwnedMonitorInfo/ownmoninf001/ownmoninf001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetOwnedMonitorInfo/ownmoninf001/ownmoninf001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 
@@ -53,7 +53,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -89,7 +89,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 jobject *getInfo(JNIEnv *env, jint point, jthread thr, int count) {
     jvmtiError err;
     jint owned_monitor_count;
-    jobject *owned_monitors = NULL;
+    jobject *owned_monitors = nullptr;
 
     err = jvmti->GetOwnedMonitorInfo(thr,
         &owned_monitor_count, &owned_monitors);
@@ -100,13 +100,13 @@ jobject *getInfo(JNIEnv *env, jint point, jthread thr, int count) {
         printf("(GetOwnedMonitorInfo#%d) unexpected error: %s (%d)\n",
                point, TranslateError(err), err);
         result = STATUS_FAILED;
-        return NULL;
+        return nullptr;
     } else {
         if (owned_monitor_count != count) {
             result = STATUS_FAILED;
             printf("Point %d: number of owned monitors expected: %d, got: %d\n",
                    point, count, owned_monitor_count);
-            return NULL;
+            return nullptr;
         }
     }
     return owned_monitors;
@@ -123,7 +123,7 @@ Java_nsk_jvmti_GetOwnedMonitorInfo_ownmoninf001_checkMon1(JNIEnv *env,
         jclass cls, jint point, jthread thr, jobject lock) {
     jobject *monitors;
     monitors = getInfo(env, point, thr, 1);
-    if (monitors == NULL) {
+    if (monitors == nullptr) {
         return;
     }
     if (!env->IsSameObject(lock, monitors[0])) {
@@ -137,7 +137,7 @@ Java_nsk_jvmti_GetOwnedMonitorInfo_ownmoninf001_checkMon2(JNIEnv *env,
         jclass cls, jint point, jthread thr, jobject lock1, jobject lock2) {
     jobject *monitors;
     monitors = getInfo(env, point, thr, 2);
-    if (monitors == NULL) {
+    if (monitors == nullptr) {
         return;
     }
     if (!env->IsSameObject(lock1, monitors[0]) && !env->IsSameObject(lock2, monitors[0])) {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetOwnedMonitorInfo/ownmoninf002/ownmoninf002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetOwnedMonitorInfo/ownmoninf002/ownmoninf002.cpp
index 7ad4e1b0ef3..f5c13cfe71d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetOwnedMonitorInfo/ownmoninf002/ownmoninf002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetOwnedMonitorInfo/ownmoninf002/ownmoninf002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 
@@ -53,7 +53,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetOwnedMonitorInfo/ownmoninf003/ownmoninf003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetOwnedMonitorInfo/ownmoninf003/ownmoninf003.cpp
index 83b39f17aaa..975be49082b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetOwnedMonitorInfo/ownmoninf003/ownmoninf003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetOwnedMonitorInfo/ownmoninf003/ownmoninf003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -98,7 +98,7 @@ Java_nsk_jvmti_GetOwnedMonitorInfo_ownmoninf003_check(JNIEnv *env,
     jint owned_monitor_count;
     jobject *owned_monitors;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -120,7 +120,7 @@ Java_nsk_jvmti_GetOwnedMonitorInfo_ownmoninf003_check(JNIEnv *env,
     if (printdump == JNI_TRUE) {
         printf(">>> (owned_monitor_count_ptr) null pointer check ...\n");
     }
-    err = jvmti->GetOwnedMonitorInfo(thr, NULL, &owned_monitors);
+    err = jvmti->GetOwnedMonitorInfo(thr, nullptr, &owned_monitors);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY &&
             !caps.can_get_monitor_info) {
         /* Ok, it's expected */
@@ -133,7 +133,7 @@ Java_nsk_jvmti_GetOwnedMonitorInfo_ownmoninf003_check(JNIEnv *env,
     if (printdump == JNI_TRUE) {
         printf(">>> (owned_monitors_ptr) null pointer check ...\n");
     }
-    err = jvmti->GetOwnedMonitorInfo(thr, &owned_monitor_count, NULL);
+    err = jvmti->GetOwnedMonitorInfo(thr, &owned_monitor_count, nullptr);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY &&
             !caps.can_get_monitor_info) {
         /* Ok, it's expected */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetPhase/getphase001/getphase001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetPhase/getphase001/getphase001.cpp
index e3c4df42cba..70228ae0274 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetPhase/getphase001/getphase001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetPhase/getphase001/getphase001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -268,7 +268,7 @@ JNIEXPORT jint JNI_OnLoad_getphase001(JavaVM *jvm, char *options, void *reserved
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv *jvmti = NULL;
+    jvmtiEnv *jvmti = nullptr;
     jvmtiPhase phase;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
@@ -284,7 +284,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* Create data access lock */
@@ -319,31 +319,31 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* enable VMStart event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_START, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_START, nullptr)))
         return JNI_ERR;
 
     /* enable VMInit event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr)))
         return JNI_ERR;
 
     /* enable NativeMethodBind event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, nullptr)))
         return JNI_ERR;
 
     /* enable ClassFileLoadHook event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
 
     /* enable VMDeath event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr)))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetPhase/getphase002/getphase002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetPhase/getphase002/getphase002.cpp
index e1d03830f70..ec67d08a9f6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetPhase/getphase002/getphase002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetPhase/getphase002/getphase002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,9 +45,9 @@ agentProc(jvmtiEnv *jvmti, JNIEnv* jni, void* arg) {
     if (!nsk_jvmti_waitForSync(timeout))
         return;
 
-    NSK_DISPLAY0("Check if GetPhase(NULL) returns JVMTI_ERROR_NULL_POINTER\n");
+    NSK_DISPLAY0("Check if GetPhase(null) returns JVMTI_ERROR_NULL_POINTER\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_NULL_POINTER,
-            jvmti->GetPhase(NULL)))
+            jvmti->GetPhase(nullptr)))
         nsk_jvmti_setFailStatus();
 
     /* resume debugee after last sync */
@@ -70,7 +70,7 @@ JNIEXPORT jint JNI_OnLoad_getphase002(JavaVM *jvm, char *options, void *reserved
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv *jvmti = NULL;
+    jvmtiEnv *jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -83,11 +83,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetPotentialCapabilities/getpotcaps001/getpotcaps001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetPotentialCapabilities/getpotcaps001/getpotcaps001.cpp
index 0e5d7159d27..f69b88176f1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetPotentialCapabilities/getpotcaps001/getpotcaps001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetPotentialCapabilities/getpotcaps001/getpotcaps001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -188,7 +188,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     success = checkCapabilities(jvmti, "VM_DEATH callback");
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -215,7 +215,7 @@ JNIEXPORT jint JNI_OnLoad_getpotcaps001(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -223,7 +223,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -239,7 +239,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Testcase #1: Check capabilities in Agent_OnLoad()\n");
@@ -248,7 +248,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceDebugExtension/srcdebugex001/srcdebugex001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceDebugExtension/srcdebugex001/srcdebugex001.cpp
index 66e4dbdceeb..ab1125b0037 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceDebugExtension/srcdebugex001/srcdebugex001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceDebugExtension/srcdebugex001/srcdebugex001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -53,7 +53,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -90,7 +90,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_GetSourceDebugExtension_srcdebugex001_getSrcDebugX(JNIEnv *env,
         jclass cls, jboolean vrb) {
     jvmtiError err;
-    char *srcDebugX = NULL;
+    char *srcDebugX = nullptr;
 
     if (!caps.can_get_source_debug_extension) return result;
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceDebugExtension/srcdebugex002/srcdebugex002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceDebugExtension/srcdebugex002/srcdebugex002.cpp
index b05b1b38225..420f38f84c6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceDebugExtension/srcdebugex002/srcdebugex002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceDebugExtension/srcdebugex002/srcdebugex002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -53,7 +53,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -90,18 +90,18 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_GetSourceDebugExtension_srcdebugex002_getSrcDebugX(JNIEnv *env,
         jclass cls, jint t_case) {
     jvmtiError err;
-    char *srcDebugX = NULL;
+    char *srcDebugX = nullptr;
     jobject invalCls; /* used as invalid class */
 
     if (!caps.can_get_source_debug_extension) return result;
 
     switch (t_case) {
-        case 1: /* NULL pointer in test debug mode */
-            printf("\nInvoke GetSourceDebugExtension() with NULL pointer...\n");
+        case 1: /* nullptr pointer in test debug mode */
+            printf("\nInvoke GetSourceDebugExtension() with null pointer...\n");
             fflush(stdout);
             // fallthrough
-        case 0: /* NULL pointer */
-            err = jvmti->GetSourceDebugExtension(cls, NULL);
+        case 0: /* nullptr pointer */
+            err = jvmti->GetSourceDebugExtension(cls, nullptr);
             if (err != JVMTI_ERROR_NULL_POINTER) {
                 printf("TEST FAILED: the function GetSourceDebugExtension() returned the error %s (%d)\n",
                        TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceDebugExtension/srcdebugex003/srcdebugex003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceDebugExtension/srcdebugex003/srcdebugex003.cpp
index e4759cf49df..37fc8742807 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceDebugExtension/srcdebugex003/srcdebugex003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceDebugExtension/srcdebugex003/srcdebugex003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -55,7 +55,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -92,7 +92,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_GetSourceDebugExtension_srcdebugex003_getSrcDebugX(JNIEnv *env,
         jclass cls, jboolean vrb) {
     jvmtiError err;
-    char *srcDebugX = NULL;
+    char *srcDebugX = nullptr;
 
     if (!caps.can_get_source_debug_extension) return result;
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceFileName/getsrcfn004/getsrcfn004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceFileName/getsrcfn004/getsrcfn004.cpp
index 18d96711181..e9a2aff2a52 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceFileName/getsrcfn004/getsrcfn004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceFileName/getsrcfn004/getsrcfn004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static jvmtiCapabilities caps;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint code;
     jvmtiError res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     code = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (code != JNI_OK || jvmti == NULL) {
+    if (code != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -96,7 +96,7 @@ Java_nsk_jvmti_GetSourceFileName_getsrcfn004_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     char *name;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -104,7 +104,7 @@ Java_nsk_jvmti_GetSourceFileName_getsrcfn004_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid class check ...\n");
     }
-    err = jvmti->GetSourceFileName(NULL, &name);
+    err = jvmti->GetSourceFileName(nullptr, &name);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY && caps.can_get_source_file_name) {
         printf("Error expected: JVMTI_ERROR_INVALID_CLASS,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -118,7 +118,7 @@ Java_nsk_jvmti_GetSourceFileName_getsrcfn004_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->GetSourceFileName(cls, NULL);
+    err = jvmti->GetSourceFileName(cls, nullptr);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY && caps.can_get_source_file_name) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceFileName/getsrcfn005/getsrcfn005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceFileName/getsrcfn005/getsrcfn005.cpp
index 63676521f85..16bf11e65f1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceFileName/getsrcfn005/getsrcfn005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceFileName/getsrcfn005/getsrcfn005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static jvmtiCapabilities caps;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError res;
     jint code;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     code = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (code != JNI_OK || jvmti == NULL) {
+    if (code != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -96,7 +96,7 @@ Java_nsk_jvmti_GetSourceFileName_getsrcfn005_check(JNIEnv *env, jclass cls, jint
     jvmtiError err;
     char *name;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceFileName/getsrcfn006/getsrcfn006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceFileName/getsrcfn006/getsrcfn006.cpp
index 9edb42aa836..390c9c1e124 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceFileName/getsrcfn006/getsrcfn006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSourceFileName/getsrcfn006/getsrcfn006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static jvmtiCapabilities caps;
@@ -59,12 +59,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError res;
     jint code;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     code = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (code != JNI_OK || jvmti == NULL) {
+    if (code != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -102,7 +102,7 @@ Java_nsk_jvmti_GetSourceFileName_getsrcfn006_check(JNIEnv *env, jclass cls, jint
     jvmtiError err;
     char *name;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperties/getsysprops001/getsysprops001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperties/getsysprops001/getsysprops001.cpp
index ec770b75655..13a391227cb 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperties/getsysprops001/getsysprops001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperties/getsysprops001/getsysprops001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ static jlong timeout = 0;
 static int checkProperties(jvmtiEnv* jvmti, const char phase[]) {
     int success = NSK_TRUE;
     jint count = 0;
-    char** properties = NULL;
+    char** properties = nullptr;
 
     NSK_DISPLAY0("Invoke GetSystemProperties()\n");
     if (!NSK_JVMTI_VERIFY(
@@ -56,8 +56,8 @@ static int checkProperties(jvmtiEnv* jvmti, const char phase[]) {
         success = NSK_FALSE;
     }
 
-    if (properties == NULL) {
-        NSK_COMPLAIN2("In %s phase GetSystemProperties() returned NULL pointer for properties list: 0x%p\n",
+    if (properties == nullptr) {
+        NSK_COMPLAIN2("In %s phase GetSystemProperties() returned null pointer for properties list: 0x%p\n",
                         phase, (void*)properties);
         success = NSK_FALSE;
     } else {
@@ -66,8 +66,8 @@ static int checkProperties(jvmtiEnv* jvmti, const char phase[]) {
         NSK_DISPLAY1("Check each property: %d properties\n", (int)count);
         for (i = 0; i < count; i++) {
             NSK_DISPLAY2("    property #%d: [%s]\n", i, nsk_null_string(properties[i]));
-            if (properties[i] == NULL) {
-                NSK_COMPLAIN3("In %s phase GetSystemProperties() returned NULL for property #%d: 0x%p\n",
+            if (properties[i] == nullptr) {
+                NSK_COMPLAIN3("In %s phase GetSystemProperties() returned null for property #%d: 0x%p\n",
                                 phase, i, (void*)properties[i]);
                 success = NSK_FALSE;
             }
@@ -118,7 +118,7 @@ JNIEXPORT jint JNI_OnLoad_getsysprops001(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -126,7 +126,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Check system properties in OnLoad phase\n");
@@ -134,7 +134,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         nsk_jvmti_setFailStatus();
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperties/getsysprops002/getsysprops002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperties/getsysprops002/getsysprops002.cpp
index a48128e2bc6..81bd1819948 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperties/getsysprops002/getsysprops002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperties/getsysprops002/getsysprops002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,7 +52,7 @@ static PropertyDesc propDescList[PROPERTIES_COUNT] = {
 static int checkProperties (jvmtiEnv* jvmti, const char phase[]) {
     int success = NSK_TRUE;
     jint count = 0;
-    char** properties = NULL;
+    char** properties = nullptr;
 
     NSK_DISPLAY0("Get system properties list\n");
     if (!NSK_JVMTI_VERIFY(
@@ -61,7 +61,7 @@ static int checkProperties (jvmtiEnv* jvmti, const char phase[]) {
     }
     NSK_DISPLAY1("  ... got properties: %d\n", (int)count);
 
-    if (!NSK_VERIFY(properties != NULL)) {
+    if (!NSK_VERIFY(properties != nullptr)) {
         return NSK_FALSE;
     }
 
@@ -77,7 +77,7 @@ static int checkProperties (jvmtiEnv* jvmti, const char phase[]) {
 
         for (i = 0; i < count; i++) {
             NSK_DISPLAY2("    property #%d: [%s]\n", i, nsk_null_string(properties[i]));
-            if (properties[i] != NULL) {
+            if (properties[i] != nullptr) {
                 for (j = 0; j < PROPERTIES_COUNT; j++) {
                     if (strcmp(properties[i], propDescList[j].name) == 0) {
                         NSK_DISPLAY1("SUCCESS: found tested property: %s\n",
@@ -150,7 +150,7 @@ JNIEXPORT jint JNI_OnLoad_getsysprops002(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -158,7 +158,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Check system properties in OnLoad phase\n");
@@ -166,7 +166,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         nsk_jvmti_setFailStatus();
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperty/getsysprop001/getsysprop001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperty/getsysprop001/getsysprop001.cpp
index 126712c66f8..0540d756238 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperty/getsysprop001/getsysprop001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperty/getsysprop001/getsysprop001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ static jlong timeout = 0;
 static int checkProperties(jvmtiEnv* jvmti, const char phase[]) {
     int success = NSK_TRUE;
     jint count = 0;
-    char** properties = NULL;
+    char** properties = nullptr;
 
     NSK_DISPLAY0("Get system properties names\n");
     if (!NSK_JVMTI_VERIFY(
@@ -47,7 +47,7 @@ static int checkProperties(jvmtiEnv* jvmti, const char phase[]) {
     }
     NSK_DISPLAY1("  ... got properties: %d\n", (int)count);
 
-    if (!NSK_VERIFY(properties != NULL)) {
+    if (!NSK_VERIFY(properties != nullptr)) {
         return NSK_FALSE;
     }
 
@@ -56,10 +56,10 @@ static int checkProperties(jvmtiEnv* jvmti, const char phase[]) {
         int i;
 
         for (i = 0; i < count; i++) {
-            char* value = NULL;
+            char* value = nullptr;
 
             NSK_DISPLAY2("  property #%d: [%s]:\n", i, nsk_null_string(properties[i]));
-            if (!NSK_VERIFY(properties[i] != NULL)) {
+            if (!NSK_VERIFY(properties[i] != nullptr)) {
                 success = NSK_FALSE;
                 continue;
             }
@@ -71,8 +71,8 @@ static int checkProperties(jvmtiEnv* jvmti, const char phase[]) {
             }
             NSK_DISPLAY1("    value: \"%s\"\n", nsk_null_string(value));
 
-            if (value == NULL) {
-                NSK_COMPLAIN4("In %s phase GetSystemProperty() returned NULL for property #%d:\n"
+            if (value == nullptr) {
+                NSK_COMPLAIN4("In %s phase GetSystemProperty() returned null for property #%d:\n"
                               "#   property name: %s\n"
                               "#   got value:     0x%p\n",
                                 phase, i,
@@ -131,7 +131,7 @@ JNIEXPORT jint JNI_OnLoad_getsysprop001(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -139,7 +139,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Check system properties in OnLoad phase\n");
@@ -147,7 +147,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         nsk_jvmti_setFailStatus();
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperty/getsysprop002/getsysprop002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperty/getsysprop002/getsysprop002.cpp
index a9704eed75b..38687ba8e9a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperty/getsysprop002/getsysprop002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetSystemProperty/getsysprop002/getsysprop002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,7 +49,7 @@ static PropertyDesc propDescList[PROPERTIES_COUNT] = {
 
 static int checkProperty(jvmtiEnv* jvmti, const char phase[], PropertyDesc* desc) {
     int success = NSK_TRUE;
-    char* value = NULL;
+    char* value = nullptr;
 
     NSK_DISPLAY1("Get value of tested property: %s\n", desc->name);
     if (!NSK_JVMTI_VERIFY(
@@ -58,8 +58,8 @@ static int checkProperty(jvmtiEnv* jvmti, const char phase[], PropertyDesc* desc
     }
     NSK_DISPLAY1("  ... got value: \"%s\"\n", nsk_null_string(value));
 
-    if (value == NULL) {
-        NSK_COMPLAIN4("In %s phase GetSystemProperty() returned NULL value for property:\n"
+    if (value == nullptr) {
+        NSK_COMPLAIN4("In %s phase GetSystemProperty() returned null value for property:\n"
                       "#   defined as: -D%s=\"%s\"\n"
                       "#   got value:  0x%p\n",
                         phase, desc->name, desc->value, (void*)value);
@@ -130,7 +130,7 @@ JNIEXPORT jint JNI_OnLoad_getsysprop002(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -138,7 +138,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Check defined system properties in OnLoad phase\n");
@@ -146,7 +146,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         nsk_jvmti_setFailStatus();
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTag/gettag001/gettag001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTag/gettag001/gettag001.cpp
index 801d210de35..926ef71ddab 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTag/gettag001/gettag001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTag/gettag001/gettag001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -51,17 +51,17 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     /* perform testing */
     {
-        jobject testedObject = NULL;
+        jobject testedObject = nullptr;
         jlong objectTag = 0;
 
         NSK_DISPLAY0(">>> Obtain tested object from a static field of debugee class\n");
         {
-            jclass debugeeClass = NULL;
-            jfieldID objectField = NULL;
+            jclass debugeeClass = nullptr;
+            jfieldID objectField = nullptr;
 
             NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
             if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-                    jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+                    jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -69,7 +69,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
             NSK_DISPLAY1("Find static field: %s\n", OBJECT_FIELD_NAME);
             if (!NSK_JNI_VERIFY(jni, (objectField =
-                    jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, OBJECT_CLASS_SIG)) != NULL)) {
+                    jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, OBJECT_CLASS_SIG)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -77,7 +77,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
             NSK_DISPLAY1("Get object from static field: %s\n", OBJECT_FIELD_NAME);
             if (!NSK_JNI_VERIFY(jni, (testedObject =
-                    jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+                    jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -85,7 +85,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
             NSK_DISPLAY1("Create global reference for object: 0x%p\n", (void*)testedObject);
             if (!NSK_JNI_VERIFY(jni, (testedObject =
-                    jni->NewGlobalRef(testedObject)) != NULL)) {
+                    jni->NewGlobalRef(testedObject)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -142,7 +142,7 @@ JNIEXPORT jint JNI_OnLoad_gettag001(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -152,7 +152,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add required capabilities */
@@ -168,7 +168,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadCpuTime/thrcputime001/thrcputime001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadCpuTime/thrcputime001/thrcputime001.cpp
index 4effa902072..127ae04a0f9 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadCpuTime/thrcputime001/thrcputime001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadCpuTime/thrcputime001/thrcputime001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -69,9 +69,9 @@ static int checkCpuTime(jvmtiEnv* jvmti, jthread thread, julong* time,
     char buf[64], buf2[64], buf3[64];
     int success = NSK_TRUE;
 
-    NSK_DISPLAY1("GetThreadCpuTime() for current thread (passing NULL): 0x%p\n", (void*)thread);
+    NSK_DISPLAY1("GetThreadCpuTime() for current thread (passing null): 0x%p\n", (void*)thread);
     if (!NSK_JVMTI_VERIFY(
-            jvmti->GetThreadCpuTime(NULL, (jlong *)time))) {
+            jvmti->GetThreadCpuTime(nullptr, (jlong *)time))) {
         return NSK_FALSE;
     }
     NSK_DISPLAY1("  ... got cpu time: %s\n", julong_to_string(*time, buf));
@@ -81,7 +81,7 @@ static int checkCpuTime(jvmtiEnv* jvmti, jthread thread, julong* time,
                             where, julong_to_string(*time, buf));
     }
 
-    if (prevTime != NULL) {
+    if (prevTime != nullptr) {
         julong diff = *time - *prevTime;
 
         NSK_DISPLAY1("Compare with previous time: %s\n",
@@ -148,7 +148,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     NSK_DISPLAY0(">>> Testcase #2: Check initial cpu time in agent thread\n");
     {
-        if (!checkCpuTime(jvmti, testAgentThread, &prevAgentThreadTime, NULL, "agent thread")) {
+        if (!checkCpuTime(jvmti, testAgentThread, &prevAgentThreadTime, nullptr, "agent thread")) {
             nsk_jvmti_setFailStatus();
         }
     }
@@ -158,7 +158,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         runIterations(iterations);
 
         NSK_DISPLAY1("Enable thread events: %d events\n", THREAD_EVENTS_COUNT);
-        if (nsk_jvmti_enableEvents(JVMTI_ENABLE, THREAD_EVENTS_COUNT, threadEvents, NULL)) {
+        if (nsk_jvmti_enableEvents(JVMTI_ENABLE, THREAD_EVENTS_COUNT, threadEvents, nullptr)) {
             NSK_DISPLAY0("  ... enabled\n");
         }
 
@@ -185,7 +185,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             return;
 
         NSK_DISPLAY1("Disable thread events: %d events\n", THREAD_EVENTS_COUNT);
-        if (nsk_jvmti_enableEvents(JVMTI_DISABLE, THREAD_EVENTS_COUNT, threadEvents, NULL)) {
+        if (nsk_jvmti_enableEvents(JVMTI_DISABLE, THREAD_EVENTS_COUNT, threadEvents, nullptr)) {
             NSK_DISPLAY0("  ... disabled\n");
         }
     }
@@ -215,7 +215,7 @@ callbackVMInit(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
     NSK_DISPLAY0(">>> Testcase #1: Check initial cpu time in VM_INIT callback\n");
     {
         julong time = 0;
-        if (!checkCpuTime(jvmti, thread, &time, NULL, "VM_INIT callback")) {
+        if (!checkCpuTime(jvmti, thread, &time, nullptr, "VM_INIT callback")) {
             nsk_jvmti_setFailStatus();
         }
     }
@@ -231,14 +231,14 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     NSK_DISPLAY0(">>> Testcase #7: Check initial cpu time in VM_DEATH callback\n");
     {
         julong time = 0;
-        if (!checkCpuTime(jvmti, NULL, &time, NULL, "VM_DEATH callback")) {
+        if (!checkCpuTime(jvmti, nullptr, &time, nullptr, "VM_DEATH callback")) {
             success = NSK_FALSE;
             nsk_jvmti_setFailStatus();
         }
     }
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -268,9 +268,9 @@ callbackThreadStart(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
         NSK_DISPLAY1("    <THREAD_START> for thread: %s\n", nsk_null_string(threadInfo.name));
     }
 
-    if (threadInfo.name != NULL && strcmp(threadInfo.name, TESTED_THREAD_NAME) == 0) {
+    if (threadInfo.name != nullptr && strcmp(threadInfo.name, TESTED_THREAD_NAME) == 0) {
         NSK_DISPLAY0(">>> Testcase #3: Check initial cpu time in THREAD_START callback\n");
-        if (!checkCpuTime(jvmti, thread, &prevTestedThreadTime, NULL, "THREAD_START callback")) {
+        if (!checkCpuTime(jvmti, thread, &prevTestedThreadTime, nullptr, "THREAD_START callback")) {
             nsk_jvmti_setFailStatus();
         }
     }
@@ -292,7 +292,7 @@ callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
         NSK_DISPLAY1("    <THREAD_END>   for thread: %s\n", nsk_null_string(threadInfo.name));
     }
 
-    if (threadInfo.name != NULL && strcmp(threadInfo.name, TESTED_THREAD_NAME) == 0) {
+    if (threadInfo.name != nullptr && strcmp(threadInfo.name, TESTED_THREAD_NAME) == 0) {
         julong time = 0;
         NSK_DISPLAY0(">>> Testcase #5: Check final cpu time in THREAD_END callback\n");
         if (!checkCpuTime(jvmti, thread, &time, &prevTestedThreadTime, "THREAD_END callback")) {
@@ -316,7 +316,7 @@ JNIEXPORT jint JNI_OnLoad_thrcputime001(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -328,7 +328,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("Add required capability: %s\n", "can_get_thread_cpu_time");
@@ -360,11 +360,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
     NSK_DISPLAY0("  ... callbacks set\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadCpuTime/thrcputime002/thrcputime002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadCpuTime/thrcputime002/thrcputime002.cpp
index 2782c060621..e69f2de6286 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadCpuTime/thrcputime002/thrcputime002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadCpuTime/thrcputime002/thrcputime002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -55,8 +55,8 @@ static jvmtiEvent threadEvents[THREAD_EVENTS_COUNT] = {
 static julong prevTestedThreadTime = 0;
 static julong prevAgentThreadTime = 0;
 
-static jthread testedThread = NULL;
-static jthread testAgentThread = NULL;
+static jthread testedThread = nullptr;
+static jthread testAgentThread = nullptr;
 
 static int iterations = 0;
 
@@ -83,7 +83,7 @@ static int checkCpuTime(jvmtiEnv* jvmti, jthread thread, julong* time,
                             where, julong_to_string(*time, buf));
     }
 
-    if (prevTime != NULL) {
+    if (prevTime != nullptr) {
         julong diff = *time - *prevTime;
 
         NSK_DISPLAY1("Compare with previous time: %s\n",
@@ -150,7 +150,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     NSK_DISPLAY0(">>> Testcase #2: Check initial cpu time in agent thread\n");
     {
-        if (!checkCpuTime(jvmti, testAgentThread, &prevAgentThreadTime, NULL, "agent thread")) {
+        if (!checkCpuTime(jvmti, testAgentThread, &prevAgentThreadTime, nullptr, "agent thread")) {
             nsk_jvmti_setFailStatus();
         }
     }
@@ -160,7 +160,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         runIterations(iterations);
 
         NSK_DISPLAY1("Enable thread events: %d events\n", THREAD_EVENTS_COUNT);
-        if (nsk_jvmti_enableEvents(JVMTI_ENABLE, THREAD_EVENTS_COUNT, threadEvents, NULL)) {
+        if (nsk_jvmti_enableEvents(JVMTI_ENABLE, THREAD_EVENTS_COUNT, threadEvents, nullptr)) {
             NSK_DISPLAY0("  ... enabled\n");
         }
 
@@ -180,7 +180,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             }
         }
 
-        if (testedThread != NULL) {
+        if (testedThread != nullptr) {
             NSK_DISPLAY0(">>> Testcase #6: Check tested thread cpu time from agent thread\n");
             {
                 julong time = 0;
@@ -198,7 +198,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             return;
 
         NSK_DISPLAY1("Disable thread events: %d events\n", THREAD_EVENTS_COUNT);
-        if (nsk_jvmti_enableEvents(JVMTI_DISABLE, THREAD_EVENTS_COUNT, threadEvents, NULL)) {
+        if (nsk_jvmti_enableEvents(JVMTI_DISABLE, THREAD_EVENTS_COUNT, threadEvents, nullptr)) {
             NSK_DISPLAY0("  ... disabled\n");
         }
     }
@@ -228,7 +228,7 @@ callbackVMInit(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
     NSK_DISPLAY0(">>> Testcase #1: Check initial cpu time in VM_INIT callback\n");
     {
         julong time = 0;
-        if (!checkCpuTime(jvmti, thread, &time, NULL, "VM_INIT callback")) {
+        if (!checkCpuTime(jvmti, thread, &time, nullptr, "VM_INIT callback")) {
             nsk_jvmti_setFailStatus();
         }
     }
@@ -242,7 +242,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     int success = NSK_TRUE;
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -279,13 +279,13 @@ callbackThreadStart(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
         }
     }
 
-    if (threadInfo.name != NULL && strcmp(threadInfo.name, TESTED_THREAD_NAME) == 0) {
-        if (!NSK_JNI_VERIFY(jni, (testedThread = jni->NewGlobalRef(thread)) != NULL)) {
+    if (threadInfo.name != nullptr && strcmp(threadInfo.name, TESTED_THREAD_NAME) == 0) {
+        if (!NSK_JNI_VERIFY(jni, (testedThread = jni->NewGlobalRef(thread)) != nullptr)) {
             nsk_jvmti_setFailStatus();
         }
 
         NSK_DISPLAY0(">>> Testcase #4: Check initial cpu time in THREAD_START callback\n");
-        if (!checkCpuTime(jvmti, thread, &prevTestedThreadTime, NULL, "THREAD_START callback")) {
+        if (!checkCpuTime(jvmti, thread, &prevTestedThreadTime, nullptr, "THREAD_START callback")) {
             nsk_jvmti_setFailStatus();
         }
     }
@@ -314,14 +314,14 @@ callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
         }
     }
 
-    if (threadInfo.name != NULL && strcmp(threadInfo.name, TESTED_THREAD_NAME) == 0) {
+    if (threadInfo.name != nullptr && strcmp(threadInfo.name, TESTED_THREAD_NAME) == 0) {
         julong time = 0;
         NSK_DISPLAY0(">>> Testcase #8: Check final cpu time in THREAD_END callback\n");
         if (!checkCpuTime(jvmti, thread, &time, &prevTestedThreadTime, "THREAD_END callback")) {
             nsk_jvmti_setFailStatus();
         }
         NSK_TRACE(jni->DeleteGlobalRef(testedThread));
-        testedThread = NULL;
+        testedThread = nullptr;
     }
 }
 
@@ -340,7 +340,7 @@ JNIEXPORT jint JNI_OnLoad_thrcputime002(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -352,7 +352,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("Add required capability: %s\n", "can_get_thread_cpu_time");
@@ -382,11 +382,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
     NSK_DISPLAY0("  ... callbacks set\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadCpuTimerInfo/thrtimerinfo001/thrtimerinfo001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadCpuTimerInfo/thrtimerinfo001/thrtimerinfo001.cpp
index 81bfb416b58..5d7ee5fb8a5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadCpuTimerInfo/thrtimerinfo001/thrtimerinfo001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadCpuTimerInfo/thrtimerinfo001/thrtimerinfo001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -76,7 +76,7 @@ static int checkTimerInfo(jvmtiEnv* jvmti, jvmtiTimerInfo* info,
     NSK_DISPLAY1("    may_skip_forward:  %d\n", (int)info->may_skip_forward);
     NSK_DISPLAY1("    may_skip_backward: %d\n", (int)info->may_skip_backward);
 
-    if (initInfo != NULL) {
+    if (initInfo != nullptr) {
         NSK_DISPLAY0("Compare with initial timer info\n");
         if (info->max_value != initInfo->max_value) {
             NSK_COMPLAIN4("In %s GetThreadCpuTimerInfo() returned different info:\n"
@@ -132,7 +132,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     NSK_DISPLAY0(">>> Testcases #3,4: Check timer info in thread events\n");
     {
         NSK_DISPLAY1("Enable thread events: %d events\n", THREAD_EVENTS_COUNT);
-        if (nsk_jvmti_enableEvents(JVMTI_ENABLE, THREAD_EVENTS_COUNT, threadEvents, NULL)) {
+        if (nsk_jvmti_enableEvents(JVMTI_ENABLE, THREAD_EVENTS_COUNT, threadEvents, nullptr)) {
             NSK_DISPLAY0("  ... enabled\n");
         }
 
@@ -143,7 +143,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             return;
 
         NSK_DISPLAY1("Disable thread events: %d events\n", THREAD_EVENTS_COUNT);
-        if (nsk_jvmti_enableEvents(JVMTI_DISABLE, THREAD_EVENTS_COUNT, threadEvents, NULL)) {
+        if (nsk_jvmti_enableEvents(JVMTI_DISABLE, THREAD_EVENTS_COUNT, threadEvents, nullptr)) {
             NSK_DISPLAY0("  ... disabled\n");
         }
     }
@@ -163,7 +163,7 @@ callbackVMInit(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
 
     NSK_DISPLAY0(">>> Testcase #1: Check initial timer info in VM_INIT callback\n");
     {
-        if (!checkTimerInfo(jvmti, &initInfo, NULL, "VM_INIT callback")) {
+        if (!checkTimerInfo(jvmti, &initInfo, nullptr, "VM_INIT callback")) {
             nsk_jvmti_setFailStatus();
         }
     }
@@ -183,7 +183,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     }
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -242,7 +242,7 @@ JNIEXPORT jint JNI_OnLoad_thrtimerinfo001(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -250,7 +250,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("Add required capability: %s\n", "can_get_thread_cpu_time");
@@ -282,11 +282,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
     NSK_DISPLAY0("  ... callbacks set\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadGroupChildren/getthrdgrpchld001/getthrdgrpchld001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadGroupChildren/getthrdgrpchld001/getthrdgrpchld001.cpp
index 4c04b046d70..e81cf933140 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadGroupChildren/getthrdgrpchld001/getthrdgrpchld001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadGroupChildren/getthrdgrpchld001/getthrdgrpchld001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* constant names */
@@ -69,15 +69,15 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     /* perform testing */
     {
-        jthreadGroup rootGroup = NULL;
-        jthreadGroup runningGroup = NULL;
-        jthreadGroup notStartedGroup = NULL;
-        jthreadGroup finishedGroup = NULL;
+        jthreadGroup rootGroup = nullptr;
+        jthreadGroup runningGroup = nullptr;
+        jthreadGroup notStartedGroup = nullptr;
+        jthreadGroup finishedGroup = nullptr;
 
         /* find root thread group */
         {
             jint topGroupsCount = 0;
-            jthreadGroup* topGroups = NULL;
+            jthreadGroup* topGroups = nullptr;
 
             NSK_DISPLAY0("Get top level thread groups\n");
             if (!NSK_JVMTI_VERIFY(
@@ -87,13 +87,13 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             }
             NSK_DISPLAY1("  ... got groups: %d\n", (int)topGroupsCount);
 
-            if (!NSK_VERIFY(topGroupsCount > 0 && topGroups != NULL))
+            if (!NSK_VERIFY(topGroupsCount > 0 && topGroups != nullptr))
                 return;
 
             NSK_DISPLAY1("Find thread group by name: %s\n", ROOT_GROUP_NAME);
             if (!NSK_VERIFY((rootGroup =
                     findThreadGroupByName(jvmti, jni, ROOT_GROUP_NAME,
-                                            topGroupsCount, topGroups)) != NULL)) {
+                                            topGroupsCount, topGroups)) != nullptr)) {
                 NSK_COMPLAIN1("No tested root thread group found: %s\n", ROOT_GROUP_NAME);
                 nsk_jvmti_setFailStatus();
                 return;
@@ -105,8 +105,8 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         {
             jint groupsCount = 0;
             jint threadsCount = 0;
-            jthread* threads = NULL;
-            jthreadGroup* groups = NULL;
+            jthread* threads = nullptr;
+            jthreadGroup* groups = nullptr;
 
             NSK_DISPLAY1("Get children of root thread group: %p\n", (void*)rootGroup);
             if (!NSK_JVMTI_VERIFY(
@@ -150,7 +150,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
                         if (strcmp(info.name, RUNNING_GROUP_NAME) == 0) {
                             NSK_DISPLAY2("  ... found runningThreadGroup: %p (%s)\n",
                                                                 groups[i], info.name);
-                            if (runningGroup != NULL) {
+                            if (runningGroup != nullptr) {
                                 NSK_COMPLAIN6("Duplicated runningThreadGroup in rootThreadGroup:\n"
                                               "#   parent group:   %p (%s)\n"
                                               "#   existing group: %p (%s)\n"
@@ -168,7 +168,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
                         if (strcmp(info.name, NOT_STARTED_GROUP_NAME) == 0) {
                             NSK_DISPLAY2("  ... found notStartedThreadGroup: %p (%s)\n",
                                                                 groups[i], info.name);
-                            if (notStartedGroup != NULL) {
+                            if (notStartedGroup != nullptr) {
                                 NSK_COMPLAIN6("Duplicated notStartedThreadGroup in rootThreadGroup:\n"
                                               "#   parent group:   %p (%s)\n"
                                               "#   existing group: %p (%s)\n"
@@ -186,7 +186,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
                         if (strcmp(info.name, FINISHED_GROUP_NAME) == 0) {
                             NSK_DISPLAY2("  ... found finishedThreadGroup: %p (%s)\n",
                                                                 groups[i], info.name);
-                            if (finishedGroup != NULL) {
+                            if (finishedGroup != nullptr) {
                                 NSK_COMPLAIN6("Duplicated finishedThreadGroup in rootThreadGroup:\n"
                                               "#   parent group:   %p (%s)\n"
                                               "#   existing group: %p (%s)\n"
@@ -243,7 +243,7 @@ static int checkThreadGroup(jvmtiEnv* jvmti, JNIEnv* jni,
                                 jint expectedThreadsCount, const char expectedThreadName[]) {
     size_t threadNameLen = strlen(expectedThreadName);
 
-    if (group == NULL) {
+    if (group == nullptr) {
         NSK_COMPLAIN1("No expected group found in rootThreadGroup: %s\n", groupName);
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
@@ -253,8 +253,8 @@ static int checkThreadGroup(jvmtiEnv* jvmti, JNIEnv* jni,
     {
         jint threadsCount = 0;
         jint groupsCount = 0;
-        jthread* threads = NULL;
-        jthreadGroup* groups = NULL;
+        jthread* threads = nullptr;
+        jthreadGroup* groups = nullptr;
 
         if (!NSK_JVMTI_VERIFY(
                 jvmti->GetThreadGroupChildren(group, &threadsCount, &threads, &groupsCount, &groups))) {
@@ -296,7 +296,7 @@ static int checkThreadGroup(jvmtiEnv* jvmti, JNIEnv* jni,
                 NSK_DISPLAY2("  ... found thread: %p (%s)\n",
                                     (void*)threads[i], nsk_null_string(info.name));
 
-                if (info.name == NULL ||
+                if (info.name == nullptr ||
                             strncmp(info.name, expectedThreadName, threadNameLen) != 0) {
                     NSK_COMPLAIN5("Found unexpected thread in thread group:\n"
                                   "#   thread group:  %p (%s)\n"
@@ -327,31 +327,31 @@ static int checkThreadGroup(jvmtiEnv* jvmti, JNIEnv* jni,
 /** Recursively find thread group by its name among given groups and their childrens. */
 static jthreadGroup findThreadGroupByName(jvmtiEnv* jvmti, JNIEnv* jni, const char name[],
                                                 jint count, jthreadGroup groupsList[]) {
-    jthreadGroup foundGroup = NULL;
+    jthreadGroup foundGroup = nullptr;
     int i;
 
-    for (i = 0; i < count && foundGroup == NULL; i++) {
+    for (i = 0; i < count && foundGroup == nullptr; i++) {
         jint threadsCount = 0;
         jint groupsCount = 0;
-        jthread* threads = NULL;
-        jthreadGroup * groups = NULL;
+        jthread* threads = nullptr;
+        jthreadGroup * groups = nullptr;
 
         if (!NSK_JVMTI_VERIFY(
                 jvmti->GetThreadGroupChildren(groupsList[i], &threadsCount, &threads, &groupsCount, &groups))) {
             nsk_jvmti_setFailStatus();
-            return NULL;
+            return nullptr;
         }
 
         if (groupsCount > 0) {
             int j;
 
-            if (!NSK_VERIFY(groups != NULL))
-                return NULL;
+            if (!NSK_VERIFY(groups != nullptr))
+                return nullptr;
 
             for (j = 0; j < groupsCount; j++) {
                 jvmtiThreadGroupInfo info;
 
-                if (groups[j] != NULL) {
+                if (groups[j] != nullptr) {
 
                     if (!NSK_JVMTI_VERIFY(
                             jvmti->GetThreadGroupInfo(groups[j], &info))) {
@@ -366,7 +366,7 @@ static jthreadGroup findThreadGroupByName(jvmtiEnv* jvmti, JNIEnv* jni, const ch
                 }
             }
 
-            if (foundGroup == NULL) {
+            if (foundGroup == nullptr) {
                 foundGroup = findThreadGroupByName(jvmti, jni, name, groupsCount, groups);
             }
         }
@@ -400,7 +400,7 @@ JNIEXPORT jint JNI_OnLoad_getthrdgrpchld001(JavaVM *jvm, char *options, void *re
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -415,11 +415,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadGroupInfo/thrgrpinfo001/thrgrpinfo001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadGroupInfo/thrgrpinfo001/thrgrpinfo001.cpp
index 92134d1e0ff..1d8bf4c02d2 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadGroupInfo/thrgrpinfo001/thrgrpinfo001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadGroupInfo/thrgrpinfo001/thrgrpinfo001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static jint stage = 0;
@@ -53,12 +53,12 @@ JNIEXPORT jint JNI_OnLoad_thrgrpinfo001(JavaVM *jvm, char *options, void *reserv
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -72,7 +72,7 @@ Java_nsk_jvmti_GetThreadGroupInfo_thrgrpinfo001_check(JNIEnv *env, jclass cls, j
     jvmtiError err;
     jvmtiThreadGroupInfo inf;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -97,7 +97,7 @@ Java_nsk_jvmti_GetThreadGroupInfo_thrgrpinfo001_check(JNIEnv *env, jclass cls, j
                (inf.is_daemon == JNI_TRUE) ? "true" : "false");
     }
 
-    if (inf.name == NULL || strcmp(inf.name, expName) != 0) {
+    if (inf.name == nullptr || strcmp(inf.name, expName) != 0) {
         printf("(%d) unexpected name: \"%s\",", stage, inf.name);
         printf(" expected: \"%s\"\n", expName);
         result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadGroupInfo/thrgrpinfo002/thrgrpinfo002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadGroupInfo/thrgrpinfo002/thrgrpinfo002.cpp
index 0a57ad0ea8f..02a4161f64e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadGroupInfo/thrgrpinfo002/thrgrpinfo002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadGroupInfo/thrgrpinfo002/thrgrpinfo002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_thrgrpinfo002(JavaVM *jvm, char *options, void *reserv
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -71,7 +71,7 @@ Java_nsk_jvmti_GetThreadGroupInfo_thrgrpinfo002_check(JNIEnv *env, jclass cls) {
     jthreadGroup *groups;
     jvmtiThreadGroupInfo inf;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -89,7 +89,7 @@ Java_nsk_jvmti_GetThreadGroupInfo_thrgrpinfo002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid group check ...\n");
     }
-    err = jvmti->GetThreadGroupInfo(NULL, &inf);
+    err = jvmti->GetThreadGroupInfo(nullptr, &inf);
     if (err != JVMTI_ERROR_INVALID_THREAD_GROUP) {
         printf("Error expected: JVMTI_ERROR_INVALID_THREAD_GROUP,\n");
         printf("           got: %s (%d)\n", TranslateError(err), err);
@@ -99,7 +99,7 @@ Java_nsk_jvmti_GetThreadGroupInfo_thrgrpinfo002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->GetThreadGroupInfo(*groups, NULL);
+    err = jvmti->GetThreadGroupInfo(*groups, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("           got: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadLocalStorage/getthrdstor001/getthrdstor001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadLocalStorage/getthrdstor001/getthrdstor001.cpp
index a37007735d0..aa962164c15 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadLocalStorage/getthrdstor001/getthrdstor001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetThreadLocalStorage/getthrdstor001/getthrdstor001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,12 +48,12 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     /* perform testing */
     {
-        jthread testedThread = NULL;
-        void* storage = NULL;
+        jthread testedThread = nullptr;
+        void* storage = nullptr;
 
         NSK_DISPLAY1("Find thread: %s\n", THREAD_NAME);
         if (!NSK_VERIFY((testedThread =
-                nsk_jvmti_threadByName(THREAD_NAME)) != NULL))
+                nsk_jvmti_threadByName(THREAD_NAME)) != nullptr))
             return;
         NSK_DISPLAY1("  ... found thread: %p\n", (void*)testedThread);
 
@@ -65,9 +65,9 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         }
         NSK_DISPLAY1("  ... got storage: %p\n", (void*)storage);
 
-        NSK_DISPLAY0("Check obtained storage pointer against NULL\n");
-        if (storage != NULL) {
-            NSK_COMPLAIN2("GetThreadLocalStorage() returned NOT NULL storage for tested thread:\n"
+        NSK_DISPLAY0("Check obtained storage pointer against null\n");
+        if (storage != nullptr) {
+            NSK_COMPLAIN2("GetThreadLocalStorage() returned NOT null storage for tested thread:\n"
                           "#   thread:  %p\n"
                           "#   storage: %p\n",
                             (void*)testedThread, (void*)storage);
@@ -76,15 +76,15 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
         NSK_DISPLAY0("GetThreadLocalStorage() for current agent thread\n");
         if (!NSK_JVMTI_VERIFY(
-                jvmti->GetThreadLocalStorage(NULL, &storage))) {
+                jvmti->GetThreadLocalStorage(nullptr, &storage))) {
             nsk_jvmti_setFailStatus();
             return;
         }
         NSK_DISPLAY1("  ... got storage: %p\n", (void*)storage);
 
-        NSK_DISPLAY0("Check obtained storage pointer against NULL\n");
-        if (storage != NULL) {
-            NSK_COMPLAIN1("GetThreadLocalStorage() returned NOT NULL storage for current agent thread:\n"
+        NSK_DISPLAY0("Check obtained storage pointer against null\n");
+        if (storage != nullptr) {
+            NSK_COMPLAIN1("GetThreadLocalStorage() returned NOT null storage for current agent thread:\n"
                           "#   storage: %p\n",
                             (void*)storage);
             nsk_jvmti_setFailStatus();
@@ -114,7 +114,7 @@ JNIEXPORT jint JNI_OnLoad_getthrdstor001(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -124,11 +124,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTime/gettime001/gettime001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTime/gettime001/gettime001.cpp
index 3ed38448feb..df8312be312 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTime/gettime001/gettime001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTime/gettime001/gettime001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -64,7 +64,7 @@ static bool checkTime(jvmtiEnv* jvmti, julong* time,
     }
     NSK_DISPLAY1("  ... got time: %s\n", julong_to_string(*time, buf));
 
-    if (prevTime != NULL) {
+    if (prevTime != nullptr) {
         julong diff = *time - *prevTime;
 
         NSK_DISPLAY1("Compare with previous time: %s\n",
@@ -141,7 +141,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     }
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = false;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -168,7 +168,7 @@ JNIEXPORT jint JNI_OnLoad_gettime001(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -176,7 +176,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -192,18 +192,18 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Testcase #1: Check initial time in Agent_OnLoad()\n");
     {
-        if (!checkTime(jvmti, &prevTime, NULL, "Agent_OnLoad()")) {
+        if (!checkTime(jvmti, &prevTime, nullptr, "Agent_OnLoad()")) {
             nsk_jvmti_setFailStatus();
         }
     }
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTimerInfo/timerinfo001/timerinfo001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTimerInfo/timerinfo001/timerinfo001.cpp
index daa5778d194..eebbfa837b6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTimerInfo/timerinfo001/timerinfo001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTimerInfo/timerinfo001/timerinfo001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -69,7 +69,7 @@ static bool checkTimerInfo(jvmtiEnv* jvmti, jvmtiTimerInfo* info,
     NSK_DISPLAY1("    may_skip_forward:  %d\n", (int)info->may_skip_forward);
     NSK_DISPLAY1("    may_skip_backward: %d\n", (int)info->may_skip_backward);
 
-    if (initInfo != NULL) {
+    if (initInfo != nullptr) {
         NSK_DISPLAY0("Compare with initial timer info\n");
         if (info->max_value != initInfo->max_value) {
             NSK_COMPLAIN4("In %s GetTimerInfo() returned different info:\n"
@@ -158,7 +158,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     }
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = false;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -185,7 +185,7 @@ JNIEXPORT jint JNI_OnLoad_timerinfo001(JavaVM *jvm, char *options, void *reserve
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -193,7 +193,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -209,18 +209,18 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Testcase #1: Check initial timer info in Agent_OnLoad()\n");
     {
-        if (!checkTimerInfo(jvmti, &initInfo, NULL, "Agent_OnLoad()")) {
+        if (!checkTimerInfo(jvmti, &initInfo, nullptr, "Agent_OnLoad()")) {
             nsk_jvmti_setFailStatus();
         }
     }
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTopThreadGroups/topthrgrp001/topthrgrp001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTopThreadGroups/topthrgrp001/topthrgrp001.cpp
index 748880fee41..69baf58e6a7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTopThreadGroups/topthrgrp001/topthrgrp001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTopThreadGroups/topthrgrp001/topthrgrp001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_topthrgrp001(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -68,10 +68,10 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_GetTopThreadGroups_topthrgrp001_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jint i, groupCount = 0;
-    jthreadGroup *groups = NULL;
+    jthreadGroup *groups = nullptr;
     jvmtiThreadGroupInfo inf;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -105,7 +105,7 @@ Java_nsk_jvmti_GetTopThreadGroups_topthrgrp001_check(JNIEnv *env, jclass cls) {
                 printf(">>>      is daemon: %s\n",
                        (inf.is_daemon == JNI_TRUE) ? "true" : "false");
             }
-            if (inf.parent != NULL) {
+            if (inf.parent != nullptr) {
                 printf("ERROR: thread group is not parentless!\n");
                 printf("   group name: %s\n", inf.name);
                 printf("       parent: 0x%p\n", inf.parent);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTopThreadGroups/topthrgrp002/topthrgrp002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTopThreadGroups/topthrgrp002/topthrgrp002.cpp
index 50b23125dfa..b8817fcc1be 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTopThreadGroups/topthrgrp002/topthrgrp002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetTopThreadGroups/topthrgrp002/topthrgrp002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_topthrgrp002(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,7 +70,7 @@ Java_nsk_jvmti_GetTopThreadGroups_topthrgrp002_check(JNIEnv *env, jclass cls) {
     jint groupCount;
     jthreadGroup *groups;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -78,7 +78,7 @@ Java_nsk_jvmti_GetTopThreadGroups_topthrgrp002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (groupCountPtr) null pointer check ...\n");
     }
-    err = jvmti->GetTopThreadGroups(NULL, &groups);
+    err = jvmti->GetTopThreadGroups(nullptr, &groups);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("(groupCountPtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("           got: %s (%d)\n", TranslateError(err), err);
@@ -88,7 +88,7 @@ Java_nsk_jvmti_GetTopThreadGroups_topthrgrp002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> (groupsPtr) null pointer check ...\n");
     }
-    err = jvmti->GetTopThreadGroups(&groupCount, NULL);
+    err = jvmti->GetTopThreadGroups(&groupCount, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("(groupsPtr) error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("           got: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetVersionNumber/getvern001/getvern001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetVersionNumber/getvern001/getvern001.cpp
index 1d8071891fc..80ba1ffe5c7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetVersionNumber/getvern001/getvern001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetVersionNumber/getvern001/getvern001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_getvern001(JavaVM *jvm, char *options, void *reserved)
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -68,7 +68,7 @@ JNIEXPORT jint JNICALL Java_nsk_jvmti_GetVersionNumber_getvern001_check(JNIEnv *
     jvmtiError err;
     jint ver = 0;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -90,7 +90,7 @@ JNIEXPORT jint JNICALL Java_nsk_jvmti_GetVersionNumber_getvern001_check(JNIEnv *
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->GetVersionNumber(NULL);
+    err = jvmti->GetVersionNumber(nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER, got: %s\n",
                TranslateError(err));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/InterruptThread/intrpthrd001/intrpthrd001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/InterruptThread/intrpthrd001/intrpthrd001.cpp
index 2bdfea11a6f..e89a4ea7b4f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/InterruptThread/intrpthrd001/intrpthrd001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/InterruptThread/intrpthrd001/intrpthrd001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,9 +38,9 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jthread runningThread = NULL;
-static jthread waitingThread = NULL;
-static jthread sleepingThread = NULL;
+static jthread runningThread = nullptr;
+static jthread waitingThread = nullptr;
+static jthread sleepingThread = nullptr;
 
 /* ========================================================================== */
 
@@ -49,7 +49,7 @@ static int prepare(jvmtiEnv* jvmti) {
     const char* WAITING_THREAD_NAME = "DebuggeeWaitingThread";
     const char* SLEEPING_THREAD_NAME = "DebuggeeSleepingThread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -60,12 +60,12 @@ static int prepare(jvmtiEnv* jvmti) {
            jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -76,7 +76,7 @@ static int prepare(jvmtiEnv* jvmti) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL) {
+        if (info.name != nullptr) {
             if (strcmp(info.name, RUNNING_THREAD_NAME) == 0) {
                 runningThread = threads[i];
             } else if (strcmp(info.name, WAITING_THREAD_NAME) == 0) {
@@ -109,7 +109,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     NSK_DISPLAY0("Testcase #1: call InterruptThread for runningThread\n");
-    if (!NSK_VERIFY(runningThread != NULL)) {
+    if (!NSK_VERIFY(runningThread != nullptr)) {
         nsk_jvmti_setFailStatus();
     } else {
         if (!NSK_JVMTI_VERIFY(jvmti->InterruptThread(runningThread)))
@@ -117,7 +117,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     NSK_DISPLAY0("Testcase #2: call InterruptThread for waitingThread\n");
-    if (!NSK_VERIFY(waitingThread != NULL)) {
+    if (!NSK_VERIFY(waitingThread != nullptr)) {
         nsk_jvmti_setFailStatus();
     } else {
         if (!NSK_JVMTI_VERIFY(jvmti->InterruptThread(waitingThread)))
@@ -125,7 +125,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     NSK_DISPLAY0("Testcase #3: call InterruptThread for sleepingThread\n");
-    if (!NSK_VERIFY(sleepingThread != NULL)) {
+    if (!NSK_VERIFY(sleepingThread != nullptr)) {
         nsk_jvmti_setFailStatus();
     } else {
         if (!NSK_JVMTI_VERIFY(jvmti->InterruptThread(sleepingThread)))
@@ -151,7 +151,7 @@ JNIEXPORT jint JNI_OnLoad_intrpthrd001(JavaVM *jvm, char *options, void *reserve
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
 
     NSK_DISPLAY0("Agent_OnLoad\n");
@@ -162,10 +162,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/InterruptThread/intrpthrd002/intrpthrd002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/InterruptThread/intrpthrd002/intrpthrd002.cpp
index 60c2384b1c1..9411e9365d4 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/InterruptThread/intrpthrd002/intrpthrd002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/InterruptThread/intrpthrd002/intrpthrd002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -53,7 +53,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/InterruptThread/intrpthrd003/intrpthrd003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/InterruptThread/intrpthrd003/intrpthrd003.cpp
index b05c5d5cd7d..dd81a65cb21 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/InterruptThread/intrpthrd003/intrpthrd003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/InterruptThread/intrpthrd003/intrpthrd003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -55,7 +55,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsArrayClass/isarray004/isarray004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsArrayClass/isarray004/isarray004.cpp
index 30277bcc619..ac14708af83 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsArrayClass/isarray004/isarray004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsArrayClass/isarray004/isarray004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_isarray004(JavaVM *jvm, char *options, void *reserved)
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -69,7 +69,7 @@ Java_nsk_jvmti_IsArrayClass_isarray004_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jboolean isArrayClass;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -77,7 +77,7 @@ Java_nsk_jvmti_IsArrayClass_isarray004_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid class check ...\n");
     }
-    err = jvmti->IsArrayClass(NULL, &isArrayClass);
+    err = jvmti->IsArrayClass(nullptr, &isArrayClass);
     if (err != JVMTI_ERROR_INVALID_CLASS) {
         printf("Error expected: JVMTI_ERROR_INVALID_CLASS,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -87,7 +87,7 @@ Java_nsk_jvmti_IsArrayClass_isarray004_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->IsArrayClass(cls, NULL);
+    err = jvmti->IsArrayClass(cls, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsArrayClass/isarray005/isarray005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsArrayClass/isarray005/isarray005.cpp
index 4aacc6f21fe..774ec0574be 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsArrayClass/isarray005/isarray005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsArrayClass/isarray005/isarray005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_isarray005(JavaVM *jvm, char *options, void *reserved)
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -75,7 +75,7 @@ Java_nsk_jvmti_IsArrayClass_isarray005_check(JNIEnv *env,
     jboolean isArrayClass;
     char *sig, *generic;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsFieldSynthetic/isfldsin002/isfldsin002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsFieldSynthetic/isfldsin002/isfldsin002.cpp
index ca52e5801d2..1d4a737551d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsFieldSynthetic/isfldsin002/isfldsin002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsFieldSynthetic/isfldsin002/isfldsin002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -97,13 +97,13 @@ Java_nsk_jvmti_IsFieldSynthetic_isfldsin002_check(JNIEnv *env, jclass cls) {
     jfieldID fid;
     jboolean isSynthetic;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     fid = env->GetFieldID(cls, "fld", "I");
-    if (fid == NULL) {
+    if (fid == nullptr) {
         printf("Cannot get field ID!\n");
         return STATUS_FAILED;
     }
@@ -111,7 +111,7 @@ Java_nsk_jvmti_IsFieldSynthetic_isfldsin002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid class check ...\n");
     }
-    err = jvmti->IsFieldSynthetic(NULL, fid, &isSynthetic);
+    err = jvmti->IsFieldSynthetic(nullptr, fid, &isSynthetic);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY &&
             !caps.can_get_synthetic_attribute) {
         /* It is OK */
@@ -124,7 +124,7 @@ Java_nsk_jvmti_IsFieldSynthetic_isfldsin002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid field check ...\n");
     }
-    err = jvmti->IsFieldSynthetic(cls, NULL, &isSynthetic);
+    err = jvmti->IsFieldSynthetic(cls, nullptr, &isSynthetic);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY &&
             !caps.can_get_synthetic_attribute) {
         /* It is OK */
@@ -137,7 +137,7 @@ Java_nsk_jvmti_IsFieldSynthetic_isfldsin002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->IsFieldSynthetic(cls, fid, NULL);
+    err = jvmti->IsFieldSynthetic(cls, fid, nullptr);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY &&
             !caps.can_get_synthetic_attribute) {
         /* It is OK */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsFieldSynthetic/isfldsin003/isfldsin003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsFieldSynthetic/isfldsin003/isfldsin003.cpp
index a06e1fd1dff..0089b0e6f70 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsFieldSynthetic/isfldsin003/isfldsin003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsFieldSynthetic/isfldsin003/isfldsin003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ typedef struct {
     jboolean is_synthetic;
 } field_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -64,12 +64,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -114,14 +114,14 @@ Java_nsk_jvmti_IsFieldSynthetic_isfldsin003a_check(JNIEnv *env,
     jboolean isSynthetic;
     size_t i;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     for (i = 0; i < sizeof(fields) / sizeof(field_info); i++) {
         fid = env->GetFieldID(clazz, fields[i].name, fields[i].sig);
-        if (fid == NULL) {
+        if (fid == nullptr) {
             printf("(%" PRIuPTR ") cannot get field ID for %s:\"%s\"\n",
                    i, fields[i].name, fields[i].sig);
             result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsInterface/isintrf004/isintrf004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsInterface/isintrf004/isintrf004.cpp
index 01c232547f7..fdc8da2bc78 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsInterface/isintrf004/isintrf004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsInterface/isintrf004/isintrf004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_isintrf004(JavaVM *jvm, char *options, void *reserved)
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -69,7 +69,7 @@ Java_nsk_jvmti_IsInterface_isintrf004_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jboolean isInterface;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -77,7 +77,7 @@ Java_nsk_jvmti_IsInterface_isintrf004_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid class check ...\n");
     }
-    err = jvmti->IsInterface(NULL, &isInterface);
+    err = jvmti->IsInterface(nullptr, &isInterface);
     if (err != JVMTI_ERROR_INVALID_CLASS) {
         printf("Error expected: JVMTI_ERROR_INVALID_CLASS,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -87,7 +87,7 @@ Java_nsk_jvmti_IsInterface_isintrf004_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->IsInterface(cls, NULL);
+    err = jvmti->IsInterface(cls, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsInterface/isintrf005/isintrf005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsInterface/isintrf005/isintrf005.cpp
index 887cd625052..57f0386f2a9 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsInterface/isintrf005/isintrf005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsInterface/isintrf005/isintrf005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_isintrf005(JavaVM *jvm, char *options, void *reserved)
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -74,7 +74,7 @@ Java_nsk_jvmti_IsInterface_isintrf005_check(JNIEnv *env, jclass cls, jclass claz
     jboolean isInterface;
     char *sig, *generic;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodNative/isnative001/isnative001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodNative/isnative001/isnative001.cpp
index f4af7621adb..4e2b49fa0a3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodNative/isnative001/isnative001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodNative/isnative001/isnative001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_isnative001(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -79,7 +79,7 @@ void checkMeth(JNIEnv *env, jclass cl,
     } else {
         mid = env->GetMethodID(cl, name, sig);
     }
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find MethodID for \"%s%s\"\n", name, sig);
         result = STATUS_FAILED;
         return;
@@ -116,7 +116,7 @@ Java_nsk_jvmti_IsMethodNative_isnative001_check(JNIEnv *env, jclass cls) {
     checkMeth(env, cls, "check", "()I", 1, JNI_TRUE);
 
     clsId = env->FindClass("nsk/jvmti/IsMethodNative/isnative001$Inn");
-    if (clsId == NULL) {
+    if (clsId == nullptr) {
         printf("Cannot find nsk.jvmti.IsMethodNative.isnative001$Inn class!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodNative/isnative002/isnative002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodNative/isnative002/isnative002.cpp
index 99528346766..3160237fb47 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodNative/isnative002/isnative002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodNative/isnative002/isnative002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_isnative002(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,13 +70,13 @@ Java_nsk_jvmti_IsMethodNative_isnative002_check(JNIEnv *env, jclass cls) {
     jmethodID mid;
     jboolean isNative;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     mid = env->GetMethodID(cls, "<init>", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
@@ -84,7 +84,7 @@ Java_nsk_jvmti_IsMethodNative_isnative002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid method check ...\n");
     }
-    err = jvmti->IsMethodNative(NULL, &isNative);
+    err = jvmti->IsMethodNative(nullptr, &isNative);
     if (err != JVMTI_ERROR_INVALID_METHODID) {
         printf("Error expected: JVMTI_ERROR_INVALID_METHODID,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
@@ -94,7 +94,7 @@ Java_nsk_jvmti_IsMethodNative_isnative002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->IsMethodNative(mid, NULL);
+    err = jvmti->IsMethodNative(mid, nullptr);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodObsolete/isobsolete001/isobsolete001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodObsolete/isobsolete001/isobsolete001.cpp
index 399d894f9b4..fcc857134bf 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodObsolete/isobsolete001/isobsolete001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodObsolete/isobsolete001/isobsolete001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -95,10 +95,10 @@ static void checkStackMethodsObsolete(jvmtiEnv* jvmti, jthread thread,
         int i;
 
         for (i = 0; i < frameCount; i++) {
-            char* name = NULL;
-            char* signature = NULL;
-            char* generic = NULL;
-            char* kind = NULL;
+            char* name = nullptr;
+            char* signature = nullptr;
+            char* generic = nullptr;
+            char* kind = nullptr;
 
             NSK_DISPLAY1("  frame #%i:\n", i);
             NSK_DISPLAY1("     methodID:  %p\n", (void*)frameStack[i].method);
@@ -110,7 +110,7 @@ static void checkStackMethodsObsolete(jvmtiEnv* jvmti, jthread thread,
             NSK_DISPLAY1("     name:      %s\n", nsk_null_string(name));
             NSK_DISPLAY1("     signature: %s\n", nsk_null_string(signature));
             NSK_DISPLAY1("     generic:   %s\n", nsk_null_string(generic));
-            if (name != NULL
+            if (name != nullptr
                     && (strcmp(STATIC_METHOD_NAME, name) == 0
                         || strcmp(INSTANCE_METHOD_NAME, name) == 0)) {
                 found++;
@@ -166,15 +166,15 @@ static int redefineClass(jvmtiEnv* jvmti, jclass klass, const char className[],
 /** Get classfile bytes to redefine. */
 static int getClassfileBytes(JNIEnv* jni, jvmtiEnv* jvmti,
                                     jint* size, unsigned char* *bytes) {
-    jclass debugeeClass = NULL;
-    jfieldID fieldID = NULL;
-    jbyteArray array = NULL;
+    jclass debugeeClass = nullptr;
+    jfieldID fieldID = nullptr;
+    jbyteArray array = nullptr;
     jbyte* elements;
     int i;
 
     NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-            jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+            jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -182,7 +182,7 @@ static int getClassfileBytes(JNIEnv* jni, jvmtiEnv* jvmti,
 
     NSK_DISPLAY1("Find static field: %s\n", CLASSFILE_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (fieldID =
-            jni->GetStaticFieldID(debugeeClass, CLASSFILE_FIELD_NAME, CLASSFILE_FIELD_SIG)) != NULL)) {
+            jni->GetStaticFieldID(debugeeClass, CLASSFILE_FIELD_NAME, CLASSFILE_FIELD_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -190,7 +190,7 @@ static int getClassfileBytes(JNIEnv* jni, jvmtiEnv* jvmti,
 
     NSK_DISPLAY1("Get classfile bytes array from static field: %s\n", CLASSFILE_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (array = (jbyteArray)
-            jni->GetStaticObjectField(debugeeClass, fieldID)) != NULL)) {
+            jni->GetStaticObjectField(debugeeClass, fieldID)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -206,7 +206,7 @@ static int getClassfileBytes(JNIEnv* jni, jvmtiEnv* jvmti,
     {
         jboolean isCopy;
         if (!NSK_JNI_VERIFY(jni, (elements =
-                jni->GetByteArrayElements(array, &isCopy)) != NULL)) {
+                jni->GetByteArrayElements(array, &isCopy)) != nullptr)) {
             nsk_jvmti_setFailStatus();
         return NSK_FALSE;
         }
@@ -242,11 +242,11 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     /* perform testing */
     {
-        jclass testedClass = NULL;
-        jobject testedThread = NULL;
-        jmethodID staticMethodID = NULL;
-        jmethodID instanceMethodID = NULL;
-        unsigned char* classfileBytes = NULL;
+        jclass testedClass = nullptr;
+        jobject testedThread = nullptr;
+        jmethodID staticMethodID = nullptr;
+        jmethodID instanceMethodID = nullptr;
+        unsigned char* classfileBytes = nullptr;
         jint classfileSize = 0;
 
         NSK_DISPLAY0(">>> Obtain bytes for class file redefinition\n");
@@ -259,7 +259,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         {
             NSK_DISPLAY1("Find tested class: %s\n", TESTED_CLASS_NAME);
             if (!NSK_JNI_VERIFY(jni, (testedClass =
-                    jni->FindClass(TESTED_CLASS_NAME)) != NULL)) {
+                    jni->FindClass(TESTED_CLASS_NAME)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -267,7 +267,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
             NSK_DISPLAY1("Make global reference for class object: %p\n", (void*)testedClass);
             if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass)
-                    jni->NewGlobalRef(testedClass)) != NULL)) {
+                    jni->NewGlobalRef(testedClass)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -275,7 +275,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
             NSK_DISPLAY1("Get static methodID: %s\n", STATIC_METHOD_NAME);
             if (!NSK_JNI_VERIFY(jni, (staticMethodID =
-                    jni->GetStaticMethodID(testedClass, STATIC_METHOD_NAME, STATIC_METHOD_SIG)) != NULL)) {
+                    jni->GetStaticMethodID(testedClass, STATIC_METHOD_NAME, STATIC_METHOD_SIG)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -283,7 +283,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
             NSK_DISPLAY1("Get instance methodID: %s\n", INSTANCE_METHOD_NAME);
             if (!NSK_JNI_VERIFY(jni, (instanceMethodID =
-                    jni->GetMethodID(testedClass, INSTANCE_METHOD_NAME, INSTANCE_METHOD_SIG)) != NULL)) {
+                    jni->GetMethodID(testedClass, INSTANCE_METHOD_NAME, INSTANCE_METHOD_SIG)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -291,7 +291,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
             NSK_DISPLAY1("Find thread with running methods by name: %s\n", TESTED_THREAD_NAME);
             if (!NSK_VERIFY((testedThread =
-                    nsk_jvmti_threadByName(TESTED_THREAD_NAME)) != NULL)) {
+                    nsk_jvmti_threadByName(TESTED_THREAD_NAME)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -367,7 +367,7 @@ JNIEXPORT jint JNI_OnLoad_isobsolete001(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -377,7 +377,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add required capabilities */
@@ -393,7 +393,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodSynthetic/issynth001/issynth001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodSynthetic/issynth001/issynth001.cpp
index e9088348e02..a10f3b8e0ee 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodSynthetic/issynth001/issynth001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodSynthetic/issynth001/issynth001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,7 +41,7 @@ typedef struct {
     jboolean is_synthetic;
 } method_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -76,12 +76,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -139,7 +139,7 @@ Java_nsk_jvmti_IsMethodSynthetic_issynth001a_check(JNIEnv *env,
         } else {
             mid = env->GetMethodID(cl, methods[i].name, methods[i].signature);
         }
-        if (mid == NULL) {
+        if (mid == nullptr) {
             printf("Cannot find MethodID for \"%s%s\"\n",
                 methods[i].name, methods[i].signature);
             result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodSynthetic/issynth002/issynth002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodSynthetic/issynth002/issynth002.cpp
index 96eb657d238..ab344596ab7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodSynthetic/issynth002/issynth002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IsMethodSynthetic/issynth002/issynth002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -97,13 +97,13 @@ Java_nsk_jvmti_IsMethodSynthetic_issynth002_check(JNIEnv *env, jclass cls) {
     jmethodID mid;
     jboolean isSynthetic;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     mid = env->GetMethodID(cls, "<init>", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find method \"<init>()V\"!\n");
         return STATUS_FAILED;
     }
@@ -111,7 +111,7 @@ Java_nsk_jvmti_IsMethodSynthetic_issynth002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid method check ...\n");
     }
-    err = jvmti->IsMethodSynthetic(NULL, &isSynthetic);
+    err = jvmti->IsMethodSynthetic(nullptr, &isSynthetic);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY &&
             !caps.can_get_synthetic_attribute) {
         /* It is OK */
@@ -124,7 +124,7 @@ Java_nsk_jvmti_IsMethodSynthetic_issynth002_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->IsMethodSynthetic(mid, NULL);
+    err = jvmti->IsMethodSynthetic(mid, nullptr);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY &&
             !caps.can_get_synthetic_attribute) {
         /* It is OK */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap001/iterheap001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap001/iterheap001.cpp
index 3d54b28b6c8..fbfaac26708 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap001/iterheap001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap001/iterheap001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -65,7 +65,7 @@ typedef struct ObjectDescStruct {
 static int chainLength = 0;
 static int objectsCount = 0;
 
-static ObjectDesc* objectDescList = NULL;
+static ObjectDesc* objectDescList = nullptr;
 
 static volatile int foundUntagged = 0;
 
@@ -82,7 +82,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
                                     jlong tag, int reachable) {
 
     int success = NSK_TRUE;
-    jobject obj = NULL;
+    jobject obj = nullptr;
     jlong objTag = (!reachable ? -tag : (tag % 2 != 0) ? tag : (jlong)0);
 
     if (count <= 0)
@@ -92,7 +92,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
     tag++;
 
     if (!NSK_JNI_VERIFY(jni, (obj =
-            jni->GetObjectField(firstObject, firstField)) != NULL)) {
+            jni->GetObjectField(firstObject, firstField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -118,16 +118,16 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
 /** Obtain all tested objects from debugee class and tag them recursively. */
 static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                     int *objectsCount, ObjectDesc* *objectDescList) {
-    jclass debugeeClass = NULL;
-    jclass rootObjectClass = NULL;
-    jclass chainObjectClass = NULL;
+    jclass debugeeClass = nullptr;
+    jclass rootObjectClass = nullptr;
+    jclass chainObjectClass = nullptr;
 
-    jfieldID objectField = NULL;
-    jfieldID reachableChainField = NULL;
-    jfieldID unreachableChainField = NULL;
-    jfieldID tailField = NULL;
+    jfieldID objectField = nullptr;
+    jfieldID reachableChainField = nullptr;
+    jfieldID unreachableChainField = nullptr;
+    jfieldID tailField = nullptr;
 
-    jobject rootObject = NULL;
+    jobject rootObject = nullptr;
 
     jlong chainObjectTag = 100;
 
@@ -151,7 +151,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-            jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+            jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -159,7 +159,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find root object class: %s\n", ROOT_OBJECT_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (rootObjectClass =
-            jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -167,7 +167,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find chain object class: %s\n", CHAIN_OBJECT_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (chainObjectClass =
-            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -175,7 +175,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find static field in debugee class: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (objectField =
-            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -183,7 +183,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", REACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (reachableChainField =
-            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -191,7 +191,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", UNREACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (unreachableChainField =
-            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -199,7 +199,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in chain object class: %s\n", TAIL_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (tailField =
-            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -207,7 +207,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Get root object from static field: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (rootObject =
-            jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+            jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -302,7 +302,7 @@ static int checkTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni,
 /** Release references to the tested objects and free allocated memory. */
 static int releaseTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                                     ObjectDesc* objectDescList) {
-    if (objectDescList != NULL) {
+    if (objectDescList != nullptr) {
         NSK_DISPLAY1("Deallocate objects list: 0x%p\n", (void*)objectDescList);
         if (!NSK_JVMTI_VERIFY(
             jvmti->Deallocate((unsigned char*)objectDescList))) {
@@ -322,9 +322,9 @@ heapObjectCallback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data)
     if (info & INFO_HEAPOBJ) {
         NSK_DISPLAY3("  heapObjectCallback: class_tag=%-3ld size=%-3ld *tag_ptr=%-5ld\n",
                         (long)class_tag, (long)size,
-                        (long)(tag_ptr == NULL ? (jlong)0 : *tag_ptr));
+                        (long)(tag_ptr == nullptr ? (jlong)0 : *tag_ptr));
     } else if ((info & INFO_TAGGED) != 0 &&
-                    tag_ptr != NULL && *tag_ptr != 0) {
+                    tag_ptr != nullptr && *tag_ptr != 0) {
         NSK_DISPLAY3("  heapObjectCallback: class_tag=%-3ld size=%-3ld *tag_ptr=%-5ld\n",
                         (long)class_tag, (long)size,
                         (long)*tag_ptr);
@@ -341,8 +341,8 @@ heapObjectCallback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data)
         nsk_jvmti_setFailStatus();
     }
 
-    if (tag_ptr == NULL) {
-        NSK_COMPLAIN3("NULL tag_ptr is passed to heapObjectCallback:\n"
+    if (tag_ptr == nullptr) {
+        NSK_COMPLAIN3("null tag_ptr is passed to heapObjectCallback:\n"
                       "#   tag_ptr:        0x%p\n"
                       "#   class_tag:      %ld\n"
                       "#   size:           %ld\n",
@@ -411,7 +411,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0(">>> Enable OBJECT_FREE event and let debugee to clean links to unreachable objects\n");
         {
             jvmtiEvent event = JVMTI_EVENT_OBJECT_FREE;
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
                 return;
 
             if (!NSK_VERIFY(nsk_jvmti_resumeSync()))
@@ -432,7 +432,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0(">>> Disable OBJECT_FREE event and check if tagged/untagged objects were iterated:\n");
         {
             jvmtiEvent event = JVMTI_EVENT_OBJECT_FREE;
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr)))
                 return;
 
             if (!checkTestedObjects(jvmti, jni, chainLength, objectDescList)) {
@@ -487,7 +487,7 @@ JNIEXPORT jint JNI_OnLoad_iterheap001(JavaVM *jvm, char *options, void *reserved
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -496,7 +496,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     {
         const char* infoOpt = nsk_jvmti_findOptionValue("info");
-        if (infoOpt != NULL) {
+        if (infoOpt != nullptr) {
             if (strcmp(infoOpt, "none") == 0)
                 info = INFO_NONE;
             else if (strcmp(infoOpt, "all") == 0)
@@ -523,7 +523,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -547,7 +547,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
             return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap002/iterheap002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap002/iterheap002.cpp
index 9d4171ef71c..e1d5a366266 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap002/iterheap002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap002/iterheap002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -65,7 +65,7 @@ typedef struct ObjectDescStruct {
 static int chainLength = 0;
 static int objectsCount = 0;
 
-static ObjectDesc* objectDescList = NULL;
+static ObjectDesc* objectDescList = nullptr;
 
 static volatile int foundUntagged = 0;
 
@@ -82,7 +82,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
                                     jlong tag, int reachable) {
 
     int success = NSK_TRUE;
-    jobject obj = NULL;
+    jobject obj = nullptr;
     jlong objTag = (!reachable ? -tag : (tag % 2 != 0) ? tag : (jlong)0);
 
     if (count <= 0)
@@ -92,7 +92,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
     tag++;
 
     if (!NSK_JNI_VERIFY(jni, (obj =
-            jni->GetObjectField(firstObject, firstField)) != NULL)) {
+            jni->GetObjectField(firstObject, firstField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -118,16 +118,16 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
 /** Obtain all tested objects from debugee class and tag them recursively. */
 static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                     int *objectsCount, ObjectDesc* *objectDescList) {
-    jclass debugeeClass = NULL;
-    jclass rootObjectClass = NULL;
-    jclass chainObjectClass = NULL;
+    jclass debugeeClass = nullptr;
+    jclass rootObjectClass = nullptr;
+    jclass chainObjectClass = nullptr;
 
-    jfieldID objectField = NULL;
-    jfieldID reachableChainField = NULL;
-    jfieldID unreachableChainField = NULL;
-    jfieldID tailField = NULL;
+    jfieldID objectField = nullptr;
+    jfieldID reachableChainField = nullptr;
+    jfieldID unreachableChainField = nullptr;
+    jfieldID tailField = nullptr;
 
-    jobject rootObject = NULL;
+    jobject rootObject = nullptr;
 
     jlong chainObjectTag = 100;
 
@@ -151,7 +151,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-            jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+            jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -159,7 +159,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find root object class: %s\n", ROOT_OBJECT_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (rootObjectClass =
-            jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -167,7 +167,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find chain object class: %s\n", CHAIN_OBJECT_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (chainObjectClass =
-            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -175,7 +175,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find static field in debugee class: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (objectField =
-            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -183,7 +183,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", REACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (reachableChainField =
-            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -191,7 +191,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", UNREACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (unreachableChainField =
-            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -199,7 +199,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in chain object class: %s\n", TAIL_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (tailField =
-            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -207,7 +207,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Get root object from static field: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (rootObject =
-            jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+            jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -302,7 +302,7 @@ static int checkTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni,
 /** Release references to the tested objects and free allocated memory. */
 static int releaseTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                                     ObjectDesc* objectDescList) {
-    if (objectDescList != NULL) {
+    if (objectDescList != nullptr) {
         NSK_DISPLAY1("Deallocate objects list: 0x%p\n", (void*)objectDescList);
         if (!NSK_JVMTI_VERIFY(
             jvmti->Deallocate((unsigned char*)objectDescList))) {
@@ -322,9 +322,9 @@ heapObjectCallback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data)
     if (info & INFO_HEAPOBJ) {
         NSK_DISPLAY3("  heapObjectCallback: class_tag=%-3ld size=%-3ld *tag_ptr=%-5ld\n",
                         (long)class_tag, (long)size,
-                        (long)(tag_ptr == NULL ? (jlong)0 : *tag_ptr));
+                        (long)(tag_ptr == nullptr ? (jlong)0 : *tag_ptr));
     } else if ((info & INFO_TAGGED) != 0 &&
-                    tag_ptr != NULL && *tag_ptr != 0) {
+                    tag_ptr != nullptr && *tag_ptr != 0) {
         NSK_DISPLAY3("  heapObjectCallback: class_tag=%-3ld size=%-3ld *tag_ptr=%-5ld\n",
                         (long)class_tag, (long)size,
                         (long)*tag_ptr);
@@ -341,8 +341,8 @@ heapObjectCallback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data)
         nsk_jvmti_setFailStatus();
     }
 
-    if (tag_ptr == NULL) {
-        NSK_COMPLAIN3("NULL tag_ptr is passed to heapObjectCallback:\n"
+    if (tag_ptr == nullptr) {
+        NSK_COMPLAIN3("null tag_ptr is passed to heapObjectCallback:\n"
                       "#   tag_ptr:        0x%p\n"
                       "#   class_tag:      %ld\n"
                       "#   size:           %ld\n",
@@ -419,7 +419,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0(">>> Enable OBJECT_FREE event and let debugee to clean links to unreachable objects\n");
         {
             jvmtiEvent event = JVMTI_EVENT_OBJECT_FREE;
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
                 return;
 
             if (!NSK_VERIFY(nsk_jvmti_resumeSync()))
@@ -440,7 +440,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0(">>> Disable OBJECT_FREE event and check if tagged objects were iterated:\n");
         {
             jvmtiEvent event = JVMTI_EVENT_OBJECT_FREE;
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr)))
                 return;
 
             if (!checkTestedObjects(jvmti, jni, chainLength, objectDescList)) {
@@ -495,7 +495,7 @@ JNIEXPORT jint JNI_OnLoad_iterheap002(JavaVM *jvm, char *options, void *reserved
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -504,7 +504,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     {
         const char* infoOpt = nsk_jvmti_findOptionValue("info");
-        if (infoOpt != NULL) {
+        if (infoOpt != nullptr) {
             if (strcmp(infoOpt, "none") == 0)
                 info = INFO_NONE;
             else if (strcmp(infoOpt, "all") == 0)
@@ -531,7 +531,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -555,7 +555,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
             return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap003/iterheap003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap003/iterheap003.cpp
index a485c4bb6ee..488ce612a1b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap003/iterheap003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap003/iterheap003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -65,7 +65,7 @@ typedef struct ObjectDescStruct {
 static int chainLength = 0;
 static int objectsCount = 0;
 
-static ObjectDesc* objectDescList = NULL;
+static ObjectDesc* objectDescList = nullptr;
 
 static volatile int foundUntagged = 0;
 
@@ -82,7 +82,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
                                     jlong tag, int reachable) {
 
     int success = NSK_TRUE;
-    jobject obj = NULL;
+    jobject obj = nullptr;
     jlong objTag = (!reachable ? -tag : (tag % 2 != 0) ? tag : (jlong)0);
 
     if (count <= 0)
@@ -92,7 +92,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
     tag++;
 
     if (!NSK_JNI_VERIFY(jni, (obj =
-            jni->GetObjectField(firstObject, firstField)) != NULL)) {
+            jni->GetObjectField(firstObject, firstField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -118,16 +118,16 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
 /** Obtain all tested objects from debugee class and tag them recursively. */
 static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                     int *objectsCount, ObjectDesc* *objectDescList) {
-    jclass debugeeClass = NULL;
-    jclass rootObjectClass = NULL;
-    jclass chainObjectClass = NULL;
+    jclass debugeeClass = nullptr;
+    jclass rootObjectClass = nullptr;
+    jclass chainObjectClass = nullptr;
 
-    jfieldID objectField = NULL;
-    jfieldID reachableChainField = NULL;
-    jfieldID unreachableChainField = NULL;
-    jfieldID tailField = NULL;
+    jfieldID objectField = nullptr;
+    jfieldID reachableChainField = nullptr;
+    jfieldID unreachableChainField = nullptr;
+    jfieldID tailField = nullptr;
 
-    jobject rootObject = NULL;
+    jobject rootObject = nullptr;
 
     jlong chainObjectTag = 100;
 
@@ -151,7 +151,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-            jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+            jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -159,7 +159,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find root object class: %s\n", ROOT_OBJECT_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (rootObjectClass =
-            jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -167,7 +167,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find chain object class: %s\n", CHAIN_OBJECT_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (chainObjectClass =
-            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -175,7 +175,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find static field in debugee class: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (objectField =
-            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -183,7 +183,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", REACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (reachableChainField =
-            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -191,7 +191,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", UNREACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (unreachableChainField =
-            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -199,7 +199,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in chain object class: %s\n", TAIL_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (tailField =
-            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -207,7 +207,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Get root object from static field: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (rootObject =
-            jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+            jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -302,7 +302,7 @@ static int checkTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni,
 /** Release references to the tested objects and free allocated memory. */
 static int releaseTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                                     ObjectDesc* objectDescList) {
-    if (objectDescList != NULL) {
+    if (objectDescList != nullptr) {
         NSK_DISPLAY1("Deallocate objects list: 0x%p\n", (void*)objectDescList);
         if (!NSK_JVMTI_VERIFY(
             jvmti->Deallocate((unsigned char*)objectDescList))) {
@@ -322,9 +322,9 @@ heapObjectCallback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data)
     if (info & INFO_HEAPOBJ) {
         NSK_DISPLAY3("  heapObjectCallback: class_tag=%-3ld size=%-3ld *tag_ptr=%-5ld\n",
                         (long)class_tag, (long)size,
-                        (long)(tag_ptr == NULL ? (jlong)0 : *tag_ptr));
+                        (long)(tag_ptr == nullptr ? (jlong)0 : *tag_ptr));
     } else if ((info & INFO_TAGGED) != 0 &&
-                    tag_ptr != NULL && *tag_ptr != 0) {
+                    tag_ptr != nullptr && *tag_ptr != 0) {
         NSK_DISPLAY3("  heapObjectCallback: class_tag=%-3ld size=%-3ld *tag_ptr=%-5ld\n",
                         (long)class_tag, (long)size,
                         (long)*tag_ptr);
@@ -341,8 +341,8 @@ heapObjectCallback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data)
         nsk_jvmti_setFailStatus();
     }
 
-    if (tag_ptr == NULL) {
-        NSK_COMPLAIN3("NULL tag_ptr is passed to heapObjectCallback:\n"
+    if (tag_ptr == nullptr) {
+        NSK_COMPLAIN3("null tag_ptr is passed to heapObjectCallback:\n"
                       "#   tag_ptr:        0x%p\n"
                       "#   class_tag:      %ld\n"
                       "#   size:           %ld\n",
@@ -420,7 +420,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0(">>> Enable OBJECT_FREE event and let debugee to clean links to unreachable objects\n");
         {
             jvmtiEvent event = JVMTI_EVENT_OBJECT_FREE;
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
                 return;
 
             if (!NSK_VERIFY(nsk_jvmti_resumeSync()))
@@ -441,7 +441,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0(">>> Disable OBJECT_FREE event and check if untagged objects were iterated:\n");
         {
             jvmtiEvent event = JVMTI_EVENT_OBJECT_FREE;
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr)))
                 return;
 
             if (!checkTestedObjects(jvmti, jni, chainLength, objectDescList)) {
@@ -496,7 +496,7 @@ JNIEXPORT jint JNI_OnLoad_iterheap003(JavaVM *jvm, char *options, void *reserved
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -505,7 +505,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     {
         const char* infoOpt = nsk_jvmti_findOptionValue("info");
-        if (infoOpt != NULL) {
+        if (infoOpt != nullptr) {
             if (strcmp(infoOpt, "none") == 0)
                 info = INFO_NONE;
             else if (strcmp(infoOpt, "all") == 0)
@@ -532,7 +532,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -556,7 +556,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
             return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap004/iterheap004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap004/iterheap004.cpp
index 54eb590a962..8e30927f00b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap004/iterheap004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap004/iterheap004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,8 +29,8 @@
 
 extern "C" {
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jlong timeout = 0;
 
@@ -126,7 +126,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     {
         do {
-            objectDescList = NULL;
+            objectDescList = nullptr;
 
             NSK_DISPLAY0("Calling IterateOverHeap with filter JVMTI_HEAP_OBJECT_UNTAGGED\n");
             {
@@ -170,7 +170,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             }
 
             /* Verify objectDescCount and objectDescList length in agreement */
-            if (!NSK_VERIFY(objectDesc == NULL)) {
+            if (!NSK_VERIFY(objectDesc == nullptr)) {
                nsk_jvmti_setFailStatus();
                break;
             }
@@ -242,7 +242,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -258,7 +258,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!caps.can_tag_objects)
         NSK_DISPLAY0("Warning: tagging objects is not available\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap005/iterheap005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap005/iterheap005.cpp
index d2ccacfe2d2..86b1c537a2c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap005/iterheap005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap005/iterheap005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 
 static jlong timeout = 0;
 static int fakeUserData = 0, objCounter = 0;
-static jvmtiEnv* st_jvmti = NULL;
+static jvmtiEnv* st_jvmti = nullptr;
 
 /* ============================================================================= */
 
@@ -44,7 +44,7 @@ heapObjectCallback(jlong class_tag,
                    void* user_data) {
 
     const char* name = "monitorName";
-    jrawMonitorID monitor_ptr = NULL;
+    jrawMonitorID monitor_ptr = nullptr;
 
     /*  Check RawMonitor functions for first 10 objects */
     if (objCounter >= 10) return JVMTI_ITERATION_ABORT;
@@ -150,7 +150,7 @@ JNIEXPORT jint JNI_OnLoad_iterheap005(JavaVM *jvm, char *options, void *reserved
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -158,7 +158,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* save pointer to environment to use it in callbacks */
@@ -175,7 +175,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap006/iterheap006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap006/iterheap006.cpp
index 9e387542ca3..cc8da20efcc 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap006/iterheap006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap006/iterheap006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,9 +32,9 @@ extern "C" {
 /* ============================================================================= */
 
 static jlong timeout = 0;
-static jvmtiEnv* st_jvmti = NULL;
+static jvmtiEnv* st_jvmti = nullptr;
 static const char *storage_data = "local_storage_data";
-static void *storage_ptr = NULL;
+static void *storage_ptr = nullptr;
 
 
 /* ============================================================================= */
@@ -111,7 +111,7 @@ JNIEXPORT jint JNI_OnLoad_iterheap006(JavaVM *jvm, char *options, void *reserved
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -119,7 +119,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* save pointer to environment to use it in callbacks */
@@ -136,7 +136,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap007/iterheap007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap007/iterheap007.cpp
index 467fd6bc796..7075025ec09 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap007/iterheap007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverHeap/iterheap007/iterheap007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ extern "C" {
 /* ============================================================================= */
 
 static jlong timeout = 0;
-static jvmtiEnv* st_jvmti = NULL;
+static jvmtiEnv* st_jvmti = nullptr;
 static jlong nanos = 0;
 static jvmtiTimerInfo timer_info1, timer_info2;
 static int *user_data = 0;
@@ -135,7 +135,7 @@ JNIEXPORT jint JNI_OnLoad_iterheap007(JavaVM *jvm, char *options, void *reserved
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -143,7 +143,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* save pointer to environment to use it in callbacks */
@@ -160,7 +160,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls001/iterinstcls001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls001/iterinstcls001.cpp
index c9a0acc33ee..32b7adc30de 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls001/iterinstcls001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls001/iterinstcls001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -65,7 +65,7 @@ typedef struct ObjectDescStruct {
 static int chainLength = 0;
 static int objectsCount = 0;
 
-static ObjectDesc* objectDescList = NULL;
+static ObjectDesc* objectDescList = nullptr;
 
 static volatile int foundUntagged = 0;
 
@@ -82,7 +82,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
                                     jlong tag, int reachable) {
 
     int success = NSK_TRUE;
-    jobject obj = NULL;
+    jobject obj = nullptr;
     jlong objTag = (!reachable ? -tag : (tag % 2 != 0) ? tag : (jlong)0);
 
     if (count <= 0)
@@ -92,7 +92,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
     tag++;
 
     if (!NSK_JNI_VERIFY(jni, (obj =
-            jni->GetObjectField(firstObject, firstField)) != NULL)) {
+            jni->GetObjectField(firstObject, firstField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -119,16 +119,16 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
 static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                     int *objectsCount, ObjectDesc* *objectDescList,
                                     jclass *testedClass) {
-    jclass debugeeClass = NULL;
-    jclass rootObjectClass = NULL;
-    jclass chainObjectClass = NULL;
+    jclass debugeeClass = nullptr;
+    jclass rootObjectClass = nullptr;
+    jclass chainObjectClass = nullptr;
 
-    jfieldID objectField = NULL;
-    jfieldID reachableChainField = NULL;
-    jfieldID unreachableChainField = NULL;
-    jfieldID tailField = NULL;
+    jfieldID objectField = nullptr;
+    jfieldID reachableChainField = nullptr;
+    jfieldID unreachableChainField = nullptr;
+    jfieldID tailField = nullptr;
 
-    jobject rootObject = NULL;
+    jobject rootObject = nullptr;
 
     jlong testedClassTag = 1;
     jlong chainObjectTag = 100;
@@ -153,7 +153,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-            jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+            jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -161,7 +161,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find root object class: %s\n", ROOT_OBJECT_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (rootObjectClass =
-            jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -169,7 +169,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find chain object class: %s\n", CHAIN_OBJECT_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (chainObjectClass =
-            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -177,7 +177,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Create global ref to tested class: 0x%p\n", chainObjectClass);
     if (!NSK_JNI_VERIFY(jni, (*testedClass = (jclass)
-            jni->NewGlobalRef(chainObjectClass)) != NULL)) {
+            jni->NewGlobalRef(chainObjectClass)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -185,7 +185,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find static field in debugee class: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (objectField =
-            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -193,7 +193,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", REACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (reachableChainField =
-            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -201,7 +201,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", UNREACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (unreachableChainField =
-            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -209,7 +209,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in chain object class: %s\n", TAIL_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (tailField =
-            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -217,7 +217,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Get root object from static field: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (rootObject =
-            jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+            jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -320,12 +320,12 @@ static int checkTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni,
 /** Release references to the tested objects and free allocated memory. */
 static int releaseTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                         ObjectDesc* objectDescList, jclass testedClass) {
-    if (testedClass != NULL) {
+    if (testedClass != nullptr) {
         NSK_DISPLAY1("Release object reference to tested class: 0x%p\n", testedClass);
         NSK_TRACE(jni->DeleteGlobalRef(testedClass));
     }
 
-    if (objectDescList != NULL) {
+    if (objectDescList != nullptr) {
         NSK_DISPLAY1("Deallocate objects list: 0x%p\n", (void*)objectDescList);
         if (!NSK_JVMTI_VERIFY(
             jvmti->Deallocate((unsigned char*)objectDescList))) {
@@ -345,7 +345,7 @@ heapObjectCallback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data)
     if (info & INFO_HEAPOBJ) {
         NSK_DISPLAY3("  heapObjectCallback: class_tag=%-3ld size=%-3ld *tag_ptr=%-5ld\n",
                         (long)class_tag, (long)size,
-                        (long)(tag_ptr == NULL ? (jlong)0 : *tag_ptr));
+                        (long)(tag_ptr == nullptr ? (jlong)0 : *tag_ptr));
     }
 
     if (class_tag != 1) {
@@ -359,8 +359,8 @@ heapObjectCallback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data)
         nsk_jvmti_setFailStatus();
     }
 
-    if (tag_ptr == NULL) {
-        NSK_COMPLAIN3("NULL tag_ptr is passed to heapObjectCallback:\n"
+    if (tag_ptr == nullptr) {
+        NSK_COMPLAIN3("null tag_ptr is passed to heapObjectCallback:\n"
                       "#   tag_ptr:        0x%p\n"
                       "#   class_tag:      %ld\n"
                       "#   size:           %ld\n",
@@ -419,7 +419,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         return;
 
     {
-        jclass testedClass = NULL;
+        jclass testedClass = nullptr;
 
         NSK_DISPLAY0(">>> Obtain and tag tested objects from debugee class\n");
         {
@@ -431,7 +431,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0(">>> Enable OBJECT_FREE event and let debugee to clean links to unreachable objects\n");
         {
             jvmtiEvent event = JVMTI_EVENT_OBJECT_FREE;
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
                 return;
 
             if (!NSK_VERIFY(nsk_jvmti_resumeSync()))
@@ -452,7 +452,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0(">>> Disable OBJECT_FREE event and check if tagged/untagged objects were iterated:\n");
         {
             jvmtiEvent event = JVMTI_EVENT_OBJECT_FREE;
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr)))
                 return;
 
             if (!checkTestedObjects(jvmti, jni, chainLength, objectDescList)) {
@@ -508,7 +508,7 @@ JNIEXPORT jint JNI_OnLoad_iterinstcls001(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -517,7 +517,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     {
         const char* infoOpt = nsk_jvmti_findOptionValue("info");
-        if (infoOpt != NULL) {
+        if (infoOpt != nullptr) {
             if (strcmp(infoOpt, "none") == 0)
                 info = INFO_NONE;
             else if (strcmp(infoOpt, "all") == 0)
@@ -542,7 +542,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -566,7 +566,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
             return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls002/iterinstcls002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls002/iterinstcls002.cpp
index 13288e2fd5e..b048103203b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls002/iterinstcls002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls002/iterinstcls002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -65,7 +65,7 @@ typedef struct ObjectDescStruct {
 static int chainLength = 0;
 static int objectsCount = 0;
 
-static ObjectDesc* objectDescList = NULL;
+static ObjectDesc* objectDescList = nullptr;
 
 static volatile int foundUntagged = 0;
 
@@ -82,7 +82,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
                                     jlong tag, int reachable) {
 
     int success = NSK_TRUE;
-    jobject obj = NULL;
+    jobject obj = nullptr;
     jlong objTag = (!reachable ? -tag : (tag % 2 != 0) ? tag : (jlong)0);
 
     if (count <= 0)
@@ -92,7 +92,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
     tag++;
 
     if (!NSK_JNI_VERIFY(jni, (obj =
-            jni->GetObjectField(firstObject, firstField)) != NULL)) {
+            jni->GetObjectField(firstObject, firstField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -119,16 +119,16 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
 static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                     int *objectsCount, ObjectDesc* *objectDescList,
                                     jclass *testedClass) {
-    jclass debugeeClass = NULL;
-    jclass rootObjectClass = NULL;
-    jclass chainObjectClass = NULL;
+    jclass debugeeClass = nullptr;
+    jclass rootObjectClass = nullptr;
+    jclass chainObjectClass = nullptr;
 
-    jfieldID objectField = NULL;
-    jfieldID reachableChainField = NULL;
-    jfieldID unreachableChainField = NULL;
-    jfieldID tailField = NULL;
+    jfieldID objectField = nullptr;
+    jfieldID reachableChainField = nullptr;
+    jfieldID unreachableChainField = nullptr;
+    jfieldID tailField = nullptr;
 
-    jobject rootObject = NULL;
+    jobject rootObject = nullptr;
 
     jlong testedClassTag = 1;
     jlong chainObjectTag = 100;
@@ -153,7 +153,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-            jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+            jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -161,7 +161,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find root object class: %s\n", ROOT_OBJECT_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (rootObjectClass =
-            jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -169,7 +169,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find chain object class: %s\n", CHAIN_OBJECT_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (chainObjectClass =
-            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -177,7 +177,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Create global ref to tested class: 0x%p\n", chainObjectClass);
     if (!NSK_JNI_VERIFY(jni, (*testedClass = (jclass)
-            jni->NewGlobalRef(chainObjectClass)) != NULL)) {
+            jni->NewGlobalRef(chainObjectClass)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -185,7 +185,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find static field in debugee class: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (objectField =
-            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -193,7 +193,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", REACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (reachableChainField =
-            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -201,7 +201,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", UNREACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (unreachableChainField =
-            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -209,7 +209,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in chain object class: %s\n", TAIL_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (tailField =
-            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -217,7 +217,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Get root object from static field: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (rootObject =
-            jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+            jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -320,12 +320,12 @@ static int checkTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni,
 /** Release references to the tested objects and free allocated memory. */
 static int releaseTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                         ObjectDesc* objectDescList, jclass testedClass) {
-    if (testedClass != NULL) {
+    if (testedClass != nullptr) {
         NSK_DISPLAY1("Release object reference to tested class: 0x%p\n", testedClass);
         NSK_TRACE(jni->DeleteGlobalRef(testedClass));
     }
 
-    if (objectDescList != NULL) {
+    if (objectDescList != nullptr) {
         NSK_DISPLAY1("Deallocate objects list: 0x%p\n", (void*)objectDescList);
         if (!NSK_JVMTI_VERIFY(
             jvmti->Deallocate((unsigned char*)objectDescList))) {
@@ -345,7 +345,7 @@ heapObjectCallback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data)
     if (info & INFO_HEAPOBJ) {
         NSK_DISPLAY3("  heapObjectCallback: class_tag=%-3ld size=%-3ld *tag_ptr=%-5ld\n",
                         (long)class_tag, (long)size,
-                        (long)(tag_ptr == NULL ? (jlong)0 : *tag_ptr));
+                        (long)(tag_ptr == nullptr ? (jlong)0 : *tag_ptr));
     }
 
     if (class_tag != 1) {
@@ -359,8 +359,8 @@ heapObjectCallback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data)
         nsk_jvmti_setFailStatus();
     }
 
-    if (tag_ptr == NULL) {
-        NSK_COMPLAIN3("NULL tag_ptr is passed to heapObjectCallback:\n"
+    if (tag_ptr == nullptr) {
+        NSK_COMPLAIN3("null tag_ptr is passed to heapObjectCallback:\n"
                       "#   tag_ptr:        0x%p\n"
                       "#   class_tag:      %ld\n"
                       "#   size:           %ld\n",
@@ -427,7 +427,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         return;
 
     {
-        jclass testedClass = NULL;
+        jclass testedClass = nullptr;
 
         NSK_DISPLAY0(">>> Obtain and tag tested objects from debugee class\n");
         {
@@ -439,7 +439,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0(">>> Enable OBJECT_FREE event and let debugee to clean links to unreachable objects\n");
         {
             jvmtiEvent event = JVMTI_EVENT_OBJECT_FREE;
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
                 return;
 
             if (!NSK_VERIFY(nsk_jvmti_resumeSync()))
@@ -460,7 +460,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0(">>> Disable OBJECT_FREE event and check if tagged objects were iterated:\n");
         {
             jvmtiEvent event = JVMTI_EVENT_OBJECT_FREE;
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr)))
                 return;
 
             if (!checkTestedObjects(jvmti, jni, chainLength, objectDescList)) {
@@ -516,7 +516,7 @@ JNIEXPORT jint JNI_OnLoad_iterinstcls002(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -525,7 +525,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     {
         const char* infoOpt = nsk_jvmti_findOptionValue("info");
-        if (infoOpt != NULL) {
+        if (infoOpt != nullptr) {
             if (strcmp(infoOpt, "none") == 0)
                 info = INFO_NONE;
             else if (strcmp(infoOpt, "all") == 0)
@@ -550,7 +550,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -574,7 +574,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
             return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls003/iterinstcls003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls003/iterinstcls003.cpp
index e552dc0b3b9..147003ff77f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls003/iterinstcls003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls003/iterinstcls003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -65,7 +65,7 @@ typedef struct ObjectDescStruct {
 static int chainLength = 0;
 static int objectsCount = 0;
 
-static ObjectDesc* objectDescList = NULL;
+static ObjectDesc* objectDescList = nullptr;
 
 static volatile int foundUntagged = 0;
 
@@ -82,7 +82,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
                                     jlong tag, int reachable) {
 
     int success = NSK_TRUE;
-    jobject obj = NULL;
+    jobject obj = nullptr;
     jlong objTag = (!reachable ? -tag : (tag % 2 != 0) ? tag : (jlong)0);
 
     if (count <= 0)
@@ -92,7 +92,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
     tag++;
 
     if (!NSK_JNI_VERIFY(jni, (obj =
-            jni->GetObjectField(firstObject, firstField)) != NULL)) {
+            jni->GetObjectField(firstObject, firstField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -119,16 +119,16 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
 static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                     int *objectsCount, ObjectDesc* *objectDescList,
                                     jclass *testedClass) {
-    jclass debugeeClass = NULL;
-    jclass rootObjectClass = NULL;
-    jclass chainObjectClass = NULL;
+    jclass debugeeClass = nullptr;
+    jclass rootObjectClass = nullptr;
+    jclass chainObjectClass = nullptr;
 
-    jfieldID objectField = NULL;
-    jfieldID reachableChainField = NULL;
-    jfieldID unreachableChainField = NULL;
-    jfieldID tailField = NULL;
+    jfieldID objectField = nullptr;
+    jfieldID reachableChainField = nullptr;
+    jfieldID unreachableChainField = nullptr;
+    jfieldID tailField = nullptr;
 
-    jobject rootObject = NULL;
+    jobject rootObject = nullptr;
 
     jlong testedClassTag = 1;
     jlong chainObjectTag = 100;
@@ -153,7 +153,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-            jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+            jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -161,7 +161,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find root object class: %s\n", ROOT_OBJECT_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (rootObjectClass =
-            jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -169,7 +169,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find chain object class: %s\n", CHAIN_OBJECT_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (chainObjectClass =
-            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -177,7 +177,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Create global ref to tested class: 0x%p\n", chainObjectClass);
     if (!NSK_JNI_VERIFY(jni, (*testedClass = (jclass)
-            jni->NewGlobalRef(chainObjectClass)) != NULL)) {
+            jni->NewGlobalRef(chainObjectClass)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -185,7 +185,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find static field in debugee class: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (objectField =
-            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -193,7 +193,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", REACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (reachableChainField =
-            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -201,7 +201,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", UNREACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (unreachableChainField =
-            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -209,7 +209,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in chain object class: %s\n", TAIL_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (tailField =
-            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -217,7 +217,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Get root object from static field: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (rootObject =
-            jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+            jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -320,12 +320,12 @@ static int checkTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni,
 /** Release references to the tested objects and free allocated memory. */
 static int releaseTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                         ObjectDesc* objectDescList, jclass testedClass) {
-    if (testedClass != NULL) {
+    if (testedClass != nullptr) {
         NSK_DISPLAY1("Release object reference to tested class: 0x%p\n", testedClass);
         NSK_TRACE(jni->DeleteGlobalRef(testedClass));
     }
 
-    if (objectDescList != NULL) {
+    if (objectDescList != nullptr) {
         NSK_DISPLAY1("Deallocate objects list: 0x%p\n", (void*)objectDescList);
         if (!NSK_JVMTI_VERIFY(
             jvmti->Deallocate((unsigned char*)objectDescList))) {
@@ -345,7 +345,7 @@ heapObjectCallback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data)
     if (info & INFO_HEAPOBJ) {
         NSK_DISPLAY3("  heapObjectCallback: class_tag=%-3ld size=%-3ld *tag_ptr=%-5ld\n",
                         (long)class_tag, (long)size,
-                        (long)(tag_ptr == NULL ? (jlong)0 : *tag_ptr));
+                        (long)(tag_ptr == nullptr ? (jlong)0 : *tag_ptr));
     }
 
     if (class_tag != 1) {
@@ -359,8 +359,8 @@ heapObjectCallback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data)
         nsk_jvmti_setFailStatus();
     }
 
-    if (tag_ptr == NULL) {
-        NSK_COMPLAIN3("NULL tag_ptr is passed to heapObjectCallback:\n"
+    if (tag_ptr == nullptr) {
+        NSK_COMPLAIN3("null tag_ptr is passed to heapObjectCallback:\n"
                       "#   tag_ptr:        0x%p\n"
                       "#   class_tag:      %ld\n"
                       "#   size:           %ld\n",
@@ -428,7 +428,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         return;
 
     {
-        jclass testedClass = NULL;
+        jclass testedClass = nullptr;
 
         NSK_DISPLAY0(">>> Obtain and tag tested objects from debugee class\n");
         {
@@ -440,7 +440,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0(">>> Enable OBJECT_FREE event and let debugee to clean links to unreachable objects\n");
         {
             jvmtiEvent event = JVMTI_EVENT_OBJECT_FREE;
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr)))
                 return;
 
             if (!NSK_VERIFY(nsk_jvmti_resumeSync()))
@@ -461,7 +461,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0(">>> Disable OBJECT_FREE event and check if untagged objects were iterated:\n");
         {
             jvmtiEvent event = JVMTI_EVENT_OBJECT_FREE;
-            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL)))
+            if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr)))
                 return;
 
             if (!checkTestedObjects(jvmti, jni, chainLength, objectDescList)) {
@@ -517,7 +517,7 @@ JNIEXPORT jint JNI_OnLoad_iterinstcls003(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -526,7 +526,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     {
         const char* infoOpt = nsk_jvmti_findOptionValue("info");
-        if (infoOpt != NULL) {
+        if (infoOpt != nullptr) {
             if (strcmp(infoOpt, "none") == 0)
                 info = INFO_NONE;
             else if (strcmp(infoOpt, "all") == 0)
@@ -551,7 +551,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -575,7 +575,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
             return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls004/iterinstcls004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls004/iterinstcls004.cpp
index 43e378571f4..6790635654c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls004/iterinstcls004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls004/iterinstcls004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@ typedef struct ObjectDescStruct {
 } ObjectDesc;
 
 static ObjectDesc *objectDescBuf;
-static jvmtiEnv* st_jvmti = NULL;
+static jvmtiEnv* st_jvmti = nullptr;
 static const char debugeeClassSignature[] = "Lnsk/jvmti/IterateOverInstancesOfClass/iterinstcls004;";
 
 /* ============================================================================= */
@@ -99,12 +99,12 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         return;
 
     {
-        jclass debugeeClass = NULL;
+        jclass debugeeClass = nullptr;
 
         do {
             NSK_DISPLAY1("Find debugee class: %s\n", debugeeClassSignature);
             debugeeClass = nsk_jvmti_classBySignature(debugeeClassSignature);
-            if (debugeeClass == NULL) {
+            if (debugeeClass == nullptr) {
                 nsk_jvmti_setFailStatus();
                 break;
             }
@@ -167,7 +167,7 @@ JNIEXPORT jint JNI_OnLoad_iterinstcls004(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -175,7 +175,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* save pointer to environment to use it in callbacks */
@@ -192,7 +192,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls005/iterinstcls005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls005/iterinstcls005.cpp
index 0907650299a..7e7d6ff85be 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls005/iterinstcls005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls005/iterinstcls005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 
 static jlong timeout = 0;
 static int fakeUserData = 0, objCounter = 0;
-static jvmtiEnv* st_jvmti = NULL;
+static jvmtiEnv* st_jvmti = nullptr;
 static const char debugeeClassSignature[] = "Lnsk/jvmti/IterateOverInstancesOfClass/iterinstcls005;";
 
 /* ============================================================================= */
@@ -45,7 +45,7 @@ heapObjectCallback(jlong class_tag,
                    void* user_data) {
 
     const char* name = "monitorName";
-    jrawMonitorID monitor_ptr = NULL;
+    jrawMonitorID monitor_ptr = nullptr;
 
     objCounter++;
 
@@ -106,11 +106,11 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         return;
 
     do {
-        jclass debugeeClass = NULL;
+        jclass debugeeClass = nullptr;
 
         NSK_DISPLAY1("Find debugee class: %s\n", debugeeClassSignature);
         debugeeClass = nsk_jvmti_classBySignature(debugeeClassSignature);
-        if (debugeeClass == NULL) {
+        if (debugeeClass == nullptr) {
             nsk_jvmti_setFailStatus();
             break;
         }
@@ -152,7 +152,7 @@ JNIEXPORT jint JNI_OnLoad_iterinstcls005(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -160,7 +160,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* save pointer to environment to use it in callbacks */
@@ -176,7 +176,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls006/iterinstcls006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls006/iterinstcls006.cpp
index 56868adb9b7..9129af82476 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls006/iterinstcls006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls006/iterinstcls006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,9 +32,9 @@ extern "C" {
 /* ============================================================================= */
 
 static jlong timeout = 0;
-static jvmtiEnv* st_jvmti = NULL;
+static jvmtiEnv* st_jvmti = nullptr;
 static const char *storage_data = "local_storage_data";
-static void *storage_ptr = NULL;
+static void *storage_ptr = nullptr;
 static const char debugeeClassSignature[] = "Lnsk/jvmti/IterateOverInstancesOfClass/iterinstcls006;";
 
 /* ============================================================================= */
@@ -68,11 +68,11 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         return;
 
     do {
-        jclass debugeeClass = NULL;
+        jclass debugeeClass = nullptr;
 
         NSK_DISPLAY1("Find debugee class: %s\n", debugeeClassSignature);
         debugeeClass = nsk_jvmti_classBySignature(debugeeClassSignature);
-        if (debugeeClass == NULL) {
+        if (debugeeClass == nullptr) {
             nsk_jvmti_setFailStatus();
             break;
         }
@@ -121,7 +121,7 @@ JNIEXPORT jint JNI_OnLoad_iterinstcls006(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -129,7 +129,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* save pointer to environment to use it in callbacks */
@@ -145,7 +145,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls007/iterinstcls007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls007/iterinstcls007.cpp
index 5e93a860167..01026bad68e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls007/iterinstcls007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverInstancesOfClass/iterinstcls007/iterinstcls007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ extern "C" {
 /* ============================================================================= */
 
 static jlong timeout = 0;
-static jvmtiEnv* st_jvmti = NULL;
+static jvmtiEnv* st_jvmti = nullptr;
 static int *user_data = 0;
 static const char debugeeClassSignature[] = "Lnsk/jvmti/IterateOverInstancesOfClass/iterinstcls007;";
 static jlong nanos = 0;
@@ -109,11 +109,11 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     do {
         NSK_DISPLAY0("Calling IterateOverInstancesOfClass with filter JVMTI_HEAP_OBJECT_EITHER\n");
         {
-            jclass debugeeClass = NULL;
+            jclass debugeeClass = nullptr;
 
             NSK_DISPLAY1("Find debugee class: %s\n", debugeeClassSignature);
             debugeeClass = nsk_jvmti_classBySignature(debugeeClassSignature);
-            if (debugeeClass == NULL) {
+            if (debugeeClass == nullptr) {
                 nsk_jvmti_setFailStatus();
                 break;
             }
@@ -148,7 +148,7 @@ JNIEXPORT jint JNI_OnLoad_iterinstcls007(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -156,7 +156,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* save pointer to environment to use it in callbacks */
@@ -173,7 +173,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj001/iterobjreachobj001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj001/iterobjreachobj001.cpp
index 487ca0fd703..ba158a475ae 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj001/iterobjreachobj001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj001/iterobjreachobj001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -63,7 +63,7 @@ typedef struct ObjectDescStruct {
 static int chainLength = 0;
 static int objectsCount = 0;
 
-static ObjectDesc* objectDescList = NULL;
+static ObjectDesc* objectDescList = nullptr;
 
 static int fakeUserData = 0;
 static int userDataError = 0;
@@ -76,7 +76,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
                                     jfieldID nextField, const char nextFieldName[],
                                     int count, ObjectDesc objectDescList[],
                                     jlong tag, int reachable) {
-    jobject obj = NULL;
+    jobject obj = nullptr;
     jlong objTag = (reachable ? tag : -tag);
 
     if (count <= 0)
@@ -85,7 +85,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
     count--;
     tag++;
 
-    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetObjectField(firstObject, firstField)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetObjectField(firstObject, firstField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -110,14 +110,14 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
 static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                     int *objectsCount, ObjectDesc* *objectDescList,
                                     jobject* rootObject) {
-    jclass debugeeClass = NULL;
-    jclass rootObjectClass = NULL;
-    jclass chainObjectClass = NULL;
+    jclass debugeeClass = nullptr;
+    jclass rootObjectClass = nullptr;
+    jclass chainObjectClass = nullptr;
 
-    jfieldID objectField = NULL;
-    jfieldID reachableChainField = NULL;
-    jfieldID unreachableChainField = NULL;
-    jfieldID tailField = NULL;
+    jfieldID objectField = nullptr;
+    jfieldID reachableChainField = nullptr;
+    jfieldID unreachableChainField = nullptr;
+    jfieldID tailField = nullptr;
 
     jlong rootObjectTag = 1;
     jlong chainObjectTag = 100;
@@ -141,14 +141,14 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
     }
 
     NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
     NSK_DISPLAY1("  ... found class: 0x%p\n", (void*)debugeeClass);
 
     NSK_DISPLAY1("Find root object class: %s\n", ROOT_OBJECT_CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (rootObjectClass = jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (rootObjectClass = jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -156,7 +156,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find chain object class: %s\n", CHAIN_OBJECT_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (chainObjectClass =
-            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -164,7 +164,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find static field in debugee class: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (objectField = jni->GetStaticFieldID(
-            debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != NULL)) {
+            debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -172,7 +172,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", REACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (reachableChainField = jni->GetFieldID(
-            rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -180,7 +180,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", UNREACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (unreachableChainField = jni->GetFieldID(
-            rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -188,7 +188,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in chain object class: %s\n", TAIL_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (tailField =
-            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -196,13 +196,13 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Get root object from static field: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (*rootObject =
-            jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+            jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
     NSK_DISPLAY1("  ... got object: 0x%p\n", (void*)*rootObject);
 
-    if (!NSK_JNI_VERIFY(jni, (*rootObject = jni->NewGlobalRef(*rootObject)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (*rootObject = jni->NewGlobalRef(*rootObject)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -290,12 +290,12 @@ static int checkTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni,
 /** Release references to the tested objects and free allocated memory. */
 static int releaseTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                         ObjectDesc* objectDescList, jobject rootObject) {
-    if (rootObject != NULL) {
+    if (rootObject != nullptr) {
         NSK_DISPLAY1("Release object reference to root tested object: 0x%p\n", rootObject);
         NSK_TRACE(jni->DeleteGlobalRef(rootObject));
     }
 
-    if (objectDescList != NULL) {
+    if (objectDescList != nullptr) {
         NSK_DISPLAY1("Deallocate objects list: 0x%p\n", (void*)objectDescList);
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)objectDescList))) {
             nsk_jvmti_setFailStatus();
@@ -318,12 +318,12 @@ objectReferenceCallback(jvmtiObjectReferenceKind reference_kind,
         NSK_DISPLAY6("  objectReferenceCallback: ref_kind=%1d class_tag=%-3ld size=%-3ld"
                         " *tag_ptr=%-5ld ref_tag=%-5ld ref_idx=%d\n",
                         (int)reference_kind, (long)class_tag, (long)size,
-                        (long)(tag_ptr == NULL ? (jlong)0 : *tag_ptr),
+                        (long)(tag_ptr == nullptr ? (jlong)0 : *tag_ptr),
                         (long)refferrer_tag, (int)refferrer_index);
     }
 
-    if (tag_ptr == NULL) {
-        NSK_COMPLAIN6("NULL tag_ptr is passed to objectReferenceCallback:\n"
+    if (tag_ptr == nullptr) {
+        NSK_COMPLAIN6("null tag_ptr is passed to objectReferenceCallback:\n"
                       "#   tag_ptr:        0x%p\n"
                       "#   reference_kind: %d\n"
                       "#   class_tag:      %ld\n"
@@ -339,7 +339,7 @@ objectReferenceCallback(jvmtiObjectReferenceKind reference_kind,
         nsk_jvmti_setFailStatus();
     }
 
-    if (tag_ptr != NULL && *tag_ptr != 0) {
+    if (tag_ptr != nullptr && *tag_ptr != 0) {
         int found = 0;
         int i;
 
@@ -412,7 +412,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         return;
 
     {
-        jobject rootObject = NULL;
+        jobject rootObject = nullptr;
 
         NSK_DISPLAY0(">>> Obtain and tag tested objects from debugee class\n");
         {
@@ -474,7 +474,7 @@ JNIEXPORT jint JNI_OnLoad_iterobjreachobj001(JavaVM *jvm, char *options, void *r
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -483,7 +483,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     {
         const char* infoOpt = nsk_jvmti_findOptionValue("info");
-        if (infoOpt != NULL) {
+        if (infoOpt != nullptr) {
             if (strcmp(infoOpt, "none") == 0)
                 info = INFO_NONE;
             else if (strcmp(infoOpt, "all") == 0)
@@ -508,7 +508,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -521,7 +521,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj002/iterobjreachobj002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj002/iterobjreachobj002.cpp
index 2bc628d73d2..9f5e130341d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj002/iterobjreachobj002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj002/iterobjreachobj002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,7 +36,7 @@ static jlong timeout = 0;
 static long objectCount = 0;
 static int userData = 0, allocationError = 0;
 
-static jvmtiEnv* st_jvmti = NULL;
+static jvmtiEnv* st_jvmti = nullptr;
 static const char* debugeeClassSignature = "Lnsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj002;";
 static const char* objectFieldName = "object";
 
@@ -108,28 +108,28 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         return;
 
     {
-        jclass debugeeClass = NULL;
-        jfieldID objectField = NULL;
-        jobject object = NULL;
+        jclass debugeeClass = nullptr;
+        jfieldID objectField = nullptr;
+        jobject object = nullptr;
 
         do {
             NSK_DISPLAY1("Find debugee class: %s\n", debugeeClassSignature);
             debugeeClass = nsk_jvmti_classBySignature(debugeeClassSignature);
-            if (debugeeClass == NULL) {
+            if (debugeeClass == nullptr) {
                 nsk_jvmti_setFailStatus();
                 break;
             }
 
             NSK_DISPLAY1("Find static field in debugee class: %s\n", objectFieldName);
             if (!NSK_JNI_VERIFY(jni, (objectField = jni->GetStaticFieldID(
-                    debugeeClass, objectFieldName, debugeeClassSignature)) != NULL)) {
+                    debugeeClass, objectFieldName, debugeeClassSignature)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 break;
             }
 
             NSK_DISPLAY1("Find value of static field in debugee class: %s\n", objectFieldName);
             if (!NSK_JNI_VERIFY(jni, (object =
-                    jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+                    jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 break;
             }
@@ -190,7 +190,7 @@ JNIEXPORT jint JNI_OnLoad_iterobjreachobj002(JavaVM *jvm, char *options, void *r
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -198,7 +198,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* save pointer to environment to use it in callbacks */
@@ -214,7 +214,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj003/iterobjreachobj003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj003/iterobjreachobj003.cpp
index 0bca38f4ada..0681864d99a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj003/iterobjreachobj003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj003/iterobjreachobj003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 
 static jlong timeout = 0;
 static int fakeUserData = 0, objCounter = 0;
-static jvmtiEnv* st_jvmti = NULL;
+static jvmtiEnv* st_jvmti = nullptr;
 static const char* debugeeClassSignature = "Lnsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj003;";
 static const char* objectFieldName = "object";
 
@@ -49,7 +49,7 @@ objectReferenceCallback(jvmtiObjectReferenceKind reference_kind,
                         void*  user_data) {
 
     const char* name = "monitorName";
-    jrawMonitorID monitor_ptr = NULL;
+    jrawMonitorID monitor_ptr = nullptr;
 
     objCounter++;
 
@@ -110,27 +110,27 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         return;
 
     do {
-        jclass debugeeClass = NULL;
-        jfieldID objectField = NULL;
-        jobject object = NULL;
+        jclass debugeeClass = nullptr;
+        jfieldID objectField = nullptr;
+        jobject object = nullptr;
 
         NSK_DISPLAY1("Find debugee class: %s\n", debugeeClassSignature);
         debugeeClass = nsk_jvmti_classBySignature(debugeeClassSignature);
-        if (debugeeClass == NULL) {
+        if (debugeeClass == nullptr) {
             nsk_jvmti_setFailStatus();
             break;
         }
 
         NSK_DISPLAY1("Find static field in debugee class: %s\n", objectFieldName);
         if (!NSK_JNI_VERIFY(jni, (objectField = jni->GetStaticFieldID(
-                debugeeClass, objectFieldName, debugeeClassSignature)) != NULL)) {
+                debugeeClass, objectFieldName, debugeeClassSignature)) != nullptr)) {
             nsk_jvmti_setFailStatus();
             break;
         }
 
         NSK_DISPLAY1("Find value of static field in debugee class: %s\n", objectFieldName);
         if (!NSK_JNI_VERIFY(jni, (object =
-                jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+                jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
             nsk_jvmti_setFailStatus();
             break;
         }
@@ -169,7 +169,7 @@ JNIEXPORT jint JNI_OnLoad_iterobjreachobj003(JavaVM *jvm, char *options, void *r
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -177,7 +177,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* save pointer to environment to use it in callbacks */
@@ -193,7 +193,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj004/iterobjreachobj004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj004/iterobjreachobj004.cpp
index d363e18c754..44ae2c3e327 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj004/iterobjreachobj004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj004/iterobjreachobj004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,9 +33,9 @@ extern "C" {
 
 static jlong timeout = 0;
 static int fakeUserData = 0, objCounter = 0;
-static jvmtiEnv* st_jvmti = NULL;
+static jvmtiEnv* st_jvmti = nullptr;
 static const char *storage_data = "local_storage_data";
-static void *storage_ptr = NULL;
+static void *storage_ptr = nullptr;
 static const char* debugeeClassSignature = "Lnsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj004;";
 static const char* objectFieldName = "object";
 
@@ -75,27 +75,27 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         return;
 
     do {
-        jclass debugeeClass = NULL;
-        jfieldID objectField = NULL;
-        jobject object = NULL;
+        jclass debugeeClass = nullptr;
+        jfieldID objectField = nullptr;
+        jobject object = nullptr;
 
         NSK_DISPLAY1("Find debugee class: %s\n", debugeeClassSignature);
         debugeeClass = nsk_jvmti_classBySignature(debugeeClassSignature);
-        if (debugeeClass == NULL) {
+        if (debugeeClass == nullptr) {
             nsk_jvmti_setFailStatus();
             break;
         }
 
         NSK_DISPLAY1("Find static field in debugee class: %s\n", objectFieldName);
         if (!NSK_JNI_VERIFY(jni, (objectField = jni->GetStaticFieldID(
-                debugeeClass, objectFieldName, debugeeClassSignature)) != NULL)) {
+                debugeeClass, objectFieldName, debugeeClassSignature)) != nullptr)) {
             nsk_jvmti_setFailStatus();
             break;
         }
 
         NSK_DISPLAY1("Find value of static field in debugee class: %s\n", objectFieldName);
         if (!NSK_JNI_VERIFY(jni, (object =
-                jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+                jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
             nsk_jvmti_setFailStatus();
             break;
         }
@@ -146,7 +146,7 @@ JNIEXPORT jint JNI_OnLoad_iterobjreachobj004(JavaVM *jvm, char *options, void *r
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -154,7 +154,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* save pointer to environment to use it in callbacks */
@@ -170,7 +170,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj005/iterobjreachobj005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj005/iterobjreachobj005.cpp
index cbba7ba2902..5da3d9fa52c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj005/iterobjreachobj005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverObjectsReachableFromObject/iterobjreachobj005/iterobjreachobj005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ extern "C" {
 /* ============================================================================= */
 
 static jlong timeout = 0;
-static jvmtiEnv* st_jvmti = NULL;
+static jvmtiEnv* st_jvmti = nullptr;
 static int *user_data = 0, objCounter = 0;
 static jlong nanos = 0;
 static jvmtiTimerInfo timer_info1, timer_info2;
@@ -115,27 +115,27 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     do {
         NSK_DISPLAY0("Calling IterateOverInstancesOfClass with filter JVMTI_HEAP_OBJECT_EITHER\n");
         {
-            jclass debugeeClass = NULL;
-            jfieldID objectField = NULL;
-            jobject object = NULL;
+            jclass debugeeClass = nullptr;
+            jfieldID objectField = nullptr;
+            jobject object = nullptr;
 
             NSK_DISPLAY1("Find debugee class: %s\n", debugeeClassSignature);
             debugeeClass = nsk_jvmti_classBySignature(debugeeClassSignature);
-            if (debugeeClass == NULL) {
+            if (debugeeClass == nullptr) {
                 nsk_jvmti_setFailStatus();
                 break;
             }
 
             NSK_DISPLAY1("Find static field in debugee class: %s\n", objectFieldName);
             if (!NSK_JNI_VERIFY(jni, (objectField = jni->GetStaticFieldID(
-                    debugeeClass, objectFieldName, debugeeClassSignature)) != NULL)) {
+                    debugeeClass, objectFieldName, debugeeClassSignature)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 break;
             }
 
             NSK_DISPLAY1("Find value of static field in debugee class: %s\n", objectFieldName);
             if (!NSK_JNI_VERIFY(jni, (object =
-                    jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+                    jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 break;
             }
@@ -175,7 +175,7 @@ JNIEXPORT jint JNI_OnLoad_iterobjreachobj005(JavaVM *jvm, char *options, void *r
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -183,7 +183,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* save pointer to environment to use it in callbacks */
@@ -200,7 +200,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj001/iterreachobj001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj001/iterreachobj001.cpp
index 9052297cacf..a30d854ee0d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj001/iterreachobj001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj001/iterreachobj001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -63,7 +63,7 @@ typedef struct ObjectDescStruct {
 static int chainLength = 0;
 static int objectsCount = 0;
 
-static ObjectDesc* objectDescList = NULL;
+static ObjectDesc* objectDescList = nullptr;
 
 static int fakeUserData = 0;
 static int userDataError = 0;
@@ -78,7 +78,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
                                     jlong tag, int reachable) {
 
     int success = NSK_TRUE;
-    jobject obj = NULL;
+    jobject obj = nullptr;
     jlong objTag = (reachable ? tag : -tag);
 
     if (count <= 0)
@@ -87,7 +87,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
     count--;
     tag++;
 
-    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetObjectField(firstObject, firstField)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetObjectField(firstObject, firstField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -112,16 +112,16 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
 /** Obtain all tested objects from debugee class and tag them recursively. */
 static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                     int *objectsCount, ObjectDesc* *objectDescList) {
-    jclass debugeeClass = NULL;
-    jclass rootObjectClass = NULL;
-    jclass chainObjectClass = NULL;
+    jclass debugeeClass = nullptr;
+    jclass rootObjectClass = nullptr;
+    jclass chainObjectClass = nullptr;
 
-    jfieldID objectField = NULL;
-    jfieldID reachableChainField = NULL;
-    jfieldID unreachableChainField = NULL;
-    jfieldID tailField = NULL;
+    jfieldID objectField = nullptr;
+    jfieldID reachableChainField = nullptr;
+    jfieldID unreachableChainField = nullptr;
+    jfieldID tailField = nullptr;
 
-    jobject rootObject = NULL;
+    jobject rootObject = nullptr;
 
     jlong rootObjectTag = 1;
     jlong chainObjectTag = 100;
@@ -145,14 +145,14 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
     }
 
     NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
     NSK_DISPLAY1("  ... found class: 0x%p\n", (void*)debugeeClass);
 
     NSK_DISPLAY1("Find root object class: %s\n", ROOT_OBJECT_CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (rootObjectClass = jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (rootObjectClass = jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -160,7 +160,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find chain object class: %s\n", CHAIN_OBJECT_CLASS_NAME);
     if (!NSK_JNI_VERIFY(jni, (chainObjectClass =
-            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -168,7 +168,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find static field in debugee class: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (objectField = jni->GetStaticFieldID(
-            debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != NULL)) {
+            debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -176,7 +176,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", REACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (reachableChainField = jni->GetFieldID(
-            rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -184,7 +184,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in root object class: %s\n", UNREACHABLE_CHAIN_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (unreachableChainField = jni->GetFieldID(
-            rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -192,7 +192,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Find instance field in chain object class: %s\n", TAIL_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (tailField =
-            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -200,7 +200,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     NSK_DISPLAY1("Get root object from static field: %s\n", OBJECT_FIELD_NAME);
     if (!NSK_JNI_VERIFY(jni, (rootObject =
-            jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+            jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -276,7 +276,7 @@ static int checkTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni,
 /** Release references to the tested objects and free allocated memory. */
 static int releaseTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                                         ObjectDesc* objectDescList) {
-    if (objectDescList != NULL) {
+    if (objectDescList != nullptr) {
         NSK_DISPLAY1("Deallocate objects list: 0x%p\n", (void*)objectDescList);
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)objectDescList))) {
             nsk_jvmti_setFailStatus();
@@ -297,11 +297,11 @@ heapRootCallback(jvmtiHeapRootKind root_kind,
     if (info & INFO_HEAPROOT) {
         NSK_DISPLAY4("  heapRootCallback: root_kind=%2d class_tag=%-3ld size=%-3ld *tag_ptr=%-5ld\n",
                         (int)root_kind, (long)class_tag, (long)size,
-                        (long)(tag_ptr == NULL ? (jlong)0 : *tag_ptr));
+                        (long)(tag_ptr == nullptr ? (jlong)0 : *tag_ptr));
     }
 
-    if (tag_ptr == NULL) {
-        NSK_COMPLAIN4("NULL tag_ptr is passed to heapRootCallback:\n"
+    if (tag_ptr == nullptr) {
+        NSK_COMPLAIN4("null tag_ptr is passed to heapRootCallback:\n"
                       "#   tag_ptr:        0x%p\n"
                       "#   root_kind:      %d\n"
                       "#   class_tag:      %ld\n"
@@ -313,7 +313,7 @@ heapRootCallback(jvmtiHeapRootKind root_kind,
         nsk_jvmti_setFailStatus();
     }
 
-    if (tag_ptr != NULL && *tag_ptr != 0) {
+    if (tag_ptr != nullptr && *tag_ptr != 0) {
         int found = 0;
         int i;
 
@@ -389,12 +389,12 @@ stackReferenceCallback(jvmtiHeapRootKind root_kind,
         NSK_DISPLAY8("  stackReferenceCallback: root_kind=%1d class_tag=%-3ld size=%-3ld"
                         " *tag_ptr=%-5ld thread_tag=%-3ld depth=%3d method=0x%p slot=%d\n",
                         (int)root_kind, (long)class_tag, (long)size,
-                        (long)(tag_ptr == NULL ? (jlong)0 : *tag_ptr),
+                        (long)(tag_ptr == nullptr ? (jlong)0 : *tag_ptr),
                         (long)thread_tag, (int)depth, (void*)method, (int)slot);
     }
 
-    if (tag_ptr == NULL) {
-        NSK_COMPLAIN8("NULL tag_ptr is passed to stackReferenceCallback:\n"
+    if (tag_ptr == nullptr) {
+        NSK_COMPLAIN8("null tag_ptr is passed to stackReferenceCallback:\n"
                       "#   tag_ptr:        0x%p\n"
                       "#   root_kind:      %d\n"
                       "#   class_tag:      %ld\n"
@@ -414,7 +414,7 @@ stackReferenceCallback(jvmtiHeapRootKind root_kind,
         nsk_jvmti_setFailStatus();
     }
 
-    if (tag_ptr != NULL && *tag_ptr != 0) {
+    if (tag_ptr != nullptr && *tag_ptr != 0) {
         int found = 0;
         int i;
 
@@ -514,12 +514,12 @@ objectReferenceCallback(jvmtiObjectReferenceKind reference_kind,
         NSK_DISPLAY6("  objectReferenceCallback: ref_kind=%1d class_tag=%-3ld size=%-3ld"
                         " *tag_ptr=%-5ld ref_tag=%-5ld ref_idx=%d\n",
                         (int)reference_kind, (long)class_tag, (long)size,
-                        (long)(tag_ptr == NULL ? (jlong)0 : *tag_ptr),
+                        (long)(tag_ptr == nullptr ? (jlong)0 : *tag_ptr),
                         (long)refferrer_tag, (int)refferrer_index);
     }
 
-    if (tag_ptr == NULL) {
-        NSK_COMPLAIN6("NULL tag_ptr is passed to objectReferenceCallback:\n"
+    if (tag_ptr == nullptr) {
+        NSK_COMPLAIN6("null tag_ptr is passed to objectReferenceCallback:\n"
                       "#   tag_ptr:        0x%p\n"
                       "#   reference_kind: %d\n"
                       "#   class_tag:      %ld\n"
@@ -535,7 +535,7 @@ objectReferenceCallback(jvmtiObjectReferenceKind reference_kind,
         nsk_jvmti_setFailStatus();
     }
 
-    if (tag_ptr != NULL && *tag_ptr != 0) {
+    if (tag_ptr != nullptr && *tag_ptr != 0) {
         int found = 0;
         int i;
 
@@ -670,7 +670,7 @@ JNIEXPORT jint JNI_OnLoad_iterreachobj001(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -679,7 +679,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     {
         const char* infoOpt = nsk_jvmti_findOptionValue("info");
-        if (infoOpt != NULL) {
+        if (infoOpt != nullptr) {
             if (strcmp(infoOpt, "none") == 0)
                 info = INFO_NONE;
             else if (strcmp(infoOpt, "all") == 0)
@@ -704,7 +704,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -717,7 +717,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj002/iterreachobj002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj002/iterreachobj002.cpp
index f732196a778..549a1f3370f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj002/iterreachobj002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj002/iterreachobj002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,8 +29,8 @@
 
 extern "C" {
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 static jlong timeout = 0;
@@ -446,7 +446,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -477,11 +477,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("enabling JVMTI events ...\n");
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_OBJECT_FREE,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done.\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj003/iterreachobj003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj003/iterreachobj003.cpp
index 2f8ba14ad66..296fddccb97 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj003/iterreachobj003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj003/iterreachobj003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,7 +35,7 @@ static jlong timeout = 0;
 
 static long objCounter = 0;
 static int userData = 0;
-static jvmtiEnv* st_jvmti = NULL;
+static jvmtiEnv* st_jvmti = nullptr;
 
 /* ============================================================================= */
 
@@ -50,7 +50,7 @@ heapRootCallback(jvmtiHeapRootKind root_kind,
                  jlong* tag_ptr,
                  void* user_data) {
 
-    jrawMonitorID monitor_ptr = NULL;
+    jrawMonitorID monitor_ptr = nullptr;
 
     *tag_ptr = (jlong)++objCounter;
 
@@ -114,7 +114,7 @@ stackReferenceCallback(jvmtiHeapRootKind root_kind,
                        jint      slot,
                        void*     user_data) {
 
-    jrawMonitorID monitor_ptr = NULL;
+    jrawMonitorID monitor_ptr = nullptr;
 
     *tag_ptr = (jlong)++objCounter;
 
@@ -177,7 +177,7 @@ objectReferenceCallback(jvmtiObjectReferenceKind reference_kind,
                         jint   referrer_index,
                         void*  user_data) {
 
-    jrawMonitorID monitor_ptr = NULL;
+    jrawMonitorID monitor_ptr = nullptr;
 
     *tag_ptr = (jlong)++objCounter;
 
@@ -285,7 +285,7 @@ JNIEXPORT jint JNI_OnLoad_iterreachobj003(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -293,7 +293,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* save pointer to environment to use it in callbacks */
@@ -309,7 +309,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj004/iterreachobj004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj004/iterreachobj004.cpp
index 6557dbf9d5b..b6299fc09cb 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj004/iterreachobj004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj004/iterreachobj004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,9 +35,9 @@ static jlong timeout = 0;
 
 static long objCounter = 0;
 static int userData = 0;
-static jvmtiEnv* st_jvmti = NULL;
+static jvmtiEnv* st_jvmti = nullptr;
 static const char *storage_data = "local_storage_data";
-static void *storage_ptr = NULL;
+static void *storage_ptr = nullptr;
 
 /* ============================================================================= */
 
@@ -226,7 +226,7 @@ JNIEXPORT jint JNI_OnLoad_iterreachobj004(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -234,7 +234,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* save pointer to environment to use it in callbacks */
@@ -250,7 +250,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj005/iterreachobj005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj005/iterreachobj005.cpp
index 27137426b19..b3a3a6fc288 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj005/iterreachobj005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateOverReachableObjects/iterreachobj005/iterreachobj005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,7 +35,7 @@ static jlong timeout = 0;
 
 static long objCounter = 0;
 static int userData = 0;
-static jvmtiEnv* st_jvmti = NULL;
+static jvmtiEnv* st_jvmti = nullptr;
 static jlong nanos = 0;
 static jvmtiTimerInfo timer_info1, timer_info2;
 
@@ -295,7 +295,7 @@ JNIEXPORT jint JNI_OnLoad_iterreachobj005(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -303,7 +303,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* save pointer to environment to use it in callbacks */
@@ -320,7 +320,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/abort/Abort.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/abort/Abort.cpp
index 9e1bd12bcc1..b019be65f49 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/abort/Abort.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/abort/Abort.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -81,7 +81,7 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
   int invocations = 0;
 
   NSK_DISPLAY0("Waiting debugee.\n");
-  if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL))) {
+  if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr))) {
     return;
   }
   if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout))) {
@@ -95,7 +95,7 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
   primitive_callbacks.heap_iteration_callback = &heap_callback;
 
   NSK_DISPLAY0("Iterating over reachable objects.\n");
-  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(0, NULL, &primitive_callbacks, &invocations))) {
+  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(0, nullptr, &primitive_callbacks, &invocations))) {
     nsk_jvmti_setFailStatus();
     return;
   }
@@ -127,7 +127,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jvmtiEventCallbacks event_callbacks;
 
   jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-  if (!NSK_VERIFY(jvmti != NULL)) {
+  if (!NSK_VERIFY(jvmti != nullptr)) {
     return JNI_ERR;
   }
 
@@ -148,7 +148,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agent, NULL))) {
+  if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agent, nullptr))) {
     return JNI_ERR;
   }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/callbacks/Callbacks.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/callbacks/Callbacks.cpp
index 315a07f38e2..b1438acceb0 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/callbacks/Callbacks.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/callbacks/Callbacks.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -368,13 +368,13 @@ int tag_objects(jvmtiEnv *jvmti, JNIEnv *jni) {
   jobjectArray testObjects;
   int object;
 
-  if (!NSK_VERIFY(NULL != (debugee = jni->FindClass(className))))
+  if (!NSK_VERIFY(nullptr != (debugee = jni->FindClass(className))))
     return JNI_ERR;
 
-  if (!NSK_VERIFY(NULL != (testObjectsField = jni->GetStaticFieldID(debugee, fieldName, fieldSig))))
+  if (!NSK_VERIFY(nullptr != (testObjectsField = jni->GetStaticFieldID(debugee, fieldName, fieldSig))))
     return JNI_ERR;
 
-  if (!NSK_VERIFY(NULL != (testObjects = (jobjectArray)(jni->GetStaticObjectField(
+  if (!NSK_VERIFY(nullptr != (testObjects = (jobjectArray)(jni->GetStaticObjectField(
           debugee, testObjectsField)))))
     return JNI_ERR;
 
@@ -386,13 +386,13 @@ int tag_objects(jvmtiEnv *jvmti, JNIEnv *jni) {
     jint field;
 
     memset(&objects_info[object],0,sizeof(object_info_t));
-    if (!NSK_VERIFY(NULL != (target = jni->GetObjectArrayElement(testObjects, object))))
+    if (!NSK_VERIFY(nullptr != (target = jni->GetObjectArrayElement(testObjects, object))))
       return JNI_ERR;
 
-    if (!NSK_VERIFY(NULL != (targetClass = jni->GetObjectClass(target))))
+    if (!NSK_VERIFY(nullptr != (targetClass = jni->GetObjectClass(target))))
       return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(targetClass, &(objects_info[object].name), NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(targetClass, &(objects_info[object].name), nullptr)))
       return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->GetClassFields(
@@ -407,7 +407,7 @@ int tag_objects(jvmtiEnv *jvmti, JNIEnv *jni) {
                                                 targetFields[field],
                                                 &objects_info[object].fields[field].name,
                                                 &objects_info[object].fields[field].signature,
-                                                NULL)))
+                                                nullptr)))
         return JNI_ERR;
       if (is_primitive_type(objects_info[object].fields[field].signature)) {
         objects_info[object].fields[field].primitive = 1;
@@ -420,12 +420,12 @@ int tag_objects(jvmtiEnv *jvmti, JNIEnv *jni) {
           return JNI_ERR;
         }
         if (modifiers & STATIC_FIELD) {
-          if (!NSK_VERIFY(NULL != (value = jni->GetStaticObjectField(targetClass,
+          if (!NSK_VERIFY(nullptr != (value = jni->GetStaticObjectField(targetClass,
                                                                      targetFields[field])))) {
             return JNI_ERR;
           }
         } else {
-          if (!NSK_VERIFY(NULL != (value = jni->GetObjectField(target, targetFields[field])))) {
+          if (!NSK_VERIFY(nullptr != (value = jni->GetObjectField(target, targetFields[field])))) {
             return JNI_ERR;
           }
         }
@@ -515,7 +515,7 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
   jvmtiHeapCallbacks primitive_callbacks;
 
   NSK_DISPLAY0("Waiting debugee.\n");
-  if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL))) {
+  if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr))) {
     return;
   }
   if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout))) {
@@ -534,7 +534,7 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
   primitive_callbacks.heap_iteration_callback = &heap_callback;
 
   NSK_DISPLAY0("Iterating over reachable objects.\n");
-  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(0, NULL, &primitive_callbacks, NULL))) {
+  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(0, nullptr, &primitive_callbacks, nullptr))) {
     nsk_jvmti_setFailStatus();
     return;
   }
@@ -551,7 +551,7 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
   }
 
   NSK_DISPLAY0("Iterating over unreachable objects.\n");
-  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(0, NULL, &primitive_callbacks, NULL))) {
+  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(0, nullptr, &primitive_callbacks, nullptr))) {
     nsk_jvmti_setFailStatus();
     return;
   }
@@ -559,7 +559,7 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
   NSK_DISPLAY0("Verifying that all filds were found.\n");
   verify_objects();
 
-  if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, NULL))) {
+  if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_DISABLE, 1, &event, nullptr))) {
     return;
   }
 
@@ -586,7 +586,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jvmtiEventCallbacks event_callbacks;
 
   jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-  if (!NSK_VERIFY(jvmti != NULL)) {
+  if (!NSK_VERIFY(jvmti != nullptr)) {
     return JNI_ERR;
   }
 
@@ -608,7 +608,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agent, NULL))) {
+  if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agent, nullptr))) {
     return JNI_ERR;
   }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/concrete-klass-filter/ConcreteKlassFilter.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/concrete-klass-filter/ConcreteKlassFilter.cpp
index 599f95bc479..1886e1cc3d6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/concrete-klass-filter/ConcreteKlassFilter.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/concrete-klass-filter/ConcreteKlassFilter.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -152,16 +152,16 @@ int tag_objects(jvmtiEnv *jvmti, JNIEnv *jni) {
   jobject testObject;
   jclass testObjectClass;
 
-  if (!NSK_VERIFY(NULL != (debugee = jni->FindClass(className))))
+  if (!NSK_VERIFY(nullptr != (debugee = jni->FindClass(className))))
     return JNI_ERR;
 
-  if (!NSK_VERIFY(NULL != (testObjectField = jni->GetStaticFieldID(debugee, fieldName, fieldSig))))
+  if (!NSK_VERIFY(nullptr != (testObjectField = jni->GetStaticFieldID(debugee, fieldName, fieldSig))))
     return JNI_ERR;
 
-  if (!NSK_VERIFY(NULL != (testObject = (jni->GetStaticObjectField(debugee, testObjectField)))))
+  if (!NSK_VERIFY(nullptr != (testObject = (jni->GetStaticObjectField(debugee, testObjectField)))))
     return JNI_ERR;
 
-  if (!NSK_VERIFY(NULL != (testObjectClass = (jni->GetObjectClass(testObject)))))
+  if (!NSK_VERIFY(nullptr != (testObjectClass = (jni->GetObjectClass(testObject)))))
     return JNI_ERR;
 
   // tag class and it's instance to pass this tag into primitive field callback
@@ -197,14 +197,14 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
   jvmtiHeapCallbacks primitive_callbacks;
   jclass klass;
 
-  if (!NSK_VERIFY(NULL != (klass = jni->FindClass(testClassName)))) {
+  if (!NSK_VERIFY(nullptr != (klass = jni->FindClass(testClassName)))) {
     NSK_COMPLAIN1("Can't find class %s.\n",testClassName);
     nsk_jvmti_setFailStatus();
     return;
   }
 
   NSK_DISPLAY0("Waiting debugee.\n");
-  if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL))) {
+  if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr))) {
     return;
   }
   if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout))) {
@@ -223,7 +223,7 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
   primitive_callbacks.heap_iteration_callback = &heap_callback;
 
   NSK_DISPLAY0("Iterating over reachable objects.\n");
-  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(0, klass, &primitive_callbacks, NULL))) {
+  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(0, klass, &primitive_callbacks, nullptr))) {
     nsk_jvmti_setFailStatus();
     return;
   }
@@ -240,7 +240,7 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
   }
 
   NSK_DISPLAY0("Iterating over unreachable objects.\n");
-  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(0, klass, &primitive_callbacks, NULL))) {
+  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(0, klass, &primitive_callbacks, nullptr))) {
     nsk_jvmti_setFailStatus();
     return;
   }
@@ -269,7 +269,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jvmtiEventCallbacks event_callbacks;
 
   jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-  if (!NSK_VERIFY(jvmti != NULL)) {
+  if (!NSK_VERIFY(jvmti != nullptr)) {
     return JNI_ERR;
   }
 
@@ -291,7 +291,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agent, NULL))) {
+  if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agent, nullptr))) {
     return JNI_ERR;
   }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/filter-tagged/HeapFilter.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/filter-tagged/HeapFilter.cpp
index 983aa4a122d..ea3ad39b92a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/filter-tagged/HeapFilter.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/filter-tagged/HeapFilter.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -294,13 +294,13 @@ int tag_objects(jvmtiEnv *jvmti, JNIEnv *jni) {
   jobjectArray testObjects;
   int object;
 
-  if (!NSK_VERIFY(NULL != (debugee = jni->FindClass(className))))
+  if (!NSK_VERIFY(nullptr != (debugee = jni->FindClass(className))))
     return JNI_ERR;
 
-  if (!NSK_VERIFY(NULL != (testObjectsField = jni->GetStaticFieldID(debugee, fieldName, fieldSig))))
+  if (!NSK_VERIFY(nullptr != (testObjectsField = jni->GetStaticFieldID(debugee, fieldName, fieldSig))))
     return JNI_ERR;
 
-  if (!NSK_VERIFY(NULL != (testObjects = (jobjectArray)(jni->GetStaticObjectField(
+  if (!NSK_VERIFY(nullptr != (testObjects = (jobjectArray)(jni->GetStaticObjectField(
           debugee, testObjectsField)))))
     return JNI_ERR;
 
@@ -313,13 +313,13 @@ int tag_objects(jvmtiEnv *jvmti, JNIEnv *jni) {
     int tagged = object == 0;
 
     memset(&objects_info[object],0,sizeof(object_info_t));
-    if (!NSK_VERIFY(NULL != (target = jni->GetObjectArrayElement(testObjects, object))))
+    if (!NSK_VERIFY(nullptr != (target = jni->GetObjectArrayElement(testObjects, object))))
       return JNI_ERR;
 
-    if (!NSK_VERIFY(NULL != (targetClass = jni->GetObjectClass(target))))
+    if (!NSK_VERIFY(nullptr != (targetClass = jni->GetObjectClass(target))))
       return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(targetClass, &(objects_info[object].name), NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(targetClass, &(objects_info[object].name), nullptr)))
       return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->GetClassFields(
@@ -337,7 +337,7 @@ int tag_objects(jvmtiEnv *jvmti, JNIEnv *jni) {
                                                 targetFields[field],
                                                 &objects_info[object].fields[field].name,
                                                 &objects_info[object].fields[field].signature,
-                                                NULL)))
+                                                nullptr)))
         return JNI_ERR;
       if (!NSK_JVMTI_VERIFY(jvmti->GetFieldModifiers(
               targetClass, targetFields[field], &modifiers))) {
@@ -362,12 +362,12 @@ int tag_objects(jvmtiEnv *jvmti, JNIEnv *jni) {
           return JNI_ERR;
         }
         if (is_static) {
-          if (!NSK_VERIFY(NULL != (value = jni->GetStaticObjectField(
+          if (!NSK_VERIFY(nullptr != (value = jni->GetStaticObjectField(
                   targetClass, targetFields[field])))) {
             return JNI_ERR;
           }
         } else {
-          if (!NSK_VERIFY(NULL != (value = jni->GetObjectField(target, targetFields[field])))) {
+          if (!NSK_VERIFY(nullptr != (value = jni->GetObjectField(target, targetFields[field])))) {
             return JNI_ERR;
           }
         }
@@ -456,7 +456,7 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
   jvmtiEventCallbacks event_callbacks;
 
   NSK_DISPLAY0("Waiting debugee.\n");
-  if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL))) {
+  if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr))) {
     return;
   }
   if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout))) {
@@ -475,7 +475,7 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
   primitive_callbacks.heap_iteration_callback = &heap_callback;
 
   NSK_DISPLAY0("Iterating over reachable objects.\n");
-  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(filter_type, NULL, &primitive_callbacks, NULL))) {
+  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(filter_type, nullptr, &primitive_callbacks, nullptr))) {
     nsk_jvmti_setFailStatus();
     return;
   }
@@ -492,7 +492,7 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
   }
 
   NSK_DISPLAY0("Iterating over unreachable objects.\n");
-  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(filter_type, NULL, &primitive_callbacks, NULL))) {
+  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(filter_type, nullptr, &primitive_callbacks, nullptr))) {
     nsk_jvmti_setFailStatus();
     return;
   }
@@ -533,14 +533,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   const char *type;
 
   jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-  if (!NSK_VERIFY(jvmti != NULL)) {
+  if (!NSK_VERIFY(jvmti != nullptr)) {
     return JNI_ERR;
   }
 
   nsk_jvmti_parseOptions(options);
 
   type = nsk_jvmti_findOptionValue("filter");
-  if (type != NULL) {
+  if (type != nullptr) {
     if (0 == strcmp(type, "JVMTI_HEAP_FILTER_TAGGED")) {
       filter_type = JVMTI_HEAP_FILTER_TAGGED;
     } else if (0 == strcmp(type, "JVMTI_HEAP_FILTER_UNTAGGED")) {
@@ -574,7 +574,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agent, NULL))) {
+  if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agent, nullptr))) {
     return JNI_ERR;
   }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/non-concrete-klass-filter/NonConcreteKlassFilter.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/non-concrete-klass-filter/NonConcreteKlassFilter.cpp
index b0617bce297..20515df1b86 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/non-concrete-klass-filter/NonConcreteKlassFilter.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/IterateThroughHeap/non-concrete-klass-filter/NonConcreteKlassFilter.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -141,7 +141,7 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
   int i;
 
   NSK_DISPLAY0("Waiting debugee.\n");
-  if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, NULL))) {
+  if (!NSK_VERIFY(nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, &event, nullptr))) {
     return;
   }
   if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout))) {
@@ -156,13 +156,13 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
   phase = ZERO_INVOCATIONS_PHASE;
   for (i = 0; i < FILTER_COUNT; i++) {
-    if (!NSK_VERIFY(NULL != (klass = jni->FindClass(types[i])))) {
+    if (!NSK_VERIFY(nullptr != (klass = jni->FindClass(types[i])))) {
       NSK_COMPLAIN1("Can't find class %s.\n",types[i]);
       nsk_jvmti_setFailStatus();
       return;
     }
     NSK_DISPLAY1("Iterating through heap with klass-filter '%s'.\n",types[i]);
-    if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(0, klass, &primitive_callbacks, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(0, klass, &primitive_callbacks, nullptr))) {
       nsk_jvmti_setFailStatus();
       return;
     }
@@ -170,12 +170,12 @@ agent(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
   phase = STATIC_FIELDS_FINDING_PHASE;
   NSK_DISPLAY0("Iterating through heap with klass-filter 'java/lang/Class'.\n");
-  if (!NSK_VERIFY(NULL != (klass = jni->FindClass("java/lang/Class")))) {
+  if (!NSK_VERIFY(nullptr != (klass = jni->FindClass("java/lang/Class")))) {
     NSK_COMPLAIN0("Can't find class java/lang/Class.\n");
     nsk_jvmti_setFailStatus();
     return;
   }
-  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(0, klass, &primitive_callbacks, NULL))) {
+  if (!NSK_JVMTI_VERIFY(jvmti->IterateThroughHeap(0, klass, &primitive_callbacks, nullptr))) {
     nsk_jvmti_setFailStatus();
     return;
   }
@@ -209,7 +209,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jvmtiEventCallbacks event_callbacks;
 
   jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-  if (!NSK_VERIFY(jvmti != NULL)) {
+  if (!NSK_VERIFY(jvmti != nullptr)) {
     return JNI_ERR;
   }
 
@@ -230,7 +230,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     return JNI_ERR;
   }
 
-  if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agent, NULL))) {
+  if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agent, nullptr))) {
     return JNI_ERR;
   }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/NotifyFramePop/nframepop001/nframepop001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/NotifyFramePop/nframepop001/nframepop001.cpp
index 31e569a39aa..50f52d7c0cf 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/NotifyFramePop/nframepop001/nframepop001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/NotifyFramePop/nframepop001/nframepop001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,15 +33,15 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jmethodID mid1, mid2;
 
-static jthread currThread = NULL, popThread = NULL;
-static jclass currClass = NULL, popClass = NULL;
-static jmethodID currMethod = NULL, popMethod = NULL;
+static jthread currThread = nullptr, popThread = nullptr;
+static jclass currClass = nullptr, popClass = nullptr;
+static jmethodID currMethod = nullptr, popMethod = nullptr;
 static jboolean currFlag = JNI_FALSE, popFlag = JNI_FALSE;
 static jint currLoc = 0, popLoc = 0;
 
@@ -133,7 +133,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -190,7 +190,7 @@ Java_nsk_jvmti_NotifyFramePop_nframepop001_getMethIds(JNIEnv *env, jclass cl) {
 
     if (caps.can_generate_frame_pop_events) {
         err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_FRAME_POP, NULL);
+            JVMTI_EVENT_FRAME_POP, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to enable FRAME_POP event: %s (%d)\n",
                    TranslateError(err), err);
@@ -200,14 +200,14 @@ Java_nsk_jvmti_NotifyFramePop_nframepop001_getMethIds(JNIEnv *env, jclass cl) {
     }
 
     mid1 = env->GetMethodID(cl, "meth01", "(I)V");
-    if (mid1 == NULL) {
+    if (mid1 == nullptr) {
         printf("Cannot find method \"meth01\"\n");
         result = STATUS_FAILED;
         return;
     }
 
     mid2 = env->GetMethodID(cl, "meth02", "(I)V");
-    if (mid2 == NULL) {
+    if (mid2 == nullptr) {
         printf("Cannot find method \"meth02\"\n");
         result = STATUS_FAILED;
         return;
@@ -215,7 +215,7 @@ Java_nsk_jvmti_NotifyFramePop_nframepop001_getMethIds(JNIEnv *env, jclass cl) {
 
     if (caps.can_generate_exception_events) {
         err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_EXCEPTION_CATCH, NULL);
+            JVMTI_EVENT_EXCEPTION_CATCH, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to enable EXCEPTION_CATCH event: %s (%d)\n",
                    TranslateError(err), err);
@@ -245,7 +245,7 @@ Java_nsk_jvmti_NotifyFramePop_nframepop001_setFramePopNotif(JNIEnv *env,
     currThread = env->NewGlobalRef(thr);
 
     currClass = env->FindClass("nsk/jvmti/NotifyFramePop/nframepop001a");
-    if (currClass == NULL) {
+    if (currClass == nullptr) {
         printf("Cannot find nsk.jvmti.NotifyFramePop.nframepop001a class!\n");
         result = STATUS_FAILED;
         return;
@@ -253,7 +253,7 @@ Java_nsk_jvmti_NotifyFramePop_nframepop001_setFramePopNotif(JNIEnv *env,
     currClass = (jclass) env->NewGlobalRef(currClass);
 
     currMethod = env->GetMethodID(currClass, "run", "()V");
-    if (currMethod == NULL) {
+    if (currMethod == nullptr) {
         printf("Cannot find method \"run\"\n");
         result = STATUS_FAILED;
     }
@@ -319,9 +319,9 @@ Java_nsk_jvmti_NotifyFramePop_nframepop001_checkFrame(JNIEnv *env,
         result = STATUS_FAILED;
     }
 
-    currThread = NULL; popThread = NULL;
-    currClass = NULL; popClass = NULL;
-    currMethod = NULL; popMethod = NULL;
+    currThread = nullptr; popThread = nullptr;
+    currClass = nullptr; popClass = nullptr;
+    currMethod = nullptr; popMethod = nullptr;
     currFlag = JNI_FALSE; popFlag = JNI_FALSE;
     currLoc = 0; popLoc = 0;
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/NotifyFramePop/nframepop002/nframepop002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/NotifyFramePop/nframepop002/nframepop002.cpp
index 8faa9177cb5..09f6da40b33 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/NotifyFramePop/nframepop002/nframepop002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/NotifyFramePop/nframepop002/nframepop002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 
@@ -53,7 +53,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -91,7 +91,7 @@ Java_nsk_jvmti_NotifyFramePop_nframepop002_check(JNIEnv *env,
         jclass cls, jthread thread) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/NotifyFramePop/nframepop003/nframepop003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/NotifyFramePop/nframepop003/nframepop003.cpp
index 201a7cd26b9..325eb23f3b9 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/NotifyFramePop/nframepop003/nframepop003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/NotifyFramePop/nframepop003/nframepop003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 
@@ -53,7 +53,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -91,7 +91,7 @@ Java_nsk_jvmti_NotifyFramePop_nframepop003_check(JNIEnv *env,
         jclass cls, jthread thread) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ObjectFree/objfree001/objfree001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ObjectFree/objfree001/objfree001.cpp
index 2a14eee0629..b81c2c9a43e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ObjectFree/objfree001/objfree001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ObjectFree/objfree001/objfree001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@ extern "C" {
 static const char *CLASS_SIG =
     "Lnsk/jvmti/ObjectFree/objfree001u;";
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 
 static volatile jint result = PASSED;
@@ -131,7 +131,7 @@ static void memoryFunc(jvmtiEnv *jvmti_env, const char *msg) {
 }
 
 static void envStorageFunc(jvmtiEnv *jvmti_env, const char *msg) {
-    LocalStorage* obtainedData = NULL;
+    LocalStorage* obtainedData = nullptr;
     LocalStorage* storedData = &stor;
 
     NSK_DISPLAY2("%s: setting an environment local storage 0x%p ...\n",
@@ -253,7 +253,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capability to generate compiled method events */
@@ -282,11 +282,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("setting event callbacks done\nenabling JVMTI events ...\n");
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_VM_DEATH,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_OBJECT_FREE,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ObjectFree/objfree002/objfree002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ObjectFree/objfree002/objfree002.cpp
index 7e1be9da537..c3fc8621feb 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ObjectFree/objfree002/objfree002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ObjectFree/objfree002/objfree002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,7 +39,7 @@ extern "C" {
 
 #define MEM_SIZE 1024
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -161,7 +161,7 @@ static void memoryFunc(jvmtiEnv *jvmti_env, const char *msg) {
 }
 
 static void envStorageFunc(jvmtiEnv *jvmti_env, const char *msg) {
-    LocalStorage* obtainedData = NULL;
+    LocalStorage* obtainedData = nullptr;
     LocalStorage* storedData = &stor;
 
     NSK_DISPLAY2("%s: setting an environment local storage 0x%p ...\n",
@@ -273,7 +273,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capability to generate compiled method events */
@@ -302,11 +302,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("setting event callbacks done\nenabling JVMTI events ...\n");
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_VM_DEATH,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_OBJECT_FREE,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe001/popframe001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe001/popframe001.cpp
index 4d3332c2079..661219e3174 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe001/popframe001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe001/popframe001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define PASSED 0
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static int watch_ev = 0;        /* ignore JVMTI events by default */
@@ -175,7 +175,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe002/popframe002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe002/popframe002.cpp
index 429af71866a..6be72a9ee18 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe002/popframe002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe002/popframe002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -102,12 +102,12 @@ Java_nsk_jvmti_PopFrame_popframe002_doPopFrame(JNIEnv *env,
     }
 
     switch (t_case) {
-    /* NULL pointer to the thread*/
+    /* nullptr pointer to the thread*/
     case 1:
-        printf("\nInvoke PopFrame() with NULL pointer to a thread...\n");
+        printf("\nInvoke PopFrame() with null pointer to a thread...\n");
         fflush(stdout);
         set_watch_ev(1); /* watch JVMTI events */
-        err = (jvmti->PopFrame(NULL)); /* explode the bomb */
+        err = (jvmti->PopFrame(nullptr)); /* explode the bomb */
         if (err != JVMTI_ERROR_INVALID_THREAD) {
             printf("TEST FAILED: the function PopFrame() returned the error %d: %s\n",
                 err, TranslateError(err));
@@ -193,7 +193,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe003/popframe003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe003/popframe003.cpp
index f956c01f3aa..958d14a52c2 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe003/popframe003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe003/popframe003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -177,7 +177,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe004/popframe004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe004/popframe004.cpp
index 3c8f1743d0d..46457aced4d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe004/popframe004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe004/popframe004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -219,7 +219,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -286,10 +286,10 @@ Java_nsk_jvmti_PopFrame_popframe004_getResult(JNIEnv *env, jclass cls) {
 
 void nativeMeth2(JNIEnv *env, jobject obj, jobject frameThr) {
     jclass cls = env->GetObjectClass(frameThr);
-    jmethodID mid = NULL;
+    jmethodID mid = nullptr;
 
     mid = env->GetMethodID(cls, "activeMethod", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("TEST FAILURE: nativeMeth2(): Unable to get method ID\n");
         tot_result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe005/popframe005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe005/popframe005.cpp
index ca918df7575..089c4dd5514 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe005/popframe005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe005/popframe005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ extern "C" {
 
 // Deallocate memory region allocated by VM
 #define DEALLOCATE(p) \
-    if (p != NULL)                 \
+    if (p != nullptr)                 \
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate(p)))        \
         {                          \
             NSK_COMPLAIN0("Failed to deallocate: ##p##\n"); \
@@ -106,12 +106,12 @@ MethodExit(
                 break;
             }
 
-            if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(klass, &class_signature, NULL)))
+            if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(klass, &class_signature, nullptr)))
             {
                 break;
             }
 
-            if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(method, &entry_name, &entry_sig, NULL)))
+            if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(method, &entry_name, &entry_sig, nullptr)))
             {
                 break;
             }
@@ -119,7 +119,7 @@ MethodExit(
             failure = 0;
             NSK_COMPLAIN5("#### MethodExit event occurred: (tid: %d), thread: %s, %s %s %s\n"
                     , thread
-                    , thr_info.name == NULL ? "<Unnamed>" : thr_info.name
+                    , thr_info.name == nullptr ? "<Unnamed>" : thr_info.name
                     , class_signature
                     , entry_name
                     , entry_sig
@@ -254,7 +254,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
     }
 
     if (!NSK_VERIFY(
-            (jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != NULL
+            (jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != nullptr
             ))
     {
         return JNI_ERR;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe006/popframe006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe006/popframe006.cpp
index 2c288f29d94..324160b40d7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe006/popframe006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe006/popframe006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ typedef struct {
     jlocation loc;
 } check_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
@@ -109,17 +109,17 @@ void check(jvmtiEnv *jvmti_env, jmethodID mid, jlocation loc, int i) {
         return;
     }
 
-    if (sigClass == NULL || strcmp(sigClass, checks[i].cls) != 0) {
+    if (sigClass == nullptr || strcmp(sigClass, checks[i].cls) != 0) {
         printf("(%s, %d) wrong class sig: \"%s\",\n", note, i, sigClass);
         printf(" expected: \"%s\"\n", checks[i].cls);
         result = STATUS_FAILED;
     }
-    if (name == NULL || strcmp(name, checks[i].name) != 0) {
+    if (name == nullptr || strcmp(name, checks[i].name) != 0) {
         printf("(%s, %d) wrong method name: \"%s\",", note, i, name);
         printf(" expected: \"%s\"\n", checks[i].name);
         result = STATUS_FAILED;
     }
-    if (sig == NULL || strcmp(sig, checks[i].sig) != 0) {
+    if (sig == nullptr || strcmp(sig, checks[i].sig) != 0) {
         printf("(%s, %d) wrong method sig: \"%s\",", note, i, sig);
         printf(" expected: \"%s\"\n", checks[i].sig);
         result = STATUS_FAILED;
@@ -349,12 +349,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -409,7 +409,7 @@ Java_nsk_jvmti_PopFrame_popframe006_getReady(JNIEnv *env,
     jvmtiError err;
     jclass clazz;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -424,35 +424,35 @@ Java_nsk_jvmti_PopFrame_popframe006_getReady(JNIEnv *env,
     }
 
     clazz = env->GetObjectClass(thr);
-    if (clazz == NULL) {
+    if (clazz == nullptr) {
         printf("Cannot get the class of thread object\n");
         result = STATUS_FAILED;
         return;
     }
 
     mid_run = env->GetMethodID(clazz, "run", "()V");
-    if (mid_run == NULL) {
+    if (mid_run == nullptr) {
         printf("Cannot find Method ID for method \"run\"\n");
         result = STATUS_FAILED;
         return;
     }
 
     mid_A = env->GetStaticMethodID(clazz, "A", "()V");
-    if (mid_A == NULL) {
+    if (mid_A == nullptr) {
         printf("Cannot find Method ID for method \"A\"\n");
         result = STATUS_FAILED;
         return;
     }
 
     mid_B = env->GetStaticMethodID(clazz, "B", "()V");
-    if (mid_B == NULL) {
+    if (mid_B == nullptr) {
         printf("Cannot find Method ID for method \"B\"\n");
         result = STATUS_FAILED;
         return;
     }
 
     mid_C = env->GetStaticMethodID(clazz, "C", "()V");
-    if (mid_C == NULL) {
+    if (mid_C == nullptr) {
         printf("Cannot find Method ID for method \"C\"\n");
         result = STATUS_FAILED;
         return;
@@ -467,7 +467,7 @@ Java_nsk_jvmti_PopFrame_popframe006_getReady(JNIEnv *env,
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
@@ -481,7 +481,7 @@ Java_nsk_jvmti_PopFrame_popframe006_getReady(JNIEnv *env,
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_FRAME_POP, NULL);
+        JVMTI_EVENT_FRAME_POP, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable FRAME_POP event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe007/popframe007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe007/popframe007.cpp
index ca4b9004595..db699216695 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe007/popframe007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe007/popframe007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
@@ -86,12 +86,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -142,7 +142,7 @@ Java_nsk_jvmti_PopFrame_popframe007_getReady(JNIEnv *env,
     jvmtiError err;
     jclass clazz;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -153,14 +153,14 @@ Java_nsk_jvmti_PopFrame_popframe007_getReady(JNIEnv *env,
     }
 
     clazz = env->GetObjectClass(thr);
-    if (clazz == NULL) {
+    if (clazz == nullptr) {
         printf("Cannot get class of the thread object\n");
         result = STATUS_FAILED;
         return;
     }
 
     mid = env->GetStaticMethodID(clazz, "C", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find Method ID for method \"C\"\n");
         result = STATUS_FAILED;
         return;
@@ -175,7 +175,7 @@ Java_nsk_jvmti_PopFrame_popframe007_getReady(JNIEnv *env,
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
@@ -190,7 +190,7 @@ Java_nsk_jvmti_PopFrame_popframe007_getRes(JNIEnv *env, jclass cls) {
 
 JNIEXPORT void JNICALL
 Java_nsk_jvmti_PopFrame_popframe007_B(JNIEnv *env, jclass cls) {
-    if (mid != NULL) {
+    if (mid != nullptr) {
         env->CallStaticVoidMethod(cls, mid);
     }
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe008/popframe008.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe008/popframe008.cpp
index 8c669c20318..430f19624d0 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe008/popframe008.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe008/popframe008.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,13 +40,13 @@ typedef struct {
     jlocation loc;
 } frame_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
-static jmethodID midD = NULL;
-static jmethodID midRun = NULL;
+static jmethodID midD = nullptr;
+static jmethodID midRun = nullptr;
 static int framesExpected = 0;
 static int framesCount = 0;
 static frame_info frames[] = {
@@ -83,17 +83,17 @@ void check(jvmtiEnv *jvmti_env, jmethodID mid, jlocation loc, int i) {
         result = STATUS_FAILED;
     }
 
-    if (sigClass == NULL || strcmp(sigClass, frames[i].cls) != 0) {
+    if (sigClass == nullptr || strcmp(sigClass, frames[i].cls) != 0) {
         printf("(%d) wrong class sig: \"%s\",\n", i, sigClass);
         printf(" expected: \"%s\"\n", frames[i].cls);
         result = STATUS_FAILED;
     }
-    if (name == NULL || strcmp(name, frames[i].name) != 0) {
+    if (name == nullptr || strcmp(name, frames[i].name) != 0) {
         printf("(%d) wrong method name: \"%s\",", i, name);
         printf(" expected: \"%s\"\n", frames[i].name);
         result = STATUS_FAILED;
     }
-    if (sig == NULL || strcmp(sig, frames[i].sig) != 0) {
+    if (sig == nullptr || strcmp(sig, frames[i].sig) != 0) {
         printf("(%d) wrong method sig: \"%s\",", i, sig);
         printf(" expected: \"%s\"\n", frames[i].sig);
         result = STATUS_FAILED;
@@ -195,12 +195,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -253,7 +253,7 @@ Java_nsk_jvmti_PopFrame_popframe008_getReady(JNIEnv *env,
     jvmtiError err;
     jclass clazz;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -266,21 +266,21 @@ Java_nsk_jvmti_PopFrame_popframe008_getReady(JNIEnv *env,
     }
 
     clazz = env->GetObjectClass(thr);
-    if (clazz == NULL) {
+    if (clazz == nullptr) {
         printf("Cannot get class of the thread object\n");
         result = STATUS_FAILED;
         return;
     }
 
     midD = env->GetMethodID(clazz, "D", "()V");
-    if (midD == NULL) {
+    if (midD == nullptr) {
         printf("Cannot get Method ID for method \"D\"\n");
         result = STATUS_FAILED;
         return;
     }
 
     midRun = env->GetMethodID(clazz, "run", "()V");
-    if (midRun == NULL) {
+    if (midRun == nullptr) {
         printf("Cannot get Method ID for method \"run\"\n");
         result = STATUS_FAILED;
         return;
@@ -295,7 +295,7 @@ Java_nsk_jvmti_PopFrame_popframe008_getReady(JNIEnv *env,
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe009/popframe009.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe009/popframe009.cpp
index 2e72d3858b3..c15146e660f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe009/popframe009.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe009/popframe009.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,17 +34,17 @@ extern "C" {
 #define STATUS_FAILED 2
 #define WAIT_FOREVER ((jlong)(3600*1000))
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
-static jrawMonitorID breakpointLock = NULL;
-static jrawMonitorID popFrameLock = NULL;
-static jrawMonitorID suspendLock = NULL;
+static jrawMonitorID breakpointLock = nullptr;
+static jrawMonitorID popFrameLock = nullptr;
+static jrawMonitorID suspendLock = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static jboolean popDone = JNI_FALSE;
-static jmethodID midCheckPoint = NULL;
-static jmethodID midRun = NULL;
+static jmethodID midCheckPoint = nullptr;
+static jmethodID midRun = nullptr;
 static int bpCount = 0;
 static int framesCount = 0;
 
@@ -165,12 +165,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -225,7 +225,7 @@ JNIEXPORT void JNICALL
 Java_nsk_jvmti_PopFrame_popframe009_getReady(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -238,7 +238,7 @@ Java_nsk_jvmti_PopFrame_popframe009_getReady(JNIEnv *env, jclass cls) {
     }
 
     midCheckPoint = env->GetStaticMethodID(cls, "checkPoint", "()V");
-    if (midCheckPoint == NULL) {
+    if (midCheckPoint == nullptr) {
         printf("Cannot find Method ID for method checkPoint\n");
         result = STATUS_FAILED;
         return;
@@ -261,7 +261,7 @@ Java_nsk_jvmti_PopFrame_popframe009_getReady(JNIEnv *env, jclass cls) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
@@ -331,14 +331,14 @@ Java_nsk_jvmti_PopFrame_popframe009_check(JNIEnv *env, jclass cls, jthread thr)
     jvmtiError err;
     jmethodID midFibonacci;
     jclass clazz;
-    jmethodID method = NULL;
+    jmethodID method = nullptr;
     jlocation loc;
     char *name, *sig, *generic;
     jlong delayTime = 1;
     int popCount = 0;
     int i;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -412,19 +412,19 @@ Java_nsk_jvmti_PopFrame_popframe009_check(JNIEnv *env, jclass cls, jthread thr)
     }
 
     midFibonacci = env->GetStaticMethodID(cls, "fibonacci", "(I)I");
-    if (midFibonacci == NULL) {
+    if (midFibonacci == nullptr) {
         printf("Cannot get method ID for method \"fibonacci\"\n");
         result = STATUS_FAILED;
     }
 
     clazz = env->GetObjectClass(thr);
-    if (clazz == NULL) {
+    if (clazz == nullptr) {
         printf("Cannot get class of thread object\n");
         return STATUS_FAILED;
     }
 
     midRun = env->GetMethodID(clazz, "run", "()V");
-    if (midRun == NULL) {
+    if (midRun == nullptr) {
         printf("Cannot get method ID for \"run\"\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe010/popframe010.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe010/popframe010.cpp
index c0b3f8924fd..68e0aa7c7bd 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe010/popframe010.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe010/popframe010.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,13 +33,13 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
-static jmethodID midCheckPoint = NULL;
-static jmethodID midRun = NULL;
+static jmethodID midCheckPoint = nullptr;
+static jmethodID midRun = nullptr;
 static jint framesExpected = 0;
 static jint framesCount = 0;
 static const char *cls_exp = "Lnsk/jvmti/PopFrame/popframe010$TestThread;";
@@ -52,7 +52,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid, jlocation loc, jint
     jclass cls;
     jlocation loc_exp = (i == 0) ? 15 : 8;
     char *sigClass, *name, *sig, *generic;
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLocalVariableEntry *table = nullptr;
     jint entryCount = 0;
     jint argValue;
     jint j;
@@ -85,7 +85,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid, jlocation loc, jint
                i, TranslateError(err), err);
         result = STATUS_FAILED;
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             if (strcmp(table[j].name, argName) == 0) {
                 err = jvmti_env->GetLocalInt(thr, 0,
@@ -105,17 +105,17 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid, jlocation loc, jint
         printf(", arg value: %d\n", argValue);
     }
 
-    if (sigClass == NULL || strcmp(sigClass, cls_exp) != 0) {
+    if (sigClass == nullptr || strcmp(sigClass, cls_exp) != 0) {
         printf("(step %d) wrong class sig: \"%s\",\n", i, sigClass);
         printf(" expected: \"%s\"\n", cls_exp);
         result = STATUS_FAILED;
     }
-    if (name == NULL || strcmp(name, name_exp) != 0) {
+    if (name == nullptr || strcmp(name, name_exp) != 0) {
         printf("(step %d) wrong method name: \"%s\",", i, name);
         printf(" expected: \"%s\"\n", name_exp);
         result = STATUS_FAILED;
     }
-    if (sig == NULL || strcmp(sig, sig_exp) != 0) {
+    if (sig == nullptr || strcmp(sig, sig_exp) != 0) {
         printf("(step %d) wrong method sig: \"%s\",", i, sig);
         printf(" expected: \"%s\"\n", sig_exp);
         result = STATUS_FAILED;
@@ -132,16 +132,16 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid, jlocation loc, jint
         result = STATUS_FAILED;
     }
 
-    if (sigClass != NULL) {
+    if (sigClass != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sigClass);
     }
-    if (name != NULL) {
+    if (name != nullptr) {
         jvmti_env->Deallocate((unsigned char*)name);
     }
-    if (sig != NULL) {
+    if (sig != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sig);
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             jvmti_env->Deallocate((unsigned char*)(table[j].name));
             jvmti_env->Deallocate((unsigned char*)(table[j].signature));
@@ -232,12 +232,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -288,7 +288,7 @@ JNIEXPORT void JNICALL
 Java_nsk_jvmti_PopFrame_popframe010_getReady(JNIEnv *env, jclass c, jclass cls, jint depth) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -301,14 +301,14 @@ Java_nsk_jvmti_PopFrame_popframe010_getReady(JNIEnv *env, jclass c, jclass cls,
     }
 
     midRun = env->GetMethodID(cls, "run", "()V");
-    if (midRun == NULL) {
+    if (midRun == nullptr) {
         printf("Cannot find Method ID for method run\n");
         result = STATUS_FAILED;
         return;
     }
 
     midCheckPoint = env->GetMethodID(cls, "checkPoint", "()V");
-    if (midCheckPoint == NULL) {
+    if (midCheckPoint == nullptr) {
         printf("Cannot find Method ID for method checkPoint\n");
         result = STATUS_FAILED;
         return;
@@ -323,7 +323,7 @@ Java_nsk_jvmti_PopFrame_popframe010_getReady(JNIEnv *env, jclass c, jclass cls,
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe011/popframe011.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe011/popframe011.cpp
index 114f7cd1d71..32bf69ea853 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe011/popframe011.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/PopFrame/popframe011/popframe011.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -111,15 +111,15 @@ Java_nsk_jvmti_PopFrame_popframe011_doPopFrame(JNIEnv *env,
     }
 
     switch (t_case) {
-/* NULL pointer to the thread in debug mode */
+/* nullptr pointer to the thread in debug mode */
     case 1:
-        printf("\nInvoke PopFrame() with NULL pointer to a thread...\n");
+        printf("\nInvoke PopFrame() with null pointer to a thread...\n");
         fflush(stdout);
         // fallthrough
-/* NULL pointer to the thread */
+/* nullptr pointer to the thread */
     case 0:
         set_watch_ev(1); /* watch JVMTI events */
-        popframe_err = (jvmti->PopFrame(NULL)); /* explode the bomb */
+        popframe_err = (jvmti->PopFrame(nullptr)); /* explode the bomb */
         if (popframe_err != JVMTI_ERROR_INVALID_THREAD) {
             printf("TEST FAILED: the function PopFrame() returned the error %d: %s\n",
                 popframe_err, TranslateError(popframe_err));
@@ -245,7 +245,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter001/rawmonenter001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter001/rawmonenter001.cpp
index 337de1e3cc8..aeb2f3c4cd7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter001/rawmonenter001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter001/rawmonenter001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define RAW_MONITORS_NUMBER 1024
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -102,12 +102,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -121,7 +121,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_VM_INIT, NULL);
+            JVMTI_EVENT_VM_INIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable JVMTI_EVENT_VM_INIT: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter002/rawmonenter002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter002/rawmonenter002.cpp
index 8588fa65636..790cafb1cfc 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter002/rawmonenter002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter002/rawmonenter002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_rawmonenter002(JavaVM *jvm, char *options, void *reser
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -68,7 +68,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_RawMonitorEnter_rawmonenter002_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -77,7 +77,7 @@ Java_nsk_jvmti_RawMonitorEnter_rawmonenter002_check(JNIEnv *env, jclass cls) {
         printf(">>> invalid monitor check ...\n");
     }
 
-    err = jvmti->RawMonitorEnter(NULL);
+    err = jvmti->RawMonitorEnter(nullptr);
     if (err != JVMTI_ERROR_INVALID_MONITOR) {
         printf("Error expected: JVMTI_ERROR_INVALID_MONITOR,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter003/rawmonenter003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter003/rawmonenter003.cpp
index 984c73cb0f7..36aaa1cdbfb 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter003/rawmonenter003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter003/rawmonenter003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static char bad_buf[] = "this is a bad raw monitor";
@@ -53,12 +53,12 @@ JNIEXPORT jint JNI_OnLoad_rawmonenter003(JavaVM *jvm, char *options, void *reser
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,7 +70,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_RawMonitorEnter_rawmonenter003_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter004/rawmonenter004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter004/rawmonenter004.cpp
index 2c9fdb8f2f0..b2c5b8a929f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter004/rawmonenter004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorEnter/rawmonenter004/rawmonenter004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,7 +36,7 @@ extern "C" {
 #define INCREMENT_LIMIT 1000
 #define DELAY 100
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static jrawMonitorID monitor;
@@ -57,12 +57,12 @@ JNIEXPORT jint JNI_OnLoad_rawmonenter004(JavaVM *jvm, char *options, void *reser
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -104,7 +104,7 @@ Java_nsk_jvmti_RawMonitorEnter_rawmonenter004_check(JNIEnv *env, jclass cls, job
     jthread thr;
     jint wait_time = wtime * 60000;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -131,7 +131,7 @@ Java_nsk_jvmti_RawMonitorEnter_rawmonenter004_check(JNIEnv *env, jclass cls, job
 
     for (i = 0; i < threads_limit; i++) {
         thr = env->GetObjectArrayElement(threads, i);
-        err = jvmti->RunAgentThread(thr, increment_thread, NULL,
+        err = jvmti->RunAgentThread(thr, increment_thread, nullptr,
                                     JVMTI_THREAD_NORM_PRIORITY);
         if (err != JVMTI_ERROR_NONE) {
             printf("(RunDebugThread) unexpected error: %s (%d)\n",
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit001/rawmonexit001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit001/rawmonexit001.cpp
index 6fcd8db139e..fd1a2c47f6a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit001/rawmonexit001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit001/rawmonexit001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define RAW_MONITORS_NUMBER 1024
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -115,12 +115,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -134,7 +134,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_VM_INIT, NULL);
+            JVMTI_EVENT_VM_INIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable JVMTI_EVENT_VM_INIT: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit002/rawmonexit002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit002/rawmonexit002.cpp
index b378bef82df..50fed1c7f1a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit002/rawmonexit002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit002/rawmonexit002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_rawmonexit002(JavaVM *jvm, char *options, void *reserv
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -68,7 +68,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_RawMonitorExit_rawmonexit002_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -77,7 +77,7 @@ Java_nsk_jvmti_RawMonitorExit_rawmonexit002_check(JNIEnv *env, jclass cls) {
         printf(">>> invalid monitor check ...\n");
     }
 
-    err = jvmti->RawMonitorExit(NULL);
+    err = jvmti->RawMonitorExit(nullptr);
     if (err != JVMTI_ERROR_INVALID_MONITOR) {
         printf("Error expected: JVMTI_ERROR_INVALID_MONITOR,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit003/rawmonexit003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit003/rawmonexit003.cpp
index 2c9a1847c3b..31221547a08 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit003/rawmonexit003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit003/rawmonexit003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static char bad_buf[] = "this is a bad raw monitor";
@@ -53,12 +53,12 @@ JNIEXPORT jint JNI_OnLoad_rawmonexit003(JavaVM *jvm, char *options, void *reserv
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,7 +70,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_RawMonitorExit_rawmonexit003_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit005/rawmonexit005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit005/rawmonexit005.cpp
index 58c60ca1561..11b8a83e03b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit005/rawmonexit005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorExit/rawmonexit005/rawmonexit005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_rawmonexit005(JavaVM *jvm, char *options, void *reserv
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -69,7 +69,7 @@ Java_nsk_jvmti_RawMonitorExit_rawmonexit005_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jrawMonitorID monitor;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy001/rawmnntfy001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy001/rawmnntfy001.cpp
index f0824faf11c..d7070469880 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy001/rawmnntfy001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy001/rawmnntfy001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define RAW_MONITORS_NUMBER 1024
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -128,12 +128,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -147,7 +147,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_VM_INIT, NULL);
+            JVMTI_EVENT_VM_INIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable JVMTI_EVENT_VM_INIT: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy002/rawmnntfy002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy002/rawmnntfy002.cpp
index a06fd549572..5900fa46ac8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy002/rawmnntfy002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy002/rawmnntfy002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_rawmnntfy002(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -68,7 +68,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_RawMonitorNotify_rawmnntfy002_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -77,7 +77,7 @@ Java_nsk_jvmti_RawMonitorNotify_rawmnntfy002_check(JNIEnv *env, jclass cls) {
         printf(">>> invalid monitor check ...\n");
     }
 
-    err = jvmti->RawMonitorNotify(NULL);
+    err = jvmti->RawMonitorNotify(nullptr);
     if (err != JVMTI_ERROR_INVALID_MONITOR) {
         printf("Error expected: JVMTI_ERROR_INVALID_MONITOR,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy003/rawmnntfy003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy003/rawmnntfy003.cpp
index 0250ed50ae7..2ab8362bd13 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy003/rawmnntfy003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy003/rawmnntfy003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static char bad_buf[] = "this is a bad raw monitor";
@@ -53,12 +53,12 @@ JNIEXPORT jint JNI_OnLoad_rawmnntfy003(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,7 +70,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_RawMonitorNotify_rawmnntfy003_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy004/rawmnntfy004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy004/rawmnntfy004.cpp
index 5e210000407..259f0b526b3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy004/rawmnntfy004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotify/rawmnntfy004/rawmnntfy004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_rawmnntfy004(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -69,7 +69,7 @@ Java_nsk_jvmti_RawMonitorNotify_rawmnntfy004_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jrawMonitorID monitor;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall001/rawmnntfyall001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall001/rawmnntfyall001.cpp
index c669763560d..42da7b3606c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall001/rawmnntfyall001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall001/rawmnntfyall001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define RAW_MONITORS_NUMBER 1024
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -128,12 +128,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -147,7 +147,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_VM_INIT, NULL);
+            JVMTI_EVENT_VM_INIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable JVMTI_EVENT_VM_INIT: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall002/rawmnntfyall002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall002/rawmnntfyall002.cpp
index 6801be39731..74559aefd80 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall002/rawmnntfyall002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall002/rawmnntfyall002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_rawmnntfyall002(JavaVM *jvm, char *options, void *rese
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -68,7 +68,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_RawMonitorNotifyAll_rawmnntfyall002_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -77,7 +77,7 @@ Java_nsk_jvmti_RawMonitorNotifyAll_rawmnntfyall002_check(JNIEnv *env, jclass cls
         printf(">>> invalid monitor check ...\n");
     }
 
-    err = jvmti->RawMonitorNotifyAll(NULL);
+    err = jvmti->RawMonitorNotifyAll(nullptr);
     if (err != JVMTI_ERROR_INVALID_MONITOR) {
         printf("Error expected: JVMTI_ERROR_INVALID_MONITOR,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall003/rawmnntfyall003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall003/rawmnntfyall003.cpp
index b5bfb676385..71aaa848a74 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall003/rawmnntfyall003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall003/rawmnntfyall003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static char bad_buf[] = "this is a bad raw monitor";
@@ -53,12 +53,12 @@ JNIEXPORT jint JNI_OnLoad_rawmnntfyall003(JavaVM *jvm, char *options, void *rese
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,7 +70,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_RawMonitorNotifyAll_rawmnntfyall003_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall004/rawmnntfyall004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall004/rawmnntfyall004.cpp
index 96c0a2545d7..163d46e9e54 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall004/rawmnntfyall004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorNotifyAll/rawmnntfyall004/rawmnntfyall004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_rawmnntfyall004(JavaVM *jvm, char *options, void *rese
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -69,7 +69,7 @@ Java_nsk_jvmti_RawMonitorNotifyAll_rawmnntfyall004_check(JNIEnv *env, jclass cls
     jvmtiError err;
     jrawMonitorID monitor;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait001/rawmnwait001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait001/rawmnwait001.cpp
index 155e4e7e513..589090ba211 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait001/rawmnwait001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait001/rawmnwait001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,7 +35,7 @@ extern "C" {
 #define RAW_MONITORS_NUMBER 1024
 #define MONITOR_WAIT_TIMEOUT ((jlong)10)
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -129,12 +129,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -148,7 +148,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_VM_INIT, NULL);
+            JVMTI_EVENT_VM_INIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable JVMTI_EVENT_VM_INIT: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait002/rawmnwait002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait002/rawmnwait002.cpp
index 2b2ad239c16..f0efca275f3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait002/rawmnwait002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait002/rawmnwait002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define MONITOR_WAIT_TIMEOUT ((jlong)100)
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -52,12 +52,12 @@ JNIEXPORT jint JNI_OnLoad_rawmnwait002(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -69,7 +69,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_RawMonitorWait_rawmnwait002_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -78,7 +78,7 @@ Java_nsk_jvmti_RawMonitorWait_rawmnwait002_check(JNIEnv *env, jclass cls) {
         printf(">>> invalid monitor check ...\n");
     }
 
-    err = jvmti->RawMonitorWait(NULL, MONITOR_WAIT_TIMEOUT);
+    err = jvmti->RawMonitorWait(nullptr, MONITOR_WAIT_TIMEOUT);
     if (err != JVMTI_ERROR_INVALID_MONITOR) {
         printf("Error expected: JVMTI_ERROR_INVALID_MONITOR,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait003/rawmnwait003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait003/rawmnwait003.cpp
index c4d307dbcc7..74778ffcadf 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait003/rawmnwait003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait003/rawmnwait003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define MONITOR_WAIT_TIMEOUT ((jlong)100)
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static char bad_buf[] = "this is a bad raw monitor";
@@ -54,12 +54,12 @@ JNIEXPORT jint JNI_OnLoad_rawmnwait003(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -71,7 +71,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_RawMonitorWait_rawmnwait003_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait004/rawmnwait004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait004/rawmnwait004.cpp
index e1e7db5c7b8..c356e9007e6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait004/rawmnwait004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait004/rawmnwait004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define MONITOR_WAIT_TIMEOUT ((jlong)100)
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -52,12 +52,12 @@ JNIEXPORT jint JNI_OnLoad_rawmnwait004(JavaVM *jvm, char *options, void *reserve
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -70,7 +70,7 @@ Java_nsk_jvmti_RawMonitorWait_rawmnwait004_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jrawMonitorID monitor;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait005/rawmnwait005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait005/rawmnwait005.cpp
index ba861bd9757..4df5817fcb5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait005/rawmnwait005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RawMonitorWait/rawmnwait005/rawmnwait005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define MILLIS_PER_MINUTE (60 * 1000)
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_TRUE;
@@ -57,12 +57,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -206,7 +206,7 @@ Java_nsk_jvmti_RawMonitorWait_rawmnwait005_check(JNIEnv *env,
 
     wait_time = wtime * MILLIS_PER_MINUTE;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -261,7 +261,7 @@ Java_nsk_jvmti_RawMonitorWait_rawmnwait005_check(JNIEnv *env,
     // before we terminate - else the test will end before it checks
     // it was interrupted!
 
-    err = jvmti->RunAgentThread(thr, test_thread, NULL,
+    err = jvmti->RunAgentThread(thr, test_thread, nullptr,
                                 JVMTI_THREAD_NORM_PRIORITY);
     if (err != JVMTI_ERROR_NONE) {
         printf("(RunDebugThread) unexpected error: %s (%d)\n",
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/StressRedefine/stressRedefine.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/StressRedefine/stressRedefine.cpp
index e186ee1be6a..56f5e5af1fe 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/StressRedefine/stressRedefine.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/StressRedefine/stressRedefine.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define PASSED 0
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 
 jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
@@ -80,7 +80,7 @@ Java_nsk_jvmti_RedefineClasses_StressRedefine_makeRedefinition(JNIEnv *env,
     jvmtiClassDefinition classDef;
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -92,7 +92,7 @@ Java_nsk_jvmti_RedefineClasses_StressRedefine_makeRedefinition(JNIEnv *env,
 /* filling the structure jvmtiClassDefinition */
     classDef.klass = redefCls;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, nullptr);
 
     if (fl == 2) {
         printf(">>>>>>>> Invoke RedefineClasses():\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass001/redefclass001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass001/redefclass001.cpp
index 0bf04741b57..8b1992d011c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass001/redefclass001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass001/redefclass001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define PASSED 0
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 
 #ifdef STATIC_BUILD
@@ -91,7 +91,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass001_makeRedefinition(JNIEnv *env,
     jvmtiClassDefinition classDef;
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -103,7 +103,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass001_makeRedefinition(JNIEnv *env,
 /* filling the structure jvmtiClassDefinition */
     classDef.klass = redefCls;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, nullptr);
 
     if (fl == 2) {
         printf(">>>>>>>> Invoke RedefineClasses():\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass002/redefclass002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass002/redefclass002.cpp
index 2ad16a006bb..31732b1566f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass002/redefclass002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass002/redefclass002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define PASSED 0
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 
 #ifdef STATIC_BUILD
@@ -133,7 +133,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass002_makeRedefinition(JNIEnv *env, jclas
     jvmtiClassDefinition classDef;
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -145,7 +145,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass002_makeRedefinition(JNIEnv *env, jclas
 /* filling the structure jvmtiClassDefinition */
     classDef.klass = redefCls;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, nullptr);
 
     if (vrb == 1)
         printf(">>>>>>>> Invoke RedefineClasses():\n\tnew class byte count=%d\n",
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass003/redefclass003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass003/redefclass003.cpp
index 77fbacb64cd..44654ac13ef 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass003/redefclass003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass003/redefclass003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,7 +35,7 @@ extern "C" {
 #define PASSED 0
 #define NO_RESULTS 3
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 
 #ifdef STATIC_BUILD
@@ -94,7 +94,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass003_makeRedefinition(JNIEnv *env, jclas
     jvmtiClassDefinition classDef;
     int no_results = 0;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -106,7 +106,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass003_makeRedefinition(JNIEnv *env, jclas
 /* filling the structure jvmtiClassDefinition */
     classDef.klass = redefCls;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, nullptr);
 
     if (vrb == 1)
         printf(">>>>>>>> Invoke RedefineClasses():\n\tnew class byte count=%d\n",
@@ -140,7 +140,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass003_checkNewFields(JNIEnv *env,
     jlong longFld;
 
     fid = env->GetStaticFieldID(redefCls, "intComplNewFld", "I");
-    if (fid == NULL) {
+    if (fid == nullptr) {
         printf("%s: Failed to get the field ID for the static field \"intComplNewFld\"\n",
             __FILE__);
         return STATUS_FAILED;
@@ -148,7 +148,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass003_checkNewFields(JNIEnv *env,
     intFld = env->GetStaticIntField(redefCls, fid);
 
     fid = env->GetStaticFieldID(redefCls, "longComplNewFld", "J");
-    if (fid == NULL) {
+    if (fid == nullptr) {
         printf("%s: Failed to get the field ID for the static field \"longComplNewFld\"\n",
             __FILE__);
         return STATUS_FAILED;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass004/redefclass004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass004/redefclass004.cpp
index baef48d901e..68ca36f6959 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass004/redefclass004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass004/redefclass004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,7 +40,7 @@ static jint INTFLD = 333;
 static jlong LONGFLD = 444;
 #define STRFLD "completely new String field"
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 
 #ifdef STATIC_BUILD
@@ -99,7 +99,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass004_makeRedefinition(JNIEnv *env,
     jvmtiClassDefinition classDef;
     int no_results = 0;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -111,7 +111,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass004_makeRedefinition(JNIEnv *env,
 /* fill the structure jvmtiClassDefinition */
     classDef.klass = redefCls;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, nullptr);
 
     if (vrb == 1)
         printf(">>>>>>>> Invoke RedefineClasses():\n\tnew class byte count=%d\n",
@@ -146,11 +146,11 @@ Java_nsk_jvmti_RedefineClasses_redefclass004_checkNewFields(JNIEnv *env,
     jint intFld;
     jlong longFld;
     jstring stringObj;
-    const char *strFld = NULL;
+    const char *strFld = nullptr;
 
 /* get value of new instance field "intComplNewFld" */
     fid = env->GetFieldID(redefCls, "intComplNewFld", "I");
-    if (fid == NULL) {
+    if (fid == nullptr) {
         printf("%s: Failed to get the field ID for the field \"intComplNewFld\"\n",
             __FILE__);
         return STATUS_FAILED;
@@ -159,7 +159,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass004_checkNewFields(JNIEnv *env,
 
 /* get value of new instance field "longComplNewFld" */
     fid = env->GetFieldID(redefCls, "longComplNewFld", "J");
-    if (fid == NULL) {
+    if (fid == nullptr) {
         printf("%s: Failed to get the field ID for the field \"longComplNewFld\"\n",
             __FILE__);
         return STATUS_FAILED;
@@ -168,7 +168,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass004_checkNewFields(JNIEnv *env,
 
 /* get value of new instance field "stringComplNewFld" */
     fid = env->GetFieldID(redefCls, "stringComplNewFld", "Ljava/lang/String;");
-    if (fid == NULL) {
+    if (fid == nullptr) {
         printf("%s: Failed to get the field ID for the field \"stringComplNewFld\"\n",
             __FILE__);
         return STATUS_FAILED;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass005/redefclass005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass005/redefclass005.cpp
index 6e932a9551f..0e7d2703eb3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass005/redefclass005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass005/redefclass005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define PASSED 0
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static int watch_ev = 0;    /* ignore JVMTI events by default */
@@ -59,7 +59,7 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *env, jclass class_being_redefined
 
     jvmti->RawMonitorEnter(watch_ev_monitor);
 
-    if (watch_ev && class_being_redefined != NULL) {
+    if (watch_ev && class_being_redefined != nullptr) {
         printf("#### JVMTI_EVENT_CLASS_FILE_LOAD_HOOK occurred ####\n");
         CFLH_gen_ev++;
     }
@@ -164,7 +164,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass005_makeRedefinition(JNIEnv *env,
     jthread thread;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -180,7 +180,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass005_makeRedefinition(JNIEnv *env,
         return STATUS_FAILED;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable event JVMTI_EVENT_CLASS_FILE_LOAD_HOOK: %s (%d)\n",
                TranslateError(err), err);
@@ -202,7 +202,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass005_makeRedefinition(JNIEnv *env,
 /* filling the structure jvmtiClassDefinition */
     classDef.klass = redefCls;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, nullptr);
 
     set_watch_ev(1); /* watch JVMTI events */
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass006/redefclass006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass006/redefclass006.cpp
index 7f140b73182..9eea0a6e2d7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass006/redefclass006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass006/redefclass006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define PASSED 0
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 
 #ifdef STATIC_BUILD
@@ -90,9 +90,9 @@ Java_nsk_jvmti_RedefineClasses_redefclass006_makeRedefinition(JNIEnv *env,
         jclass cls, jint t_case, jclass redefCls, jbyteArray classBytes) {
     jvmtiError err;
     jvmtiClassDefinition classDef;
-    jvmtiClassDefinition* classDefPtr = NULL;
+    jvmtiClassDefinition* classDefPtr = nullptr;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -102,25 +102,25 @@ Java_nsk_jvmti_RedefineClasses_redefclass006_makeRedefinition(JNIEnv *env,
     }
 
     switch (t_case) {
-/* NULL pointer to the jvmtiClassDefinition */
+/* nullptr pointer to the jvmtiClassDefinition */
         case 0:
             break;
-/* NULL pointer to the jvmtiClassDefinition in debug mode */
+/* nullptr pointer to the jvmtiClassDefinition in debug mode */
         case 1:
-            printf("Invoke RedefineClasses() with NULL pointer to the structure jvmtiClassDefinition\n");
+            printf("Invoke RedefineClasses() with null pointer to the structure jvmtiClassDefinition\n");
             fflush(stdout);
             break;
-/* NULL pointer to the jvmtiClassDefinition->class_bytes in debug mode */
+/* nullptr pointer to the jvmtiClassDefinition->class_bytes in debug mode */
         case 3:
-            printf("Invoke RedefineClasses() with NULL pointer to the field jvmtiClassDefinition->class_bytes\n");
+            printf("Invoke RedefineClasses() with null pointer to the field jvmtiClassDefinition->class_bytes\n");
             fflush(stdout);
             // fallthrough
-/* NULL pointer to the jvmtiClassDefinition->class_bytes */
+/* nullptr pointer to the jvmtiClassDefinition->class_bytes */
         case 2:
             /* partly fill the structure jvmtiClassDefinition */
             classDef.klass = redefCls;
             classDef.class_byte_count = env->GetArrayLength(classBytes);
-            classDef.class_bytes = NULL;
+            classDef.class_bytes = nullptr;
             classDefPtr = &classDef;
             break;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass008/redefclass008.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass008/redefclass008.cpp
index a5ac03291ab..92094c887bd 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass008/redefclass008.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass008/redefclass008.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,16 +45,16 @@ typedef struct {
 
 /* list of breakpoints */
 static breakpoint breakpoints[] = {
-    { 1, (char*) "checkIt", (char*) "(Ljava/io/PrintStream;Z)I", 0, NULL },
-    { 1, (char*) "finMethod", (char*) "(JIJ)V", 5, NULL },
-    { 1, (char*) "finMethod", (char*) "(JIJ)V", 4, NULL },
-    { 1, (char*) "checkIt", (char*) "(Ljava/io/PrintStream;Z)I", 1, NULL },
-    { 0, (char*) "statMethod", (char*) "(III)I", 1, NULL }
+    { 1, (char*) "checkIt", (char*) "(Ljava/io/PrintStream;Z)I", 0, nullptr },
+    { 1, (char*) "finMethod", (char*) "(JIJ)V", 5, nullptr },
+    { 1, (char*) "finMethod", (char*) "(JIJ)V", 4, nullptr },
+    { 1, (char*) "checkIt", (char*) "(Ljava/io/PrintStream;Z)I", 1, nullptr },
+    { 0, (char*) "statMethod", (char*) "(III)I", 1, nullptr }
 };
 
 static jclass redefCls; /* JNI's Java class object */
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 
@@ -141,7 +141,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass008_setBreakpoints(JNIEnv *env,
         if (breakpoints[i].inst) { /* an instance method */
             breakpoints[i].mid = env->GetMethodID(
                 redefCls, breakpoints[i].m_name, breakpoints[i].m_sign);
-            if (breakpoints[i].mid == NULL) {
+            if (breakpoints[i].mid == nullptr) {
                 printf(
                     "%s: Failed to get the method ID for the instance method \"%s\" with signature \"%s\"\n",
                     __FILE__, breakpoints[i].m_name, breakpoints[i].m_sign);
@@ -150,7 +150,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass008_setBreakpoints(JNIEnv *env,
         } else {                   /* a static method */
             breakpoints[i].mid = env->GetStaticMethodID(
                 redefCls, breakpoints[i].m_name, breakpoints[i].m_sign);
-            if (breakpoints[i].mid == NULL) {
+            if (breakpoints[i].mid == nullptr) {
                 printf(
                     "%s: Failed to get the method ID for the static method \"%s\" with signature \"%s\"\n",
                     __FILE__, breakpoints[i].m_name, breakpoints[i].m_sign);
@@ -174,7 +174,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass008_setBreakpoints(JNIEnv *env,
             return STATUS_FAILED;
         }
 
-        err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+        err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                    TranslateError(err), err);
@@ -193,7 +193,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass008_makeRedefinition(JNIEnv *env,
     jvmtiError err;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -205,7 +205,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass008_makeRedefinition(JNIEnv *env,
 /* fill the structure jvmtiClassDefinition */
     classDef.klass = redefCls;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, nullptr);
 
     if (vrb == 1)
         printf(">>>>>>>> Invoke RedefineClasses():\n\tnew class byte count=%d\n",
@@ -243,7 +243,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass008_getResult(JNIEnv *env,
         if (breakpoints[i].inst) { /* an instance method */
             breakpoints[i].mid = env->GetMethodID(
                 redefCls, breakpoints[i].m_name, breakpoints[i].m_sign);
-            if (breakpoints[i].mid == NULL) {
+            if (breakpoints[i].mid == nullptr) {
                 printf(
                     "%s: getResult: Failed to get the method ID for the instance method"
                     "\"%s\" with signature \"%s\"\n",
@@ -253,7 +253,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass008_getResult(JNIEnv *env,
         } else {                   /* a static method */
             breakpoints[i].mid = env->GetStaticMethodID(
                 redefCls, breakpoints[i].m_name, breakpoints[i].m_sign);
-            if (breakpoints[i].mid == NULL) {
+            if (breakpoints[i].mid == nullptr) {
                 printf(
                     "%s: getResult: Failed to get the method ID for the static method"
                     "\"%s\" with signature \"%s\"\n",
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass009/redefclass009.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass009/redefclass009.cpp
index b324acf12fd..e91f9f5e895 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass009/redefclass009.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass009/redefclass009.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -80,23 +80,23 @@ typedef struct {    /* local variables of a method */
     jmethodID mid;  /* JNI's method ID */
 } methInfo;
 
-/* list of original methods with NULL pointers to localVar */
+/* list of original methods with nullptr pointers to localVar */
 static methInfo origMethInfo[] = {
-    { 1, (char*) "<init>", (char*) "()V", 1, NULL, NULL },
-    { 1, (char*) "checkIt", (char*) "(Ljava/io/PrintStream;Z)I", 4, NULL, NULL },
-    { 1, (char*) "finMethod", (char*) "(CJIJ)V", 5, NULL, NULL },
-    { 0, (char*) "statMethod", (char*) "(III)D", 3, NULL, NULL }
+    { 1, (char*) "<init>", (char*) "()V", 1, nullptr, nullptr },
+    { 1, (char*) "checkIt", (char*) "(Ljava/io/PrintStream;Z)I", 4, nullptr, nullptr },
+    { 1, (char*) "finMethod", (char*) "(CJIJ)V", 5, nullptr, nullptr },
+    { 0, (char*) "statMethod", (char*) "(III)D", 3, nullptr, nullptr }
 };
 
 /* list of redefined methods */
 static methInfo redefMethInfo[] = {
-    { 1, (char*) "<init>", (char*) "()V", 6, constr_lv, NULL },
-    { 1, (char*) "checkIt", (char*) "(Ljava/io/PrintStream;Z)I", 3, checkIt_lv, NULL },
-    { 1, (char*) "finMethod", (char*) "(CJIJ)V", 7, finMeth_lv, NULL },
-    { 0, (char*) "statMethod", (char*) "(III)D", 5, statMeth_lv, NULL }
+    { 1, (char*) "<init>", (char*) "()V", 6, constr_lv, nullptr },
+    { 1, (char*) "checkIt", (char*) "(Ljava/io/PrintStream;Z)I", 3, checkIt_lv, nullptr },
+    { 1, (char*) "finMethod", (char*) "(CJIJ)V", 7, finMeth_lv, nullptr },
+    { 0, (char*) "statMethod", (char*) "(III)D", 5, statMeth_lv, nullptr }
 };
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 
 #ifdef STATIC_BUILD
@@ -174,7 +174,7 @@ int checkAttr(JNIEnv *env, jclass redefCls, methInfo methodsInfo[],
             methodsInfo[i].mid = env->GetStaticMethodID(redefCls,
                 methodsInfo[i].m_name, methodsInfo[i].m_sign);
         }
-        if (methodsInfo[i].mid == NULL) {
+        if (methodsInfo[i].mid == nullptr) {
             printf("%s: Failed to get the method ID for the%s%s method \"%s\", signature \"%s\"\n",
                 __FILE__, full ? " " : " original ", methodsInfo[i].inst ? "instance":"static",
                 methodsInfo[i].m_name, methodsInfo[i].m_sign);
@@ -250,7 +250,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass009_makeRedefinition(JNIEnv *env,
     jvmtiError err;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -262,7 +262,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass009_makeRedefinition(JNIEnv *env,
     /* fill the structure jvmtiClassDefinition */
     classDef.klass = redefCls;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, nullptr);
 
     if (vrb)
         printf("\n>>>>>>>> Invoke RedefineClasses():\n\tnew class byte count=%d\n",
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass010/redefclass010.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass010/redefclass010.cpp
index 91620d38fe9..8d0831dfcb3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass010/redefclass010.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass010/redefclass010.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -61,21 +61,21 @@ typedef struct {   /* line numbers of a method */
 
 /* list of original methods */
 static methInfo origMethInfo[] = {
-    { 1, (char*) "<init>", (char*) "()V", 1, NULL },
-    { 1, (char*) "checkIt", (char*) "(Ljava/io/PrintStream;Z)I", 3, NULL },
-    { 1, (char*) "finMethod", (char*) "(CJIJ)V", 1, NULL },
-    { 0, (char*) "statMethod", (char*) "(III)D", 5, NULL }
+    { 1, (char*) "<init>", (char*) "()V", 1, nullptr },
+    { 1, (char*) "checkIt", (char*) "(Ljava/io/PrintStream;Z)I", 3, nullptr },
+    { 1, (char*) "finMethod", (char*) "(CJIJ)V", 1, nullptr },
+    { 0, (char*) "statMethod", (char*) "(III)D", 5, nullptr }
 };
 
 /* list of redefined methods */
 static methInfo redefMethInfo[] = {
-    { 1, (char*) "<init>", (char*) "()V", 8, NULL },
-    { 1, (char*) "checkIt", (char*) "(Ljava/io/PrintStream;Z)I", 3, NULL },
-    { 1, (char*) "finMethod", (char*) "(CJIJ)V", 7, NULL },
-    { 0, (char*) "statMethod", (char*) "(III)D", 1, NULL }
+    { 1, (char*) "<init>", (char*) "()V", 8, nullptr },
+    { 1, (char*) "checkIt", (char*) "(Ljava/io/PrintStream;Z)I", 3, nullptr },
+    { 1, (char*) "finMethod", (char*) "(CJIJ)V", 7, nullptr },
+    { 0, (char*) "statMethod", (char*) "(III)D", 1, nullptr }
 };
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 
 #ifdef STATIC_BUILD
@@ -152,7 +152,7 @@ int checkAttr(JNIEnv *env, jclass redefCls, methInfo methodsInfo[], jint vrb) {
             methodsInfo[i].mid = env->GetStaticMethodID(redefCls,
                     methodsInfo[i].m_name, methodsInfo[i].m_sign);
         }
-        if (methodsInfo[i].mid == NULL) {
+        if (methodsInfo[i].mid == nullptr) {
             printf("%s: Failed to get the method ID for the%s%s method \"%s\", signature \"%s\"\n",
                 __FILE__, (vrb == 2) ? " original " : " ",
                 methodsInfo[i].inst ? "instance" : "static",
@@ -227,7 +227,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass010_makeRedefinition(JNIEnv *env,
     jvmtiError err;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -239,7 +239,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass010_makeRedefinition(JNIEnv *env,
     /* fill the structure jvmtiClassDefinition */
     classDef.klass = redefCls;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, nullptr);
 
     if (vrb)
         printf("\n>>>>>>>> Invoke RedefineClasses():\n\tnew class byte count=%d\n",
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass011/redefclass011.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass011/redefclass011.cpp
index 2aaef98a0f2..af4ca7ec417 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass011/redefclass011.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass011/redefclass011.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -97,14 +97,14 @@ Java_nsk_jvmti_RedefineClasses_redefclass011_check(JNIEnv *env,
     jvmtiError err;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
-    classDef.klass = NULL;
+    classDef.klass = nullptr;
     classDef.class_byte_count = env->GetArrayLength(bytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, nullptr);
 
     if (printdump == JNI_TRUE) {
         printf(">>> invalid class check ...\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass012/redefclass012.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass012/redefclass012.cpp
index c1a79e1fef9..1fe8077d6b7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass012/redefclass012.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass012/redefclass012.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -98,14 +98,14 @@ Java_nsk_jvmti_RedefineClasses_redefclass012_check(JNIEnv *env,
     unsigned char *bytes;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     classDef.klass = cls;
     classDef.class_byte_count = env->GetArrayLength(jbytes);
-    bytes = (unsigned char *) env->GetByteArrayElements(jbytes, NULL);
+    bytes = (unsigned char *) env->GetByteArrayElements(jbytes, nullptr);
 
     /* put 0,0 into version fields */
     bytes[4] = 0;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass013/redefclass013.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass013/redefclass013.cpp
index c525e6c20e3..c3612a7aab1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass013/redefclass013.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass013/redefclass013.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -98,14 +98,14 @@ Java_nsk_jvmti_RedefineClasses_redefclass013_check(JNIEnv *env,
     unsigned char *bytes;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     classDef.klass = cls;
     classDef.class_byte_count = env->GetArrayLength(jbytes);
-    bytes = (unsigned char *) env->GetByteArrayElements(jbytes, NULL);
+    bytes = (unsigned char *) env->GetByteArrayElements(jbytes, nullptr);
 
     /* put 0 into magic field */
     bytes[0] = 0;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass014/redefclass014.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass014/redefclass014.cpp
index 9c6170b6904..90080ef43d8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass014/redefclass014.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass014/redefclass014.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -96,7 +96,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass014_check(JNIEnv *env, jclass cls, jbyt
     jvmtiError err;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -111,7 +111,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass014_check(JNIEnv *env, jclass cls, jbyt
 
     classDef.klass = cls;
     classDef.class_byte_count = env->GetArrayLength(bytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, nullptr);
 
     if (printdump == JNI_TRUE) {
         printf(">>> circularity error check ...\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass015/redefclass015.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass015/redefclass015.cpp
index 1df2cb4a1eb..5e18751e53a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass015/redefclass015.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass015/redefclass015.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -97,14 +97,14 @@ Java_nsk_jvmti_RedefineClasses_redefclass015_check(JNIEnv *env, jclass cls,
     jvmtiError err;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     classDef.klass = clazz;
     classDef.class_byte_count = env->GetArrayLength(bytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, nullptr);
 
     if (printdump == JNI_TRUE) {
         printf(">>> verify error check ...\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass016/redefclass016.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass016/redefclass016.cpp
index 4e266edd3db..82e72f8befa 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass016/redefclass016.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass016/redefclass016.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,12 +33,12 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
-static jmethodID mid = NULL;
+static jmethodID mid = nullptr;
 static jint bpeakpointsExpected = 0;
 static jint bpeakpointsCount = 0;
 static jlocation loc = 0;
@@ -48,7 +48,7 @@ static jint magicNumber;
 void check(jvmtiEnv *jvmti_env, jthread thr, jclass cls, jmethodID mid, jint i) {
     jvmtiError err;
     char *sigClass, *name, *sig, *generic;
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLocalVariableEntry *table = nullptr;
     jint entryCount = 0;
     jint varValue = -1;
     jint j;
@@ -77,7 +77,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jclass cls, jmethodID mid, jint i)
         result = STATUS_FAILED;
         return;
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             if (strcmp(table[j].name, "localVar") == 0) {
                 err = jvmti_env->GetLocalInt(thr, 0,
@@ -102,16 +102,16 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jclass cls, jmethodID mid, jint i)
         result = STATUS_FAILED;
     }
 
-    if (sigClass != NULL) {
+    if (sigClass != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sigClass);
     }
-    if (name != NULL) {
+    if (name != nullptr) {
         jvmti_env->Deallocate((unsigned char*)name);
     }
-    if (sig != NULL) {
+    if (sig != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sig);
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             jvmti_env->Deallocate((unsigned char*)(table[j].name));
             jvmti_env->Deallocate((unsigned char*)(table[j].signature));
@@ -148,7 +148,7 @@ void JNICALL Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *env,
 
     classDef.klass = klass;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
-    bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);
+    bytes = (unsigned char *) env->GetByteArrayElements(classBytes, nullptr);
 
     for (i = 0; i < classDef.class_byte_count - 3; i++) {
         if (((jint)bytes[i+3] |
@@ -202,12 +202,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -264,10 +264,10 @@ JNIEXPORT void JNICALL
 Java_nsk_jvmti_RedefineClasses_redefclass016_getReady(JNIEnv *env, jclass cls,
         jclass clazz, jbyteArray bytes, jint magic, jint line) {
     jvmtiError err;
-    jvmtiLineNumberEntry *lines = NULL;
+    jvmtiLineNumberEntry *lines = nullptr;
     jint i = 0, entryCount = 0;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -279,7 +279,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass016_getReady(JNIEnv *env, jclass cls,
         !caps.can_access_local_variables) return;
 
     mid = env->GetMethodID(clazz, "run", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find Method ID for method run\n");
         result = STATUS_FAILED;
         return;
@@ -295,7 +295,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass016_getReady(JNIEnv *env, jclass cls,
         return;
     }
 
-    if (lines != NULL && entryCount > 0) {
+    if (lines != nullptr && entryCount > 0) {
         for (i = 0; i < entryCount; i++) {
             if (line == lines[i].line_number) {
                 loc = lines[i].start_location;
@@ -318,7 +318,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass016_getReady(JNIEnv *env, jclass cls,
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass017/redefclass017.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass017/redefclass017.cpp
index cd2076cf9a7..65fe8b5572c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass017/redefclass017.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass017/redefclass017.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,12 +33,12 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
-static jmethodID mid = NULL;
+static jmethodID mid = nullptr;
 static jbyteArray classBytes;
 
 void JNICALL Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *env,
@@ -64,7 +64,7 @@ void JNICALL Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *env,
     classDef.klass = klass;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
     classDef.class_bytes = (unsigned char *)
-        env->GetByteArrayElements(classBytes, NULL);
+        env->GetByteArrayElements(classBytes, nullptr);
 
     if (printdump == JNI_TRUE) {
         printf(">>> bp: about to call RedefineClasses\n");
@@ -93,12 +93,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -148,7 +148,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass017_getReady(JNIEnv *env, jclass cls,
         jclass clazz, jbyteArray bytes) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -158,7 +158,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass017_getReady(JNIEnv *env, jclass cls,
         !caps.can_generate_breakpoint_events) return;
 
     mid = env->GetMethodID(clazz, "checkPoint", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find Method ID for method run\n");
         result = STATUS_FAILED;
         return;
@@ -175,7 +175,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass017_getReady(JNIEnv *env, jclass cls,
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass018/redefclass018.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass018/redefclass018.cpp
index 68d2ac89263..37fc8d71108 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass018/redefclass018.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass018/redefclass018.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
@@ -49,7 +49,7 @@ Exception(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thread,
     jvmtiClassDefinition classDef;
 
     err = jvmti->SetEventNotificationMode(JVMTI_DISABLE,
-            JVMTI_EVENT_EXCEPTION, NULL);
+            JVMTI_EVENT_EXCEPTION, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to disable JVMTI_EVENT_EXCEPTION: %s (%d)\n",
                TranslateError(err), err);
@@ -66,7 +66,7 @@ Exception(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thread,
 
     classDef.klass = klass;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, nullptr);
 
     if (printdump == JNI_TRUE) {
         printf(">>> about to call RedefineClasses\n");
@@ -95,12 +95,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -151,7 +151,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass018_getReady(JNIEnv *env, jclass cls,
     jvmtiError err;
     jthread thread;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass019/redefclass019.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass019/redefclass019.cpp
index 414005124eb..ee650ff1914 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass019/redefclass019.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass019/redefclass019.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,14 +48,14 @@ typedef struct {
     var_info *vars;
 } frame_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static jbyteArray classBytes;
-static jmethodID midCheckPoint = NULL;
-static jmethodID midRun = NULL;
+static jmethodID midCheckPoint = nullptr;
+static jmethodID midRun = nullptr;
 static jint framesExpected = 0;
 static jint framesCount = 0;
 
@@ -96,10 +96,10 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid, jint i) {
     jvmtiError err;
     jclass cls;
     jlocation loc;
-    char *sigClass, *name = NULL, *sig = NULL, *generic;
+    char *sigClass, *name = nullptr, *sig = nullptr, *generic;
     jboolean is_obsolete;
-    jvmtiLineNumberEntry *lines = NULL;
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLineNumberEntry *lines = nullptr;
+    jvmtiLocalVariableEntry *table = nullptr;
     jint line = -1;
     jint entryCount = 0;
     jint varValue = -1;
@@ -135,10 +135,10 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid, jint i) {
         return;
     }
 
-    if (sigClass == NULL || strcmp(sigClass, cls_exp) != 0) {
+    if (sigClass == nullptr || strcmp(sigClass, cls_exp) != 0) {
         printf("(pop %d) wrong class sig: \"%s\",", i, sigClass);
         printf(" expected: \"%s\"\n", cls_exp);
-        if (sigClass != NULL) {
+        if (sigClass != nullptr) {
             jvmti_env->Deallocate((unsigned char*)sigClass);
         }
         result = STATUS_FAILED;
@@ -167,12 +167,12 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid, jint i) {
                 (is_obsolete == JNI_TRUE) ? "unexpected" : "should be");
             result = STATUS_FAILED;
         }
-        if (name == NULL || strcmp(name, frames[i].name) != 0) {
+        if (name == nullptr || strcmp(name, frames[i].name) != 0) {
             printf("(pop %d) wrong method name: \"%s\",", i, name);
             printf(" expected: \"%s\"\n", frames[i].name);
             result = STATUS_FAILED;
         }
-        if (sig == NULL || strcmp(sig, frames[i].sig) != 0) {
+        if (sig == nullptr || strcmp(sig, frames[i].sig) != 0) {
             printf("(pop %d) wrong method sig: \"%s\",", i, sig);
             printf(" expected: \"%s\"\n", frames[i].sig);
             result = STATUS_FAILED;
@@ -187,7 +187,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid, jint i) {
             return;
         }
 
-        if (lines != NULL && entryCount > 0) {
+        if (lines != nullptr && entryCount > 0) {
             for (k = 0; k < entryCount; k++) {
                 if (loc < lines[k].start_location) {
                     break;
@@ -216,7 +216,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid, jint i) {
             result = STATUS_FAILED;
         }
 
-        if (table != NULL) {
+        if (table != nullptr) {
             for (k = 0; k < frames[i].count; k++) {
                 for (j = 0; j < entryCount; j++) {
                     if (strcmp(table[j].name, frames[i].vars[k].name) == 0 &&
@@ -256,19 +256,19 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid, jint i) {
         }
     }
 
-    if (sigClass != NULL) {
+    if (sigClass != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sigClass);
     }
-    if (name != NULL) {
+    if (name != nullptr) {
         jvmti_env->Deallocate((unsigned char*)name);
     }
-    if (sig != NULL) {
+    if (sig != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sig);
     }
-    if (lines != NULL) {
+    if (lines != nullptr) {
         jvmti_env->Deallocate((unsigned char*)lines);
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             jvmti_env->Deallocate((unsigned char*)(table[j].name));
             jvmti_env->Deallocate((unsigned char*)(table[j].signature));
@@ -311,7 +311,7 @@ void JNICALL Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *env,
     classDef.klass = klass;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
     classDef.class_bytes = (unsigned char *)
-        env->GetByteArrayElements(classBytes, NULL);
+        env->GetByteArrayElements(classBytes, nullptr);
 
     if (printdump == JNI_TRUE) {
         printf(">>> about to call RedefineClasses\n");
@@ -368,12 +368,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -433,7 +433,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass019_getReady(JNIEnv *env, jclass cls,
         jclass clazz, jbyteArray bytes, jint depth) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -448,14 +448,14 @@ Java_nsk_jvmti_RedefineClasses_redefclass019_getReady(JNIEnv *env, jclass cls,
     classBytes = (jbyteArray) env->NewGlobalRef(bytes);
 
     midRun = env->GetMethodID(clazz, "run", "()V");
-    if (midRun == NULL) {
+    if (midRun == nullptr) {
         printf("Cannot find Method ID for method run\n");
         result = STATUS_FAILED;
         return;
     }
 
     midCheckPoint = env->GetMethodID(clazz, "checkPoint", "()V");
-    if (midCheckPoint == NULL) {
+    if (midCheckPoint == nullptr) {
         printf("Cannot find Method ID for method checkPoint\n");
         result = STATUS_FAILED;
         return;
@@ -470,7 +470,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass019_getReady(JNIEnv *env, jclass cls,
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
@@ -479,7 +479,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass019_getReady(JNIEnv *env, jclass cls,
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_FRAME_POP, NULL);
+        JVMTI_EVENT_FRAME_POP, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable FRAME_POP event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass020/redefclass020.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass020/redefclass020.cpp
index 955fd841aaa..c8eee73de4d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass020/redefclass020.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass020/redefclass020.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -97,14 +97,14 @@ Java_nsk_jvmti_RedefineClasses_redefclass020_check(JNIEnv *env, jclass cls,
     jvmtiError err;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     classDef.klass = clazz;
     classDef.class_byte_count = env->GetArrayLength(bytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, nullptr);
 
     if (printdump == JNI_TRUE) {
         printf(">>> add method capability check ...\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass021/redefclass021.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass021/redefclass021.cpp
index e44872125f6..8e8f75e344f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass021/redefclass021.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass021/redefclass021.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -97,14 +97,14 @@ Java_nsk_jvmti_RedefineClasses_redefclass021_check(JNIEnv *env, jclass cls,
     jvmtiError err;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     classDef.klass = clazz;
     classDef.class_byte_count = env->GetArrayLength(bytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, nullptr);
 
     if (printdump == JNI_TRUE) {
         printf(">>> delete method capability check ...\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass022/redefclass022.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass022/redefclass022.cpp
index e931801f560..dfda41c4b84 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass022/redefclass022.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass022/redefclass022.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -97,14 +97,14 @@ Java_nsk_jvmti_RedefineClasses_redefclass022_check(JNIEnv *env, jclass cls,
     jvmtiError err;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     classDef.klass = clazz;
     classDef.class_byte_count = env->GetArrayLength(bytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, nullptr);
 
     if (printdump == JNI_TRUE) {
         printf(">>> change fields capability check ...\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass023/redefclass023.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass023/redefclass023.cpp
index 4d118e726d3..7a10b9dc5ee 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass023/redefclass023.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass023/redefclass023.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -97,14 +97,14 @@ Java_nsk_jvmti_RedefineClasses_redefclass023_check(JNIEnv *env, jclass cls,
     jvmtiError err;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     classDef.klass = clazz;
     classDef.class_byte_count = env->GetArrayLength(bytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, nullptr);
 
     if (printdump == JNI_TRUE) {
         printf(">>> change implemented interface capability check ...\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass024/redefclass024.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass024/redefclass024.cpp
index 41c4a849275..bd877d2e0b3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass024/redefclass024.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass024/redefclass024.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -97,14 +97,14 @@ Java_nsk_jvmti_RedefineClasses_redefclass024_check(JNIEnv *env, jclass cls,
     jvmtiError err;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     classDef.klass = clazz;
     classDef.class_byte_count = env->GetArrayLength(bytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, nullptr);
 
     if (printdump == JNI_TRUE) {
         printf(">>> change class modifiers capability check ...\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass025/redefclass025.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass025/redefclass025.cpp
index ee5b364dc7e..d992762d4ca 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass025/redefclass025.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass025/redefclass025.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -97,14 +97,14 @@ Java_nsk_jvmti_RedefineClasses_redefclass025_check(JNIEnv *env, jclass cls,
     jvmtiError err;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     classDef.klass = clazz;
     classDef.class_byte_count = env->GetArrayLength(bytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, nullptr);
 
     if (printdump == JNI_TRUE) {
         printf(">>> change method modifiers capability check ...\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass026/redefclass026.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass026/redefclass026.cpp
index 68366880a65..efa2b86fa10 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass026/redefclass026.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass026/redefclass026.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -97,14 +97,14 @@ Java_nsk_jvmti_RedefineClasses_redefclass026_check(JNIEnv *env, jclass cls,
     jvmtiError err;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
 
     classDef.klass = clazz;
     classDef.class_byte_count = env->GetArrayLength(bytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(bytes, nullptr);
 
     if (printdump == JNI_TRUE) {
         printf(">>> changed class name check ...\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass027/redefclass027.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass027/redefclass027.cpp
index cdcf5f4868e..badd984de77 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass027/redefclass027.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass027/redefclass027.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -50,17 +50,17 @@ typedef struct {
     const char *desc;
 } frame_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static jbyteArray classBytes;
-static jmethodID midRun = NULL;
-static jmethodID mid1 = NULL;
-static jmethodID mid2 = NULL;
-static jfieldID fid1 = NULL;
-static jfieldID fid2 = NULL;
+static jmethodID midRun = nullptr;
+static jmethodID mid1 = nullptr;
+static jmethodID mid2 = nullptr;
+static jfieldID fid1 = nullptr;
+static jfieldID fid2 = nullptr;
 static jint stepEventsExpected = 0;
 static jint bpEventsExpected = 0;
 static jint popEventsExpected = 0;
@@ -118,11 +118,11 @@ static frame_info frames[] = {
 void check(jvmtiEnv *jvmti_env, jthread thr, jclass cls, jmethodID mid,
         jlocation loc, jint i) {
     jvmtiError err;
-    char *sigClass, *name = NULL, *sig = NULL, *generic;
+    char *sigClass, *name = nullptr, *sig = nullptr, *generic;
     const char *desc;
     jboolean is_obsolete;
-    jvmtiLineNumberEntry *lines = NULL;
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLineNumberEntry *lines = nullptr;
+    jvmtiLocalVariableEntry *table = nullptr;
     jint line = -1;
     jint entryCount = 0;
     jint varValue = -1;
@@ -144,10 +144,10 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jclass cls, jmethodID mid,
         result = STATUS_FAILED;
     }
 
-    if (sigClass == NULL || strcmp(sigClass, cls_exp) != 0) {
+    if (sigClass == nullptr || strcmp(sigClass, cls_exp) != 0) {
         printf("(%s) wrong class sig: \"%s\",", desc, sigClass);
         printf(" expected: \"%s\"\n", cls_exp);
-        if (sigClass != NULL) {
+        if (sigClass != nullptr) {
             jvmti_env->Deallocate((unsigned char *)sigClass);
         }
         result = STATUS_FAILED;
@@ -176,12 +176,12 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jclass cls, jmethodID mid,
                 (is_obsolete == JNI_TRUE) ? "unexpected" : "should be");
             result = STATUS_FAILED;
         }
-        if (name == NULL || strcmp(name, frames[i].name) != 0) {
+        if (name == nullptr || strcmp(name, frames[i].name) != 0) {
             printf("(%s) wrong method name: \"%s\",", desc, name);
             printf(" expected: \"%s\"\n", frames[i].name);
             result = STATUS_FAILED;
         }
-        if (sig == NULL || strcmp(sig, frames[i].sig) != 0) {
+        if (sig == nullptr || strcmp(sig, frames[i].sig) != 0) {
             printf("(%s) wrong method sig: \"%s\",", desc, sig);
             printf(" expected: \"%s\"\n", frames[i].sig);
             result = STATUS_FAILED;
@@ -195,7 +195,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jclass cls, jmethodID mid,
             result = STATUS_FAILED;
         }
 
-        if (lines != NULL && entryCount > 0) {
+        if (lines != nullptr && entryCount > 0) {
             for (k = 0; k < entryCount; k++) {
                 if (loc < lines[k].start_location) {
                     break;
@@ -223,7 +223,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jclass cls, jmethodID mid,
             result = STATUS_FAILED;
         }
 
-        if (table != NULL) {
+        if (table != nullptr) {
           for (k = 0; k < frames[i].count; k++) {
             for (j = 0; j < entryCount; j++) {
               if (strcmp(table[j].name, frames[i].vars[k].name) == 0 &&
@@ -272,19 +272,19 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jclass cls, jmethodID mid,
         }
     }
 
-    if (sigClass != NULL) {
+    if (sigClass != nullptr) {
         jvmti_env->Deallocate((unsigned char *)sigClass);
     }
-    if (name != NULL) {
+    if (name != nullptr) {
         jvmti_env->Deallocate((unsigned char *)name);
     }
-    if (sig != NULL) {
+    if (sig != nullptr) {
         jvmti_env->Deallocate((unsigned char *)sig);
     }
-    if (lines != NULL) {
+    if (lines != nullptr) {
         jvmti_env->Deallocate((unsigned char *)lines);
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             jvmti_env->Deallocate((unsigned char *)(table[j].name));
             jvmti_env->Deallocate((unsigned char *)(table[j].signature));
@@ -299,7 +299,7 @@ void redefine(jvmtiEnv *jvmti_env, JNIEnv *env, jclass cls) {
 
     classDef.klass = cls;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, nullptr);
 
     if (printdump == JNI_TRUE) {
         printf(">>> about to call RedefineClasses %d\n", redefinesCount);
@@ -531,7 +531,7 @@ void JNICALL ExceptionCatch(jvmtiEnv *jvmti_env, JNIEnv *env,
 
     if (caps.can_generate_frame_pop_events) {
         err = jvmti_env->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_FRAME_POP, NULL);
+            JVMTI_EVENT_FRAME_POP, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to enable FRAME_POP event: %s (%d)\n",
                    TranslateError(err), err);
@@ -596,12 +596,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -687,7 +687,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass027_getReady(JNIEnv *env, jclass cls,
         jclass clazz, jbyteArray bytes) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -700,24 +700,24 @@ Java_nsk_jvmti_RedefineClasses_redefclass027_getReady(JNIEnv *env, jclass cls,
     classBytes = (jbyteArray) env->NewGlobalRef(bytes);
 
     midRun = env->GetMethodID(clazz, "run", "()V");
-    if (midRun == NULL) {
+    if (midRun == nullptr) {
         printf("Cannot find Method ID for method run\n");
         result = STATUS_FAILED;
     }
 
     mid1 = env->GetMethodID(clazz, "method1", "(I)V");
-    if (mid1 == NULL) {
+    if (mid1 == nullptr) {
         printf("Cannot find Method ID for method1\n");
         result = STATUS_FAILED;
     }
 
     mid2 = env->GetMethodID(clazz, "method2", "(I)V");
-    if (mid2 == NULL) {
+    if (mid2 == nullptr) {
         printf("Cannot find Method ID for method2\n");
         result = STATUS_FAILED;
     }
 
-    if (caps.can_generate_breakpoint_events && midRun != NULL) {
+    if (caps.can_generate_breakpoint_events && midRun != nullptr) {
         err = jvmti->SetBreakpoint(midRun, 0);
         if (err != JVMTI_ERROR_NONE) {
             printf("(SetBreakpoint) unexpected error: %s (%d)\n",
@@ -725,7 +725,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass027_getReady(JNIEnv *env, jclass cls,
             result = STATUS_FAILED;
         } else {
             err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                JVMTI_EVENT_BREAKPOINT, NULL);
+                JVMTI_EVENT_BREAKPOINT, nullptr);
             if (err != JVMTI_ERROR_NONE) {
                 printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                        TranslateError(err), err);
@@ -737,12 +737,12 @@ Java_nsk_jvmti_RedefineClasses_redefclass027_getReady(JNIEnv *env, jclass cls,
     }
 
     fid1 = env->GetStaticFieldID(clazz, "staticInt", "I");
-    if (fid1 == NULL) {
+    if (fid1 == nullptr) {
         printf("Cannot find Field ID for staticInt\n");
         result = STATUS_FAILED;
     }
 
-    if (caps.can_generate_field_modification_events && fid1 != NULL) {
+    if (caps.can_generate_field_modification_events && fid1 != nullptr) {
         err = jvmti->SetFieldModificationWatch(clazz, fid1);
         if (err != JVMTI_ERROR_NONE) {
             printf("(SetFieldModificationWatch) unexpected error: %s (%d)\n",
@@ -750,7 +750,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass027_getReady(JNIEnv *env, jclass cls,
             result = STATUS_FAILED;
         } else {
             err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                JVMTI_EVENT_FIELD_MODIFICATION, NULL);
+                JVMTI_EVENT_FIELD_MODIFICATION, nullptr);
             if (err != JVMTI_ERROR_NONE) {
                 printf("Failed to enable FIELD_MODIFICATION event: %s (%d)\n",
                        TranslateError(err), err);
@@ -762,12 +762,12 @@ Java_nsk_jvmti_RedefineClasses_redefclass027_getReady(JNIEnv *env, jclass cls,
     }
 
     fid2 = env->GetFieldID(clazz, "instanceInt", "I");
-    if (fid2 == NULL) {
+    if (fid2 == nullptr) {
         printf("Cannot find Field ID for instanceInt\n");
         result = STATUS_FAILED;
     }
 
-    if (caps.can_generate_field_access_events && fid2 != NULL) {
+    if (caps.can_generate_field_access_events && fid2 != nullptr) {
         err = jvmti->SetFieldAccessWatch(clazz, fid2);
         if (err != JVMTI_ERROR_NONE) {
             printf("(SetFieldAccessWatch) unexpected error: %s (%d)\n",
@@ -775,7 +775,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass027_getReady(JNIEnv *env, jclass cls,
             result = STATUS_FAILED;
         } else {
             err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                JVMTI_EVENT_FIELD_ACCESS, NULL);
+                JVMTI_EVENT_FIELD_ACCESS, nullptr);
             if (err != JVMTI_ERROR_NONE) {
                 printf("Failed to enable FIELD_ACCESS event: %s (%d)\n",
                        TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass028/redefclass028.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass028/redefclass028.cpp
index 09a8467c355..a00888c4d5b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass028/redefclass028.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass028/redefclass028.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,7 +49,7 @@ static jvmtiEvent eventsList[EVENTS_COUNT] = {
     JVMTI_EVENT_COMPILED_METHOD_UNLOAD
 };
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 static volatile int fire = 0; /* CompiledMethodLoad received for hotspot method */
 static jmethodID hsMethodID; /* hotspot method ID */
@@ -100,7 +100,7 @@ CompiledMethodLoad(jvmtiEnv *jvmti_env, jmethodID method, jint code_size,
     char *sig;
 
     NSK_DISPLAY0("CompiledMethodLoad event received for:\n");
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &sig, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &sig, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -133,7 +133,7 @@ CompiledMethodUnload(jvmtiEnv* jvmti_env, jmethodID method,
 
     NSK_DISPLAY0("CompiledMethodUnload event received\n");
     // Check for the case that the class has been unloaded
-    err = jvmti_env->GetMethodName(method, &name, &sig, NULL);
+    err = jvmti_env->GetMethodName(method, &name, &sig, nullptr);
     if (err == JVMTI_ERROR_NONE) {
         NSK_DISPLAY3("for: \tmethod: name=\"%s\" signature=\"%s\"\n\tnative address=0x%p\n",
           name, sig, code_addr);
@@ -188,7 +188,7 @@ agentProc(jvmtiEnv* jvmti_env, JNIEnv* jni_env, void* arg) {
         nsk_jvmti_resumeSync();
         return;
     }
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(decl_cls, &cls_sig, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(decl_cls, &cls_sig, nullptr))) {
         nsk_jvmti_setFailStatus();
         nsk_jvmti_resumeSync();
         return;
@@ -249,7 +249,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add required capabilities */
@@ -269,12 +269,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     NSK_DISPLAY0("setting event callbacks done\nenabling events ...\n");
     if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT,
-            eventsList, NULL))
+            eventsList, nullptr))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
     /* register agent proc */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass029/redefclass029.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass029/redefclass029.cpp
index 9f7fc1fc5a5..8662e65a4b6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass029/redefclass029.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass029/redefclass029.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,7 +49,7 @@ static jvmtiEvent eventsList[EVENTS_COUNT] = {
     JVMTI_EVENT_COMPILED_METHOD_UNLOAD
 };
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 static volatile int fire = 0; /* CompiledMethodLoad received for hotspot method */
 static jmethodID hsMethodID; /* hotspot method ID */
@@ -99,7 +99,7 @@ CompiledMethodLoad(jvmtiEnv *jvmti_env, jmethodID method, jint code_size,
     char *sig;
 
     NSK_DISPLAY0("CompiledMethodLoad event received for:\n");
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &sig, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &sig, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -132,7 +132,7 @@ CompiledMethodUnload(jvmtiEnv* jvmti_env, jmethodID method,
 
     NSK_DISPLAY0("CompiledMethodUnload event received\n");
     // Check for the case that the class has been unloaded
-    err = jvmti_env->GetMethodName(method, &name, &sig, NULL);
+    err = jvmti_env->GetMethodName(method, &name, &sig, nullptr);
     if (err == JVMTI_ERROR_NONE) {
         NSK_DISPLAY3("for: \tmethod: name=\"%s\" signature=\"%s\"\n\tnative address=0x%p\n",
           name, sig, code_addr);
@@ -187,7 +187,7 @@ agentProc(jvmtiEnv* jvmti_env, JNIEnv* jni_env, void* arg) {
         nsk_jvmti_resumeSync();
         return;
     }
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(decl_cls, &cls_sig, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(decl_cls, &cls_sig, nullptr))) {
         nsk_jvmti_setFailStatus();
         nsk_jvmti_resumeSync();
         return;
@@ -248,7 +248,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add required capabilities */
@@ -268,12 +268,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     NSK_DISPLAY0("setting event callbacks done\nenabling events ...\n");
     if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT,
-            eventsList, NULL))
+            eventsList, nullptr))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
     /* register agent proc */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass030/redefclass030.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass030/redefclass030.cpp
index b7d6daafbbd..04d3c1b2361 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass030/redefclass030.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass030/redefclass030.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,7 +49,7 @@ static jvmtiEvent eventsList[EVENTS_COUNT] = {
     JVMTI_EVENT_COMPILED_METHOD_UNLOAD
 };
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 static volatile int fire = 0; /* CompiledMethodLoad received for hotspot method */
 static jmethodID hsMethodID; /* hotspot method ID */
@@ -100,7 +100,7 @@ CompiledMethodLoad(jvmtiEnv *jvmti_env, jmethodID method, jint code_size,
     char *sig;
 
     NSK_DISPLAY0("CompiledMethodLoad event received for:\n");
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &sig, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &sig, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -133,7 +133,7 @@ CompiledMethodUnload(jvmtiEnv* jvmti_env, jmethodID method,
 
     NSK_DISPLAY0("CompiledMethodUnload event received\n");
     // Check for the case that the class has been unloaded
-    err = jvmti_env->GetMethodName(method, &name, &sig, NULL);
+    err = jvmti_env->GetMethodName(method, &name, &sig, nullptr);
     if (err == JVMTI_ERROR_NONE) {
         NSK_DISPLAY3("for: \tmethod: name=\"%s\" signature=\"%s\"\n\tnative address=0x%p\n",
           name, sig, code_addr);
@@ -188,7 +188,7 @@ agentProc(jvmtiEnv* jvmti_env, JNIEnv* jni_env, void* arg) {
         nsk_jvmti_resumeSync();
         return;
     }
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(decl_cls, &cls_sig, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(decl_cls, &cls_sig, nullptr))) {
         nsk_jvmti_setFailStatus();
         nsk_jvmti_resumeSync();
         return;
@@ -249,7 +249,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add required capabilities */
@@ -269,12 +269,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     NSK_DISPLAY0("setting event callbacks done\nenabling events ...\n");
     if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT,
-            eventsList, NULL))
+            eventsList, nullptr))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
     /* register agent proc */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass031/redefclass031.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass031/redefclass031.cpp
index 9d242130a0f..34a98b5f875 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass031/redefclass031.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass031/redefclass031.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,13 +33,13 @@ extern "C" {
 #define STATUS_FAILED 2
 #define PASSED 0
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static int watch_ev = 0;    /* ignore JVMTI events by default */
 static int gen_ev = 0;      /* number of generated events */
 static int result = PASSED; /* total result of the test */
-static jthread test_thread = NULL;
+static jthread test_thread = nullptr;
 
 static jrawMonitorID watch_ev_monitor;
 
@@ -54,9 +54,9 @@ static void set_watch_ev(JNIEnv *env, int value) {
         } else {
             test_thread = env->NewGlobalRef(test_thread);
         }
-    } else if (test_thread != NULL) {
+    } else if (test_thread != nullptr) {
         env->DeleteGlobalRef(test_thread);
-        test_thread = NULL;
+        test_thread = nullptr;
     }
 
     watch_ev = value;
@@ -85,10 +85,10 @@ NativeMethodBind(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thr, jmethodID method
             } else {
                 printf("got JVMTI_EVENT_NATIVE_METHOD_BIND event on thread '%s', ignoring", inf.name);
                 jvmti_env->Deallocate((unsigned char *)inf.name);
-                if (inf.thread_group != NULL) {
+                if (inf.thread_group != nullptr) {
                     env->DeleteLocalRef(inf.thread_group);
                 }
-                if (inf.context_class_loader != NULL) {
+                if (inf.context_class_loader != nullptr) {
                     env->DeleteLocalRef(inf.context_class_loader);
                 }
             }
@@ -168,7 +168,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass031_makeRedefinition(JNIEnv *env,
     jvmtiError err;
     jvmtiClassDefinition classDef;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -177,7 +177,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass031_makeRedefinition(JNIEnv *env,
         return PASSED;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable JVMTI_EVENT_NATIVE_METHOD_BIND: %s (%d)\n",
                TranslateError(err), err);
@@ -187,7 +187,7 @@ Java_nsk_jvmti_RedefineClasses_redefclass031_makeRedefinition(JNIEnv *env,
 /* filling the structure jvmtiClassDefinition */
     classDef.klass = redefCls;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, nullptr);
 
     set_watch_ev(env, 1); /* watch JVMTI events */
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RelinquishCapabilities/relcaps001/relcaps001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RelinquishCapabilities/relcaps001/relcaps001.cpp
index 736715c2ab6..52e076741a3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RelinquishCapabilities/relcaps001/relcaps001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RelinquishCapabilities/relcaps001/relcaps001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -302,7 +302,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     success = checkCapabilities(jvmti, &initCaps, "VM_DEATH callback");
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = false;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -329,7 +329,7 @@ JNIEXPORT jint JNI_OnLoad_relcaps001(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -337,7 +337,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -352,7 +352,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&initCaps, 0, sizeof(jvmtiCapabilities));
@@ -375,7 +375,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RelinquishCapabilities/relcaps002/relcaps002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RelinquishCapabilities/relcaps002/relcaps002.cpp
index 8ff71c76c7a..c5ad887f7f3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RelinquishCapabilities/relcaps002/relcaps002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RelinquishCapabilities/relcaps002/relcaps002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -301,7 +301,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     success = checkCapabilities(jvmti, &initCaps, "VM_DEATH callback");
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = false;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -328,7 +328,7 @@ JNIEXPORT jint JNI_OnLoad_relcaps002(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -336,7 +336,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -351,7 +351,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&initCaps, 0, sizeof(jvmtiCapabilities));
@@ -364,7 +364,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResourceExhausted/resexhausted.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResourceExhausted/resexhausted.cpp
index b3c6304ee0c..f5a68c17ec7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResourceExhausted/resexhausted.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResourceExhausted/resexhausted.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@
 
 extern "C" {
 
-static jvmtiEnv* gJvmti = NULL;
+static jvmtiEnv* gJvmti = nullptr;
 static volatile jint gEventFlags = 0;
 
 void JNICALL
@@ -80,7 +80,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
 
-    if (!NSK_VERIFY((gJvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != NULL))
+    if (!NSK_VERIFY((gJvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&capabilities, 0, sizeof(jvmtiCapabilities));
@@ -96,7 +96,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
 
     if (!NSK_JVMTI_VERIFY(gJvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                            JVMTI_EVENT_RESOURCE_EXHAUSTED,
-                                                           NULL)))
+                                                           nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThread/resumethrd001/resumethrd001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThread/resumethrd001/resumethrd001.cpp
index 97689802db3..a3e0ee7e80d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThread/resumethrd001/resumethrd001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThread/resumethrd001/resumethrd001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,11 +49,11 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     /* perform testing */
     {
-        jthread testedThread = NULL;
+        jthread testedThread = nullptr;
 
         NSK_DISPLAY1("Find thread: %s\n", THREAD_NAME);
         if (!NSK_VERIFY((testedThread =
-                nsk_jvmti_threadByName(THREAD_NAME)) != NULL))
+                nsk_jvmti_threadByName(THREAD_NAME)) != nullptr))
             return;
         NSK_DISPLAY1("  ... found thread: %p\n", (void*)testedThread);
 
@@ -118,7 +118,7 @@ JNIEXPORT jint JNI_OnLoad_resumethrd001(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -128,7 +128,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -141,7 +141,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThread/resumethrd002/resumethrd002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThread/resumethrd002/resumethrd002.cpp
index 55a06f21bbc..9afbc2a22d9 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThread/resumethrd002/resumethrd002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThread/resumethrd002/resumethrd002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -46,7 +46,7 @@ static jvmtiEvent eventsList[EVENTS_COUNT] = {
 };
 
 static volatile int eventsReceived = 0;
-static jthread testedThread = NULL;
+static jthread testedThread = nullptr;
 
 /* ============================================================================= */
 
@@ -62,13 +62,13 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     {
         NSK_DISPLAY1("Find thread: %s\n", THREAD_NAME);
         if (!NSK_VERIFY((testedThread =
-                nsk_jvmti_threadByName(THREAD_NAME)) != NULL))
+                nsk_jvmti_threadByName(THREAD_NAME)) != nullptr))
             return;
         NSK_DISPLAY1("  ... found thread: %p\n", (void*)testedThread);
 
         eventsReceived = 0;
         NSK_DISPLAY1("Enable event: %s\n", "THREAD_END");
-        if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL))
+        if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr))
             return;
 
         NSK_DISPLAY1("Suspend thread: %p\n", (void*)testedThread);
@@ -102,7 +102,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         }
 
         NSK_DISPLAY1("Disable event: %s\n", "THREAD_END");
-        if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL))
+        if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr))
             return;
 
         NSK_DISPLAY0("Wait for thread to finish\n");
@@ -124,7 +124,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 JNIEXPORT void JNICALL
 callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
     /* check if event is for tested thread */
-    if (thread != NULL &&
+    if (thread != nullptr &&
                 jni->IsSameObject(testedThread, thread)) {
         NSK_DISPLAY1("  ... received THREAD_END event for tested thread: %p\n", (void*)thread);
         eventsReceived++;
@@ -148,7 +148,7 @@ JNIEXPORT jint JNI_OnLoad_resumethrd002(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -158,7 +158,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -180,7 +180,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThreadList/resumethrdlst001/resumethrdlst001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThreadList/resumethrdlst001/resumethrdlst001.cpp
index b513fa47ec0..f0c21a7643d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThreadList/resumethrdlst001/resumethrdlst001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThreadList/resumethrdlst001/resumethrdlst001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -57,8 +57,8 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     /* perform testing */
     {
-        jthread* threads = NULL;
-        jvmtiError* results = NULL;
+        jthread* threads = nullptr;
+        jvmtiError* results = nullptr;
         int i;
 
         NSK_DISPLAY1("Allocate threads array: %d threads\n", threadsCount);
@@ -138,7 +138,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
         NSK_DISPLAY0("Delete threads references\n");
         for (i = 0; i < threadsCount; i++) {
-            if (threads[i] != NULL)
+            if (threads[i] != nullptr)
                 NSK_TRACE(jni->DeleteGlobalRef(threads[i]));
         }
 
@@ -164,14 +164,14 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 static int fillThreadsByName(jvmtiEnv* jvmti, JNIEnv* jni,
                             const char name[], int foundCount, jthread foundThreads[]) {
     jint count = 0;
-    jthread* threads = NULL;
+    jthread* threads = nullptr;
 
     size_t len = strlen(name);
     int found = 0;
     int i;
 
     for (i = 0; i < foundCount; i++) {
-        foundThreads[i] = NULL;
+        foundThreads[i] = nullptr;
     }
 
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&count, &threads))) {
@@ -188,7 +188,7 @@ static int fillThreadsByName(jvmtiEnv* jvmti, JNIEnv* jni,
             break;
         }
 
-        if (info.name != NULL && strncmp(name, info.name, len) == 0) {
+        if (info.name != nullptr && strncmp(name, info.name, len) == 0) {
             NSK_DISPLAY3("  ... found thread #%d: %p (%s)\n",
                                     found, threads[i], info.name);
             if (found < foundCount)
@@ -216,7 +216,7 @@ static int fillThreadsByName(jvmtiEnv* jvmti, JNIEnv* jni,
     NSK_DISPLAY1("Make global references for threads: %d threads\n", foundCount);
     for (i = 0; i < foundCount; i++) {
         if (!NSK_JNI_VERIFY(jni, (foundThreads[i] = (jthread)
-                    jni->NewGlobalRef(foundThreads[i])) != NULL)) {
+                    jni->NewGlobalRef(foundThreads[i])) != nullptr)) {
             nsk_jvmti_setFailStatus();
             return NSK_FALSE;
         }
@@ -241,7 +241,7 @@ JNIEXPORT jint JNI_OnLoad_resumethrdlst001(JavaVM *jvm, char *options, void *res
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -256,7 +256,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -269,7 +269,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThreadList/resumethrdlst002/resumethrdlst002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThreadList/resumethrdlst002/resumethrdlst002.cpp
index 36caf52c147..f1508b152ce 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThreadList/resumethrdlst002/resumethrdlst002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/ResumeThreadList/resumethrdlst002/resumethrdlst002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -47,7 +47,7 @@ static jvmtiEvent eventsList[EVENTS_COUNT] = {
 };
 
 static int threadsCount = 0;
-static jthread* threads = NULL;
+static jthread* threads = nullptr;
 
 static volatile int eventsReceived = 0;
 static jrawMonitorID eventsReceivedMtx = 0;
@@ -67,7 +67,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     /* perform testing */
     {
-        jvmtiError* results = NULL;
+        jvmtiError* results = nullptr;
         int i;
 
         NSK_DISPLAY1("Allocate threads array: %d threads\n", threadsCount);
@@ -106,7 +106,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
         eventsReceived = 0;
         NSK_DISPLAY1("Enable event: %s\n", "THREAD_END");
-        if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL))
+        if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr))
             return;
 
         NSK_DISPLAY0("Let threads to run and finish\n");
@@ -145,7 +145,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         }
 
         NSK_DISPLAY1("Disable event: %s\n", "THREAD_END");
-        if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL))
+        if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr))
             return;
 
         NSK_DISPLAY0("Wait for thread to finish\n");
@@ -154,7 +154,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
         NSK_DISPLAY0("Delete threads references\n");
         for (i = 0; i < threadsCount; i++) {
-            if (threads[i] != NULL)
+            if (threads[i] != nullptr)
                 NSK_TRACE(jni->DeleteGlobalRef(threads[i]));
         }
 
@@ -180,14 +180,14 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 static int fillThreadsByName(jvmtiEnv* jvmti, JNIEnv* jni,
                             const char name[], int foundCount, jthread foundThreads[]) {
     jint count = 0;
-    jthread* threads = NULL;
+    jthread* threads = nullptr;
 
     size_t len = strlen(name);
     int found = 0;
     int i;
 
     for (i = 0; i < foundCount; i++) {
-        foundThreads[i] = NULL;
+        foundThreads[i] = nullptr;
     }
 
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&count, &threads))) {
@@ -204,7 +204,7 @@ static int fillThreadsByName(jvmtiEnv* jvmti, JNIEnv* jni,
             break;
         }
 
-        if (info.name != NULL && strncmp(name, info.name, len) == 0) {
+        if (info.name != nullptr && strncmp(name, info.name, len) == 0) {
             NSK_DISPLAY3("  ... found thread #%d: %p (%s)\n",
                                     found, threads[i], info.name);
             if (found < foundCount)
@@ -232,7 +232,7 @@ static int fillThreadsByName(jvmtiEnv* jvmti, JNIEnv* jni,
     NSK_DISPLAY1("Make global references for threads: %d threads\n", foundCount);
     for (i = 0; i < foundCount; i++) {
         if (!NSK_JNI_VERIFY(jni, (foundThreads[i] = (jthread)
-                    jni->NewGlobalRef(foundThreads[i])) != NULL)) {
+                    jni->NewGlobalRef(foundThreads[i])) != nullptr)) {
             nsk_jvmti_setFailStatus();
             return NSK_FALSE;
         }
@@ -257,7 +257,7 @@ callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
 
     /* check if event is for tested thread */
     for (i = 0; i < threadsCount; i++) {
-        if (thread != NULL &&
+        if (thread != nullptr &&
                 jni->IsSameObject(threads[i], thread)) {
             NSK_DISPLAY2("  ... received THREAD_END event for thread #%d: %p\n",
                                                                     i, (void*)thread);
@@ -285,7 +285,7 @@ JNIEXPORT jint JNI_OnLoad_resumethrdlst002(JavaVM *jvm, char *options, void *res
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -300,7 +300,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -329,7 +329,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RetransformClasses/retransform002/retransform002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RetransformClasses/retransform002/retransform002.cpp
index c9078ea5784..e3bb7f6d611 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RetransformClasses/retransform002/retransform002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RetransformClasses/retransform002/retransform002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -30,7 +30,7 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 /* ============================================================================= */
 
@@ -101,7 +101,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
         return JNI_ERR;
 
     if (!NSK_VERIFY(
-                (jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != NULL
+                (jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != nullptr
                 )
        )
         return JNI_ERR;
@@ -125,7 +125,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
     // Enable class retransformation
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_CLASS_FILE_LOAD_HOOK,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RetransformClasses/retransform003/retransform003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RetransformClasses/retransform003/retransform003.cpp
index 4034dc558f8..69800c848e8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RetransformClasses/retransform003/retransform003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RetransformClasses/retransform003/retransform003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 
 /* ============================================================================= */
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 /* Class, which contains the following callback method:
  *    static public void callback(String className, int agentID) */
@@ -93,31 +93,31 @@ ClassFileLoadHook (
     jstring class_name_string;
 
     // Check whether currently retransformed class belongs to the package we are interested in
-    if (name == NULL || strncmp(TRIGGER, name,strlen(name) < strlen(TRIGGER) ? strlen(name) : strlen(TRIGGER)))
+    if (name == nullptr || strncmp(TRIGGER, name,strlen(name) < strlen(TRIGGER) ? strlen(name) : strlen(TRIGGER)))
     {
         return;
     }
 
     // Get ant the invoke callback function
-    if (!NSK_VERIFY((loader_class = jni->GetObjectClass(loader)) != NULL))
+    if (!NSK_VERIFY((loader_class = jni->GetObjectClass(loader)) != nullptr))
         return;
 
     if (!NSK_VERIFY((method_id = jni->GetMethodID(
-            loader_class, "loadClass", "(Ljava/lang/String;)Ljava/lang/Class;")) != NULL))
+            loader_class, "loadClass", "(Ljava/lang/String;)Ljava/lang/Class;")) != nullptr))
         return;
 
-    if (!NSK_VERIFY((class_name_string = jni->NewStringUTF(CALLBACK_CLASS_NAME)) != NULL))
+    if (!NSK_VERIFY((class_name_string = jni->NewStringUTF(CALLBACK_CLASS_NAME)) != nullptr))
         return;
 
     if (!NSK_VERIFY((callback_class = (jclass) jni->CallObjectMethod(
-            loader, method_id, class_name_string)) != NULL))
+            loader, method_id, class_name_string)) != nullptr))
         return;
 
     if (!NSK_VERIFY((method_id = jni->GetStaticMethodID(
-            callback_class, "callback", "(Ljava/lang/String;I)V")) != NULL))
+            callback_class, "callback", "(Ljava/lang/String;I)V")) != nullptr))
         return;
 
-    if (!NSK_VERIFY((class_name_string = jni->NewStringUTF(name)) != NULL))
+    if (!NSK_VERIFY((class_name_string = jni->NewStringUTF(name)) != nullptr))
         return;
 
     jni->CallStaticObjectMethod(callback_class, method_id, class_name_string, agent_id);
@@ -151,7 +151,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
 
     agent_id= nsk_jvmti_findOptionIntValue("id", -1);
 
-    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != NULL))
+    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->GetCapabilities(&caps)))
@@ -179,7 +179,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
     if (!NSK_JVMTI_VERIFY(
                 jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                 JVMTI_EVENT_CLASS_FILE_LOAD_HOOK,
-                                                NULL)))
+                                                nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RetransformClasses/retransform004/retransform004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RetransformClasses/retransform004/retransform004.cpp
index 78a4b31d36f..f6f6b9136f4 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RetransformClasses/retransform004/retransform004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RetransformClasses/retransform004/retransform004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 
 /* ============================================================================= */
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 /* ============================================================================= */
 
@@ -106,7 +106,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
     jvmtiCapabilities caps;
 
     if (!NSK_VERIFY(
-                (jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != NULL
+                (jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != nullptr
                 )
        )
         return JNI_ERR;
@@ -131,7 +131,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
     if (!NSK_JVMTI_VERIFY(
                 jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                 JVMTI_EVENT_CLASS_FILE_LOAD_HOOK,
-                                                NULL)))
+                                                nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RunAgentThread/agentthr001/agentthr001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RunAgentThread/agentthr001/agentthr001.cpp
index 775f564f465..bf19ddb4903 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RunAgentThread/agentthr001/agentthr001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RunAgentThread/agentthr001/agentthr001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define WAIT_TIME (jlong)100
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -92,7 +92,7 @@ sys_thread_1(jvmtiEnv* jvmti, JNIEnv* jni, void *p) {
     }
     count |= 0x01;
 
-    err = jvmti->RunAgentThread(jthr(jni), sys_thread_4, NULL,
+    err = jvmti->RunAgentThread(jthr(jni), sys_thread_4, nullptr,
         JVMTI_THREAD_MAX_PRIORITY);
     if (err != JVMTI_ERROR_NONE) {
         printf("(RunAgentThread#4) unexpected error: %s (%d)\n",
@@ -178,7 +178,7 @@ void JNICALL VMInit(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thr) {
     }
 
     err = jvmti_env->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_THREAD_START, NULL);
+            JVMTI_EVENT_THREAD_START, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable JVMTI_EVENT_THREAD_START: %s (%d)\n",
                TranslateError(err), err);
@@ -206,21 +206,21 @@ ThreadStart(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thread) {
     if (strcmp(thrInfo.name, "thr1") == 0 && !thr1_was_started) {
         thr1_was_started = 1;
         err = jvmti_env->RunAgentThread(jthr((JNIEnv *)env),
-            sys_thread_1, NULL, JVMTI_THREAD_MAX_PRIORITY);
+            sys_thread_1, nullptr, JVMTI_THREAD_MAX_PRIORITY);
         if (err != JVMTI_ERROR_NONE) {
             printf("(RunAgentThread#1) unexpected error: %s (%d)\n",
                    TranslateError(err), err);
             result = STATUS_FAILED;
         }
         err = jvmti_env->RunAgentThread(jthr((JNIEnv *)env),
-            sys_thread_2, NULL, JVMTI_THREAD_NORM_PRIORITY);
+            sys_thread_2, nullptr, JVMTI_THREAD_NORM_PRIORITY);
         if (err != JVMTI_ERROR_NONE) {
             printf("(RunAgentThread#2) unexpected error: %s (%d)\n",
                    TranslateError(err), err);
             result = STATUS_FAILED;
         }
         err = jvmti_env->RunAgentThread(jthr((JNIEnv *)env),
-            sys_thread_3, NULL, JVMTI_THREAD_MIN_PRIORITY);
+            sys_thread_3, nullptr, JVMTI_THREAD_MIN_PRIORITY);
         if (err != JVMTI_ERROR_NONE) {
             printf("(RunAgentThread#3) unexpected error: %s (%d)\n",
                    TranslateError(err), err);
@@ -244,12 +244,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -271,7 +271,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_VM_INIT, NULL);
+            JVMTI_EVENT_VM_INIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable JVMTI_EVENT_VM_INIT: %s (%d)\n",
                TranslateError(err), err);
@@ -285,7 +285,7 @@ JNIEXPORT void JNICALL
 Java_nsk_jvmti_RunAgentThread_agentthr001_startSysThr(JNIEnv *env, jclass cls) {
     jvmtiError err;
 
-    err = jvmti->RunAgentThread(jthr(env), sys_thread_5, NULL,
+    err = jvmti->RunAgentThread(jthr(env), sys_thread_5, nullptr,
         JVMTI_THREAD_MAX_PRIORITY);
     if (err != JVMTI_ERROR_NONE) {
         printf("(RunAgentThread#5) unexpected error: %s (%d)\n",
@@ -308,7 +308,7 @@ Java_nsk_jvmti_RunAgentThread_agentthr001_getRes(JNIEnv *env, jclass cls) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_DISABLE,
-            JVMTI_EVENT_THREAD_START, NULL);
+            JVMTI_EVENT_THREAD_START, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to disable JVMTI_EVENT_THREAD_START: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RunAgentThread/agentthr002/agentthr002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RunAgentThread/agentthr002/agentthr002.cpp
index b66836e8ed3..f155561f129 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RunAgentThread/agentthr002/agentthr002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RunAgentThread/agentthr002/agentthr002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static jrawMonitorID wait_lock;
@@ -52,12 +52,12 @@ JNIEXPORT jint JNI_OnLoad_agentthr002(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -94,7 +94,7 @@ Java_nsk_jvmti_RunAgentThread_agentthr002_check(JNIEnv *env, jclass cls, jthread
     jvmtiError err;
     jvmtiThreadInfo inf;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -109,7 +109,7 @@ Java_nsk_jvmti_RunAgentThread_agentthr002_check(JNIEnv *env, jclass cls, jthread
     if (printdump == JNI_TRUE) {
         printf(">>> starting debug thread ...\n");
     }
-    err = jvmti->RunAgentThread(thr, debug_thread, NULL,
+    err = jvmti->RunAgentThread(thr, debug_thread, nullptr,
                                 JVMTI_THREAD_NORM_PRIORITY);
     if (err != JVMTI_ERROR_NONE) {
         printf("(RunAgentThread) unexpected error: %s (%d)\n",
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RunAgentThread/agentthr003/agentthr003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RunAgentThread/agentthr003/agentthr003.cpp
index 607b9f00557..95bb3e30fa1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RunAgentThread/agentthr003/agentthr003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RunAgentThread/agentthr003/agentthr003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_agentthr003(JavaVM *jvm, char *options, void *reserved
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -75,7 +75,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_RunAgentThread_agentthr003_check(JNIEnv *env, jclass cls, jthread thr) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -83,7 +83,7 @@ Java_nsk_jvmti_RunAgentThread_agentthr003_check(JNIEnv *env, jclass cls, jthread
     if (printdump == JNI_TRUE) {
         printf(">>> invalid thread check ...\n");
     }
-    err = jvmti->RunAgentThread(NULL, agent_thread, NULL,
+    err = jvmti->RunAgentThread(nullptr, agent_thread, nullptr,
                                 JVMTI_THREAD_NORM_PRIORITY);
     if (err != JVMTI_ERROR_INVALID_THREAD) {
         printf("Error expected: JVMTI_ERROR_INVALID_THREAD,\n");
@@ -94,7 +94,7 @@ Java_nsk_jvmti_RunAgentThread_agentthr003_check(JNIEnv *env, jclass cls, jthread
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->RunAgentThread(thr, NULL, NULL,
+    err = jvmti->RunAgentThread(thr, nullptr, nullptr,
                                 JVMTI_THREAD_NORM_PRIORITY);
     if (err != JVMTI_ERROR_NULL_POINTER) {
         printf("Error expected: JVMTI_ERROR_NULL_POINTER,\n");
@@ -105,7 +105,7 @@ Java_nsk_jvmti_RunAgentThread_agentthr003_check(JNIEnv *env, jclass cls, jthread
     if (printdump == JNI_TRUE) {
         printf(">>> less than JVMTI_THREAD_MIN_PRIORITY check ...\n");
     }
-    err = jvmti->RunAgentThread(thr, agent_thread, NULL,
+    err = jvmti->RunAgentThread(thr, agent_thread, nullptr,
                                 JVMTI_THREAD_MIN_PRIORITY - 1);
     if (err != JVMTI_ERROR_INVALID_PRIORITY) {
         printf("Error expected: JVMTI_ERROR_INVALID_PRIORITY,\n");
@@ -116,7 +116,7 @@ Java_nsk_jvmti_RunAgentThread_agentthr003_check(JNIEnv *env, jclass cls, jthread
     if (printdump == JNI_TRUE) {
         printf(">>> greater than JVMTI_THREAD_MAX_PRIORITY check ...\n");
     }
-    err = jvmti->RunAgentThread(thr, agent_thread, NULL,
+    err = jvmti->RunAgentThread(thr, agent_thread, nullptr,
                                 JVMTI_THREAD_MAX_PRIORITY + 1);
     if (err != JVMTI_ERROR_INVALID_PRIORITY) {
         printf("Error expected: JVMTI_ERROR_INVALID_PRIORITY,\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk002/setbrk002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk002/setbrk002.cpp
index 5bee6195805..51a2c0ca72c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk002/setbrk002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk002/setbrk002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -97,7 +97,7 @@ Java_nsk_jvmti_SetBreakpoint_setbrk002_check(JNIEnv *env, jclass cls) {
     jlocation start;
     jlocation end;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -107,7 +107,7 @@ Java_nsk_jvmti_SetBreakpoint_setbrk002_check(JNIEnv *env, jclass cls) {
     }
 
     mid = env->GetStaticMethodID(cls, "run", "([Ljava/lang/String;Ljava/io/PrintStream;)I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find method run\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk003/setbrk003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk003/setbrk003.cpp
index b996ed3f021..3f61346a1ea 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk003/setbrk003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk003/setbrk003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -96,7 +96,7 @@ Java_nsk_jvmti_SetBreakpoint_setbrk003_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jmethodID mid;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -106,7 +106,7 @@ Java_nsk_jvmti_SetBreakpoint_setbrk003_check(JNIEnv *env, jclass cls) {
     }
 
     mid = env->GetStaticMethodID(cls, "check", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find method check\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk005/setbrk005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk005/setbrk005.cpp
index 462cbe0417b..8c6d5051420 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk005/setbrk005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk005/setbrk005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -96,7 +96,7 @@ Java_nsk_jvmti_SetBreakpoint_setbrk005_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jmethodID mid;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -106,7 +106,7 @@ Java_nsk_jvmti_SetBreakpoint_setbrk005_check(JNIEnv *env, jclass cls) {
     }
 
     mid = env->GetStaticMethodID(cls, "trial", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find method trial\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk007/setbrk007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk007/setbrk007.cpp
index 79b93a9fbf7..60d56f40aae 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk007/setbrk007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk007/setbrk007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -96,7 +96,7 @@ Java_nsk_jvmti_SetBreakpoint_setbrk007_check(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jmethodID mid;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -114,7 +114,7 @@ Java_nsk_jvmti_SetBreakpoint_setbrk007_check(JNIEnv *env, jclass cls) {
     if (printdump == JNI_TRUE) {
         printf(">>> invalid method check ...\n");
     }
-    err = jvmti->SetBreakpoint(NULL, 0);
+    err = jvmti->SetBreakpoint(nullptr, 0);
     if (err != JVMTI_ERROR_INVALID_METHODID) {
         printf("Error expected: JVMTI_ERROR_INVALID_METHODID,\n");
         printf("\tactual: %s (%d)\n", TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk008/setbrk008.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk008/setbrk008.cpp
index 7d893b36a50..b002b2ce371 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk008/setbrk008.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetBreakpoint/setbrk008/setbrk008.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
@@ -82,17 +82,17 @@ void JNICALL Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *env,
         printf(">>>     method: \"%s%s\"\n", name, sig);
         printf(">>>   location: 0x%x%08x\n", (jint)(loc >> 32), (jint)loc);
     }
-    if (name == NULL || strcmp(cls_sig, exp_csig) != 0) {
+    if (name == nullptr || strcmp(cls_sig, exp_csig) != 0) {
         printf("(bp#%d) wrong class: \"%s\"", eventsCount, cls_sig);
         printf(", expected: \"%s\"\n", exp_csig);
         result = STATUS_FAILED;
     }
-    if (name == NULL || strcmp(name, exp_name) != 0) {
+    if (name == nullptr || strcmp(name, exp_name) != 0) {
         printf("(bp#%d) wrong method name: \"%s\"", eventsCount, name);
         printf(", expected: \"%s\"\n", exp_name);
         result = STATUS_FAILED;
     }
-    if (sig == NULL || strcmp(sig, exp_sig) != 0) {
+    if (sig == nullptr || strcmp(sig, exp_sig) != 0) {
         printf("(bp#%d) wrong method sig: \"%s\"", eventsCount, sig);
         printf(", expected: \"%s\"\n", exp_sig);
         result = STATUS_FAILED;
@@ -119,12 +119,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -171,7 +171,7 @@ Java_nsk_jvmti_SetBreakpoint_setbrk008_getReady(JNIEnv *env,
     jvmtiError err;
     jmethodID mid;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -182,7 +182,7 @@ Java_nsk_jvmti_SetBreakpoint_setbrk008_getReady(JNIEnv *env,
     }
 
     mid = env->GetStaticMethodID(cls, exp_name, exp_sig);
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find Method ID for method checkPoint\n");
         result = STATUS_FAILED;
         return;
@@ -201,7 +201,7 @@ Java_nsk_jvmti_SetBreakpoint_setbrk008_getReady(JNIEnv *env,
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEnvironmentLocalStorage/setenvstor001/setenvstor001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEnvironmentLocalStorage/setenvstor001/setenvstor001.cpp
index 98400d75bf7..265b10c1083 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEnvironmentLocalStorage/setenvstor001/setenvstor001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEnvironmentLocalStorage/setenvstor001/setenvstor001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -85,7 +85,7 @@ static int setEnvStorage(jvmtiEnv* jvmti, StorageStructure* storage, const char
  * @returns NSK_FALSE if any error occured.
  */
 static int checkEnvStorage(jvmtiEnv* jvmti, StorageStructure* initialStorage, const char where[]) {
-    StorageStructure* storage = NULL;
+    StorageStructure* storage = nullptr;
 
     NSK_DISPLAY0("Get local storage for current JVMTI env\n");
     if (!NSK_JVMTI_VERIFY(jvmti->GetEnvironmentLocalStorage((void**)&storage))) {
@@ -170,7 +170,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     success = checkEnvStorage(jvmti, initialStorage, "VM_DEATH callback");
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -197,7 +197,7 @@ JNIEXPORT jint JNI_OnLoad_setenvstor001(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -205,7 +205,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -220,7 +220,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY1(">>> Prepare storage data at pointer: 0x%p\n", initialStorage);
@@ -237,7 +237,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEnvironmentLocalStorage/setenvstor002/setenvstor002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEnvironmentLocalStorage/setenvstor002/setenvstor002.cpp
index 9d53a2ad37a..7194016b9aa 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEnvironmentLocalStorage/setenvstor002/setenvstor002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEnvironmentLocalStorage/setenvstor002/setenvstor002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -85,7 +85,7 @@ static int setEnvStorage(jvmtiEnv* jvmti, StorageStructure* storage, const char
  * @returns NSK_FALSE if any error occured.
  */
 static int checkEnvStorage(jvmtiEnv* jvmti, StorageStructure* initialStorage, const char where[]) {
-    StorageStructure* storage = NULL;
+    StorageStructure* storage = nullptr;
 
     NSK_DISPLAY0("Get local storage for current JVMTI env\n");
     if (!NSK_JVMTI_VERIFY(jvmti->GetEnvironmentLocalStorage((void**)&storage))) {
@@ -175,7 +175,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     success = checkEnvStorage(jvmti, initialStorage, "VM_DEATH callback");
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -202,7 +202,7 @@ JNIEXPORT jint JNI_OnLoad_setenvstor002(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -210,7 +210,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -225,14 +225,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY1(">>> Prepare storage data at pointer: 0x%p\n", initialStorage);
     fillEnvStorage(initialStorage);
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEnvironmentLocalStorage/setenvstor003/setenvstor003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEnvironmentLocalStorage/setenvstor003/setenvstor003.cpp
index 6c3ec2145a3..89ee7cc2887 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEnvironmentLocalStorage/setenvstor003/setenvstor003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEnvironmentLocalStorage/setenvstor003/setenvstor003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -85,7 +85,7 @@ static int setEnvStorage(jvmtiEnv* jvmti, StorageStructure* storage, const char
  * @returns NSK_FALSE if any error occured.
  */
 static int checkEnvStorage(jvmtiEnv* jvmti, StorageStructure* initialStorage, const char where[]) {
-    StorageStructure* storage = NULL;
+    StorageStructure* storage = nullptr;
 
     NSK_DISPLAY0("Get local storage for current JVMTI env\n");
     if (!NSK_JVMTI_VERIFY(jvmti->GetEnvironmentLocalStorage((void**)&storage))) {
@@ -178,7 +178,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     success = checkEnvStorage(jvmti, initialStorage, "VM_DEATH callback");
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -205,7 +205,7 @@ JNIEXPORT jint JNI_OnLoad_setenvstor003(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -213,7 +213,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -228,14 +228,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY1(">>> Prepare storage data at pointer: 0x%p\n", initialStorage);
     fillEnvStorage(initialStorage);
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventCallbacks/setevntcallb001/setevntcallb001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventCallbacks/setevntcallb001/setevntcallb001.cpp
index 9b15148fe19..06fe61853f5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventCallbacks/setevntcallb001/setevntcallb001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventCallbacks/setevntcallb001/setevntcallb001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -101,7 +101,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     NSK_DISPLAY0("Disable events\n");
-    nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL);
+    nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr);
 
     NSK_DISPLAY0("Let debugee to finish\n");
     if (!nsk_jvmti_resumeSync())
@@ -146,7 +146,7 @@ callbackVMInit(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
         if (!NSK_JVMTI_VERIFY(jvmti->SetEventCallbacks(&eventCallbacks, sizeof(eventCallbacks)))) {
             nsk_jvmti_setFailStatus();
         } else {
-            nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT - 1, eventsList + 1, NULL);
+            nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT - 1, eventsList + 1, nullptr);
         }
     }
 }
@@ -166,7 +166,7 @@ JNIEXPORT jint JNI_OnLoad_setevntcallb001(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -174,10 +174,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Testcase #1: Set callbacks for VM_INIT event\n");
@@ -191,7 +191,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         if (!NSK_JVMTI_VERIFY(jvmti->SetEventCallbacks(&eventCallbacks, sizeof(eventCallbacks)))) {
             nsk_jvmti_setFailStatus();
         } else {
-            nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, eventsList, NULL);
+            nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, eventsList, nullptr);
         }
     }
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventCallbacks/setevntcallb002/setevntcallb002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventCallbacks/setevntcallb002/setevntcallb002.cpp
index 65f8a2fd3f4..44535b30c11 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventCallbacks/setevntcallb002/setevntcallb002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventCallbacks/setevntcallb002/setevntcallb002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -83,7 +83,7 @@ static int checkEventCounts() {
 
     for (i = 1; i < EVENTS_COUNT; i++) {
         if (eventsCountList[i] > 0) {
-            NSK_COMPLAIN2("# %s event callback was invoked after SetEventCallbacks(NULL):\n"
+            NSK_COMPLAIN2("# %s event callback was invoked after SetEventCallbacks(null):\n"
                           "#   invoked: %d times\n",
                           eventsNameList[i], eventsCountList[i]);
             success = NSK_FALSE;
@@ -108,7 +108,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     NSK_DISPLAY0("Disable events\n");
-    nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL);
+    nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr);
 
     NSK_DISPLAY0("Let debugee to finish\n");
     if (!nsk_jvmti_resumeSync())
@@ -143,13 +143,13 @@ callbackVMInit(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
     NSK_DISPLAY1("  <VM_INIT>: thread: 0x%p\n", (void*)thread);
     eventsCountList[0]++;
 
-    NSK_DISPLAY0(">>> Testcase #2: Set NULL for events callbacks\n");
+    NSK_DISPLAY0(">>> Testcase #2: Set null for events callbacks\n");
     {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventCallbacks(NULL, 0))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventCallbacks(nullptr, 0))) {
             nsk_jvmti_setFailStatus();
         }
 
-        nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT - 1, eventsList + 1, NULL);
+        nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT - 1, eventsList + 1, nullptr);
     }
 }
 
@@ -168,7 +168,7 @@ JNIEXPORT jint JNI_OnLoad_setevntcallb002(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -176,10 +176,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Testcase #1: Set callbacks for all tested events\n");
@@ -195,7 +195,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         if (!NSK_JVMTI_VERIFY(jvmti->SetEventCallbacks(&eventCallbacks, sizeof(eventCallbacks)))) {
             nsk_jvmti_setFailStatus();
         } else {
-            nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, eventsList, NULL);
+            nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, eventsList, nullptr);
         }
     }
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventCallbacks/setevntcallb003/setevntcallb003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventCallbacks/setevntcallb003/setevntcallb003.cpp
index 72511c6776d..2b4d9aa05c5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventCallbacks/setevntcallb003/setevntcallb003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventCallbacks/setevntcallb003/setevntcallb003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -108,7 +108,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     NSK_DISPLAY0("Disable events\n");
-    nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL);
+    nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr);
 
     NSK_DISPLAY0("Let debugee to finish\n");
     if (!nsk_jvmti_resumeSync())
@@ -155,7 +155,7 @@ callbackVMInit(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
             nsk_jvmti_setFailStatus();
         }
 
-        nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT - 1, eventsList + 1, NULL);
+        nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT - 1, eventsList + 1, nullptr);
     }
 }
 
@@ -174,7 +174,7 @@ JNIEXPORT jint JNI_OnLoad_setevntcallb003(JavaVM *jvm, char *options, void *rese
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -182,10 +182,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Testcase #1: Set callbacks for all tested events\n");
@@ -199,7 +199,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         if (!NSK_JVMTI_VERIFY(jvmti->SetEventCallbacks(&eventCallbacks, sizeof(eventCallbacks)))) {
             nsk_jvmti_setFailStatus();
         } else {
-            nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, eventsList, NULL);
+            nsk_jvmti_enableEvents(JVMTI_ENABLE, 1, eventsList, nullptr);
         }
     }
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventNotificationMode/setnotif001/setnotif001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventNotificationMode/setnotif001/setnotif001.cpp
index 135f51a86f9..bd2c5ab397e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventNotificationMode/setnotif001/setnotif001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetEventNotificationMode/setnotif001/setnotif001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,11 +34,11 @@ extern "C" {
 #define STATUS_FAILED 2
 #define SCALE_SIZE (JVMTI_MAX_EVENT_TYPE_VAL + 1)
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jrawMonitorID access_lock;
-static jobject notifyFramePopThread = NULL;
+static jobject notifyFramePopThread = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static int flag = 0;
@@ -78,7 +78,7 @@ void disable(jvmtiEnv *jvmti_env, jvmtiEvent kind) {
         printf(">>> disabling %s\n", TranslateEvent(kind));
     }
     err = jvmti_env->SetEventNotificationMode(
-        JVMTI_DISABLE, kind, NULL);
+        JVMTI_DISABLE, kind, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Fail to disable %s: %s (%d)\n",
                TranslateEvent(kind), TranslateError(err), err);
@@ -99,7 +99,7 @@ void enable(jvmtiEnv *jvmti_env, jvmtiEvent kind) {
         result = STATUS_FAILED;
     }
     err = jvmti_env->SetEventNotificationMode(
-        JVMTI_ENABLE, kind, NULL);
+        JVMTI_ENABLE, kind, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Fail to enable %s: %s (%d)\n",
                TranslateEvent(kind), TranslateError(err), err);
@@ -121,8 +121,8 @@ void setWatches(jvmtiEnv *jvmti_env, JNIEnv *env, jclass cls) {
     jmethodID mid;
 
     mid = env->GetStaticMethodID(cls, "meth01", "(I)V");
-    if (mid == NULL) {
-      printf("(GetStaticMethodID) returns NULL");
+    if (mid == nullptr) {
+      printf("(GetStaticMethodID) returns null");
       result = STATUS_FAILED;
       return;
     }
@@ -309,7 +309,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
@@ -317,7 +317,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     memset(ev_scale, 0, SCALE_SIZE);
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetExtensionEventCallback/setextevent001/setextevent001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetExtensionEventCallback/setextevent001/setextevent001.cpp
index 9088e6047f2..fc32a11a0ad 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetExtensionEventCallback/setextevent001/setextevent001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetExtensionEventCallback/setextevent001/setextevent001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -44,7 +44,7 @@ callbackExtensionEvent(jvmtiEnv* jvmti, ...) {
 static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
     int success = NSK_TRUE;
     jint extCount = 0;
-    jvmtiExtensionEventInfo* extList = NULL;
+    jvmtiExtensionEventInfo* extList = nullptr;
     int i;
 
     NSK_DISPLAY0("Get extension events list\n");
@@ -58,7 +58,7 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
         NSK_DISPLAY1("# WARNING: No extension events implemented to check: %d\n", extCount);
     } else {
 
-        if (!NSK_VERIFY(extList != NULL))
+        if (!NSK_VERIFY(extList != nullptr))
             return NSK_FALSE;
 
         NSK_DISPLAY1("Set/clear callback for each extension event: %d events\n", (int)extCount);
@@ -76,9 +76,9 @@ static int checkExtensions(jvmtiEnv* jvmti, const char phase[]) {
             }
             NSK_DISPLAY0("    ... done\n");
 
-            NSK_DISPLAY1("    ... clearing callback: 0x%p\n", (void*)NULL);
+            NSK_DISPLAY1("    ... clearing callback: 0x%p\n", nullptr);
             if (!NSK_JVMTI_VERIFY(
-                    jvmti->SetExtensionEventCallback(extList[i].extension_event_index, NULL))) {
+                    jvmti->SetExtensionEventCallback(extList[i].extension_event_index, nullptr))) {
                 success = NSK_FALSE;
             }
             NSK_DISPLAY0("    ... done\n");
@@ -130,7 +130,7 @@ JNIEXPORT jint JNI_OnLoad_setextevent001(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -138,7 +138,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Testcase #1: Check setting extension event callbacks in OnLoad phase\n");
@@ -148,7 +148,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw001/setfldw001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw001/setfldw001.cpp
index ddd5ed6e82c..e28cffa3bc0 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw001/setfldw001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw001/setfldw001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,12 +48,12 @@ static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static field fields[] = {
-    { "nsk/jvmti/SetFieldAccessWatch/setfldw001", "fld0", "I", 0, NULL, NULL },
-    { "nsk/jvmti/SetFieldAccessWatch/setfldw001", "fld1", "I", 1, NULL, NULL },
+    { "nsk/jvmti/SetFieldAccessWatch/setfldw001", "fld0", "I", 0, nullptr, nullptr },
+    { "nsk/jvmti/SetFieldAccessWatch/setfldw001", "fld1", "I", 1, nullptr, nullptr },
     { "nsk/jvmti/SetFieldAccessWatch/setfldw001", "fld2",
-      "Lnsk/jvmti/SetFieldAccessWatch/setfldw001a;", 0, NULL, NULL },
-    { "nsk/jvmti/SetFieldAccessWatch/setfldw001a", "fld3", "[I", 0, NULL, NULL },
-    { "nsk/jvmti/SetFieldAccessWatch/setfldw001b", "fld4", "F", 0, NULL, NULL },
+      "Lnsk/jvmti/SetFieldAccessWatch/setfldw001a;", 0, nullptr, nullptr },
+    { "nsk/jvmti/SetFieldAccessWatch/setfldw001a", "fld3", "[I", 0, nullptr, nullptr },
+    { "nsk/jvmti/SetFieldAccessWatch/setfldw001b", "fld4", "F", 0, nullptr, nullptr },
 };
 
 void setWatch(JNIEnv *env, jint ind) {
@@ -62,12 +62,12 @@ void setWatch(JNIEnv *env, jint ind) {
     field fld = fields[ind];
 
     cls = env->FindClass(fld.klass);
-    if (cls == NULL) {
+    if (cls == nullptr) {
         printf("Cannot find class \"%s\"\n", fld.klass);
         result = STATUS_FAILED;
         return;
     }
-    if (fld.fid == NULL) {
+    if (fld.fid == nullptr) {
         if (fld.stat) {
             fields[ind].fid = env->GetStaticFieldID(cls, fld.name, fld.sig);
         } else {
@@ -90,18 +90,18 @@ void JNICALL FieldAccess(jvmtiEnv *jvmti_env, JNIEnv *env,
         jthread thr, jmethodID method,
         jlocation location, jclass field_klass, jobject obj, jfieldID field) {
 
-    char *fld_name = NULL;
+    char *fld_name = nullptr;
     jint fld_ind = 0;
     size_t len = 0;
     jvmtiError err = jvmti_env->GetFieldName(field_klass, field,
-                                                &fld_name, NULL, NULL);
+                                                &fld_name, nullptr, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Error in GetFieldName: %s (%d)\n", TranslateError(err), err);
         result = STATUS_FAILED;
         return;
     }
-    if (fld_name == NULL) {
-        printf("GetFieldName returned NULL field name\n");
+    if (fld_name == nullptr) {
+        printf("GetFieldName returned null field name\n");
         result = STATUS_FAILED;
         return;
     }
@@ -133,7 +133,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -169,7 +169,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
 
         err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                JVMTI_EVENT_FIELD_ACCESS, NULL);
+                JVMTI_EVENT_FIELD_ACCESS, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to enable JVMTI_EVENT_FIELD_ACCESS: %s (%d)\n",
                    TranslateError(err), err);
@@ -203,7 +203,7 @@ Java_nsk_jvmti_SetFieldAccessWatch_setfldw001_check(JNIEnv *env,
     jfieldID thrown_fid = fields[fld_ind].thrown_fid;
 
     if (caps.can_generate_field_access_events) {
-        if (flag == JNI_FALSE && thrown_fid != NULL) {
+        if (flag == JNI_FALSE && thrown_fid != nullptr) {
             result = STATUS_FAILED;
             printf("(Field %d) FIELD_ACCESS event without access watch set\n",
                    fld_ind);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw002/setfldw002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw002/setfldw002.cpp
index 11161cffd8a..db4b0c401e3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw002/setfldw002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw002/setfldw002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -59,7 +59,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -95,7 +95,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
 
         err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                JVMTI_EVENT_FIELD_ACCESS, NULL);
+                JVMTI_EVENT_FIELD_ACCESS, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to enable JVMTI_EVENT_FIELD_ACCESS: %s (%d)\n",
                    TranslateError(err), err);
@@ -123,14 +123,14 @@ Java_nsk_jvmti_SetFieldAccessWatch_setfldw002_check(JNIEnv *env, jclass cls) {
             printf(" %s (%d)\n", TranslateError(err), err);
         }
     } else {
-        err = jvmti->SetFieldAccessWatch(NULL, fid);
+        err = jvmti->SetFieldAccessWatch(nullptr, fid);
         if (err != JVMTI_ERROR_INVALID_CLASS) {
             result = STATUS_FAILED;
             printf("Failed to return JVMTI_ERROR_INVALID_CLASS: %s (%d)\n",
                    TranslateError(err), err);
         }
 
-        err = jvmti->SetFieldAccessWatch(cls, NULL);
+        err = jvmti->SetFieldAccessWatch(cls, nullptr);
         if (err != JVMTI_ERROR_INVALID_FIELDID) {
             result = STATUS_FAILED;
             printf("Failed to return JVMTI_ERROR_INVALID_FIELDID: %s (%d)\n",
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw003/setfldw003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw003/setfldw003.cpp
index 303888a53cc..058cc381622 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw003/setfldw003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw003/setfldw003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,8 +39,8 @@ static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
-static jfieldID actual_fid = NULL;
-static jfieldID fids[4] = { NULL, NULL, NULL, NULL };
+static jfieldID actual_fid = nullptr;
+static jfieldID fids[4] = { nullptr, nullptr, nullptr, nullptr };
 
 void JNICALL FieldAccess(jvmtiEnv *jvmti_env, JNIEnv *env,
         jthread thr, jmethodID method,
@@ -66,12 +66,12 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -126,7 +126,7 @@ Java_nsk_jvmti_SetFieldAccessWatch_setfldw003_getReady(JNIEnv *env, jclass cls)
     fids[2] = env->GetFieldID(cls, "fld2", "I");
     fids[3] = env->GetFieldID(cls, "fld3", "I");
     for (i = 0; i < sizeof(fids) / sizeof(jfieldID); i++) {
-        if (fids[i] == NULL) {
+        if (fids[i] == nullptr) {
             printf("Unable to set field access watch on fld%" PRIuPTR ", fieldID=0", i);
         } else {
             if (printdump == JNI_TRUE) {
@@ -142,7 +142,7 @@ Java_nsk_jvmti_SetFieldAccessWatch_setfldw003_getReady(JNIEnv *env, jclass cls)
         }
     }
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_FIELD_ACCESS, NULL);
+        JVMTI_EVENT_FIELD_ACCESS, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("(SetEventNotificationMode) unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -161,7 +161,7 @@ Java_nsk_jvmti_SetFieldAccessWatch_setfldw003_check(JNIEnv *env,
         printf("Field fld%d: thrown field ID expected=0x%p, actual=0x%p\n",
                ind, fids[ind], actual_fid);
     }
-    actual_fid = NULL;
+    actual_fid = nullptr;
 }
 
 JNIEXPORT jint JNICALL
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw004/setfldw004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw004/setfldw004.cpp
index a09bc425576..7474fd97c1a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw004/setfldw004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw004/setfldw004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,8 +39,8 @@ static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
-static jfieldID actual_fid = NULL;
-static jfieldID fids[4] = { NULL, NULL, NULL, NULL };
+static jfieldID actual_fid = nullptr;
+static jfieldID fids[4] = { nullptr, nullptr, nullptr, nullptr };
 
 void JNICALL FieldAccess(jvmtiEnv *jvmti_env, JNIEnv *env,
         jthread thr, jmethodID method,
@@ -66,12 +66,12 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -133,7 +133,7 @@ Java_nsk_jvmti_SetFieldAccessWatch_setfldw004_getReady(JNIEnv *env, jclass cls)
     fids[2] = env->GetFieldID(cls, "fld2", "I");
     fids[3] = env->GetFieldID(cls, "fld3", "I");
     for (i = 0; i < sizeof(fids) / sizeof(jfieldID); i++) {
-        if (fids[i] == NULL) {
+        if (fids[i] == nullptr) {
             printf("Unable to set field access watch on fld%" PRIuPTR ", fieldID=0", i);
         } else {
             if (printdump == JNI_TRUE) {
@@ -149,7 +149,7 @@ Java_nsk_jvmti_SetFieldAccessWatch_setfldw004_getReady(JNIEnv *env, jclass cls)
         }
     }
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_FIELD_ACCESS, NULL);
+        JVMTI_EVENT_FIELD_ACCESS, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("(SetEventNotificationMode) unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -168,7 +168,7 @@ Java_nsk_jvmti_SetFieldAccessWatch_setfldw004_check(JNIEnv *env,
         printf("Field %d: thrown field ID expected=0x%p, actual=0x%p\n",
                ind, fids[ind], actual_fid);
     }
-    actual_fid = NULL;
+    actual_fid = nullptr;
 }
 
 JNIEXPORT jint JNICALL
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw005/setfldw005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw005/setfldw005.cpp
index bc7daad4c70..910cc4ec9dd 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw005/setfldw005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw005/setfldw005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -47,24 +47,24 @@ static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
-static jfieldID actual_fid = NULL;
+static jfieldID actual_fid = nullptr;
 static field fields[] = {
-    { "fld0", "J", JNI_TRUE, NULL, "static long" },
-    { "fld1", "J", JNI_FALSE, NULL, "long" },
-    { "fld2", "F", JNI_TRUE, NULL, "static float" },
-    { "fld3", "F", JNI_FALSE, NULL, "float" },
-    { "fld4", "D", JNI_TRUE, NULL, "static double" },
-    { "fld5", "D", JNI_FALSE, NULL, "double" },
-    { "fld6", "Ljava/lang/Object;", JNI_TRUE, NULL, "static Object" },
-    { "fld7", "Ljava/lang/Object;", JNI_FALSE, NULL, "Object" },
-    { "fld8", "Z", JNI_TRUE, NULL, "static boolean" },
-    { "fld9", "Z", JNI_FALSE, NULL, "boolean" },
-    { "fld10", "B", JNI_TRUE, NULL, "static byte" },
-    { "fld11", "B", JNI_FALSE, NULL, "byte" },
-    { "fld12", "S", JNI_TRUE, NULL, "static short" },
-    { "fld13", "S", JNI_FALSE, NULL, "short" },
-    { "fld14", "C", JNI_TRUE, NULL, "static char" },
-    { "fld15", "C", JNI_FALSE, NULL, "char" }
+    { "fld0", "J", JNI_TRUE, nullptr, "static long" },
+    { "fld1", "J", JNI_FALSE, nullptr, "long" },
+    { "fld2", "F", JNI_TRUE, nullptr, "static float" },
+    { "fld3", "F", JNI_FALSE, nullptr, "float" },
+    { "fld4", "D", JNI_TRUE, nullptr, "static double" },
+    { "fld5", "D", JNI_FALSE, nullptr, "double" },
+    { "fld6", "Ljava/lang/Object;", JNI_TRUE, nullptr, "static Object" },
+    { "fld7", "Ljava/lang/Object;", JNI_FALSE, nullptr, "Object" },
+    { "fld8", "Z", JNI_TRUE, nullptr, "static boolean" },
+    { "fld9", "Z", JNI_FALSE, nullptr, "boolean" },
+    { "fld10", "B", JNI_TRUE, nullptr, "static byte" },
+    { "fld11", "B", JNI_FALSE, nullptr, "byte" },
+    { "fld12", "S", JNI_TRUE, nullptr, "static short" },
+    { "fld13", "S", JNI_FALSE, nullptr, "short" },
+    { "fld14", "C", JNI_TRUE, nullptr, "static char" },
+    { "fld15", "C", JNI_FALSE, nullptr, "char" }
 };
 
 void JNICALL FieldAccess(jvmtiEnv *jvmti_env, JNIEnv *env,
@@ -91,12 +91,12 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -159,7 +159,7 @@ Java_nsk_jvmti_SetFieldAccessWatch_setfldw005_getReady(JNIEnv *env, jclass cls)
         } else {
             fields[i].fid = env->GetFieldID(cls, fields[i].name, fields[i].sig);
         }
-        if (fields[i].fid == NULL) {
+        if (fields[i].fid == nullptr) {
             printf("Unable to set access watch on %s fld%" PRIuPTR ", fieldID=0",
                    fields[i].descr, i);
         } else {
@@ -176,7 +176,7 @@ Java_nsk_jvmti_SetFieldAccessWatch_setfldw005_getReady(JNIEnv *env, jclass cls)
         }
     }
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_FIELD_ACCESS, NULL);
+        JVMTI_EVENT_FIELD_ACCESS, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("(SetEventNotificationMode) unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -195,7 +195,7 @@ Java_nsk_jvmti_SetFieldAccessWatch_setfldw005_check(JNIEnv *env,
         printf("Field %s fld%d: thrown field ID expected=0x%p, actual=0x%p\n",
                fields[ind].descr, ind, fields[ind].fid, actual_fid);
     }
-    actual_fid = NULL;
+    actual_fid = nullptr;
 }
 
 JNIEXPORT jint JNICALL
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw006/setfldw006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw006/setfldw006.cpp
index c70c9176a97..ac838cd5c5a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw006/setfldw006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldAccessWatch/setfldw006/setfldw006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -43,34 +43,34 @@ typedef struct {
     jint count;
 } watch_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static int missesCount = 0;
 static watch_info watches[] = {
-    { NULL, "staticBoolean", "Z", JNI_TRUE, 0, 0 },
-    { NULL, "staticByte", "B", JNI_TRUE, 0, 0 },
-    { NULL, "staticShort", "S", JNI_TRUE, 0, 0 },
-    { NULL, "staticInt", "I", JNI_TRUE, 0, 0 },
-    { NULL, "staticLong", "J", JNI_TRUE, 0, 0 },
-    { NULL, "staticFloat", "F", JNI_TRUE, 0, 0 },
-    { NULL, "staticDouble", "D", JNI_TRUE, 0, 0 },
-    { NULL, "staticChar", "C", JNI_TRUE, 0, 0 },
-    { NULL, "staticObject", "Ljava/lang/Object;", JNI_TRUE, 0, 0 },
-    { NULL, "staticArrInt", "[I", JNI_TRUE, 0, 0 },
+    { nullptr, "staticBoolean", "Z", JNI_TRUE, 0, 0 },
+    { nullptr, "staticByte", "B", JNI_TRUE, 0, 0 },
+    { nullptr, "staticShort", "S", JNI_TRUE, 0, 0 },
+    { nullptr, "staticInt", "I", JNI_TRUE, 0, 0 },
+    { nullptr, "staticLong", "J", JNI_TRUE, 0, 0 },
+    { nullptr, "staticFloat", "F", JNI_TRUE, 0, 0 },
+    { nullptr, "staticDouble", "D", JNI_TRUE, 0, 0 },
+    { nullptr, "staticChar", "C", JNI_TRUE, 0, 0 },
+    { nullptr, "staticObject", "Ljava/lang/Object;", JNI_TRUE, 0, 0 },
+    { nullptr, "staticArrInt", "[I", JNI_TRUE, 0, 0 },
 
-    { NULL, "instanceBoolean", "Z", JNI_FALSE, 0, 0 },
-    { NULL, "instanceByte", "B", JNI_FALSE, 0, 0 },
-    { NULL, "instanceShort", "S", JNI_FALSE, 0, 0 },
-    { NULL, "instanceInt", "I", JNI_FALSE, 0, 0 },
-    { NULL, "instanceLong", "J", JNI_FALSE, 0, 0 },
-    { NULL, "instanceFloat", "F", JNI_FALSE, 0, 0 },
-    { NULL, "instanceDouble", "D", JNI_FALSE, 0, 0 },
-    { NULL, "instanceChar", "C", JNI_FALSE, 0, 0 },
-    { NULL, "instanceObject", "Ljava/lang/Object;", JNI_FALSE, 0, 0 },
-    { NULL, "instanceArrInt", "[I", JNI_FALSE, 0, 0 }
+    { nullptr, "instanceBoolean", "Z", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceByte", "B", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceShort", "S", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceInt", "I", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceLong", "J", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceFloat", "F", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceDouble", "D", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceChar", "C", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceObject", "Ljava/lang/Object;", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceArrInt", "[I", JNI_FALSE, 0, 0 }
 };
 
 
@@ -103,12 +103,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -162,7 +162,7 @@ Java_nsk_jvmti_SetFieldAccessWatch_setfldw006_getReady(JNIEnv *env,
     jvmtiError err;
     size_t i;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -191,7 +191,7 @@ Java_nsk_jvmti_SetFieldAccessWatch_setfldw006_getReady(JNIEnv *env,
         }
     }
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_FIELD_ACCESS, NULL);
+        JVMTI_EVENT_FIELD_ACCESS, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("(SetEventNotificationMode) unexpected error: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw001/setfmodw001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw001/setfmodw001.cpp
index c7ec0e65035..42317001d0c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw001/setfmodw001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw001/setfmodw001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,12 +48,12 @@ static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static field fields[] = {
-    { "nsk/jvmti/SetFieldModificationWatch/setfmodw001", "fld0", "I", 0, NULL, NULL },
-    { "nsk/jvmti/SetFieldModificationWatch/setfmodw001", "fld1", "I", 1, NULL, NULL },
+    { "nsk/jvmti/SetFieldModificationWatch/setfmodw001", "fld0", "I", 0, nullptr, nullptr },
+    { "nsk/jvmti/SetFieldModificationWatch/setfmodw001", "fld1", "I", 1, nullptr, nullptr },
     { "nsk/jvmti/SetFieldModificationWatch/setfmodw001", "fld2",
-      "Lnsk/jvmti/SetFieldModificationWatch/setfmodw001a;", 0, NULL, NULL },
-    { "nsk/jvmti/SetFieldModificationWatch/setfmodw001a", "fld3", "[I", 0, NULL, NULL },
-    { "nsk/jvmti/SetFieldModificationWatch/setfmodw001b", "fld4", "F", 0, NULL, NULL },
+      "Lnsk/jvmti/SetFieldModificationWatch/setfmodw001a;", 0, nullptr, nullptr },
+    { "nsk/jvmti/SetFieldModificationWatch/setfmodw001a", "fld3", "[I", 0, nullptr, nullptr },
+    { "nsk/jvmti/SetFieldModificationWatch/setfmodw001b", "fld4", "F", 0, nullptr, nullptr },
 };
 
 void setWatch(JNIEnv *env, jint ind) {
@@ -61,7 +61,7 @@ void setWatch(JNIEnv *env, jint ind) {
     jvmtiError err;
 
     cls = env->FindClass(fields[ind].klass);
-    if (fields[ind].fid == NULL) {
+    if (fields[ind].fid == nullptr) {
         if (fields[ind].stat) {
             fields[ind].fid = env->GetStaticFieldID(cls, fields[ind].name, fields[ind].sig);
         } else {
@@ -84,18 +84,18 @@ void JNICALL FieldModification(jvmtiEnv *jvmti_env, JNIEnv *env,
         jthread thr, jmethodID method, jlocation location, jclass field_klass, jobject obj,
         jfieldID field, char sig, jvalue new_value) {
 
-    char *fld_name = NULL;
+    char *fld_name = nullptr;
     jint fld_ind = 0;
     size_t len = 0;
     jvmtiError err = jvmti_env->GetFieldName(field_klass, field,
-                                                &fld_name, NULL, NULL);
+                                                &fld_name, nullptr, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Error in GetFieldName: %s (%d)\n", TranslateError(err), err);
         result = STATUS_FAILED;
         return;
     }
-    if (fld_name == NULL) {
-        printf("GetFieldName returned NULL field name\n");
+    if (fld_name == nullptr) {
+        printf("GetFieldName returned null field name\n");
         result = STATUS_FAILED;
         return;
     }
@@ -127,7 +127,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -163,7 +163,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
 
         err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                JVMTI_EVENT_FIELD_MODIFICATION, NULL);
+                JVMTI_EVENT_FIELD_MODIFICATION, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to enable JVMTI_EVENT_FIELD_MODIFICATION: %s (%d)\n",
                    TranslateError(err), err);
@@ -195,7 +195,7 @@ Java_nsk_jvmti_SetFieldModificationWatch_setfmodw001_check(JNIEnv *env,
     jfieldID thrown_fid = fields[fld_ind].thrown_fid;
 
     if (caps.can_generate_field_modification_events) {
-        if (flag == JNI_FALSE && thrown_fid != NULL) {
+        if (flag == JNI_FALSE && thrown_fid != nullptr) {
             result = STATUS_FAILED;
             printf("(Field %d) FieldModification without modification watch set\n",
                    fld_ind);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw002/setfmodw002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw002/setfmodw002.cpp
index 3f33f677991..230d02d14f1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw002/setfmodw002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw002/setfmodw002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -59,7 +59,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -95,7 +95,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
 
         err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-                JVMTI_EVENT_FIELD_MODIFICATION, NULL);
+                JVMTI_EVENT_FIELD_MODIFICATION, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("Failed to enable JVMTI_EVENT_FIELD_MODIFICATION: %s (%d)\n",
                    TranslateError(err), err);
@@ -115,8 +115,8 @@ Java_nsk_jvmti_SetFieldModificationWatch_setfmodw002_check(JNIEnv *env,
     jfieldID fid;
 
     fid = env->GetStaticFieldID(cls, "fld1", "I");
-    if (fid == NULL) {
-      printf("(GetStaticFieldID) returns NULL");
+    if (fid == nullptr) {
+      printf("(GetStaticFieldID) returns null");
       result = STATUS_FAILED;
       return result;
     }
@@ -129,14 +129,14 @@ Java_nsk_jvmti_SetFieldModificationWatch_setfmodw002_check(JNIEnv *env,
             printf(" %s (%d)\n", TranslateError(err), err);
         }
     } else {
-        err = jvmti->SetFieldModificationWatch(NULL, fid);
+        err = jvmti->SetFieldModificationWatch(nullptr, fid);
         if (err != JVMTI_ERROR_INVALID_CLASS) {
             result = STATUS_FAILED;
             printf("Failed to return JVMTI_ERROR_INVALID_CLASS: %s (%d)\n",
                    TranslateError(err), err);
         }
 
-        err = jvmti->SetFieldModificationWatch(cls, NULL);
+        err = jvmti->SetFieldModificationWatch(cls, nullptr);
         if (err != JVMTI_ERROR_INVALID_FIELDID) {
             result = STATUS_FAILED;
             printf("Failed to return JVMTI_ERROR_INVALID_FIELDID: %s (%d)\n",
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw003/setfmodw003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw003/setfmodw003.cpp
index 987fb90913a..c105b647d32 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw003/setfmodw003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw003/setfmodw003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -47,14 +47,14 @@ static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
-static jfieldID actual_fid = NULL;
+static jfieldID actual_fid = nullptr;
 static char actual_sig = '\0';
 static jint actual_val = 0;
 static field flds[] = {
-    { "fld0", 'I', JNI_TRUE, 42, NULL },
-    { "fld1", 'I', JNI_TRUE, 43, NULL },
-    { "fld2", 'I', JNI_FALSE, 44, NULL },
-    { "fld3", 'I', JNI_FALSE, 45, NULL }
+    { "fld0", 'I', JNI_TRUE, 42, nullptr },
+    { "fld1", 'I', JNI_TRUE, 43, nullptr },
+    { "fld2", 'I', JNI_FALSE, 44, nullptr },
+    { "fld3", 'I', JNI_FALSE, 45, nullptr }
 };
 
 void JNICALL FieldModification(jvmtiEnv *jvmti_env, JNIEnv *env,
@@ -84,12 +84,12 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -146,7 +146,7 @@ Java_nsk_jvmti_SetFieldModificationWatch_setfmodw003_getReady(JNIEnv *env,
         } else {
             flds[i].fid = env->GetFieldID(cls, flds[i].name, "I");
         }
-        if (flds[i].fid == NULL) {
+        if (flds[i].fid == nullptr) {
             printf("Unable to set field modif. watch on fld%" PRIuPTR ", fieldID=0", i);
         } else {
             if (printdump == JNI_TRUE) {
@@ -162,7 +162,7 @@ Java_nsk_jvmti_SetFieldModificationWatch_setfmodw003_getReady(JNIEnv *env,
         }
     }
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_FIELD_MODIFICATION, NULL);
+        JVMTI_EVENT_FIELD_MODIFICATION, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("(SetEventNotificationMode) unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -195,7 +195,7 @@ Java_nsk_jvmti_SetFieldModificationWatch_setfmodw003_check(JNIEnv *env,
         printf("Field %s: thrown new value expected=%d, actual=%d\n",
                flds[ind].name, flds[ind].val, actual_val);
     }
-    actual_fid = NULL;
+    actual_fid = nullptr;
     actual_sig = '\0';
     actual_val = 0;
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw004/setfmodw004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw004/setfmodw004.cpp
index 403e2c1eda8..54759a984df 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw004/setfmodw004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw004/setfmodw004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -47,14 +47,14 @@ static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
-static jfieldID actual_fid = NULL;
+static jfieldID actual_fid = nullptr;
 static char actual_sig = '\0';
 static jint actual_val = 0;
 static field flds[] = {
-    { "fld0", 'I', JNI_TRUE, 96, NULL },
-    { "fld1", 'I', JNI_TRUE, 97, NULL },
-    { "fld2", 'I', JNI_FALSE, 98, NULL },
-    { "fld3", 'I', JNI_FALSE, 99, NULL }
+    { "fld0", 'I', JNI_TRUE, 96, nullptr },
+    { "fld1", 'I', JNI_TRUE, 97, nullptr },
+    { "fld2", 'I', JNI_FALSE, 98, nullptr },
+    { "fld3", 'I', JNI_FALSE, 99, nullptr }
 };
 
 void JNICALL FieldModification(jvmtiEnv *jvmti_env, JNIEnv *env,
@@ -84,12 +84,12 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -144,7 +144,7 @@ JNIEXPORT void JNICALL Java_nsk_jvmti_SetFieldModificationWatch_setfmodw004_getR
         } else {
             flds[i].fid = env->GetFieldID(cls, flds[i].name, "I");
         }
-        if (flds[i].fid == NULL) {
+        if (flds[i].fid == nullptr) {
             printf("Unable to set field modif. watch on fld%" PRIuPTR ", fieldID=0", i);
         } else {
             if (printdump == JNI_TRUE) {
@@ -160,7 +160,7 @@ JNIEXPORT void JNICALL Java_nsk_jvmti_SetFieldModificationWatch_setfmodw004_getR
         }
     }
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_FIELD_MODIFICATION, NULL);
+        JVMTI_EVENT_FIELD_MODIFICATION, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("(SetEventNotificationMode) unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -193,7 +193,7 @@ Java_nsk_jvmti_SetFieldModificationWatch_setfmodw004_check(JNIEnv *env,
         printf("Field %s: thrown new value expected=%d, actual=%d\n",
                flds[ind].name, flds[ind].val, actual_val);
     }
-    actual_fid = NULL;
+    actual_fid = nullptr;
     actual_sig = '\0';
     actual_val = 0;
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw005/setfmodw005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw005/setfmodw005.cpp
index 42e22ede75a..34cfdf628b4 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw005/setfmodw005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw005/setfmodw005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,26 +48,26 @@ static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
-static jfieldID actual_fid = NULL;
+static jfieldID actual_fid = nullptr;
 static char actual_sig = '\0';
 static jvalue actual_val = {};
 static field flds[] = {
-    { "fld0", "J", JNI_TRUE, "static long", NULL, {} },
-    { "fld1", "J", JNI_FALSE, "long", NULL, {} },
-    { "fld2", "F", JNI_TRUE, "static float", NULL, {} },
-    { "fld3", "F", JNI_FALSE, "float", NULL, {} },
-    { "fld4", "D", JNI_TRUE, "static double", NULL, {} },
-    { "fld5", "D", JNI_FALSE, "double", NULL, {} },
-    { "fld6", "Ljava/lang/Object;", JNI_TRUE, "static Object", NULL, {} },
-    { "fld7", "Ljava/lang/Object;", JNI_FALSE, "Object", NULL, {} },
-    { "fld8", "Z", JNI_TRUE, "static boolean", NULL, {} },
-    { "fld9", "Z", JNI_FALSE, "boolean", NULL, {} },
-    { "fld10", "B", JNI_TRUE, "static byte", NULL, {} },
-    { "fld11", "B", JNI_FALSE, "byte", NULL, {} },
-    { "fld12", "S", JNI_TRUE, "static short", NULL, {} },
-    { "fld13", "S", JNI_FALSE, "short", NULL, {} },
-    { "fld14", "C", JNI_TRUE, "static char", NULL, {} },
-    { "fld15", "C", JNI_FALSE, "char", NULL, {} }
+    { "fld0", "J", JNI_TRUE, "static long", nullptr, {} },
+    { "fld1", "J", JNI_FALSE, "long", nullptr, {} },
+    { "fld2", "F", JNI_TRUE, "static float", nullptr, {} },
+    { "fld3", "F", JNI_FALSE, "float", nullptr, {} },
+    { "fld4", "D", JNI_TRUE, "static double", nullptr, {} },
+    { "fld5", "D", JNI_FALSE, "double", nullptr, {} },
+    { "fld6", "Ljava/lang/Object;", JNI_TRUE, "static Object", nullptr, {} },
+    { "fld7", "Ljava/lang/Object;", JNI_FALSE, "Object", nullptr, {} },
+    { "fld8", "Z", JNI_TRUE, "static boolean", nullptr, {} },
+    { "fld9", "Z", JNI_FALSE, "boolean", nullptr, {} },
+    { "fld10", "B", JNI_TRUE, "static byte", nullptr, {} },
+    { "fld11", "B", JNI_FALSE, "byte", nullptr, {} },
+    { "fld12", "S", JNI_TRUE, "static short", nullptr, {} },
+    { "fld13", "S", JNI_FALSE, "short", nullptr, {} },
+    { "fld14", "C", JNI_TRUE, "static char", nullptr, {} },
+    { "fld15", "C", JNI_FALSE, "char", nullptr, {} }
 };
 
 void JNICALL FieldModification(jvmtiEnv *jvmti_env, JNIEnv *env,
@@ -133,12 +133,12 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -216,7 +216,7 @@ Java_nsk_jvmti_SetFieldModificationWatch_setfmodw005_getReady(JNIEnv *env,
         } else {
             flds[i].fid = env->GetFieldID(cls, flds[i].name, flds[i].sig);
         }
-        if (flds[i].fid == NULL) {
+        if (flds[i].fid == nullptr) {
             printf("Unable to set modification watch on %s fld%" PRIuPTR ", fieldID=0",
                    flds[i].descr, i);
         } else {
@@ -233,7 +233,7 @@ Java_nsk_jvmti_SetFieldModificationWatch_setfmodw005_getReady(JNIEnv *env,
         }
     }
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_FIELD_MODIFICATION, NULL);
+        JVMTI_EVENT_FIELD_MODIFICATION, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("(SetEventNotificationMode) unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -366,7 +366,7 @@ Java_nsk_jvmti_SetFieldModificationWatch_setfmodw005_check(JNIEnv *env,
     default:
         break;
     }
-    actual_fid = NULL;
+    actual_fid = nullptr;
     actual_sig = '\0';
     actual_val.j = 0L;
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw006/setfmodw006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw006/setfmodw006.cpp
index da74e1a92ca..d4f78706563 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw006/setfmodw006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetFieldModificationWatch/setfmodw006/setfmodw006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -43,34 +43,34 @@ typedef struct {
     jint count;
 } watch_info;
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static int missesCount = 0;
 static watch_info watches[] = {
-    { NULL, "staticBoolean", "Z", JNI_TRUE, 0, 0 },
-    { NULL, "staticByte", "B", JNI_TRUE, 0, 0 },
-    { NULL, "staticShort", "S", JNI_TRUE, 0, 0 },
-    { NULL, "staticInt", "I", JNI_TRUE, 0, 0 },
-    { NULL, "staticLong", "J", JNI_TRUE, 0, 0 },
-    { NULL, "staticFloat", "F", JNI_TRUE, 0, 0 },
-    { NULL, "staticDouble", "D", JNI_TRUE, 0, 0 },
-    { NULL, "staticChar", "C", JNI_TRUE, 0, 0 },
-    { NULL, "staticObject", "Ljava/lang/Object;", JNI_TRUE, 0, 0 },
-    { NULL, "staticArrInt", "[I", JNI_TRUE, 0, 0 },
+    { nullptr, "staticBoolean", "Z", JNI_TRUE, 0, 0 },
+    { nullptr, "staticByte", "B", JNI_TRUE, 0, 0 },
+    { nullptr, "staticShort", "S", JNI_TRUE, 0, 0 },
+    { nullptr, "staticInt", "I", JNI_TRUE, 0, 0 },
+    { nullptr, "staticLong", "J", JNI_TRUE, 0, 0 },
+    { nullptr, "staticFloat", "F", JNI_TRUE, 0, 0 },
+    { nullptr, "staticDouble", "D", JNI_TRUE, 0, 0 },
+    { nullptr, "staticChar", "C", JNI_TRUE, 0, 0 },
+    { nullptr, "staticObject", "Ljava/lang/Object;", JNI_TRUE, 0, 0 },
+    { nullptr, "staticArrInt", "[I", JNI_TRUE, 0, 0 },
 
-    { NULL, "instanceBoolean", "Z", JNI_FALSE, 0, 0 },
-    { NULL, "instanceByte", "B", JNI_FALSE, 0, 0 },
-    { NULL, "instanceShort", "S", JNI_FALSE, 0, 0 },
-    { NULL, "instanceInt", "I", JNI_FALSE, 0, 0 },
-    { NULL, "instanceLong", "J", JNI_FALSE, 0, 0 },
-    { NULL, "instanceFloat", "F", JNI_FALSE, 0, 0 },
-    { NULL, "instanceDouble", "D", JNI_FALSE, 0, 0 },
-    { NULL, "instanceChar", "C", JNI_FALSE, 0, 0 },
-    { NULL, "instanceObject", "Ljava/lang/Object;", JNI_FALSE, 0, 0 },
-    { NULL, "instanceArrInt", "[I", JNI_FALSE, 0, 0 }
+    { nullptr, "instanceBoolean", "Z", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceByte", "B", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceShort", "S", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceInt", "I", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceLong", "J", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceFloat", "F", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceDouble", "D", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceChar", "C", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceObject", "Ljava/lang/Object;", JNI_FALSE, 0, 0 },
+    { nullptr, "instanceArrInt", "[I", JNI_FALSE, 0, 0 }
 };
 
 
@@ -103,12 +103,12 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -155,7 +155,7 @@ Java_nsk_jvmti_SetFieldModificationWatch_setfmodw006_getReady(JNIEnv *env,
     jvmtiError err;
     size_t i;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -185,7 +185,7 @@ Java_nsk_jvmti_SetFieldModificationWatch_setfmodw006_getReady(JNIEnv *env,
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_FIELD_MODIFICATION, NULL);
+        JVMTI_EVENT_FIELD_MODIFICATION, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("(SetEventNotificationMode) unexpected error: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetJNIFunctionTable/setjniftab001/setjniftab001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetJNIFunctionTable/setjniftab001/setjniftab001.cpp
index 2e6490e34f7..ebe28d895a5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetJNIFunctionTable/setjniftab001/setjniftab001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetJNIFunctionTable/setjniftab001/setjniftab001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -46,7 +46,7 @@ static const char *classSig =
     "Lnsk/jvmti/SetJNIFunctionTable/setjniftab001a;";
 
 static JavaVM *vm;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 static volatile int verbose = 0;
 
@@ -59,10 +59,10 @@ static volatile jobject clsObj;
 static jrawMonitorID countLock;
 
 /* the original JNI function table */
-static jniNativeInterface *orig_jni_functions = NULL;
+static jniNativeInterface *orig_jni_functions = nullptr;
 
 /* the redirected JNI function table */
-static jniNativeInterface *redir_jni_functions = NULL;
+static jniNativeInterface *redir_jni_functions = nullptr;
 
 /* number of the redirected JNI function calls */
 static volatile int monent_calls = 0;
@@ -278,7 +278,7 @@ void startThreads() {
         thrStarted[i] = 0;
         waitContElem[i] = i+1;
         waitThr[i] = THREAD_new(waitingThread, &waitContElem[i]);
-        if (THREAD_start(waitThr[i]) == NULL) {
+        if (THREAD_start(waitThr[i]) == nullptr) {
             printf("TEST FAILURE: cannot start waiting thread #%d\n",
                 i+1);
             result = STATUS_FAILED;
@@ -323,16 +323,16 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_SetJNIFunctionTable_setjniftab001_check(JNIEnv *env, jobject obj) {
     int exitCode = PASSED;
     jint res;
-    JNIEnv *nextEnv = NULL; /* JNI env used to verify the assertion */
+    JNIEnv *nextEnv = nullptr; /* JNI env used to verify the assertion */
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("(%s,%d): TEST FAILURE: JVMTI client was not properly loaded\n",
             __FILE__, __LINE__);
         return STATUS_FAILED;
     }
 
     clsObj = env->NewGlobalRef(getObjectFromField(env, obj));
-    if (clsObj == NULL) {
+    if (clsObj == nullptr) {
         printf("(%s,%d): TEST FAILURE: cannot create a new global reference of class \"%s\"\n",
             __FILE__, __LINE__, classSig);
         env->FatalError("failed to create a new global reference");
@@ -382,10 +382,10 @@ Java_nsk_jvmti_SetJNIFunctionTable_setjniftab001_check(JNIEnv *env, jobject obj)
        and check the assertion with current thread and new threads */
     if (verbose)
         printf("\nc) Checking the restored JNI function table ...\n");
-    doRestore((nextEnv == NULL) ? env : nextEnv);
+    doRestore((nextEnv == nullptr) ? env : nextEnv);
 
     zeroCounter();
-    doExec((nextEnv == NULL) ? env : nextEnv, 0);
+    doExec((nextEnv == nullptr) ? env : nextEnv, 0);
     checkCall(2, 0, "main thread");
 
     zeroCounter();
@@ -413,14 +413,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "-verbose") == 0)
+    if (options != nullptr && strcmp(options, "-verbose") == 0)
         verbose = 1;
 
     if (verbose)
         printf("verbose mode on\n");
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("(%s,%d): Failed to call GetEnv\n", __FILE__, __LINE__);
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetJNIFunctionTable/setjniftab002/setjniftab002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetJNIFunctionTable/setjniftab002/setjniftab002.cpp
index 467c7abbb1f..4e3df55cbc8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetJNIFunctionTable/setjniftab002/setjniftab002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetJNIFunctionTable/setjniftab002/setjniftab002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define STATUS_FAILED  2
 
 static JavaVM *vm;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 static int verbose = 0;
 static jint result = PASSED;
@@ -45,7 +45,7 @@ void redirect(JNIEnv *env, jvmtiError exError) {
         printf("\ntrying to overwrite the JNI function table expecting the error %s to be returned ...\n",
             TranslateError(exError));
 
-    err = jvmti->SetJNIFunctionTable(NULL);
+    err = jvmti->SetJNIFunctionTable(nullptr);
     if (err != exError) {
         result = STATUS_FAILED;
         printf("(%s,%d): TEST FAILED: SetJNIFunctionTable() returns %s instead of %s as expected\n",
@@ -60,9 +60,9 @@ void redirect(JNIEnv *env, jvmtiError exError) {
 JNIEXPORT jint JNICALL
 Java_nsk_jvmti_SetJNIFunctionTable_setjniftab002_check(JNIEnv *env, jobject obj) {
     jint res;
-    JNIEnv *nextEnv = NULL;
+    JNIEnv *nextEnv = nullptr;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("(%s,%d): TEST FAILURE: JVMTI client was not properly loaded\n",
             __FILE__, __LINE__);
         return STATUS_FAILED;
@@ -114,14 +114,14 @@ JNIEXPORT jint JNI_OnLoad_setjniftab002(JavaVM *jvm, char *options, void *reserv
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "-verbose") == 0)
+    if (options != nullptr && strcmp(options, "-verbose") == 0)
         verbose = 1;
 
     if (verbose)
         printf("verbose mode on\n");
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("(%s,%d): Failed to call GetEnv\n", __FILE__, __LINE__);
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal001/setlocal001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal001/setlocal001.cpp
index e882233178c..52a6e89f175 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal001/setlocal001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal001/setlocal001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED  0
 #define STATUS_FAILED  2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
@@ -50,7 +50,7 @@ void JNICALL Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *env,
     jmethodID mid;
     jlocation loc;
     jint entryCount;
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLocalVariableEntry *table = nullptr;
     int i;
 
     err = jvmti_env->GetFrameLocation(thr, 1, &mid, &loc);
@@ -234,7 +234,7 @@ void JNICALL Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *env,
         result = STATUS_FAILED;
     }
 
-    if (table != NULL) {
+    if (table != nullptr) {
         for (i = 0; i < entryCount; i++) {
             jvmti_env->Deallocate((unsigned char*)table[i].name);
             jvmti_env->Deallocate((unsigned char*)table[i].signature);
@@ -259,7 +259,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv !\n");
         return JNI_ERR;
     }
@@ -308,7 +308,7 @@ Java_nsk_jvmti_SetLocalVariable_setlocal001_getMethReady(JNIEnv *env,
     jvmtiError err;
     jmethodID mid;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -338,7 +338,7 @@ Java_nsk_jvmti_SetLocalVariable_setlocal001_getMethReady(JNIEnv *env,
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal002/setlocal002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal002/setlocal002.cpp
index a2dbb7b9698..9ff5b3601f3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal002/setlocal002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal002/setlocal002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -99,7 +99,7 @@ Java_nsk_jvmti_SetLocalVariable_setlocal002_check(JNIEnv *env, jclass cls, jthre
     jvmtiLocalVariableEntry *table;
     int i;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -109,7 +109,7 @@ Java_nsk_jvmti_SetLocalVariable_setlocal002_check(JNIEnv *env, jclass cls, jthre
     }
 
     mid = env->GetStaticMethodID(cls, "run", "([Ljava/lang/String;Ljava/io/PrintStream;)I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find method \"run\"\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal003/setlocal003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal003/setlocal003.cpp
index 144a6614a9e..fa0324b1563 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal003/setlocal003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal003/setlocal003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define INV_SLOT (-1)
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
@@ -139,12 +139,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -192,7 +192,7 @@ Java_nsk_jvmti_SetLocalVariable_setlocal003_getReady(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jmethodID mid;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -202,7 +202,7 @@ Java_nsk_jvmti_SetLocalVariable_setlocal003_getReady(JNIEnv *env, jclass cls) {
         !caps.can_generate_breakpoint_events) return;
 
     mid = env->GetStaticMethodID(cls, "checkPoint", "()V");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find Method ID for method checkPoint\n");
         result = STATUS_FAILED;
         return;
@@ -216,7 +216,7 @@ Java_nsk_jvmti_SetLocalVariable_setlocal003_getReady(JNIEnv *env, jclass cls) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal004/setlocal004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal004/setlocal004.cpp
index 397d6e787b4..5ed6e9c5588 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal004/setlocal004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetLocalVariable/setlocal004/setlocal004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define INV_SLOT (-1)
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
@@ -145,12 +145,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -198,7 +198,7 @@ Java_nsk_jvmti_SetLocalVariable_setlocal004_getReady(JNIEnv *env, jclass cls) {
     jvmtiError err;
     jmethodID mid;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -222,7 +222,7 @@ Java_nsk_jvmti_SetLocalVariable_setlocal004_getReady(JNIEnv *env, jclass cls) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetNativeMethodPrefix/SetNativeMethodPrefix001/SetNativeMethodPrefix001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetNativeMethodPrefix/SetNativeMethodPrefix001/SetNativeMethodPrefix001.cpp
index d9631096901..c18485d4115 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetNativeMethodPrefix/SetNativeMethodPrefix001/SetNativeMethodPrefix001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetNativeMethodPrefix/SetNativeMethodPrefix001/SetNativeMethodPrefix001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -108,7 +108,7 @@ static const void *METHODS [METHODS_COUNT] = {
 
 /* ============================================================================= */
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 /* ============================================================================= */
 
@@ -120,17 +120,17 @@ Java_nsk_jvmti_SetNativeMethodPrefix_Binder_setMethodPrefix (
         )
 {
     jboolean result = JNI_TRUE;
-    char *str = NULL;
+    char *str = nullptr;
 
-    if (prefix != NULL) {
-        if (!NSK_VERIFY((str = (char *) jni->GetStringUTFChars(prefix, 0)) != NULL))
+    if (prefix != nullptr) {
+        if (!NSK_VERIFY((str = (char *) jni->GetStringUTFChars(prefix, 0)) != nullptr))
         { result = JNI_FALSE; goto finally; }
     }
 
     if (!NSK_JVMTI_VERIFY(jvmti->SetNativeMethodPrefix(str)))
     { result = JNI_FALSE; goto finally; }
 
-    if (str != NULL) {
+    if (str != nullptr) {
         NSK_DISPLAY1("New PREFIX is set: %s\n"
                 , str
                 );
@@ -139,7 +139,7 @@ Java_nsk_jvmti_SetNativeMethodPrefix_Binder_setMethodPrefix (
     }
 
 finally:
-    if (str != NULL) {
+    if (str != nullptr) {
         jni->ReleaseStringUTFChars(prefix, str);
     }
 
@@ -156,10 +156,10 @@ Java_nsk_jvmti_SetNativeMethodPrefix_Binder_setMultiplePrefixes (
         )
 {
     jboolean result = JNI_TRUE;
-    char *str = NULL;
+    char *str = nullptr;
 
-    if (prefix != NULL) {
-        if (!NSK_VERIFY((str = (char *) jni->GetStringUTFChars(prefix, 0)) != NULL))
+    if (prefix != nullptr) {
+        if (!NSK_VERIFY((str = (char *) jni->GetStringUTFChars(prefix, 0)) != nullptr))
         { result = JNI_FALSE; goto finally; }
 
         if (!NSK_JVMTI_VERIFY(jvmti->SetNativeMethodPrefixes(1, (char **) &str)))
@@ -170,7 +170,7 @@ Java_nsk_jvmti_SetNativeMethodPrefix_Binder_setMultiplePrefixes (
                 );
     } else {
         char* prefixes[1];
-        prefixes[0] = NULL;
+        prefixes[0] = nullptr;
 
         if (!NSK_JVMTI_VERIFY(jvmti->SetNativeMethodPrefixes(0, (char **)&prefixes)))
         { result = JNI_FALSE; goto finally; }
@@ -179,7 +179,7 @@ Java_nsk_jvmti_SetNativeMethodPrefix_Binder_setMultiplePrefixes (
     }
 
 finally:
-    if (str != NULL) {
+    if (str != nullptr) {
         jni->ReleaseStringUTFChars(prefix, str);
     }
 
@@ -209,11 +209,11 @@ Java_nsk_jvmti_SetNativeMethodPrefix_Binder_registerMethod (
         return JNI_FALSE;
     }
 
-    if (!NSK_VERIFY((method.name = (char *) jni->GetStringUTFChars(method_name_obj, 0)) != NULL)) {
+    if (!NSK_VERIFY((method.name = (char *) jni->GetStringUTFChars(method_name_obj, 0)) != nullptr)) {
         goto finally;
     }
 
-    if (!NSK_VERIFY((method.signature = (char *) jni->GetStringUTFChars(method_sig_obj, 0)) != NULL)) {
+    if (!NSK_VERIFY((method.signature = (char *) jni->GetStringUTFChars(method_sig_obj, 0)) != nullptr)) {
         goto finally;
     }
 
@@ -226,7 +226,7 @@ Java_nsk_jvmti_SetNativeMethodPrefix_Binder_registerMethod (
 
     if (jni->RegisterNatives(bound_klass, (const JNINativeMethod*) &method, 1) != 0)
     {
-        if (jni->ExceptionOccurred() != NULL) {
+        if (jni->ExceptionOccurred() != nullptr) {
             jni->ExceptionClear();
         }
 
@@ -237,11 +237,11 @@ Java_nsk_jvmti_SetNativeMethodPrefix_Binder_registerMethod (
 
     result = JNI_TRUE;
 finally:
-    if (method.name != NULL) {
+    if (method.name != nullptr) {
         jni->ReleaseStringUTFChars(method_name_obj, method.name);
     }
 
-    if (method.signature != NULL) {
+    if (method.signature != nullptr) {
         jni->ReleaseStringUTFChars(method_sig_obj, method.signature);
     }
 
@@ -273,7 +273,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
         return JNI_ERR;
 
     if (!NSK_VERIFY(
-                (jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != NULL
+                (jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != nullptr
                 )
        )
         return JNI_ERR;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetNativeMethodPrefix/SetNativeMethodPrefix002/SetNativeMethodPrefix002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetNativeMethodPrefix/SetNativeMethodPrefix002/SetNativeMethodPrefix002.cpp
index 7addf0cf052..d4f6e157e64 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetNativeMethodPrefix/SetNativeMethodPrefix002/SetNativeMethodPrefix002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetNativeMethodPrefix/SetNativeMethodPrefix002/SetNativeMethodPrefix002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,11 +38,11 @@ extern "C" {
 
 /* ============================================================================= */
 
-static char *prefix = NULL;
+static char *prefix = nullptr;
 
 /* ============================================================================= */
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 /* ============================================================================= */
 
@@ -95,7 +95,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
 
     // Specify native method prefix
     prefix = (char *)nsk_jvmti_findOptionValue("prefix");
-    if (prefix != NULL) {
+    if (prefix != nullptr) {
         NSK_DISPLAY1("Prefix: %s\n", prefix);
     }
 
@@ -103,7 +103,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
     apply = nsk_jvmti_findOptionIntValue("apply", 1);
 
     if (!NSK_VERIFY(
-                (jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != NULL
+                (jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != nullptr
                 )
        )
         return JNI_ERR;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetSystemProperty/setsysprop002/setsysprop002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetSystemProperty/setsysprop002/setsysprop002.cpp
index 0026afe9461..fc622764303 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetSystemProperty/setsysprop002/setsysprop002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetSystemProperty/setsysprop002/setsysprop002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -73,7 +73,7 @@ static PropertyDesc propDescList[PROPERTIES_COUNT] = {
 static int checkPropertyValue(jvmtiEnv* jvmti, const char phase[],
                                 const char name[], const char* expectedValue) {
     int success = NSK_TRUE;
-    char* value = NULL;
+    char* value = nullptr;
 
     NSK_DISPLAY1("  property: %s\n", name);
     if (!NSK_JVMTI_VERIFY(jvmti->GetSystemProperty(name, &value))) {
@@ -81,7 +81,7 @@ static int checkPropertyValue(jvmtiEnv* jvmti, const char phase[],
     }
     NSK_DISPLAY1("     value: \"%s\"\n", nsk_null_string(value));
 
-    if (value == NULL
+    if (value == nullptr
             || strcmp(value, expectedValue) != 0) {
         NSK_COMPLAIN4("In %s phase GetSystemProperty() returned unexpected value for property:\n"
                       "#   property name: %s\n"
@@ -174,7 +174,7 @@ JNIEXPORT jint JNI_OnLoad_setsysprop002(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -182,7 +182,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Check setting defined system properties in OnLoad phase\n");
@@ -190,7 +190,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         nsk_jvmti_setFailStatus();
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetSystemProperty/setsysprop003/setsysprop003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetSystemProperty/setsysprop003/setsysprop003.cpp
index 841a15c3da9..8d6f9ab12c1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetSystemProperty/setsysprop003/setsysprop003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetSystemProperty/setsysprop003/setsysprop003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -79,7 +79,7 @@ JNIEXPORT jint JNI_OnLoad_setsysprop003(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -87,7 +87,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY0(">>> Set new values for defined system properties in OnLoad phase\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetTag/settag001/settag001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetTag/settag001/settag001.cpp
index 3c19fb28ee9..f6f700d7004 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetTag/settag001/settag001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetTag/settag001/settag001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -51,17 +51,17 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     /* perform testing */
     {
-        jobject testedObject = NULL;
+        jobject testedObject = nullptr;
         jlong objectTag = 111;
 
         NSK_DISPLAY0(">>> Obtain tested object from a static field of debugee class\n");
         {
-            jclass debugeeClass = NULL;
-            jfieldID objectField = NULL;
+            jclass debugeeClass = nullptr;
+            jfieldID objectField = nullptr;
 
             NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
             if (!NSK_JNI_VERIFY(jni, (debugeeClass =
-                    jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+                    jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -69,7 +69,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
             NSK_DISPLAY1("Find static field: %s\n", OBJECT_FIELD_NAME);
             if (!NSK_JNI_VERIFY(jni, (objectField =
-                    jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, OBJECT_CLASS_SIG)) != NULL)) {
+                    jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, OBJECT_CLASS_SIG)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -77,14 +77,14 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
             NSK_DISPLAY1("Get object from static field: %s\n", OBJECT_FIELD_NAME);
             if (!NSK_JNI_VERIFY(jni, (testedObject =
-                    jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+                    jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
             NSK_DISPLAY1("  ... got object: 0x%p\n", (void*)testedObject);
 
             NSK_DISPLAY1("Create global reference for object: 0x%p\n", (void*)testedObject);
-            if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewGlobalRef(testedObject)) != NULL)) {
+            if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewGlobalRef(testedObject)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -180,7 +180,7 @@ JNIEXPORT jint JNI_OnLoad_settag001(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -190,7 +190,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add required capabilities */
@@ -205,7 +205,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetThreadLocalStorage/setthrdstor001/setthrdstor001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetThreadLocalStorage/setthrdstor001/setthrdstor001.cpp
index c04094a47c6..10b0ab40792 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetThreadLocalStorage/setthrdstor001/setthrdstor001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetThreadLocalStorage/setthrdstor001/setthrdstor001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -58,16 +58,16 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     /* perform testing */
     {
-        jthread testedThread = NULL;
+        jthread testedThread = nullptr;
         StorageStructure storageData;
         StorageStructure* initialStorage = &storageData;
-        StorageStructure* obtainedStorage = NULL;
+        StorageStructure* obtainedStorage = nullptr;
 
         memset(storageData.data, STORAGE_DATA_CHAR, STORAGE_DATA_SIZE);
 
         NSK_DISPLAY1("Find thread: %s\n", THREAD_NAME);
         if (!NSK_VERIFY((testedThread =
-                nsk_jvmti_threadByName(THREAD_NAME)) != NULL))
+                nsk_jvmti_threadByName(THREAD_NAME)) != nullptr))
             return;
         NSK_DISPLAY1("  ... found thread: %p\n", (void*)testedThread);
 
@@ -148,7 +148,7 @@ JNIEXPORT jint JNI_OnLoad_setthrdstor001(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -158,11 +158,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetThreadLocalStorage/setthrdstor002/setthrdstor002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetThreadLocalStorage/setthrdstor002/setthrdstor002.cpp
index 9528052c9ab..baf6a2a33c7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetThreadLocalStorage/setthrdstor002/setthrdstor002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetThreadLocalStorage/setthrdstor002/setthrdstor002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -60,13 +60,13 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     {
         StorageStructure storageData;
         StorageStructure* initialStorage = &storageData;
-        StorageStructure* obtainedStorage = NULL;
+        StorageStructure* obtainedStorage = nullptr;
 
         memset(storageData.data, STORAGE_DATA_CHAR, STORAGE_DATA_SIZE);
 
         NSK_DISPLAY1("SetThreadLocalStorage() for current agent thread with pointer: %p\n",
                                                     (void*)initialStorage);
-        if (!NSK_JVMTI_VERIFY(jvmti->SetThreadLocalStorage(NULL, (void*)initialStorage))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetThreadLocalStorage(nullptr, (void*)initialStorage))) {
             nsk_jvmti_setFailStatus();
             return;
         }
@@ -80,7 +80,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             return;
 
         NSK_DISPLAY0("GetThreadLocalStorage() for current agent thread\n");
-        if (!NSK_JVMTI_VERIFY(jvmti->GetThreadLocalStorage(NULL, (void**)&obtainedStorage))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->GetThreadLocalStorage(nullptr, (void**)&obtainedStorage))) {
             nsk_jvmti_setFailStatus();
             return;
         }
@@ -133,7 +133,7 @@ JNIEXPORT jint JNI_OnLoad_setthrdstor002(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -143,11 +143,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetThreadLocalStorage/setthrdstor003/setthrdstor003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetThreadLocalStorage/setthrdstor003/setthrdstor003.cpp
index ff49c9d060a..74514d40d8d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetThreadLocalStorage/setthrdstor003/setthrdstor003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetThreadLocalStorage/setthrdstor003/setthrdstor003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -78,7 +78,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         eventsStart = 0;
         eventsEnd = 0;
         NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-        if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL))
+        if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr))
             return;
 
         NSK_DISPLAY0("Let tested thread to run\n");
@@ -90,7 +90,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             return;
 
         NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-        if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL))
+        if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr))
             return;
 
         NSK_DISPLAY1("Check if all expected events received for tested thread: %s\n",
@@ -117,7 +117,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 JNIEXPORT void JNICALL
 callbackThreadStart(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
     /* check if event is for tested thread */
-    if (thread != NULL) {
+    if (thread != nullptr) {
         jvmtiThreadInfo info;
 
         if (!NSK_JVMTI_VERIFY(jvmti->GetThreadInfo(thread, &info))) {
@@ -125,14 +125,14 @@ callbackThreadStart(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
             return;
         }
 
-        if (info.name != NULL && strcmp(info.name, THREAD_NAME) == 0) {
+        if (info.name != nullptr && strcmp(info.name, THREAD_NAME) == 0) {
             NSK_DISPLAY2("  ... received THREAD_START event for tested thread: %p (%s)\n",
                                                             (void*)thread, info.name);
             eventsStart++;
 
             NSK_DISPLAY1("SetThreadLocalStorage() for current thread with pointer: %p\n",
                                                                 (void*)initialStorage);
-            if (!NSK_JVMTI_VERIFY(jvmti->SetThreadLocalStorage(NULL, (void*)initialStorage))) {
+            if (!NSK_JVMTI_VERIFY(jvmti->SetThreadLocalStorage(nullptr, (void*)initialStorage))) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -145,7 +145,7 @@ callbackThreadStart(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
 JNIEXPORT void JNICALL
 callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
     /* check if event is for tested thread */
-    if (thread != NULL) {
+    if (thread != nullptr) {
         jvmtiThreadInfo info;
 
         if (!NSK_JVMTI_VERIFY(jvmti->GetThreadInfo(thread, &info))) {
@@ -153,18 +153,18 @@ callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
             return;
         }
 
-        if (info.name != NULL && strcmp(info.name, THREAD_NAME) == 0) {
+        if (info.name != nullptr && strcmp(info.name, THREAD_NAME) == 0) {
             NSK_DISPLAY2("  ... received THREAD_END event for tested thread: %p (%s)\n",
                                                             (void*)thread, info.name);
             eventsEnd++;
 
             /* get storage data */
             {
-                StorageStructure* obtainedStorage = NULL;
+                StorageStructure* obtainedStorage = nullptr;
 
                 NSK_DISPLAY0("GetThreadLocalStorage() for current thread\n");
                 if (!NSK_JVMTI_VERIFY(
-                        jvmti->GetThreadLocalStorage(NULL, (void**)&obtainedStorage))) {
+                        jvmti->GetThreadLocalStorage(nullptr, (void**)&obtainedStorage))) {
                     nsk_jvmti_setFailStatus();
                     return;
                 }
@@ -219,7 +219,7 @@ JNIEXPORT jint JNI_OnLoad_setthrdstor003(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -229,7 +229,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* set callbacks for thread events */
@@ -243,7 +243,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetVerboseFlag/setvrbflag001/setvrbflag001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetVerboseFlag/setvrbflag001/setvrbflag001.cpp
index bc254115f5d..075cdf9a5d4 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetVerboseFlag/setvrbflag001/setvrbflag001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetVerboseFlag/setvrbflag001/setvrbflag001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -157,7 +157,7 @@ JNIEXPORT jint JNI_OnLoad_setvrbflag001(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv *jvmti = NULL;
+    jvmtiEnv *jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
 
     /* init framework and parse options */
@@ -169,7 +169,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* Create data access lock */
@@ -194,16 +194,16 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* enable VMInit event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr)))
         return JNI_ERR;
 
     /* enable ClassFileLoadHook event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetVerboseFlag/setvrbflag002/setvrbflag002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetVerboseFlag/setvrbflag002/setvrbflag002.cpp
index 8e43f0cb58b..a00da5d1226 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetVerboseFlag/setvrbflag002/setvrbflag002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SetVerboseFlag/setvrbflag002/setvrbflag002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -70,7 +70,7 @@ JNIEXPORT jint JNI_OnLoad_setvrbflag002(JavaVM *jvm, char *options, void *reserv
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv *jvmti = NULL;
+    jvmtiEnv *jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -83,11 +83,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/StopThread/stopthrd006/stopthrd006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/StopThread/stopthrd006/stopthrd006.cpp
index 89f43810c1f..f479cc966a6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/StopThread/stopthrd006/stopthrd006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/StopThread/stopthrd006/stopthrd006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -53,12 +53,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -96,7 +96,7 @@ Java_nsk_jvmti_StopThread_stopthrd006_check(JNIEnv *env,
         jclass cls, jthread thr, jobject ex) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -104,7 +104,7 @@ Java_nsk_jvmti_StopThread_stopthrd006_check(JNIEnv *env,
     if (printdump == JNI_TRUE) {
         printf(">>> invalid thread check ...\n");
     }
-    err = jvmti->StopThread(NULL, ex);
+    err = jvmti->StopThread(nullptr, ex);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY &&
             !caps.can_signal_thread) {
         /* It is OK */
@@ -117,7 +117,7 @@ Java_nsk_jvmti_StopThread_stopthrd006_check(JNIEnv *env,
     if (printdump == JNI_TRUE) {
         printf(">>> null pointer check ...\n");
     }
-    err = jvmti->StopThread(thr, NULL);
+    err = jvmti->StopThread(thr, nullptr);
     if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY &&
             !caps.can_signal_thread) {
         /* It is OK */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/StopThread/stopthrd007/stopthrd007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/StopThread/stopthrd007/stopthrd007.cpp
index da23414ab5c..bf5d20fc8fd 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/StopThread/stopthrd007/stopthrd007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/StopThread/stopthrd007/stopthrd007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,10 +38,10 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jobject threadDeath = NULL;
-static jthread runningThread = NULL;
-static jthread waitingThread = NULL;
-static jthread sleepingThread = NULL;
+static jobject threadDeath = nullptr;
+static jthread runningThread = nullptr;
+static jthread waitingThread = nullptr;
+static jthread sleepingThread = nullptr;
 
 /* ========================================================================== */
 
@@ -53,10 +53,10 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
     int i;
 
     NSK_DISPLAY0("Prepare: find tested threads\n");
@@ -65,12 +65,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -80,7 +80,7 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL) {
+        if (info.name != nullptr) {
             if (strcmp(info.name, RUNNING_THREAD_NAME) == 0) {
                 runningThread = threads[i];
             } else if (strcmp(info.name, WAITING_THREAD_NAME) == 0) {
@@ -96,14 +96,14 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
 
     NSK_DISPLAY0("Prepare: create new instance of ThreadDeath exception\n");
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (threadDeath = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (threadDeath = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -124,7 +124,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     NSK_DISPLAY0("Testcase #1: call StopThread for runningThread\n");
-    if (!NSK_VERIFY(runningThread != NULL)) {
+    if (!NSK_VERIFY(runningThread != nullptr)) {
         nsk_jvmti_setFailStatus();
     } else {
         if (!NSK_JVMTI_VERIFY(jvmti->StopThread(runningThread, threadDeath)))
@@ -132,7 +132,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     NSK_DISPLAY0("Testcase #2: call StopThread for waitingThread\n");
-    if (!NSK_VERIFY(waitingThread != NULL)) {
+    if (!NSK_VERIFY(waitingThread != nullptr)) {
         nsk_jvmti_setFailStatus();
     } else {
         if (!NSK_JVMTI_VERIFY(jvmti->StopThread(waitingThread, threadDeath)))
@@ -140,7 +140,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     NSK_DISPLAY0("Testcase #3: call StopThread for sleepingThread\n");
-    if (!NSK_VERIFY(sleepingThread != NULL)) {
+    if (!NSK_VERIFY(sleepingThread != nullptr)) {
         nsk_jvmti_setFailStatus();
     } else {
         if (!NSK_JVMTI_VERIFY(jvmti->StopThread(sleepingThread, threadDeath)))
@@ -166,7 +166,7 @@ JNIEXPORT jint JNI_OnLoad_stopthrd007(JavaVM *jvm, char *options, void *reserved
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
 
     NSK_DISPLAY0("Agent_OnLoad\n");
@@ -177,10 +177,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThread/suspendthrd001/suspendthrd001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThread/suspendthrd001/suspendthrd001.cpp
index 5d346b9bf98..97da3e1dec1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThread/suspendthrd001/suspendthrd001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThread/suspendthrd001/suspendthrd001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,11 +49,11 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     /* perform testing */
     {
-        jthread testedThread = NULL;
+        jthread testedThread = nullptr;
 
         NSK_DISPLAY1("Find thread: %s\n", THREAD_NAME);
         if (!NSK_VERIFY((testedThread =
-                nsk_jvmti_threadByName(THREAD_NAME)) != NULL))
+                nsk_jvmti_threadByName(THREAD_NAME)) != nullptr))
             return;
         NSK_DISPLAY1("  ... found thread: %p\n", (void*)testedThread);
 
@@ -118,7 +118,7 @@ JNIEXPORT jint JNI_OnLoad_suspendthrd001(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -128,7 +128,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -141,7 +141,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThread/suspendthrd002/suspendthrd002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThread/suspendthrd002/suspendthrd002.cpp
index 98a415315b4..d9eff84b63f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThread/suspendthrd002/suspendthrd002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThread/suspendthrd002/suspendthrd002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,7 +49,7 @@ static jvmtiEvent eventsList[EVENTS_COUNT] = {
 };
 
 static volatile int eventsReceived = 0;
-static jthread testedThread = NULL;
+static jthread testedThread = nullptr;
 
 /* ============================================================================= */
 
@@ -65,13 +65,13 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     {
         NSK_DISPLAY1("Find thread: %s\n", THREAD_NAME);
         if (!NSK_VERIFY((testedThread =
-                nsk_jvmti_threadByName(THREAD_NAME)) != NULL))
+                nsk_jvmti_threadByName(THREAD_NAME)) != nullptr))
             return;
         NSK_DISPLAY1("  ... found thread: %p\n", (void*)testedThread);
 
         eventsReceived = 0;
         NSK_DISPLAY1("Enable event: %s\n", "THREAD_END");
-        if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL))
+        if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr))
             return;
 
         NSK_DISPLAY1("Suspend thread: %p\n", (void*)testedThread);
@@ -99,7 +99,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         }
 
         NSK_DISPLAY1("Disable event: %s\n", "THREAD_END");
-        if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL))
+        if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr))
             return;
 
         NSK_DISPLAY1("Resume thread: %p\n", (void*)testedThread);
@@ -126,7 +126,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 JNIEXPORT void JNICALL
 callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
     /* check if event is for tested thread */
-    if (thread != NULL &&
+    if (thread != nullptr &&
                 jni->IsSameObject(testedThread, thread)) {
         NSK_DISPLAY1("  ... received THREAD_END event for tested thread: %p\n", (void*)thread);
         eventsReceived++;
@@ -150,7 +150,7 @@ JNIEXPORT jint JNI_OnLoad_suspendthrd002(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -160,7 +160,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -182,7 +182,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThread/suspendthrd003/suspendthrd003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThread/suspendthrd003/suspendthrd003.cpp
index 265d6b3d358..e172af654c8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThread/suspendthrd003/suspendthrd003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThread/suspendthrd003/suspendthrd003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,11 +52,11 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     /* perform testing */
     {
-        jthread testedThread = NULL;
+        jthread testedThread = nullptr;
 
         NSK_DISPLAY1("Find thread: %s\n", THREAD_NAME);
         if (!NSK_VERIFY((testedThread =
-                nsk_jvmti_threadByName(THREAD_NAME)) != NULL))
+                nsk_jvmti_threadByName(THREAD_NAME)) != nullptr))
             return;
         NSK_DISPLAY1("  ... found thread: %p\n", (void*)testedThread);
 
@@ -150,7 +150,7 @@ JNIEXPORT jint JNI_OnLoad_suspendthrd003(JavaVM *jvm, char *options, void *reser
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -160,7 +160,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -173,7 +173,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThreadList/suspendthrdlst001/suspendthrdlst001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThreadList/suspendthrdlst001/suspendthrdlst001.cpp
index bf17ed9a711..514dcbd43e9 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThreadList/suspendthrdlst001/suspendthrdlst001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThreadList/suspendthrdlst001/suspendthrdlst001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -57,8 +57,8 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     /* perform testing */
     {
-        jthread* threads = NULL;
-        jvmtiError* results = NULL;
+        jthread* threads = nullptr;
+        jvmtiError* results = nullptr;
         int i;
 
         NSK_DISPLAY1("Allocate threads array: %d threads\n", threadsCount);
@@ -130,7 +130,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
         NSK_DISPLAY0("Delete threads references\n");
         for (i = 0; i < threadsCount; i++) {
-            if (threads[i] != NULL)
+            if (threads[i] != nullptr)
                 NSK_TRACE(jni->DeleteGlobalRef(threads[i]));
         }
 
@@ -156,14 +156,14 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 static int fillThreadsByName(jvmtiEnv* jvmti, JNIEnv* jni,
                         const char name[], int foundCount, jthread foundThreads[]) {
     jint count = 0;
-    jthread* threads = NULL;
+    jthread* threads = nullptr;
 
     size_t len = strlen(name);
     int found = 0;
     int i;
 
     for (i = 0; i < foundCount; i++) {
-        foundThreads[i] = NULL;
+        foundThreads[i] = nullptr;
     }
 
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&count, &threads))) {
@@ -180,7 +180,7 @@ static int fillThreadsByName(jvmtiEnv* jvmti, JNIEnv* jni,
             break;
         }
 
-        if (info.name != NULL && strncmp(name, info.name, len) == 0) {
+        if (info.name != nullptr && strncmp(name, info.name, len) == 0) {
             NSK_DISPLAY3("  ... found thread #%d: %p (%s)\n",
                                     found, threads[i], info.name);
             if (found < foundCount)
@@ -208,7 +208,7 @@ static int fillThreadsByName(jvmtiEnv* jvmti, JNIEnv* jni,
     NSK_DISPLAY1("Make global references for threads: %d threads\n", foundCount);
     for (i = 0; i < foundCount; i++) {
         if (!NSK_JNI_VERIFY(jni, (foundThreads[i] = (jthread)
-                    jni->NewGlobalRef(foundThreads[i])) != NULL)) {
+                    jni->NewGlobalRef(foundThreads[i])) != nullptr)) {
             nsk_jvmti_setFailStatus();
             return NSK_FALSE;
         }
@@ -233,7 +233,7 @@ JNIEXPORT jint JNI_OnLoad_suspendthrdlst001(JavaVM *jvm, char *options, void *re
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -248,7 +248,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -261,7 +261,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThreadList/suspendthrdlst002/suspendthrdlst002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThreadList/suspendthrdlst002/suspendthrdlst002.cpp
index 1145bb3c1cb..31406434c49 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThreadList/suspendthrdlst002/suspendthrdlst002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/SuspendThreadList/suspendthrdlst002/suspendthrdlst002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -50,7 +50,7 @@ static jvmtiEvent eventsList[EVENTS_COUNT] = {
 };
 
 static int threadsCount = 0;
-static jthread* threads = NULL;
+static jthread* threads = nullptr;
 
 static volatile int eventsReceived = 0;
 
@@ -69,7 +69,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     /* perform testing */
     {
-        jvmtiError* results = NULL;
+        jvmtiError* results = nullptr;
         int i;
 
         NSK_DISPLAY1("Allocate threads array: %d threads\n", threadsCount);
@@ -108,7 +108,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
         eventsReceived = 0;
         NSK_DISPLAY1("Enable event: %s\n", "THREAD_END");
-        if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL))
+        if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr))
             return;
 
         NSK_DISPLAY0("Let threads to run and finish\n");
@@ -131,7 +131,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         }
 
         NSK_DISPLAY1("Disable event: %s\n", "THREAD_END");
-        if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL))
+        if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr))
             return;
 
         NSK_DISPLAY0("Resume threads list\n");
@@ -146,7 +146,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
         NSK_DISPLAY0("Delete threads references\n");
         for (i = 0; i < threadsCount; i++) {
-            if (threads[i] != NULL)
+            if (threads[i] != nullptr)
                 NSK_TRACE(jni->DeleteGlobalRef(threads[i]));
         }
 
@@ -172,14 +172,14 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 static int fillThreadsByName(jvmtiEnv* jvmti, JNIEnv* jni,
                             const char name[], int foundCount, jthread foundThreads[]) {
     jint count = 0;
-    jthread* threads = NULL;
+    jthread* threads = nullptr;
 
     size_t len = strlen(name);
     int found = 0;
     int i;
 
     for (i = 0; i < foundCount; i++) {
-        foundThreads[i] = NULL;
+        foundThreads[i] = nullptr;
     }
 
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&count, &threads))) {
@@ -196,7 +196,7 @@ static int fillThreadsByName(jvmtiEnv* jvmti, JNIEnv* jni,
             break;
         }
 
-        if (info.name != NULL && strncmp(name, info.name, len) == 0) {
+        if (info.name != nullptr && strncmp(name, info.name, len) == 0) {
             NSK_DISPLAY3("  ... found thread #%d: %p (%s)\n",
                                     found, threads[i], info.name);
             if (found < foundCount)
@@ -224,7 +224,7 @@ static int fillThreadsByName(jvmtiEnv* jvmti, JNIEnv* jni,
     NSK_DISPLAY1("Make global references for threads: %d threads\n", foundCount);
     for (i = 0; i < foundCount; i++) {
         if (!NSK_JNI_VERIFY(jni, (foundThreads[i] = (jthread)
-                    jni->NewGlobalRef(foundThreads[i])) != NULL)) {
+                    jni->NewGlobalRef(foundThreads[i])) != nullptr)) {
             nsk_jvmti_setFailStatus();
             return NSK_FALSE;
         }
@@ -243,7 +243,7 @@ callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
 
     /* check if event is for tested thread */
     for (i = 0; i < threadsCount; i++) {
-        if (thread != NULL &&
+        if (thread != nullptr &&
                 jni->IsSameObject(threads[i], thread)) {
             NSK_DISPLAY2("  ... received THREAD_END event for thread #%d: %p\n",
                                                                     i, (void*)thread);
@@ -269,7 +269,7 @@ JNIEXPORT jint JNI_OnLoad_suspendthrdlst002(JavaVM *jvm, char *options, void *re
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -284,7 +284,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -306,7 +306,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/VMDeath/vmdeath001/vmdeath001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/VMDeath/vmdeath001/vmdeath001.cpp
index 887b217608d..4eabc000abf 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/VMDeath/vmdeath001/vmdeath001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/VMDeath/vmdeath001/vmdeath001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ extern "C" {
 #define PASSED  0
 #define STATUS_FAILED  2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 
 /** callback functions **/
@@ -81,7 +81,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY0("setting event callbacks ...\n");
@@ -91,7 +91,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     NSK_DISPLAY0("setting event callbacks done\nenabling VMDeath event ...\n");
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling VMDeath event done\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/VMInit/vminit001/vminit001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/VMInit/vminit001/vminit001.cpp
index 7480242377a..5346f1b41fa 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/VMInit/vminit001/vminit001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/VMInit/vminit001/vminit001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define WAIT_TIME 1000
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -52,7 +52,7 @@ void JNICALL VMInit(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thr) {
     }
 
     err = jvmti_env->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_THREAD_START, NULL);
+            JVMTI_EVENT_THREAD_START, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable JVMTI_EVENT_THREAD_START: %s (%d)\n",
                TranslateError(err), err);
@@ -107,7 +107,7 @@ void JNICALL ThreadStart(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thread) {
     if (printdump == JNI_TRUE) {
         printf(">>> thread start: %s\n", inf.name);
     }
-    if (inf.name != NULL && strcmp(name, inf.name) == 0) {
+    if (inf.name != nullptr && strcmp(name, inf.name) == 0) {
         mainStarted++;
         if (eventsCount == 0) {
             printf("ThreadStart event for the main thread occurs\n");
@@ -132,12 +132,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -152,7 +152,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-            JVMTI_EVENT_VM_INIT, NULL);
+            JVMTI_EVENT_VM_INIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable JVMTI_EVENT_VM_INIT: %s (%d)\n",
                TranslateError(err), err);
@@ -164,7 +164,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
 JNIEXPORT jint JNICALL
 Java_nsk_jvmti_VMInit_vminit001_check(JNIEnv *env, jclass cls) {
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP01/ap01t001/ap01t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP01/ap01t001/ap01t001.cpp
index 667396da93e..e2210d23b64 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP01/ap01t001/ap01t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP01/ap01t001/ap01t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,8 +39,8 @@ extern "C" {
 
 #define EXP_OBJ_NUMBER 7
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -146,17 +146,17 @@ Java_nsk_jvmti_scenarios_allocation_AP01_ap01t001_newObject(JNIEnv* jni, jclass
     jmethodID cid;
     jobject result;
 
-    if (!NSK_JNI_VERIFY(jni, (cid = jni->GetMethodID(cls, "<init>", "()V")) != NULL)) {
-         NSK_COMPLAIN0("newObject: GetMethodID returned NULL\n\n");
+    if (!NSK_JNI_VERIFY(jni, (cid = jni->GetMethodID(cls, "<init>", "()V")) != nullptr)) {
+         NSK_COMPLAIN0("newObject: GetMethodID returned null\n\n");
          nsk_jvmti_setFailStatus();
-         return NULL;
+         return nullptr;
     }
 
-    if (!NSK_JNI_VERIFY(jni, (result = jni->NewObject(cls, cid)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (result = jni->NewObject(cls, cid)) != nullptr)) {
 
-         NSK_COMPLAIN0("newObject: NewObject returned NULL\n\n");
+         NSK_COMPLAIN0("newObject: NewObject returned null\n\n");
          nsk_jvmti_setFailStatus();
-         return NULL;
+         return nullptr;
     }
 
     return result;
@@ -167,25 +167,25 @@ Java_nsk_jvmti_scenarios_allocation_AP01_ap01t001_allocObject(JNIEnv* jni, jclas
     jmethodID cid;
     jobject result;
 
-    if (!NSK_JNI_VERIFY(jni, (cid = jni->GetMethodID(cls, "<init>", "()V")) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (cid = jni->GetMethodID(cls, "<init>", "()V")) != nullptr)) {
 
-         NSK_COMPLAIN0("allocObject: GetMethodID returned NULL\n\n");
+         NSK_COMPLAIN0("allocObject: GetMethodID returned null\n\n");
          nsk_jvmti_setFailStatus();
-         return NULL;
+         return nullptr;
     }
 
-    if (!NSK_JNI_VERIFY(jni, (result = jni->AllocObject(cls)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (result = jni->AllocObject(cls)) != nullptr)) {
 
-         NSK_COMPLAIN0("allocObject: AllocObject returned NULL\n\n");
+         NSK_COMPLAIN0("allocObject: AllocObject returned null\n\n");
          nsk_jvmti_setFailStatus();
-         return NULL;
+         return nullptr;
     }
 
     if (!NSK_JNI_VERIFY_VOID(jni,jni->CallNonvirtualVoidMethod(result, cls, cid))) {
 
          NSK_COMPLAIN0("newObject: CallNonvirtualVoidMethod failed\n\n");
          nsk_jvmti_setFailStatus();
-         return NULL;
+         return nullptr;
     }
 
     return result;
@@ -196,7 +196,7 @@ Java_nsk_jvmti_scenarios_allocation_AP01_ap01t001_flushObjectFreeEvents(JNIEnv*
     // Already enabled, but this triggers flush of pending events.
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_OBJECT_FREE,
-                                                          NULL))) {
+                                                          nullptr))) {
         nsk_jvmti_setFailStatus();
     }
 }
@@ -204,7 +204,7 @@ Java_nsk_jvmti_scenarios_allocation_AP01_ap01t001_flushObjectFreeEvents(JNIEnv*
 static void JNICALL
 agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
-    jclass debugeeClass = NULL;
+    jclass debugeeClass = nullptr;
 
     NSK_DISPLAY0("Wait for debugee start\n\n");
     if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout)))
@@ -212,7 +212,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_SIGNATURE);
     debugeeClass = nsk_jvmti_classBySignature(DEBUGEE_SIGNATURE);
-    if (debugeeClass == NULL) {
+    if (debugeeClass == nullptr) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -313,7 +313,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(jvmtiCapabilities));
@@ -343,15 +343,15 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("setting event callbacks done\nenabling JVMTI events ...\n");
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_OBJECT_FREE,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_VM_DEATH,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("agentProc has been set\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP02/ap02t001/ap02t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP02/ap02t001/ap02t001.cpp
index 409784d43ea..9697e1d1ef6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP02/ap02t001/ap02t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP02/ap02t001/ap02t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,8 +38,8 @@ extern "C" {
 
 #define TESTED_CLASS "ap02t001Exception"
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -50,7 +50,7 @@ static jlong timeout = 0;
 static int user_data = 0;
 static const char* TESTED_CLASS_SIGNATURE = "Lnsk/jvmti/scenarios/allocation/AP02/ap02t001Exception;";
 static const jlong TESTED_CLASS_TAG = (jlong)1024;
-static jclass testedClass = NULL;
+static jclass testedClass = nullptr;
 
 jvmtiIterationControl JNICALL
 heapObjectCallback(jlong class_tag,
@@ -142,9 +142,9 @@ static void runIterations (jvmtiEnv* jvmti, jclass testedClass, jint exp_count)
 
     NSK_DISPLAY0("Calling IterateOverReachableObjects\n");
     obj_count = 0;
-    if (!NSK_JVMTI_VERIFY(jvmti->IterateOverReachableObjects(NULL /*heapRootCallback*/,
+    if (!NSK_JVMTI_VERIFY(jvmti->IterateOverReachableObjects(nullptr /*heapRootCallback*/,
                                                              stackReferenceCallback,
-                                                             NULL /*objectReferenceCallback*/,
+                                                             nullptr /*objectReferenceCallback*/,
                                                              &user_data))) {
         nsk_jvmti_setFailStatus();
         return;
@@ -173,12 +173,12 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     NSK_DISPLAY1("Find tested class: %s\n", TESTED_CLASS_SIGNATURE);
     testedClass = nsk_jvmti_classBySignature(TESTED_CLASS_SIGNATURE);
-    if (testedClass == NULL) {
+    if (testedClass == nullptr) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
-    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass)jni->NewGlobalRef(testedClass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass)jni->NewGlobalRef(testedClass)) != nullptr))
         return;
 
     NSK_DISPLAY0("Set tag for tested class\n\n");
@@ -222,7 +222,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(jvmtiCapabilities));
@@ -236,7 +236,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!caps.can_tag_objects)
         NSK_DISPLAY0("Warning: tagging objects is not implemented\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("agentProc has been set\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP03/ap03t001/ap03t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP03/ap03t001/ap03t001.cpp
index 0ebfdadeafc..4e7473be5b6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP03/ap03t001/ap03t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP03/ap03t001/ap03t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,8 +35,8 @@ extern "C" {
 
 #define EXP_OBJ_NUMBER 1
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -98,7 +98,7 @@ Java_nsk_jvmti_scenarios_allocation_AP03_ap03t001_setTag(JNIEnv* jni, jobject ob
 static void JNICALL
 agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
-    jclass debugeeClass = NULL;
+    jclass debugeeClass = nullptr;
 
     NSK_DISPLAY0("Wait for debugee start\n\n");
     if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout)))
@@ -110,7 +110,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
         NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_SIGNATURE);
         debugeeClass = nsk_jvmti_classBySignature(DEBUGEE_SIGNATURE);
-        if (debugeeClass == NULL) {
+        if (debugeeClass == nullptr) {
             nsk_jvmti_setFailStatus();
             break;
         }
@@ -160,14 +160,14 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         }
 
         if (!NSK_JNI_VERIFY(jni, (fid =
-                jni->GetStaticFieldID(debugeeClass, "catcher", DEBUGEE_SIGNATURE)) != NULL)) {
+                jni->GetStaticFieldID(debugeeClass, "catcher", DEBUGEE_SIGNATURE)) != nullptr)) {
             nsk_jvmti_setFailStatus();
             break;
         }
 
         if (!NSK_JNI_VERIFY(jni, (catcher =
-                jni->GetStaticObjectField(debugeeClass, fid)) != NULL)) {
-            NSK_COMPLAIN0("GetStaticObjectField returned NULL for 'catcher' field value\n\n");
+                jni->GetStaticObjectField(debugeeClass, fid)) != nullptr)) {
+            NSK_COMPLAIN0("GetStaticObjectField returned null for 'catcher' field value\n\n");
             nsk_jvmti_setFailStatus();
             break;
         }
@@ -215,7 +215,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(jvmtiCapabilities));
@@ -244,11 +244,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("setting event callbacks done\nenabling JVMTI events ...\n");
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_OBJECT_FREE,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("agentProc has been set\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP04/ap04t001/ap04t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP04/ap04t001/ap04t001.cpp
index cf79fe945a1..eea3e881ccd 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP04/ap04t001/ap04t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP04/ap04t001/ap04t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,8 +35,8 @@ extern "C" {
 
 #define OBJ_MAX_COUNT 100000
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -52,9 +52,9 @@ static jvmtiEvent events[] = {
     JVMTI_EVENT_GARBAGE_COLLECTION_FINISH
 };
 
-static jclass debugeeClass = NULL;
-static jfieldID rootFieldID = NULL;
-static jmethodID unlockSecondaryID = NULL;
+static jclass debugeeClass = nullptr;
+static jfieldID rootFieldID = nullptr;
+static jmethodID unlockSecondaryID = nullptr;
 
 static volatile int eventCount = 0;
 static volatile int iterationCount = 0;
@@ -62,7 +62,7 @@ static volatile int errorCount = 0;
 
 /***********************************************************************/
 
-static jrawMonitorID counterMonitor_ptr = NULL;
+static jrawMonitorID counterMonitor_ptr = nullptr;
 
 static void increaseCounter(volatile int* counterPtr) {
 
@@ -269,7 +269,7 @@ Java_nsk_jvmti_scenarios_allocation_AP04_ap04t001_runIterateOverHeap(JNIEnv* jni
     NSK_DISPLAY0("Calling IterateOverHeap...\n");
     if (!NSK_JVMTI_VERIFY(jvmti->IterateOverHeap(JVMTI_HEAP_OBJECT_TAGGED,
                                                  heapObjectCallback,
-                                                 NULL /*user_data*/))) {
+                                                 nullptr /*user_data*/))) {
         nsk_jvmti_setFailStatus();
     }
     NSK_DISPLAY0("IterateOverHeap finished.\n");
@@ -298,7 +298,7 @@ Java_nsk_jvmti_scenarios_allocation_AP04_ap04t001_runIterateOverReachableObjects
     if (!NSK_JVMTI_VERIFY(jvmti->IterateOverReachableObjects(heapRootCallback,
                                                              stackReferenceCallback,
                                                              objectReferenceCallback,
-                                                             NULL /*user_data*/))) {
+                                                             nullptr /*user_data*/))) {
         nsk_jvmti_setFailStatus();
     }
     NSK_DISPLAY0("IterateOverReachableObjects finished.\n");
@@ -327,7 +327,7 @@ Java_nsk_jvmti_scenarios_allocation_AP04_ap04t001_runIterateOverInstancesOfClass
     if (!NSK_JVMTI_VERIFY(jvmti->IterateOverInstancesOfClass(debugeeClass,
                                                              JVMTI_HEAP_OBJECT_TAGGED,
                                                              heapObjectCallback,
-                                                             NULL /*user_data*/))) {
+                                                             nullptr /*user_data*/))) {
         nsk_jvmti_setFailStatus();
     }
     NSK_DISPLAY0("IterateOverInstancesOfClass finished.\n");
@@ -347,12 +347,12 @@ JNIEXPORT void JNICALL
 Java_nsk_jvmti_scenarios_allocation_AP04_ap04t001_runIterateOverObjectsReachableFromObject(JNIEnv* jni,
                                                                                            jclass  klass) {
 
-    jobject root = NULL;
+    jobject root = nullptr;
     int count = 0;
 
     if (!NSK_JNI_VERIFY(jni, (root =
-            jni->GetStaticObjectField(debugeeClass, rootFieldID)) != NULL)) {
-        NSK_COMPLAIN0("GetStaticObjectField returned NULL for 'root' field value\n\n");
+            jni->GetStaticObjectField(debugeeClass, rootFieldID)) != nullptr)) {
+        NSK_COMPLAIN0("GetStaticObjectField returned null for 'root' field value\n\n");
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -367,7 +367,7 @@ Java_nsk_jvmti_scenarios_allocation_AP04_ap04t001_runIterateOverObjectsReachable
     NSK_DISPLAY0("Calling IterateOverObjectsReachableFromObject...\n");
     if (!NSK_JVMTI_VERIFY(jvmti->IterateOverObjectsReachableFromObject(root,
                                                                        objectReferenceCallback,
-                                                                       NULL /*user_data*/))) {
+                                                                       nullptr /*user_data*/))) {
         nsk_jvmti_setFailStatus();
     }
     NSK_DISPLAY0("IterateOverObjectsReachableFromObject finished.\n");
@@ -392,24 +392,24 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_SIGNATURE);
     debugeeClass = nsk_jvmti_classBySignature(DEBUGEE_SIGNATURE);
-    if (debugeeClass == NULL) {
+    if (debugeeClass == nullptr) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = (jclass)jni->NewGlobalRef(debugeeClass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = (jclass)jni->NewGlobalRef(debugeeClass)) != nullptr))
         return;
 
     NSK_DISPLAY1("Find ID of 'root' field: %s\n", ROOT_SIGNATURE);
     if (!NSK_JNI_VERIFY(jni, (rootFieldID =
-            jni->GetStaticFieldID(debugeeClass, "root", ROOT_SIGNATURE)) != NULL)) {
+            jni->GetStaticFieldID(debugeeClass, "root", ROOT_SIGNATURE)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
     NSK_DISPLAY1("Find ID of 'unlockSecondary' method: %s\n", ROOT_SIGNATURE);
     if (!NSK_JNI_VERIFY(jni, (unlockSecondaryID =
-            jni->GetStaticMethodID(debugeeClass, "unlockSecondary", "()V")) != NULL)) {
+            jni->GetStaticMethodID(debugeeClass, "unlockSecondary", "()V")) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -423,7 +423,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout)))
         return;
 
-    nsk_jvmti_enableEvents(JVMTI_DISABLE, eventsCount, events, NULL);
+    nsk_jvmti_enableEvents(JVMTI_DISABLE, eventsCount, events, nullptr);
 
     NSK_TRACE(jni->DeleteGlobalRef(debugeeClass));
     NSK_TRACE(jvmti->DestroyRawMonitor(counterMonitor_ptr));
@@ -451,7 +451,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("counterMonitor", &counterMonitor_ptr))) {
@@ -489,12 +489,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("setting event callbacks done.\n");
 
     NSK_DISPLAY0("enabling JVMTI events ...\n");
-    if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, eventsCount, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, eventsCount, events, nullptr)) {
         return JNI_ERR;
     }
     NSK_DISPLAY0("enabling the events done.\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("agentProc has been set\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP04/ap04t002/ap04t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP04/ap04t002/ap04t002.cpp
index f42bb0d8680..e9f43a1cbaf 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP04/ap04t002/ap04t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP04/ap04t002/ap04t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,8 +35,8 @@ extern "C" {
 
 #define OBJ_MAX_COUNT 100000
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -49,13 +49,13 @@ static volatile int modificationCount = 0;
 static volatile int iterationCount = 0;
 static volatile int errorCount = 0;
 
-static jclass debugeeClass = NULL;
+static jclass debugeeClass = nullptr;
 static jfieldID rootFieldID;
 static jfieldID modifiedFieldID;
 
 /***********************************************************************/
 
-static jrawMonitorID counterMonitor_ptr = NULL;
+static jrawMonitorID counterMonitor_ptr = nullptr;
 
 static void increaseCounter(volatile int* counterPtr) {
 
@@ -249,7 +249,7 @@ Java_nsk_jvmti_scenarios_allocation_AP04_ap04t002_runIterateOverHeap(JNIEnv* jni
     NSK_DISPLAY0("Calling IterateOverHeap...\n");
     if (!NSK_JVMTI_VERIFY(jvmti->IterateOverHeap(JVMTI_HEAP_OBJECT_TAGGED,
                                                  heapObjectCallback,
-                                                 NULL /*user_data*/))) {
+                                                 nullptr /*user_data*/))) {
         nsk_jvmti_setFailStatus();
     }
     NSK_DISPLAY0("IterateOverHeap finished.\n");
@@ -279,7 +279,7 @@ Java_nsk_jvmti_scenarios_allocation_AP04_ap04t002_runIterateOverReachableObjects
     if (!NSK_JVMTI_VERIFY(jvmti->IterateOverReachableObjects(heapRootCallback,
                                                              stackReferenceCallback,
                                                              objectReferenceCallback,
-                                                             NULL /*user_data*/))) {
+                                                             nullptr /*user_data*/))) {
         nsk_jvmti_setFailStatus();
     }
     NSK_DISPLAY0("IterateOverReachableObjects finished.\n");
@@ -309,7 +309,7 @@ Java_nsk_jvmti_scenarios_allocation_AP04_ap04t002_runIterateOverInstancesOfClass
     if (!NSK_JVMTI_VERIFY(jvmti->IterateOverInstancesOfClass(debugeeClass,
                                                              JVMTI_HEAP_OBJECT_TAGGED,
                                                              heapObjectCallback,
-                                                             NULL /*user_data*/))) {
+                                                             nullptr /*user_data*/))) {
         nsk_jvmti_setFailStatus();
     }
     NSK_DISPLAY0("IterateOverInstancesOfClass finished.\n");
@@ -329,12 +329,12 @@ Java_nsk_jvmti_scenarios_allocation_AP04_ap04t002_runIterateOverInstancesOfClass
 JNIEXPORT void JNICALL
 Java_nsk_jvmti_scenarios_allocation_AP04_ap04t002_runIterateOverObjectsReachableFromObject(JNIEnv* jni,
                                                                                            jclass  klass) {
-    jobject root = NULL;
+    jobject root = nullptr;
     int count = 0;
 
     if (!NSK_JNI_VERIFY(jni, (root =
-                jni->GetStaticObjectField(debugeeClass, rootFieldID)) != NULL)) {
-        NSK_COMPLAIN0("GetStaticObjectField returned NULL for 'root' field value\n\n");
+                jni->GetStaticObjectField(debugeeClass, rootFieldID)) != nullptr)) {
+        NSK_COMPLAIN0("GetStaticObjectField returned null for 'root' field value\n\n");
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -346,7 +346,7 @@ Java_nsk_jvmti_scenarios_allocation_AP04_ap04t002_runIterateOverObjectsReachable
     NSK_DISPLAY0("Calling IterateOverObjectsReachableFromObject...\n");
     if (!NSK_JVMTI_VERIFY(jvmti->IterateOverObjectsReachableFromObject(root,
                                                                        objectReferenceCallback,
-                                                                       NULL /*user_data*/))) {
+                                                                       nullptr /*user_data*/))) {
         nsk_jvmti_setFailStatus();
     }
     NSK_DISPLAY0("IterateOverObjectsReachableFromObject finished.\n");
@@ -372,24 +372,24 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_SIGNATURE);
     debugeeClass = nsk_jvmti_classBySignature(DEBUGEE_SIGNATURE);
-    if (debugeeClass == NULL) {
+    if (debugeeClass == nullptr) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = (jclass)jni->NewGlobalRef(debugeeClass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = (jclass)jni->NewGlobalRef(debugeeClass)) != nullptr))
         return;
 
     NSK_DISPLAY1("Find ID of 'root' field: %s\n", ROOT_SIGNATURE);
     if (!NSK_JNI_VERIFY(jni, (rootFieldID =
-            jni->GetStaticFieldID(debugeeClass, "root", ROOT_SIGNATURE)) != NULL)) {
+            jni->GetStaticFieldID(debugeeClass, "root", ROOT_SIGNATURE)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
     NSK_DISPLAY0("Find ID of 'modified' field\n");
     if (!NSK_JNI_VERIFY(jni, (modifiedFieldID =
-            jni->GetStaticFieldID(debugeeClass, "modified", "I")) != NULL)) {
+            jni->GetStaticFieldID(debugeeClass, "modified", "I")) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -434,7 +434,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("counterMonitor", &counterMonitor_ptr))) {
@@ -469,11 +469,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("enabling JVMTI events ...\n");
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_FIELD_MODIFICATION,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done.\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("agentProc has been set\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP04/ap04t003/ap04t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP04/ap04t003/ap04t003.cpp
index 99f4ec37019..4e0673b608d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP04/ap04t003/ap04t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP04/ap04t003/ap04t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,8 +35,8 @@ extern "C" {
 
 #define OBJ_MAX_COUNT 100000
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -45,19 +45,19 @@ static jlong timeout = 0;
 static const char* DEBUGEE_SIGNATURE = "Lnsk/jvmti/scenarios/allocation/AP04/ap04t003;";
 static const char* ROOT_SIGNATURE    = "[Lnsk/jvmti/scenarios/allocation/AP04/ap04t003;";
 
-static jclass debugeeClass = NULL;
+static jclass debugeeClass = nullptr;
 static jfieldID rootFieldID;
 
-static jrawMonitorID startLock = NULL;
-static jrawMonitorID runLock = NULL;
-static jrawMonitorID endLock = NULL;
+static jrawMonitorID startLock = nullptr;
+static jrawMonitorID runLock = nullptr;
+static jrawMonitorID endLock = nullptr;
 
 static volatile int iterationCount = 0;
 static volatile int objectCount = 0;
 
 /***********************************************************************/
 
-static jrawMonitorID counterMonitor_ptr = NULL;
+static jrawMonitorID counterMonitor_ptr = nullptr;
 
 static void increaseCounter(volatile int* counterPtr) {
 
@@ -210,7 +210,7 @@ objectReferenceCallback(jvmtiObjectReferenceKind reference_kind,
 void JNICALL agent_start(jvmtiEnv* jvmti, JNIEnv* jni, void *p) {
 
     jint taggedObjectsCount = 0;
-    jobject* taggedObjectsList = NULL;
+    jobject* taggedObjectsList = nullptr;
 
     NSK_DISPLAY0("Agent thread: started.\n");
 
@@ -219,7 +219,7 @@ void JNICALL agent_start(jvmtiEnv* jvmti, JNIEnv* jni, void *p) {
         jlong tag = (jlong)1;
 
         if (!NSK_JVMTI_VERIFY(jvmti->GetObjectsWithTags(
-                1, &tag, &taggedObjectsCount, &taggedObjectsList, NULL))) {
+                1, &tag, &taggedObjectsCount, &taggedObjectsList, nullptr))) {
             nsk_jvmti_setFailStatus();
             return;
         }
@@ -315,7 +315,7 @@ static int startThread(jthread threadObj) {
 
     /* start thread */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->RunAgentThread(threadObj, agent_start, NULL, JVMTI_THREAD_NORM_PRIORITY))) {
+            jvmti->RunAgentThread(threadObj, agent_start, nullptr, JVMTI_THREAD_NORM_PRIORITY))) {
         success = NSK_FALSE;
         nsk_jvmti_setFailStatus();
     } else {
@@ -348,7 +348,7 @@ static jthread newThreadObj(JNIEnv* jni_env) {
 
 /** Clean counters and start new agent thread with agent_start() body. */
 static int prepareToIteration(JNIEnv* jni) {
-    jthread threadObj = NULL;
+    jthread threadObj = nullptr;
 
     setCounter(&iterationCount, 0);
     setCounter(&objectCount, 0);
@@ -408,7 +408,7 @@ Java_nsk_jvmti_scenarios_allocation_AP04_ap04t003_runIterateOverHeap(JNIEnv* jni
     NSK_DISPLAY0("Calling IterateOverHeap...\n");
     if (!NSK_JVMTI_VERIFY(jvmti->IterateOverHeap(JVMTI_HEAP_OBJECT_TAGGED,
                                                  heapObjectCallback,
-                                                 NULL /*user_data*/))) {
+                                                 nullptr /*user_data*/))) {
         nsk_jvmti_setFailStatus();
     }
     NSK_DISPLAY0("IterateOverHeap finished.\n");
@@ -439,7 +439,7 @@ Java_nsk_jvmti_scenarios_allocation_AP04_ap04t003_runIterateOverReachableObjects
     if (!NSK_JVMTI_VERIFY(jvmti->IterateOverReachableObjects(heapRootCallback,
                                                              stackReferenceCallback,
                                                              objectReferenceCallback,
-                                                             NULL /*user_data*/))) {
+                                                             nullptr /*user_data*/))) {
         nsk_jvmti_setFailStatus();
     }
     NSK_DISPLAY0("IterateOverReachableObjects finished.\n");
@@ -470,7 +470,7 @@ Java_nsk_jvmti_scenarios_allocation_AP04_ap04t003_runIterateOverInstancesOfClass
     if (!NSK_JVMTI_VERIFY(jvmti->IterateOverInstancesOfClass(debugeeClass,
                                                              JVMTI_HEAP_OBJECT_TAGGED,
                                                              heapObjectCallback,
-                                                             NULL /*user_data*/))) {
+                                                             nullptr /*user_data*/))) {
         nsk_jvmti_setFailStatus();
     }
     NSK_DISPLAY0("IterateOverInstancesOfClass finished.\n");
@@ -492,7 +492,7 @@ JNIEXPORT void JNICALL
 Java_nsk_jvmti_scenarios_allocation_AP04_ap04t003_runIterateOverObjectsReachableFromObject(JNIEnv* jni_env,
                                                                                            jclass  klass) {
     ExceptionCheckingJniEnvPtr ec_jni(jni_env);
-    jobject root = NULL;
+    jobject root = nullptr;
     int modified = 0;
     int found = 0;
 
@@ -504,7 +504,7 @@ Java_nsk_jvmti_scenarios_allocation_AP04_ap04t003_runIterateOverObjectsReachable
     NSK_DISPLAY0("Calling IterateOverObjectsReachableFromObject...\n");
     if (!NSK_JVMTI_VERIFY(jvmti->IterateOverObjectsReachableFromObject(root,
                                                                        objectReferenceCallback,
-                                                                       NULL /*user_data*/))) {
+                                                                       nullptr /*user_data*/))) {
         nsk_jvmti_setFailStatus();
     }
     NSK_DISPLAY0("IterateOverObjectsReachableFromObject finished.\n");
@@ -531,7 +531,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni_env, void* arg) {
 
     NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_SIGNATURE);
     debugeeClass = nsk_jvmti_classBySignature(DEBUGEE_SIGNATURE);
-    if (debugeeClass == NULL) {
+    if (debugeeClass == nullptr) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -579,7 +579,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("counterMonitor", &counterMonitor_ptr))) {
@@ -608,7 +608,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!caps.can_tag_objects)
         NSK_DISPLAY0("Warning: tagging objects is not available\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("agentProc has been set\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP05/ap05t001/ap05t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP05/ap05t001/ap05t001.cpp
index b2b5f5cbb1b..64cd66bac55 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP05/ap05t001/ap05t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP05/ap05t001/ap05t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,13 +35,13 @@ extern "C" {
 
 #define EXP_OBJ_NUMBER 1
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
 static jlong timeout = 0;
-static jobject referrer = NULL;
+static jobject referrer = nullptr;
 static const char* SUBCLASS_SIGNATURE   = "Lnsk/jvmti/scenarios/allocation/AP05/ap05t001Subclass;";
 static const int   EXPECTED_STATIC_FIELDS_COUNT = 8;
 /* 8 ones declared in ap05t001Superclass + 8 ones declared in ap05t001Subclass */
@@ -112,14 +112,14 @@ Java_nsk_jvmti_scenarios_allocation_AP05_ap05t001_setTag(JNIEnv* jni,
 
 JNIEXPORT void JNICALL
 Java_nsk_jvmti_scenarios_allocation_AP05_ap05t001_setReferrer(JNIEnv* jni, jclass klass, jobject ref) {
-    if (!NSK_JNI_VERIFY(jni, (referrer = jni->NewGlobalRef(ref)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (referrer = jni->NewGlobalRef(ref)) != nullptr))
         nsk_jvmti_setFailStatus();
 }
 
 static void JNICALL
 agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
-    jclass debugeeClass = NULL;
+    jclass debugeeClass = nullptr;
 
     NSK_DISPLAY0("Wait for debugee start\n\n");
     if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout)))
@@ -132,7 +132,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         if (!NSK_JVMTI_VERIFY(jvmti->IterateOverReachableObjects(heapRootCallback,
                                                                  stackReferenceCallback,
                                                                  objectReferenceCallback,
-                                                                 NULL /*user_data*/))) {
+                                                                 nullptr /*user_data*/))) {
             nsk_jvmti_setFailStatus();
             break;
         }
@@ -154,7 +154,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0("\nCalling IterateOverObjectsReachableFromObject\n");
         {
             if (!NSK_JVMTI_VERIFY(jvmti->IterateOverObjectsReachableFromObject(
-                    referrer, objectReferenceCallback, NULL /*user_data*/))) {
+                    referrer, objectReferenceCallback, nullptr /*user_data*/))) {
                 nsk_jvmti_setFailStatus();
                 break;
             }
@@ -200,7 +200,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(jvmtiCapabilities));
@@ -215,7 +215,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!caps.can_tag_objects)
         NSK_DISPLAY0("Warning: tagging objects is not implemented\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("agentProc has been set\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP05/ap05t002/ap05t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP05/ap05t002/ap05t002.cpp
index 2d625ee9e96..b3e5fe567f6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP05/ap05t002/ap05t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP05/ap05t002/ap05t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,13 +35,13 @@ extern "C" {
 
 #define EXP_OBJ_NUMBER 1
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
 static jlong timeout = 0;
-static jobject referrer = NULL;
+static jobject referrer = nullptr;
 static const char* SUBCLASS_SIGNATURE   = "Lnsk/jvmti/scenarios/allocation/AP05/ap05t002Subclass;";
 static const long  TAG1 = 1l, TAG2 = 2l;
 static int caseNumber = 0, forthRef = 0, backRef = 0;
@@ -111,7 +111,7 @@ Java_nsk_jvmti_scenarios_allocation_AP05_ap05t002_setTag(JNIEnv* jni,
 JNIEXPORT void JNICALL
 Java_nsk_jvmti_scenarios_allocation_AP05_ap05t002_setReferrer(JNIEnv* jni, jclass klass, jobject ref, jint caseNum) {
     caseNumber = caseNum;
-    if (!NSK_JNI_VERIFY(jni, (referrer = jni->NewGlobalRef(ref)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (referrer = jni->NewGlobalRef(ref)) != nullptr))
         nsk_jvmti_setFailStatus();
 }
 
@@ -122,7 +122,7 @@ static void runCase() {
     if (!NSK_JVMTI_VERIFY(jvmti->IterateOverReachableObjects(heapRootCallback,
                                                              stackReferenceCallback,
                                                              objectReferenceCallback,
-                                                             NULL /*user_data*/))) {
+                                                             nullptr /*user_data*/))) {
         nsk_jvmti_setFailStatus();
     }
     if (forthRef != 1) {
@@ -141,7 +141,7 @@ static void runCase() {
     backRef = 0;
     if (!NSK_JVMTI_VERIFY(jvmti->IterateOverObjectsReachableFromObject(referrer,
                                                                        objectReferenceCallback,
-                                                                       NULL /*user_data*/))) {
+                                                                       nullptr /*user_data*/))) {
         nsk_jvmti_setFailStatus();
     }
     if (forthRef != 1) {
@@ -159,7 +159,7 @@ static void runCase() {
 static void JNICALL
 agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
-    jclass debugeeClass = NULL;
+    jclass debugeeClass = nullptr;
 
     NSK_DISPLAY0("Wait for debugee start\n\n");
     if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout)))
@@ -204,7 +204,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(jvmtiCapabilities));
@@ -219,7 +219,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!caps.can_tag_objects)
         NSK_DISPLAY0("Warning: tagging objects is not implemented\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("agentProc has been set\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP06/ap06t001/ap06t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP06/ap06t001/ap06t001.cpp
index b624c673683..dafd0a59b1e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP06/ap06t001/ap06t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP06/ap06t001/ap06t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,8 +35,8 @@ extern "C" {
 
 #define EXP_OBJ_NUMBER 1
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -134,7 +134,7 @@ Java_nsk_jvmti_scenarios_allocation_AP06_ap06t001Thread_setTag(JNIEnv* jni, jobj
 static void JNICALL
 agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
-    jclass debugeeClass = NULL;
+    jclass debugeeClass = nullptr;
 
     NSK_DISPLAY0("Wait for debugee start\n\n");
     if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout)))
@@ -147,32 +147,32 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
         NSK_DISPLAY1("Find debugee class: %s\n", DEBUGEE_SIGNATURE);
         debugeeClass = nsk_jvmti_classBySignature(DEBUGEE_SIGNATURE);
-        if (debugeeClass == NULL) {
+        if (debugeeClass == nullptr) {
             nsk_jvmti_setFailStatus();
             break;
         }
 
         if (!NSK_JNI_VERIFY(jni, (fid =
-                jni->GetStaticFieldID(debugeeClass, "thread", THREAD_CLS_SIGNATURE)) != NULL)) {
+                jni->GetStaticFieldID(debugeeClass, "thread", THREAD_CLS_SIGNATURE)) != nullptr)) {
             nsk_jvmti_setFailStatus();
             break;
         }
 
         if (!NSK_JNI_VERIFY(jni, (localRefThread =
-                jni->GetStaticObjectField(debugeeClass, fid)) != NULL)) {
-            NSK_COMPLAIN0("GetStaticObjectField returned NULL for 'thread' field value\n\n");
+                jni->GetStaticObjectField(debugeeClass, fid)) != nullptr)) {
+            NSK_COMPLAIN0("GetStaticObjectField returned null for 'thread' field value\n\n");
             nsk_jvmti_setFailStatus();
             break;
         }
 
-        if (!NSK_JNI_VERIFY(jni, (globalRefThread = jni->NewGlobalRef(localRefThread)) != NULL))
+        if (!NSK_JNI_VERIFY(jni, (globalRefThread = jni->NewGlobalRef(localRefThread)) != nullptr))
             return;
 
         NSK_DISPLAY0("Calling IterateOverReachableObjects\n");
         if (!NSK_JVMTI_VERIFY(jvmti->IterateOverReachableObjects(heapRootCallback,
                                                                  stackReferenceCallback,
                                                                  objectReferenceCallback,
-                                                                 NULL /*user_data*/))) {
+                                                                 nullptr /*user_data*/))) {
             nsk_jvmti_setFailStatus();
             break;
         }
@@ -220,7 +220,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(jvmtiCapabilities));
@@ -235,7 +235,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!caps.can_tag_objects)
         NSK_DISPLAY0("Warning: tagging objects is not implemented\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("agentProc has been set\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP07/ap07t001/ap07t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP07/ap07t001/ap07t001.cpp
index 52988ac2469..16831e35524 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP07/ap07t001/ap07t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP07/ap07t001/ap07t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,13 +35,13 @@ extern "C" {
 
 #define EXP_OBJ_NUMBER 1
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
 static jlong timeout = 0;
-static jobject root = NULL;
+static jobject root = nullptr;
 static const char* DEBUGEE_SIGNATURE = "Lnsk/jvmti/scenarios/allocation/AP07/ap07t001;";
 static const jlong IGNORE_TAG = (jlong)10l;
 
@@ -118,14 +118,14 @@ Java_nsk_jvmti_scenarios_allocation_AP07_ap07t001_setTag(JNIEnv* jni,
 
 JNIEXPORT void JNICALL
 Java_nsk_jvmti_scenarios_allocation_AP07_ap07t001_setRoot(JNIEnv* jni, jobject obj) {
-    if (!NSK_JNI_VERIFY(jni, (root = jni->NewGlobalRef(obj)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (root = jni->NewGlobalRef(obj)) != nullptr))
         nsk_jvmti_setFailStatus();
 }
 
 static void JNICALL
 agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
-    jclass debugeeClass = NULL;
+    jclass debugeeClass = nullptr;
 
     NSK_DISPLAY0("Wait for debugee start\n\n");
     if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout)))
@@ -137,7 +137,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         if (!NSK_JVMTI_VERIFY(jvmti->IterateOverReachableObjects(heapRootCallback,
                                                                  stackReferenceCallback,
                                                                  objectReferenceCallback,
-                                                                 NULL /*user_data*/))) {
+                                                                 nullptr /*user_data*/))) {
             nsk_jvmti_setFailStatus();
             break;
         }
@@ -145,7 +145,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0("Calling IterateOverObjectsReachableFromObject\n");
         {
             if (!NSK_JVMTI_VERIFY(jvmti->IterateOverObjectsReachableFromObject(
-                    root, objectReferenceCallback, NULL /*user_data*/))) {
+                    root, objectReferenceCallback, nullptr /*user_data*/))) {
                 nsk_jvmti_setFailStatus();
                 break;
             }
@@ -178,7 +178,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(jvmtiCapabilities));
@@ -193,7 +193,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!caps.can_tag_objects)
         NSK_DISPLAY0("Warning: tagging objects is not implemented\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("agentProc has been set\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP07/ap07t002/ap07t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP07/ap07t002/ap07t002.cpp
index 4b5e95344f1..01fbb9471ac 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP07/ap07t002/ap07t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP07/ap07t002/ap07t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,13 +35,13 @@ extern "C" {
 
 #define EXP_OBJ_NUMBER 1
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
 static jlong timeout = 0;
-static jobject root = NULL;
+static jobject root = nullptr;
 static const char* DEBUGEE_SIGNATURE = "Lnsk/jvmti/scenarios/allocation/AP07/ap07t002;";
 static const jlong IGNORE_TAG = (jlong)10l;
 
@@ -119,7 +119,7 @@ Java_nsk_jvmti_scenarios_allocation_AP07_ap07t002_setTag(JNIEnv* jni,
 static void JNICALL
 agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
-    jclass debugeeClass = NULL;
+    jclass debugeeClass = nullptr;
 
     NSK_DISPLAY0("Wait for debugee start\n\n");
     if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout)))
@@ -131,7 +131,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         if (!NSK_JVMTI_VERIFY(jvmti->IterateOverReachableObjects(heapRootCallback,
                                                                  stackReferenceCallback,
                                                                  objectReferenceCallback,
-                                                                 NULL /*user_data*/))) {
+                                                                 nullptr /*user_data*/))) {
             nsk_jvmti_setFailStatus();
             break;
         }
@@ -161,7 +161,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(jvmtiCapabilities));
@@ -176,7 +176,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!caps.can_tag_objects)
         NSK_DISPLAY0("Warning: tagging objects is not implemented\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("agentProc has been set\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP09/ap09t001/ap09t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP09/ap09t001/ap09t001.cpp
index 00b866d1e92..229f7dba9b7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP09/ap09t001/ap09t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP09/ap09t001/ap09t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,13 +35,13 @@ extern "C" {
 
 #define EXP_OBJ_NUMBER 1
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
 static jlong timeout = 0;
-static jobject referrer = NULL;
+static jobject referrer = nullptr;
 static const char* DEBUGEE_SIGNATURE   = "Lnsk/jvmti/scenarios/allocation/AP09/ap09t001;";
 static const long OBJECT_TAG         = 1l;
 static const long CLASS_TAG          = 2l;
@@ -139,14 +139,14 @@ Java_nsk_jvmti_scenarios_allocation_AP09_ap09t001_setTag(JNIEnv* jni,
 
 JNIEXPORT void JNICALL
 Java_nsk_jvmti_scenarios_allocation_AP09_ap09t001_setReferrer(JNIEnv* jni, jclass klass, jobject ref) {
-    if (!NSK_JNI_VERIFY(jni, (referrer = jni->NewGlobalRef(ref)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (referrer = jni->NewGlobalRef(ref)) != nullptr))
         nsk_jvmti_setFailStatus();
 }
 
 static void JNICALL
 agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
-    jclass debugeeClass = NULL;
+    jclass debugeeClass = nullptr;
 
     NSK_DISPLAY0("Wait for debugee start\n\n");
     if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout)))
@@ -156,7 +156,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         NSK_DISPLAY0("\nCalling IterateOverObjectsReachableFromObject\n");
         if (!NSK_JVMTI_VERIFY(jvmti->IterateOverObjectsReachableFromObject(referrer,
                                                                            objectReferenceCallback,
-                                                                           NULL /*user_data*/))) {
+                                                                           nullptr /*user_data*/))) {
             nsk_jvmti_setFailStatus();
         }
         if (!classFound) {
@@ -214,7 +214,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(jvmtiCapabilities));
@@ -231,7 +231,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("agentProc has been set\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP10/ap10t001/ap10t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP10/ap10t001/ap10t001.cpp
index d4977a45a26..fdc0e50273c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP10/ap10t001/ap10t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP10/ap10t001/ap10t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -37,7 +37,7 @@ extern "C" {
 
 #define MAX_SIZE 256
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -56,7 +56,7 @@ typedef struct _LocalStorage {
 static LocalStorage stor;
 
 static void envStorageFunc(jvmtiEnv *jvmti_env, const char *msg) {
-    LocalStorage* obtainedData = NULL;
+    LocalStorage* obtainedData = nullptr;
     LocalStorage* storedData = &stor;
 
     NSK_DISPLAY2("%s: setting an environment local storage 0x%p ...\n",
@@ -259,7 +259,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capability to generate compiled method events */
@@ -296,19 +296,19 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("setting event callbacks done\nenabling JVMTI events ...\n");
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_GARBAGE_COLLECTION_START,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_GARBAGE_COLLECTION_FINISH,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_OBJECT_FREE,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP11/ap11t001/ap11t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP11/ap11t001/ap11t001.cpp
index 8f9d67ac6cf..59b35902bad 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP11/ap11t001/ap11t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP11/ap11t001/ap11t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -46,14 +46,14 @@ static int lookup(jvmtiEnv* jvmti,
         if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(classes[i], &signature, &generic)))
             break;
 
-        if (signature != NULL && strcmp(signature, exp_sig) == 0) {
+        if (signature != nullptr && strcmp(signature, exp_sig) == 0) {
             found = NSK_TRUE;
         }
 
-        if (signature != NULL)
+        if (signature != nullptr)
             jvmti->Deallocate((unsigned char*)signature);
 
-        if (generic != NULL)
+        if (generic != nullptr)
             jvmti->Deallocate((unsigned char*)generic);
     }
 
@@ -141,7 +141,7 @@ VMObjectAlloc(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread, jobject object,
             return;
         }
 
-        if (classes != NULL)
+        if (classes != nullptr)
             jvmti->Deallocate((unsigned char*)classes);
     } while (0);
 
@@ -174,10 +174,10 @@ VMObjectAlloc(jvmtiEnv *jvmti, JNIEnv* jni, jthread thread, jobject object,
         }
     } while (0);
 
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti->Deallocate((unsigned char*)signature);
 
-    if (generic != NULL)
+    if (generic != nullptr)
         jvmti->Deallocate((unsigned char*)generic);
 }
 
@@ -210,7 +210,7 @@ JNIEXPORT jint JNI_OnLoad_ap11t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -223,7 +223,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -239,11 +239,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* enable VMObjectAlloc event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, nullptr)))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001/ap12t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001/ap12t001.cpp
index b5236d993c1..c34bb8891f6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001/ap12t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001/ap12t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,8 +39,8 @@ extern "C" {
 
 #define EXP_OBJ_FREE 2
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jvmtiCapabilities caps;
 
@@ -89,7 +89,7 @@ Java_nsk_jvmti_scenarios_allocation_AP12_ap12t001_flushObjectFreeEvents(JNIEnv*
     // Already enabled, but this triggers flush of pending events.
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_OBJECT_FREE,
-                                                          NULL))) {
+                                                          nullptr))) {
         nsk_jvmti_setFailStatus();
     }
 }
@@ -97,7 +97,7 @@ Java_nsk_jvmti_scenarios_allocation_AP12_ap12t001_flushObjectFreeEvents(JNIEnv*
 static void JNICALL
 agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
-    jclass debugeeClass = NULL;
+    jclass debugeeClass = nullptr;
 
     NSK_DISPLAY0("Wait for debugee start\n\n");
     if (!NSK_VERIFY(nsk_jvmti_waitForSync(timeout)))
@@ -132,7 +132,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(jvmtiCapabilities));
@@ -162,15 +162,15 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("setting event callbacks done\nenabling JVMTI events ...\n");
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_OBJECT_FREE,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_VM_DEATH,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("enabling the events done\n\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
     NSK_DISPLAY0("agentProc has been set\n\n");
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI01/bi01t001/bi01t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI01/bi01t001/bi01t001.cpp
index 0ba4c3c442d..951d0c6c7c9 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI01/bi01t001/bi01t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI01/bi01t001/bi01t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -31,7 +31,7 @@
 extern "C" {
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 #define TESTED_CLASS_NAME   "nsk/jvmti/scenarios/bcinstr/BI01/bi01t001a"
@@ -106,7 +106,7 @@ cbClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv* jni_env,
             const unsigned char* class_data, jint* new_class_data_len,
             unsigned char** new_class_data) {
 
-    if (name == NULL || strcmp(name, TESTED_CLASS_NAME)) {
+    if (name == nullptr || strcmp(name, TESTED_CLASS_NAME)) {
         return;
     }
 
@@ -175,7 +175,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
     NSK_DISPLAY0("Notification disabled for CLASS_FILE_LOAD_HOOK event\n");
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE,
                                                           JVMTI_EVENT_CLASS_FILE_LOAD_HOOK,
-                                                          NULL))) {
+                                                          nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -240,7 +240,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     {
@@ -267,12 +267,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("Set notification enabled for CLASS_FILE_LOAD_HOOK event\n");
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_CLASS_FILE_LOAD_HOOK,
-                                                          NULL))) {
+                                                          nullptr))) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI01/bi01t002/bi01t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI01/bi01t002/bi01t002.cpp
index ca26caaa89b..2a3aab3a08d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI01/bi01t002/bi01t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI01/bi01t002/bi01t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -31,7 +31,7 @@
 extern "C" {
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 #define TESTED_CLASS_NAME   "nsk/jvmti/scenarios/bcinstr/BI01/bi01t002a"
@@ -109,7 +109,7 @@ cbClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv* jni_env,
             const unsigned char* class_data, jint* new_class_data_len,
             unsigned char** new_class_data) {
 
-    if (name == NULL || strcmp(name, TESTED_CLASS_NAME)) {
+    if (name == nullptr || strcmp(name, TESTED_CLASS_NAME)) {
         return;
     }
 
@@ -183,7 +183,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
     NSK_DISPLAY0("Notification disabled for CLASS_FILE_LOAD_HOOK event\n");
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE,
                                                           JVMTI_EVENT_CLASS_FILE_LOAD_HOOK,
-                                                          NULL))) {
+                                                          nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -253,7 +253,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     {
@@ -280,12 +280,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("Set notification enabled for CLASS_FILE_LOAD_HOOK event\n");
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_CLASS_FILE_LOAD_HOOK,
-                                                          NULL))) {
+                                                          nullptr))) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI02/bi02t001/bi02t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI02/bi02t001/bi02t001.cpp
index 66347ffdfef..6e732377021 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI02/bi02t001/bi02t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI02/bi02t001/bi02t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,8 +38,8 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jclass debugeeClass = NULL;
-static jbyteArray classBytes = NULL;
+static jclass debugeeClass = nullptr;
+static jbyteArray classBytes = nullptr;
 static int ClassFileLoadHookEventFlag = NSK_FALSE;
 
 const char* CLASS_NAME = "nsk/jvmti/scenarios/bcinstr/BI02/bi02t001a";
@@ -55,11 +55,11 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jint class_data_len, const unsigned char* class_data,
         jint *new_class_data_len, unsigned char** new_class_data) {
 
-    if (name != NULL && (strcmp(name, CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, CLASS_NAME) == 0)) {
         ClassFileLoadHookEventFlag = NSK_TRUE;
         NSK_DISPLAY0("ClassFileLoadHook event\n");
 
-        if (class_being_redefined == NULL) {
+        if (class_being_redefined == nullptr) {
             /* sent by class load */
 
             if (!NSK_JNI_VERIFY(jni_env, (*new_class_data_len =
@@ -69,7 +69,7 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
             }
 
             if (!NSK_JNI_VERIFY(jni_env, (*new_class_data = (unsigned char*)
-                    jni_env->GetByteArrayElements(classBytes, NULL)) != NULL)) {
+                    jni_env->GetByteArrayElements(classBytes, nullptr)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -82,29 +82,29 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* DEBUGEE_CLASS_NAME =
         "nsk/jvmti/scenarios/bcinstr/BI02/bi02t001";
-    jfieldID field = NULL;
+    jfieldID field = nullptr;
 
     NSK_DISPLAY1("Find class: %s\n", DEBUGEE_CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = (jclass)jni->NewGlobalRef(debugeeClass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = (jclass)jni->NewGlobalRef(debugeeClass)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetStaticFieldID(debugeeClass, "newClassBytes", "[B")) != NULL))
+            jni->GetStaticFieldID(debugeeClass, "newClassBytes", "[B")) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (classBytes = (jbyteArray)
-            jni->GetStaticObjectField(debugeeClass, field)) != NULL))
+            jni->GetStaticObjectField(debugeeClass, field)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (classBytes = (jbyteArray)jni->NewGlobalRef(classBytes)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (classBytes = (jbyteArray)jni->NewGlobalRef(classBytes)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_CLASS_FILE_LOAD_HOOK,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
 
     return NSK_TRUE;
@@ -137,7 +137,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE,
                                                           JVMTI_EVENT_CLASS_FILE_LOAD_HOOK,
-                                                          NULL)))
+                                                          nullptr)))
         nsk_jvmti_setFailStatus();
 
     NSK_TRACE(jni->DeleteGlobalRef(debugeeClass));
@@ -162,7 +162,7 @@ JNIEXPORT jint JNI_OnLoad_bi02t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
     jvmtiCapabilities caps;
 
@@ -174,7 +174,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -182,7 +182,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_JVMTI_VERIFY(jvmti->AddCapabilities(&caps)))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI02/bi02t002/bi02t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI02/bi02t002/bi02t002.cpp
index 2b594da6407..197d776cb45 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI02/bi02t002/bi02t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI02/bi02t002/bi02t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,9 +38,9 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jclass debugeeClass = NULL;
-static jclass testedClass = NULL;
-static jbyteArray classBytes = NULL;
+static jclass debugeeClass = nullptr;
+static jclass testedClass = nullptr;
+static jbyteArray classBytes = nullptr;
 
 const char* CLASS_NAME = "nsk/jvmti/scenarios/bcinstr/BI02/bi02t002a";
 
@@ -49,31 +49,31 @@ const char* CLASS_NAME = "nsk/jvmti/scenarios/bcinstr/BI02/bi02t002a";
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* DEBUGEE_CLASS_NAME =
         "nsk/jvmti/scenarios/bcinstr/BI02/bi02t002";
-    jfieldID field = NULL;
+    jfieldID field = nullptr;
 
     NSK_DISPLAY1("Find class: %s\n", DEBUGEE_CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = (jclass)jni->NewGlobalRef(debugeeClass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = (jclass)jni->NewGlobalRef(debugeeClass)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetStaticFieldID(debugeeClass, "newClassBytes", "[B")) != NULL))
+            jni->GetStaticFieldID(debugeeClass, "newClassBytes", "[B")) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (classBytes = (jbyteArray)
-            jni->GetStaticObjectField(debugeeClass, field)) != NULL))
+            jni->GetStaticObjectField(debugeeClass, field)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (classBytes = (jbyteArray)jni->NewGlobalRef(classBytes)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (classBytes = (jbyteArray)jni->NewGlobalRef(classBytes)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY1("Find class: %s\n", CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (testedClass = jni->FindClass(CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = jni->FindClass(CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass)jni->NewGlobalRef(testedClass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass)jni->NewGlobalRef(testedClass)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -90,7 +90,7 @@ static int redefine(jvmtiEnv* jvmti, JNIEnv* jni) {
         return NSK_TRUE;
 
     if (!NSK_JNI_VERIFY(jni, (class_def.class_bytes = (unsigned char*)
-            jni->GetByteArrayElements(classBytes, NULL)) != NULL))
+            jni->GetByteArrayElements(classBytes, nullptr)) != nullptr))
         return NSK_TRUE;
 
     class_def.klass = testedClass;
@@ -146,7 +146,7 @@ JNIEXPORT jint JNI_OnLoad_bi02t002(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
 
     NSK_DISPLAY0("Agent_OnLoad\n");
@@ -157,7 +157,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -165,7 +165,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_JVMTI_VERIFY(jvmti->AddCapabilities(&caps)))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI03/bi03t001/bi03t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI03/bi03t001/bi03t001.cpp
index f7e91f623e0..b302186df58 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI03/bi03t001/bi03t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI03/bi03t001/bi03t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,8 +38,8 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jclass debugeeClass = NULL;
-static jbyteArray classBytes = NULL;
+static jclass debugeeClass = nullptr;
+static jbyteArray classBytes = nullptr;
 static int ClassFileLoadHookEventFlag = NSK_FALSE;
 
 const char* CLASS_NAME = "nsk/jvmti/scenarios/bcinstr/BI03/bi03t001a";
@@ -55,11 +55,11 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jint class_data_len, const unsigned char* class_data,
         jint *new_class_data_len, unsigned char** new_class_data) {
 
-    if (name != NULL && (strcmp(name, CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, CLASS_NAME) == 0)) {
         ClassFileLoadHookEventFlag = NSK_TRUE;
         NSK_DISPLAY0("ClassFileLoadHook event\n");
 
-        if (class_being_redefined == NULL) {
+        if (class_being_redefined == nullptr) {
             /* sent by class load */
 
             if (!NSK_JNI_VERIFY(jni_env, (*new_class_data_len =
@@ -69,7 +69,7 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
             }
 
             if (!NSK_JNI_VERIFY(jni_env, (*new_class_data = (unsigned char*)
-                    jni_env->GetByteArrayElements(classBytes, NULL)) != NULL)) {
+                    jni_env->GetByteArrayElements(classBytes, nullptr)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -82,29 +82,29 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* DEBUGEE_CLASS_NAME =
         "nsk/jvmti/scenarios/bcinstr/BI03/bi03t001";
-    jfieldID field = NULL;
+    jfieldID field = nullptr;
 
     NSK_DISPLAY1("Find class: %s\n", DEBUGEE_CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = (jclass)jni->NewGlobalRef(debugeeClass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = (jclass)jni->NewGlobalRef(debugeeClass)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetStaticFieldID(debugeeClass, "newClassBytes", "[B")) != NULL))
+            jni->GetStaticFieldID(debugeeClass, "newClassBytes", "[B")) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (classBytes = (jbyteArray)
-            jni->GetStaticObjectField(debugeeClass, field)) != NULL))
+            jni->GetStaticObjectField(debugeeClass, field)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (classBytes = (jbyteArray)jni->NewGlobalRef(classBytes)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (classBytes = (jbyteArray)jni->NewGlobalRef(classBytes)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE,
                                                           JVMTI_EVENT_CLASS_FILE_LOAD_HOOK,
-                                                          NULL)))
+                                                          nullptr)))
         return JNI_ERR;
 
     return NSK_TRUE;
@@ -137,7 +137,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE,
                                                           JVMTI_EVENT_CLASS_FILE_LOAD_HOOK,
-                                                          NULL)))
+                                                          nullptr)))
         nsk_jvmti_setFailStatus();
 
     NSK_TRACE(jni->DeleteGlobalRef(debugeeClass));
@@ -162,7 +162,7 @@ JNIEXPORT jint JNI_OnLoad_bi03t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
     jvmtiCapabilities caps;
 
@@ -174,7 +174,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -182,7 +182,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_JVMTI_VERIFY(jvmti->AddCapabilities(&caps)))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI03/bi03t002/bi03t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI03/bi03t002/bi03t002.cpp
index 07adb527a71..575ebead06e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI03/bi03t002/bi03t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI03/bi03t002/bi03t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,9 +38,9 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jclass debugeeClass = NULL;
-static jclass testedClass = NULL;
-static jbyteArray classBytes = NULL;
+static jclass debugeeClass = nullptr;
+static jclass testedClass = nullptr;
+static jbyteArray classBytes = nullptr;
 
 const char* CLASS_NAME = "nsk/jvmti/scenarios/bcinstr/BI03/bi03t002a";
 
@@ -49,31 +49,31 @@ const char* CLASS_NAME = "nsk/jvmti/scenarios/bcinstr/BI03/bi03t002a";
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* DEBUGEE_CLASS_NAME =
         "nsk/jvmti/scenarios/bcinstr/BI03/bi03t002";
-    jfieldID field = NULL;
+    jfieldID field = nullptr;
 
     NSK_DISPLAY1("Find class: %s\n", DEBUGEE_CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = (jclass)jni->NewGlobalRef(debugeeClass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = (jclass)jni->NewGlobalRef(debugeeClass)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetStaticFieldID(debugeeClass, "newClassBytes", "[B")) != NULL))
+            jni->GetStaticFieldID(debugeeClass, "newClassBytes", "[B")) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (classBytes = (jbyteArray)
-            jni->GetStaticObjectField(debugeeClass, field)) != NULL))
+            jni->GetStaticObjectField(debugeeClass, field)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (classBytes = (jbyteArray)jni->NewGlobalRef(classBytes)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (classBytes = (jbyteArray)jni->NewGlobalRef(classBytes)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY1("Find class: %s\n", CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (testedClass = jni->FindClass(CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = jni->FindClass(CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass)jni->NewGlobalRef(testedClass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass)jni->NewGlobalRef(testedClass)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -90,7 +90,7 @@ static int redefine(jvmtiEnv* jvmti, JNIEnv* jni) {
         return NSK_TRUE;
 
     if (!NSK_JNI_VERIFY(jni, (class_def.class_bytes = (unsigned char*)
-            jni->GetByteArrayElements(classBytes, NULL)) != NULL))
+            jni->GetByteArrayElements(classBytes, nullptr)) != nullptr))
         return NSK_TRUE;
 
     class_def.klass = testedClass;
@@ -146,7 +146,7 @@ JNIEXPORT jint JNI_OnLoad_bi03t002(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
 
     NSK_DISPLAY0("Agent_OnLoad\n");
@@ -157,7 +157,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -165,7 +165,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_JVMTI_VERIFY(jvmti->AddCapabilities(&caps)))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI04/bi04t002/bi04t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI04/bi04t002/bi04t002.cpp
index c87fc546b90..6bb7ba83406 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI04/bi04t002/bi04t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/bcinstr/BI04/bi04t002/bi04t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -61,7 +61,7 @@ int readNewBytecode(jvmtiEnv* jvmti) {
                         filename);
 
     bytecode = fopen(filename, "rb");
-    if (bytecode == NULL) {
+    if (bytecode == nullptr) {
         NSK_COMPLAIN0("error opening file\n");
         return NSK_FALSE;
     }
@@ -137,7 +137,7 @@ JNIEXPORT jint JNI_OnLoad_bi04t002(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv *jvmti = NULL;
+    jvmtiEnv *jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -145,7 +145,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     {
@@ -161,7 +161,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_VERIFY(readNewBytecode(jvmti)))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t001/cm01t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t001/cm01t001.cpp
index a59b82a5c5c..2d6978c2a0e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t001/cm01t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t001/cm01t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -57,22 +57,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -82,12 +82,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -97,7 +97,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -107,16 +107,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -156,18 +156,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -186,7 +186,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -199,7 +199,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -251,8 +251,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking positive: SetTag\n");
@@ -295,7 +295,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -365,7 +365,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -393,7 +393,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -565,11 +565,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t002/cm01t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t002/cm01t002.cpp
index 63252c7765c..45761319f04 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t002/cm01t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t002/cm01t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -50,22 +50,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -75,12 +75,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -90,7 +90,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -99,22 +99,22 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threads)))
         return NSK_FALSE;
 
-    if (thread == NULL) {
+    if (thread == nullptr) {
         nsk_lcomplain(__FILE__, __LINE__, "tested thread not found\n");
         return NSK_FALSE;
     }
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -154,18 +154,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -184,7 +184,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -197,7 +197,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -249,8 +249,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -303,7 +303,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -373,7 +373,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -401,7 +401,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -574,11 +574,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t003/cm01t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t003/cm01t003.cpp
index f92d0d29805..7580d3f6a93 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t003/cm01t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t003/cm01t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,22 +52,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -77,12 +77,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -92,7 +92,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -102,16 +102,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -151,18 +151,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -181,7 +181,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -194,7 +194,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -246,8 +246,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -300,7 +300,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -370,7 +370,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -398,7 +398,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -568,11 +568,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t004/cm01t004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t004/cm01t004.cpp
index 6b52f4c9695..a5b7072692a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t004/cm01t004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t004/cm01t004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -50,22 +50,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -75,12 +75,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -90,7 +90,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -100,16 +100,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -149,18 +149,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -179,7 +179,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking positive: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY(jvmti->GetOwnedMonitorInfo(thread, &count, &monitors)))
@@ -191,7 +191,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -243,8 +243,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -297,7 +297,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -367,7 +367,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -395,7 +395,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -567,11 +567,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t005/cm01t005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t005/cm01t005.cpp
index adbb0d83cba..b91e949a8c1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t005/cm01t005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t005/cm01t005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -50,22 +50,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -75,12 +75,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -90,7 +90,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -100,16 +100,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -149,18 +149,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -179,7 +179,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -192,7 +192,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking positive: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY(jvmti->GetCurrentContendedMonitor(thread, &monitor)))
@@ -243,8 +243,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -297,7 +297,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -367,7 +367,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -395,7 +395,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -567,11 +567,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t006/cm01t006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t006/cm01t006.cpp
index 011c53aa0c9..325d6d725dd 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t006/cm01t006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t006/cm01t006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -50,22 +50,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -75,12 +75,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -90,7 +90,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -100,16 +100,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -149,18 +149,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -179,7 +179,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -192,7 +192,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -244,8 +244,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -298,7 +298,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -368,7 +368,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -396,7 +396,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -567,11 +567,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t007/cm01t007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t007/cm01t007.cpp
index b9519d59054..4576bcd2f68 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t007/cm01t007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t007/cm01t007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -50,22 +50,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -75,12 +75,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -90,7 +90,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -100,15 +100,15 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingFlag' */
-    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "waitingFlag", "Z")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "waitingFlag", "Z")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -148,18 +148,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -178,7 +178,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -191,7 +191,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -265,8 +265,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -321,7 +321,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -391,7 +391,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -419,7 +419,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -591,11 +591,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t008/cm01t008.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t008/cm01t008.cpp
index 8f35fd2bf20..6783905f6b8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t008/cm01t008.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t008/cm01t008.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,24 +52,24 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 static jint klass_byte_count = 0;
-static unsigned char *klass_bytes = NULL;
+static unsigned char *klass_bytes = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -79,12 +79,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -94,7 +94,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -104,16 +104,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -153,18 +153,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -183,7 +183,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -196,7 +196,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -248,8 +248,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -302,7 +302,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -372,7 +372,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -505,7 +505,7 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *env, jclass class_beeing_redefine
         jint class_data_len, const unsigned char* class_data,
         jint *new_class_data_len, unsigned char** new_class_data) {
 
-    if (name != NULL && (strcmp(name, CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, CLASS_NAME) == 0)) {
         NSK_DISPLAY1("ClassFileLoadHook: %s\n", name);
         if (!NSK_JVMTI_VERIFY(jvmti->Allocate(class_data_len, &klass_bytes)))
             nsk_jvmti_setFailStatus();
@@ -514,7 +514,7 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *env, jclass class_beeing_redefine
             klass_byte_count = class_data_len;
         }
         NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL));
+            jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr));
     }
 }
 
@@ -600,11 +600,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
@@ -674,7 +674,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventCallbacks(&callbacks, sizeof(callbacks))))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(
-        jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+        jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t009/cm01t009.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t009/cm01t009.cpp
index 535398b2a96..307d1045bf6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t009/cm01t009.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t009/cm01t009.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,22 +52,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -77,12 +77,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -92,7 +92,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -102,16 +102,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -151,18 +151,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking positive: InterruptThread\n");
@@ -180,7 +180,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -193,7 +193,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -245,8 +245,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -299,7 +299,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -369,7 +369,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -397,7 +397,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -569,11 +569,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t010/cm01t010.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t010/cm01t010.cpp
index f7e8c060772..143cc6127e9 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t010/cm01t010.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t010/cm01t010.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -51,22 +51,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -76,12 +76,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -91,7 +91,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -101,16 +101,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -150,18 +150,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -180,7 +180,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -193,7 +193,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -245,8 +245,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -299,7 +299,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -369,7 +369,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking positive: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY(jvmti->GetSourceFileName(klass, &name)))
@@ -396,7 +396,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -568,11 +568,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t011/cm01t011.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t011/cm01t011.cpp
index fdd3e7207da..075c7e1bb27 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t011/cm01t011.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t011/cm01t011.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -61,22 +61,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -86,12 +86,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -101,7 +101,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -111,16 +111,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -160,18 +160,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -190,7 +190,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -203,7 +203,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -255,8 +255,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -309,7 +309,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -399,7 +399,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -427,7 +427,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -599,11 +599,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t012/cm01t012.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t012/cm01t012.cpp
index 68b6461161c..b8a18cf6179 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t012/cm01t012.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t012/cm01t012.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -54,22 +54,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -79,12 +79,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -94,7 +94,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -104,16 +104,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -151,18 +151,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -181,7 +181,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -194,7 +194,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -246,8 +246,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -300,7 +300,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -370,7 +370,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -398,7 +398,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -570,11 +570,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t013/cm01t013.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t013/cm01t013.cpp
index b6ce11d590e..aebd93910f6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t013/cm01t013.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t013/cm01t013.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -51,22 +51,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -76,12 +76,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -91,7 +91,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -101,16 +101,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -150,18 +150,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -180,7 +180,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -193,7 +193,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -245,8 +245,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -299,7 +299,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -369,7 +369,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -396,7 +396,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -568,11 +568,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t014/cm01t014.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t014/cm01t014.cpp
index 58d80995614..7875901b8aa 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t014/cm01t014.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t014/cm01t014.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,22 +52,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -77,12 +77,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -92,7 +92,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -102,16 +102,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -216,18 +216,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -246,7 +246,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -259,7 +259,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -311,8 +311,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -365,7 +365,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -435,7 +435,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -463,7 +463,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -694,11 +694,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t015/cm01t015.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t015/cm01t015.cpp
index 4919c2874dc..aab9c8f47a1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t015/cm01t015.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t015/cm01t015.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -54,22 +54,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -79,12 +79,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -94,7 +94,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -104,16 +104,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -218,18 +218,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -248,7 +248,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -261,7 +261,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -313,8 +313,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -367,7 +367,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -437,7 +437,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -465,7 +465,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -698,11 +698,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t016/cm01t016.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t016/cm01t016.cpp
index 0952ff8d3dc..59d23a8e373 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t016/cm01t016.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t016/cm01t016.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,22 +52,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -77,12 +77,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -92,7 +92,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -102,16 +102,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -216,18 +216,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -246,7 +246,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -259,7 +259,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -311,8 +311,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -365,7 +365,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -435,7 +435,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -463,7 +463,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -692,11 +692,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t017/cm01t017.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t017/cm01t017.cpp
index 13804681b1a..dc7ad64d8d5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t017/cm01t017.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t017/cm01t017.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -54,22 +54,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -79,12 +79,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -94,7 +94,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -104,16 +104,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -218,18 +218,18 @@ static int checkSignalThread(int positive) {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     if (positive) {
@@ -259,7 +259,7 @@ static int checkSignalThread(int positive) {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -272,7 +272,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -324,8 +324,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -378,7 +378,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -448,7 +448,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -476,7 +476,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -699,11 +699,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t018/cm01t018.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t018/cm01t018.cpp
index 7e53745ccac..bd22d800877 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t018/cm01t018.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t018/cm01t018.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -56,22 +56,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -81,12 +81,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -96,7 +96,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -106,16 +106,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -240,18 +240,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -270,7 +270,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -283,7 +283,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -335,8 +335,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -389,7 +389,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -459,7 +459,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -487,7 +487,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -710,11 +710,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t019/cm01t019.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t019/cm01t019.cpp
index 9fe8b204387..89475b798f5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t019/cm01t019.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t019/cm01t019.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -51,22 +51,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -76,12 +76,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -91,7 +91,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -101,16 +101,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -150,18 +150,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -180,7 +180,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -193,7 +193,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -245,8 +245,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -299,7 +299,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -369,7 +369,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -397,7 +397,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -569,11 +569,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t020/cm01t020.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t020/cm01t020.cpp
index 25d4ed9a06e..ccb3a84ea32 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t020/cm01t020.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t020/cm01t020.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,22 +52,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -77,12 +77,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -92,7 +92,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -102,16 +102,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -151,18 +151,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -181,7 +181,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -194,7 +194,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -246,8 +246,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -300,7 +300,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -370,7 +370,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -398,7 +398,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -568,11 +568,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t021/cm01t021.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t021/cm01t021.cpp
index 829a7c8f3dd..3f6bf3fd92b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t021/cm01t021.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM01/cm01t021/cm01t021.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,22 +52,22 @@ extern "C" {
 /* ========================================================================== */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 
 /* ========================================================================== */
 
 static int prepare() {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -77,12 +77,12 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -92,7 +92,7 @@ static int prepare() {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
@@ -102,16 +102,16 @@ static int prepare() {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingMonitor' */
     if (!NSK_JNI_VERIFY(jni, (field =
-            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != NULL))
+            jni->GetFieldID(klass, "waitingMonitor", "Ljava/lang/Object;")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -151,18 +151,18 @@ static int checkSignalThread() {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking negative: StopThread\n");
@@ -181,7 +181,7 @@ static int checkSignalThread() {
  */
 static int checkGetOwnedMonitorInfo() {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -194,7 +194,7 @@ static int checkGetOwnedMonitorInfo() {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor() {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -246,8 +246,8 @@ static int checkHeapFunctions() {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking negative: SetTag\n");
@@ -300,7 +300,7 @@ static int checkHeapFunctions() {
  */
 static int checkLocalVariableFunctions() {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -370,7 +370,7 @@ static int checkLocalVariableFunctions() {
 static int checkSourceInfoFunctions() {
     char *name;
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking negative: GetSourceFileName\n");
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
@@ -398,7 +398,7 @@ static int checkRedefineClasses() {
     NSK_DISPLAY0("Checking negative: RedefineClasses\n");
     class_def.klass = klass;
     class_def.class_byte_count = 0;
-    class_def.class_bytes = NULL;
+    class_def.class_bytes = nullptr;
     if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
             jvmti->RedefineClasses(1, &class_def)))
         return NSK_FALSE;
@@ -568,11 +568,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* testcase #1: check GetPotentialCapabilities */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM02/cm02t001/cm02t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM02/cm02t001/cm02t001.cpp
index d9037173ae3..94e16b7e98d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM02/cm02t001/cm02t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM02/cm02t001/cm02t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -58,9 +58,9 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jobject testedObject = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jobject testedObject = nullptr;
 const jlong TESTED_TAG_VALUE = 5555555L;
 static bool testedObjectNotified = false;
 
@@ -98,34 +98,34 @@ static void JNICALL
 CompiledMethodLoad(jvmtiEnv *jvmti_env, jmethodID method,
         jint code_size, const void* code_addr, jint map_length,
         const jvmtiAddrLocationMap* map, const void* compile_info) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     CompiledMethodLoadEventsCount++;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY3("CompiledMethodLoad event: %s%s (0x%p)\n",
         name, signature, code_addr);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
 static void JNICALL
 CompiledMethodUnload(jvmtiEnv *jvmti_env, jmethodID method,
         const void* code_addr) {
-    char *name = NULL;
-    char *sig = NULL;
+    char *name = nullptr;
+    char *sig = nullptr;
     jvmtiError err;
     CompiledMethodUnloadEventsCount++;
 
     NSK_DISPLAY0("CompiledMethodUnload event received\n");
     // Check for the case that the class has been unloaded
-    err = jvmti_env->GetMethodName(method, &name, &sig, NULL);
+    err = jvmti_env->GetMethodName(method, &name, &sig, nullptr);
     if (err == JVMTI_ERROR_NONE) {
         NSK_DISPLAY3("for: \tmethod: name=\"%s\" signature=\"%s\"\n\tnative address=0x%p\n",
           name, sig, code_addr);
@@ -206,12 +206,12 @@ VMObjectAlloc(jvmtiEnv *jvmti_env, JNIEnv* jni_env,
 
     VMObjectAllocEventsCount++;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(object_klass, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(object_klass, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY2("VMObjectAlloc: \"%s\", size=%d\n", signature, size);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -219,8 +219,8 @@ static void JNICALL
 NativeMethodBind(jvmtiEnv* jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method, void* func, void** func_ptr) {
     jvmtiPhase phase;
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     NativeMethodBindEventsCount++;
 
@@ -232,16 +232,16 @@ NativeMethodBind(jvmtiEnv* jvmti_env, JNIEnv *jni_env,
     if (phase != JVMTI_PHASE_START && phase != JVMTI_PHASE_LIVE)
         return;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
     NSK_DISPLAY2("NativeMethodBind event: %s%s\n", name, signature);
 
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -274,7 +274,7 @@ ObjectFree(jvmtiEnv *jvmti_env, jlong tag) {
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -284,12 +284,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -299,12 +299,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
 
-    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != nullptr))
         return NSK_FALSE;
 
     /* deallocate threads list */
@@ -312,7 +312,7 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -366,7 +366,7 @@ static int checkGetCapabilities(jvmtiEnv* jvmti) {
  */
 static int checkGetOwnedMonitorInfo(jvmtiEnv* jvmti) {
     jint count;
-    jobject *monitors = NULL;
+    jobject *monitors = nullptr;
 
     NSK_DISPLAY0("Checking positive: GetOwnedMonitorInfo\n");
     if (!NSK_JVMTI_VERIFY(jvmti->GetOwnedMonitorInfo(thread, &count, &monitors)))
@@ -378,7 +378,7 @@ static int checkGetOwnedMonitorInfo(jvmtiEnv* jvmti) {
 /* Check "can_get_current_contended_monitor" function
  */
 static int checkGetCurrentContendedMonitor(jvmtiEnv* jvmti) {
-    jobject monitor = NULL;
+    jobject monitor = nullptr;
 
     NSK_DISPLAY0("Checking positive: GetCurrentContendedMonitor\n");
     if (!NSK_JVMTI_VERIFY(jvmti->GetCurrentContendedMonitor(thread, &monitor)))
@@ -433,20 +433,20 @@ class NewFrame {
     _jni->PushLocalFrame(16);
   }
   ~NewFrame() {
-    _jni->PopLocalFrame(NULL);
+    _jni->PopLocalFrame(nullptr);
   }
 };
 
 static int checkObjectTagEvent(jvmtiEnv* jvmti, JNIEnv* jni) {
     jlong tag = TESTED_TAG_VALUE;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
 
     NewFrame local_frame(jni);
 
     // Create a tested object to tag.
-    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewStringUTF("abcde")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewStringUTF("abcde")) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking positive: SetTag\n");
@@ -468,8 +468,8 @@ static int checkObjectTagEvent(jvmtiEnv* jvmti, JNIEnv* jni) {
 static int checkObjectFreeEvent(jvmtiEnv* jvmti) {
     jlong tag = TESTED_TAG_VALUE;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
 
     // Make some GCs happen
     for (int i = 0; i < 5; i++) {
@@ -493,8 +493,8 @@ static int checkHeapFunctions(jvmtiEnv* jvmti) {
     const jlong TAG_VALUE = (123456789L);
     jlong tag;
     jint count;
-    jobject *res_objects = NULL;
-    jlong *res_tags = NULL;
+    jobject *res_objects = nullptr;
+    jlong *res_tags = nullptr;
     jint dummy_user_data = 0;
 
     NSK_DISPLAY0("Checking positive: SetTag\n");
@@ -737,7 +737,7 @@ JNIEXPORT jint JNI_OnLoad_cm02t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -750,7 +750,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capabilities */
@@ -791,44 +791,44 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* enable events */
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(
-            JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+            JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(
-            JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL)))
+            JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(
-            JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_UNLOAD, NULL)))
+            JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_UNLOAD, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(
-            JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, NULL)))
+            JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(
-            JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, NULL)))
+            JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(
-            JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAIT, NULL)))
+            JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAIT, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(
-            JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAITED, NULL)))
+            JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAITED, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(
-            JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, NULL)))
+            JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(
-            JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, NULL)))
+            JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(
-            JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, NULL)))
+            JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(
-            JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, NULL)))
+            JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(
-            JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, NULL)))
+            JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, nullptr)))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM03/cm03t001/cm03t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM03/cm03t001/cm03t001.cpp
index 40e03426cc0..2c70abc9cb4 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM03/cm03t001/cm03t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/capability/CM03/cm03t001/cm03t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -62,12 +62,12 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jclass klass = NULL;
-static jmethodID method = NULL;
-static jfieldID field = NULL;
+static jthread thread = nullptr;
+static jclass klass = nullptr;
+static jmethodID method = nullptr;
+static jfieldID field = nullptr;
 static jint klass_byte_count = 0;
-static unsigned char *klass_bytes = NULL;
+static unsigned char *klass_bytes = nullptr;
 
 /* event counts */
 static int FieldAccessEventsCount = 0;
@@ -93,7 +93,7 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jint class_data_len, const unsigned char* class_data,
         jint *new_class_data_len, unsigned char** new_class_data) {
 
-    if (name != NULL && (strcmp(name, CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, CLASS_NAME) == 0)) {
         NSK_DISPLAY1("ClassFileLoadHook: %s\n", name);
         if (!NSK_JVMTI_VERIFY(jvmti_env->Allocate(class_data_len, &klass_bytes)))
             nsk_jvmti_setFailStatus();
@@ -103,7 +103,7 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         }
         NSK_JVMTI_VERIFY(
             jvmti_env->SetEventNotificationMode(
-                JVMTI_DISABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL));
+                JVMTI_DISABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr));
     }
 }
 
@@ -111,22 +111,22 @@ static void JNICALL
 FieldAccess(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method, jlocation location,
         jclass field_klass, jobject object, jfieldID field) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     FieldAccessEventsCount++;
 
     if (!NSK_JVMTI_VERIFY(jvmti_env->ClearFieldAccessWatch(klass, field)))
         return;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetFieldName(field_klass, field, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetFieldName(field_klass, field, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY2("FieldAccess event: %s:%s\n", name, signature);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -135,42 +135,42 @@ FieldModification(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method, jlocation location,
         jclass field_klass, jobject object,
         jfieldID field, char sig, jvalue new_value) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     FieldModificationEventsCount++;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetFieldName(field_klass, field, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetFieldName(field_klass, field, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY2("FieldModification event: %s:%s\n", name, signature);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
 static void JNICALL
 SingleStep(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
         jmethodID method, jlocation location) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     SingleStepEventsCount++;
 
     NSK_JVMTI_VERIFY(
         jvmti_env->SetEventNotificationMode(
-            JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, NULL));
+            JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, nullptr));
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY2("SingleStep event: %s%s\n", name, signature);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -178,60 +178,60 @@ static void JNICALL
 Exception(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jthread thread,
         jmethodID method, jlocation location, jobject exception,
         jmethodID catch_method, jlocation catch_location) {
-    jclass klass = NULL;
-    char *signature = NULL;
+    jclass klass = nullptr;
+    char *signature = nullptr;
 
     ExceptionEventsCount++;
 
-    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY1("Exception event: %s\n", signature);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
 void JNICALL
 ExceptionCatch(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jthread thread,
         jmethodID method, jlocation location, jobject exception) {
-    jclass klass = NULL;
-    char *signature = NULL;
+    jclass klass = nullptr;
+    char *signature = nullptr;
 
     ExceptionCatchEventsCount++;
 
-    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY1("ExceptionCatch event: %s\n", signature);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
 static void JNICALL
 Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method, jlocation location) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     BreakpointEventsCount++;
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY2("Breakpoint event: %s%s\n", name, signature);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 
     jvmti_env->NotifyFramePop(thread, 0);
@@ -241,36 +241,36 @@ static void JNICALL
 FramePop(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method,
         jboolean wasPopedByException) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     FramePopEventsCount++;
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY2("FramePop event: %s%s\n", name, signature);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
 static void JNICALL
 MethodEntry(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     MethodEntryEventsCount++;
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY2("MethodEntry event: %s%s\n", name, signature);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -278,18 +278,18 @@ static void JNICALL
 MethodExit(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method,
         jboolean was_poped_by_exception, jvalue return_value) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     MethodExitEventsCount++;
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY2("MethodExit event: %s%s\n", name, signature);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -298,7 +298,7 @@ MethodExit(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -308,12 +308,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -323,12 +323,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
 
-    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != nullptr))
         return NSK_FALSE;
 
     /* deallocate threads list */
@@ -336,19 +336,19 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* klass is used by other threads - convert to global handle */
-    if (!NSK_JNI_VERIFY(jni, (klass = (jclass)jni->NewGlobalRef(klass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = (jclass)jni->NewGlobalRef(klass)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'delay' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "delay", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "delay", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingFlag' */
-    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "waitingFlag", "Z")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "waitingFlag", "Z")) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -358,11 +358,11 @@ static int prepareEvents(jvmtiEnv* jvmti, JNIEnv* jni) {
     NSK_DISPLAY0("Prepare events ...\n");
 
     /* get tested thread method 'letItGo' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "letItGo", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "letItGo", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'waitingFlag' */
-    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "waitingFlag", "Z")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "waitingFlag", "Z")) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JVMTI_VERIFY(jvmti->SetFieldAccessWatch(klass, field)))
@@ -376,13 +376,13 @@ static int prepareEvents(jvmtiEnv* jvmti, JNIEnv* jni) {
 
     /* enable events */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION_CATCH, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION_CATCH, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(
             jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, thread)))
@@ -483,7 +483,7 @@ static int checkRedefineClasses(jvmtiEnv* jvmti) {
     jvmtiClassDefinition class_def;
     jboolean is_obsolete;
 
-    if (!NSK_VERIFY(klass_byte_count != 0 && klass_bytes != NULL))
+    if (!NSK_VERIFY(klass_byte_count != 0 && klass_bytes != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking positive: RedefineClasses\n");
@@ -516,7 +516,7 @@ static int checkGetSourceFileName(jvmtiEnv* jvmti) {
  */
 static int checkGetLineNumberTable(jvmtiEnv* jvmti) {
     jint count;
-    jvmtiLineNumberEntry *line_number_table = NULL;
+    jvmtiLineNumberEntry *line_number_table = nullptr;
 
     NSK_DISPLAY0("Checking positive: GetLineNumberTable\n");
     if (!NSK_JVMTI_VERIFY(jvmti->GetLineNumberTable(method, &count, &line_number_table)))
@@ -542,7 +542,7 @@ static int checkGetSourceDebugExtension(jvmtiEnv* jvmti) {
  */
 static int checkLocalVariableFunctions(jvmtiEnv* jvmti) {
     jint count;
-    jvmtiLocalVariableEntry *local_variable_table = NULL;
+    jvmtiLocalVariableEntry *local_variable_table = nullptr;
     jobject object_value;
     jint int_value;
     jlong long_value;
@@ -680,18 +680,18 @@ static int checkSignalThread(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_DEATH_CLASS_NAME = "java/lang/ThreadDeath";
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
-    jobject exception = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
+    jobject exception = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (exception = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Checking positive: InterruptThread\n");
@@ -848,7 +848,7 @@ JNIEXPORT jint JNI_OnLoad_cm03t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -861,7 +861,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capabilities */
@@ -904,23 +904,23 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* enable events */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_ACCESS, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_ACCESS, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_MODIFICATION, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_MODIFICATION, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr)))
         return JNI_ERR;
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, nullptr)))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC01/tc01t001/tc01t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC01/tc01t001/tc01t001.cpp
index 852c148dc6d..c744347213e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC01/tc01t001/tc01t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC01/tc01t001/tc01t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,9 +35,9 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jobject object_M1 = NULL;
-static jobject object_M2 = NULL;
+static jthread thread = nullptr;
+static jobject object_M1 = nullptr;
+static jobject object_M2 = nullptr;
 
 /* ========================================================================== */
 
@@ -45,10 +45,10 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_NAME = "Debuggee Thread";
     const char* FIELD_SIG = "Ljava/lang/Object;";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
-    jfieldID field = NULL;
-    jclass klass = NULL;
+    jfieldID field = nullptr;
+    jclass klass = nullptr;
     int i;
 
     NSK_DISPLAY0("Prepare: find tested thread\n");
@@ -57,12 +57,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -72,11 +72,11 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
 
-        if (info.name != NULL) {
+        if (info.name != nullptr) {
             if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)info.name)))
                 return NSK_FALSE;
         }
@@ -87,21 +87,21 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'M1' */
-    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "M1", FIELD_SIG)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "M1", FIELD_SIG)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (object_M1 = jni->GetObjectField(thread, field)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (object_M1 = jni->GetObjectField(thread, field)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'M2' */
-    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "M2", FIELD_SIG)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "M2", FIELD_SIG)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (object_M2 = jni->GetObjectField(thread, field)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (object_M2 = jni->GetObjectField(thread, field)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -121,14 +121,14 @@ static int checkGetObjectMonitorUsage(jvmtiEnv* jvmti, JNIEnv* jni,
         return NSK_FALSE;
 
     if (nsk_getVerboseMode()) {
-        if (inf.owner == NULL) {
+        if (inf.owner == nullptr) {
             NSK_DISPLAY0("\towner: none (0x0)\n");
         } else {
             if (!NSK_JVMTI_VERIFY(jvmti->GetThreadInfo(inf.owner, &tinf))) {
                 result = NSK_FALSE;
             } else {
                 NSK_DISPLAY2("\towner: %s (0x%p)\n", tinf.name, inf.owner);
-                if (tinf.name != NULL) {
+                if (tinf.name != nullptr) {
                     if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)tinf.name)))
                         result = NSK_FALSE;
                 }
@@ -145,7 +145,7 @@ static int checkGetObjectMonitorUsage(jvmtiEnv* jvmti, JNIEnv* jni,
                 } else {
                     NSK_DISPLAY3("\t\t%2d: %s (0x%p)\n",
                         i, tinf.name, inf.waiters[i]);
-                    if (tinf.name != NULL) {
+                    if (tinf.name != nullptr) {
                         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)tinf.name)))
                             result = NSK_FALSE;
                     }
@@ -162,7 +162,7 @@ static int checkGetObjectMonitorUsage(jvmtiEnv* jvmti, JNIEnv* jni,
                 } else {
                     NSK_DISPLAY3("\t\t%2d: %s (0x%p)\n",
                         i, tinf.name, inf.notify_waiters[i]);
-                    if (tinf.name != NULL) {
+                    if (tinf.name != nullptr) {
                         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)tinf.name)))
                             result = NSK_FALSE;
                     }
@@ -185,11 +185,11 @@ static int checkGetObjectMonitorUsage(jvmtiEnv* jvmti, JNIEnv* jni,
         result = NSK_FALSE;
 
     /* deallocate monitor waiters arrays */
-    if (inf.waiters != NULL) {
+    if (inf.waiters != nullptr) {
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)inf.waiters)))
             result = NSK_FALSE;
     }
-    if (inf.notify_waiters != NULL) {
+    if (inf.notify_waiters != nullptr) {
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)inf.notify_waiters)))
             result = NSK_FALSE;
     }
@@ -242,7 +242,7 @@ JNIEXPORT jint JNI_OnLoad_tc01t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
 
     /* init framework and parse options */
@@ -254,7 +254,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capabilities */
@@ -264,7 +264,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC02/tc02t001/tc02t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC02/tc02t001/tc02t001.cpp
index 0c3fbf88cb1..e3e4a244ba8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC02/tc02t001/tc02t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC02/tc02t001/tc02t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,8 +35,8 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jobject object_M = NULL;
+static jthread thread = nullptr;
+static jobject object_M = nullptr;
 /* line numbers of "synchronized (M)" clauses in java part of the test */
 static jint lines[] = { 48, 53, 58 };
 static volatile int enterEventsCount = 0;
@@ -45,9 +45,9 @@ static volatile int enteredEventsCount = 0;
 /* ========================================================================== */
 
 static jint findLineNumber(jvmtiEnv *jvmti, jthread thread) {
-    jmethodID method = NULL;
+    jmethodID method = nullptr;
     jlocation location;
-    jvmtiLineNumberEntry* table = NULL;
+    jvmtiLineNumberEntry* table = nullptr;
     jint count = 0;
     jint line = 0;
     int i;
@@ -55,7 +55,7 @@ static jint findLineNumber(jvmtiEnv *jvmti, jthread thread) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetFrameLocation(thread, 0, &method, &location)))
         return 0;
 
-    if (!NSK_VERIFY(method != NULL))
+    if (!NSK_VERIFY(method != nullptr))
         return 0;
 
     if (!NSK_VERIFY(location != -1))
@@ -64,7 +64,7 @@ static jint findLineNumber(jvmtiEnv *jvmti, jthread thread) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetLineNumberTable(method, &count, &table)))
         return 0;
 
-    if (!NSK_VERIFY(table != NULL))
+    if (!NSK_VERIFY(table != nullptr))
         return 0;
 
     if (!NSK_VERIFY(count > 0))
@@ -78,7 +78,7 @@ static jint findLineNumber(jvmtiEnv *jvmti, jthread thread) {
 
     line = table[i-1].line_number;
 
-    if (table != NULL) {
+    if (table != nullptr) {
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)table)))
             return 0;
     }
@@ -92,13 +92,13 @@ void JNICALL
 MonitorContendedEnter(jvmtiEnv *jvmti, JNIEnv* jni, jthread thr, jobject obj) {
     jint line = 0;
 
-    if (!NSK_VERIFY(thr != NULL)) {
+    if (!NSK_VERIFY(thr != nullptr)) {
         nsk_jvmti_setFailStatus();
         NSK_COMPLAIN1("MonitorContendedEnter event: thread=%p\n", thr);
         return;
     }
 
-    if (!NSK_VERIFY(obj != NULL)) {
+    if (!NSK_VERIFY(obj != nullptr)) {
         nsk_jvmti_setFailStatus();
         NSK_COMPLAIN1("MonitorContendedEnter event: object=%p\n", obj);
         return;
@@ -137,13 +137,13 @@ void JNICALL
 MonitorContendedEntered(jvmtiEnv *jvmti, JNIEnv* jni, jthread thr, jobject obj) {
     jint line = 0;
 
-    if (!NSK_VERIFY(thr != NULL)) {
+    if (!NSK_VERIFY(thr != nullptr)) {
         nsk_jvmti_setFailStatus();
         NSK_COMPLAIN1("MonitorContendedEntered event: thread=%p\n", thr);
         return;
     }
 
-    if (!NSK_VERIFY(obj != NULL)) {
+    if (!NSK_VERIFY(obj != nullptr)) {
         nsk_jvmti_setFailStatus();
         NSK_COMPLAIN1("MonitorContendedEntered event: object=%p\n", obj);
         return;
@@ -184,10 +184,10 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_NAME = "Debuggee Thread";
     const char* FIELD_SIG = "Ljava/lang/Object;";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
-    jfieldID field = NULL;
-    jclass klass = NULL;
+    jfieldID field = nullptr;
+    jclass klass = nullptr;
     int i;
 
     NSK_DISPLAY0("Prepare: find tested thread\n");
@@ -196,12 +196,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -211,11 +211,11 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
 
-        if (info.name != NULL) {
+        if (info.name != nullptr) {
             if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)info.name)))
                 return NSK_FALSE;
         }
@@ -225,40 +225,40 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threads)))
         return NSK_FALSE;
 
-    if (thread == NULL) {
+    if (thread == nullptr) {
         NSK_COMPLAIN0("Debuggee thread not found");
         return NSK_FALSE;
     }
 
     /* make thread accessable for a long time */
-    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'M' */
-    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "M", FIELD_SIG)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "M", FIELD_SIG)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (object_M = jni->GetObjectField(thread, field)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (object_M = jni->GetObjectField(thread, field)) != nullptr))
         return NSK_FALSE;
 
     /* make object accessable for a long time */
-    if (!NSK_JNI_VERIFY(jni, (object_M = jni->NewGlobalRef(object_M)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (object_M = jni->NewGlobalRef(object_M)) != nullptr))
         return NSK_FALSE;
 
     /* enable MonitorContendedEntered event */
     if (!NSK_JVMTI_VERIFY(
             jvmti->SetEventNotificationMode(
-                JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, NULL)))
+                JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, nullptr)))
         return NSK_FALSE;
 
     /* enable MonitorContendedEntered event */
     if (!NSK_JVMTI_VERIFY(
             jvmti->SetEventNotificationMode(
-                JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, NULL)))
+                JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, nullptr)))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -269,7 +269,7 @@ static int clean(jvmtiEnv* jvmti, JNIEnv* jni) {
     /* disable MonitorContendedEntered event */
     if (!NSK_JVMTI_VERIFY(
             jvmti->SetEventNotificationMode(
-                JVMTI_DISABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, NULL)))
+                JVMTI_DISABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, nullptr)))
         nsk_jvmti_setFailStatus();
 
     return NSK_TRUE;
@@ -334,7 +334,7 @@ JNIEXPORT jint JNI_OnLoad_tc02t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -347,7 +347,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capabilities */
@@ -364,7 +364,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC03/tc03t001/tc03t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC03/tc03t001/tc03t001.cpp
index 9760e0c0207..73d8ef539a6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC03/tc03t001/tc03t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC03/tc03t001/tc03t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,15 +41,15 @@ typedef struct {
 static jlong timeout = 0;
 
 /* test objects */
-static threadDesc *threadList = NULL;
+static threadDesc *threadList = nullptr;
 static jint threads_count = 0;
 static int numberOfDeadlocks = 0;
 
 /* ========================================================================== */
 
 static int printDeadlock(jvmtiEnv* jvmti, JNIEnv* jni, int dThread) {
-    jobject monitor = NULL;
-    jclass klass = NULL;
+    jobject monitor = nullptr;
+    jclass klass = nullptr;
     jvmtiMonitorUsage usageInfo;
     int pThread, cThread;
     char* name;
@@ -60,10 +60,10 @@ static int printDeadlock(jvmtiEnv* jvmti, JNIEnv* jni, int dThread) {
         if (!NSK_JVMTI_VERIFY(
                 jvmti->GetCurrentContendedMonitor(threadList[pThread].thread, &monitor)))
             return NSK_FALSE;
-        if (monitor != NULL) {
-            if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(monitor)) != NULL))
+        if (monitor != nullptr) {
+            if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(monitor)) != nullptr))
                 return NSK_FALSE;
-            if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(klass, &name, NULL)))
+            if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(klass, &name, nullptr)))
                 return NSK_FALSE;
             NSK_DISPLAY2("    waiting to lock %p (%s),\n", monitor, name);
             jvmti->Deallocate((unsigned char*)name);
@@ -72,16 +72,16 @@ static int printDeadlock(jvmtiEnv* jvmti, JNIEnv* jni, int dThread) {
         }
         if (!NSK_JVMTI_VERIFY(jvmti->GetObjectMonitorUsage(monitor, &usageInfo)))
             return NSK_FALSE;
-        if (usageInfo.owner == NULL)
+        if (usageInfo.owner == nullptr)
             break;
         for (cThread = 0; cThread < threads_count; cThread++) {
             if (jni->IsSameObject(threadList[cThread].thread, usageInfo.owner))
                 break;
         }
-        if (usageInfo.waiters != NULL) {
+        if (usageInfo.waiters != nullptr) {
             jvmti->Deallocate((unsigned char*)usageInfo.waiters);
         }
-        if (usageInfo.notify_waiters != NULL) {
+        if (usageInfo.notify_waiters != nullptr) {
             jvmti->Deallocate((unsigned char*)usageInfo.notify_waiters);
         }
         if (!NSK_VERIFY(cThread != threads_count))
@@ -97,8 +97,8 @@ static int printDeadlock(jvmtiEnv* jvmti, JNIEnv* jni, int dThread) {
 
 static int findDeadlockThreads(jvmtiEnv* jvmti, JNIEnv* jni) {
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
-    jobject monitor = NULL;
+    jthread *threads = nullptr;
+    jobject monitor = nullptr;
     jvmtiMonitorUsage usageInfo;
     int tDfn = 0, gDfn = 0;
     int pThread, cThread;
@@ -110,7 +110,7 @@ static int findDeadlockThreads(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JVMTI_VERIFY(
@@ -118,7 +118,7 @@ static int findDeadlockThreads(jvmtiEnv* jvmti, JNIEnv* jni) {
         return NSK_FALSE;
 
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -144,20 +144,20 @@ static int findDeadlockThreads(jvmtiEnv* jvmti, JNIEnv* jni) {
                 if (!NSK_JVMTI_VERIFY(
                         jvmti->GetCurrentContendedMonitor(threadList[pThread].thread, &monitor)))
                     return NSK_FALSE;
-                if (monitor == NULL)
+                if (monitor == nullptr)
                     break;
                 if (!NSK_JVMTI_VERIFY(jvmti->GetObjectMonitorUsage(monitor, &usageInfo)))
                     return NSK_FALSE;
-                if (usageInfo.owner == NULL)
+                if (usageInfo.owner == nullptr)
                     break;
                 for (cThread = 0; cThread < threads_count; cThread++) {
                     if (jni->IsSameObject(threadList[cThread].thread, usageInfo.owner))
                         break;
                 }
-                if (usageInfo.waiters != NULL) {
+                if (usageInfo.waiters != nullptr) {
                     jvmti->Deallocate((unsigned char*)usageInfo.waiters);
                 }
-                if (usageInfo.notify_waiters != NULL) {
+                if (usageInfo.notify_waiters != nullptr) {
                     jvmti->Deallocate((unsigned char*)usageInfo.notify_waiters);
                 }
                 if (!NSK_VERIFY(cThread != threads_count))
@@ -180,7 +180,7 @@ static int findDeadlockThreads(jvmtiEnv* jvmti, JNIEnv* jni) {
 
     /* deallocate thread names */
     for (i = 0; i < threads_count; i++) {
-        if (threadList[i].name != NULL) {
+        if (threadList[i].name != nullptr) {
             if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threadList[i].name)))
                 return NSK_FALSE;
         }
@@ -228,7 +228,7 @@ JNIEXPORT jint JNI_OnLoad_tc03t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
 
     /* init framework and parse options */
@@ -240,7 +240,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capabilities */
@@ -251,7 +251,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC03/tc03t002/tc03t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC03/tc03t002/tc03t002.cpp
index f98c80c34c1..9740919cdcd 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC03/tc03t002/tc03t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC03/tc03t002/tc03t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,15 +41,15 @@ typedef struct {
 static jlong timeout = 0;
 
 /* test objects */
-static threadDesc *threadList = NULL;
+static threadDesc *threadList = nullptr;
 static jint threads_count = 0;
 static int numberOfDeadlocks = 0;
 
 /* ========================================================================== */
 
 static int printDeadlock(jvmtiEnv* jvmti, JNIEnv* jni, int dThread) {
-    jobject monitor = NULL;
-    jclass klass = NULL;
+    jobject monitor = nullptr;
+    jclass klass = nullptr;
     jvmtiMonitorUsage usageInfo;
     int pThread, cThread;
     char* name;
@@ -60,10 +60,10 @@ static int printDeadlock(jvmtiEnv* jvmti, JNIEnv* jni, int dThread) {
         if (!NSK_JVMTI_VERIFY(
                 jvmti->GetCurrentContendedMonitor(threadList[pThread].thread, &monitor)))
             return NSK_FALSE;
-        if (monitor != NULL) {
-            if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(monitor)) != NULL))
+        if (monitor != nullptr) {
+            if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(monitor)) != nullptr))
                 return NSK_FALSE;
-            if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(klass, &name, NULL)))
+            if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(klass, &name, nullptr)))
                 return NSK_FALSE;
             NSK_DISPLAY2("    waiting to lock %p (%s),\n", monitor, name);
             jvmti->Deallocate((unsigned char*)name);
@@ -72,16 +72,16 @@ static int printDeadlock(jvmtiEnv* jvmti, JNIEnv* jni, int dThread) {
         }
         if (!NSK_JVMTI_VERIFY(jvmti->GetObjectMonitorUsage(monitor, &usageInfo)))
             return NSK_FALSE;
-        if (usageInfo.owner == NULL)
+        if (usageInfo.owner == nullptr)
             break;
         for (cThread = 0; cThread < threads_count; cThread++) {
             if (jni->IsSameObject(threadList[cThread].thread, usageInfo.owner))
                 break;
         }
-        if (usageInfo.waiters != NULL) {
+        if (usageInfo.waiters != nullptr) {
             jvmti->Deallocate((unsigned char*)usageInfo.waiters);
         }
-        if (usageInfo.notify_waiters != NULL) {
+        if (usageInfo.notify_waiters != nullptr) {
             jvmti->Deallocate((unsigned char*)usageInfo.notify_waiters);
         }
         if (!NSK_VERIFY(cThread != threads_count))
@@ -97,8 +97,8 @@ static int printDeadlock(jvmtiEnv* jvmti, JNIEnv* jni, int dThread) {
 
 static int findDeadlockThreads(jvmtiEnv* jvmti, JNIEnv* jni) {
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
-    jobject monitor = NULL;
+    jthread *threads = nullptr;
+    jobject monitor = nullptr;
     jvmtiMonitorUsage usageInfo;
     int tDfn = 0, gDfn = 0;
     int pThread, cThread;
@@ -110,7 +110,7 @@ static int findDeadlockThreads(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JVMTI_VERIFY(
@@ -118,7 +118,7 @@ static int findDeadlockThreads(jvmtiEnv* jvmti, JNIEnv* jni) {
         return NSK_FALSE;
 
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -144,20 +144,20 @@ static int findDeadlockThreads(jvmtiEnv* jvmti, JNIEnv* jni) {
                 if (!NSK_JVMTI_VERIFY(
                         jvmti->GetCurrentContendedMonitor(threadList[pThread].thread, &monitor)))
                     return NSK_FALSE;
-                if (monitor == NULL)
+                if (monitor == nullptr)
                     break;
                 if (!NSK_JVMTI_VERIFY(jvmti->GetObjectMonitorUsage(monitor, &usageInfo)))
                     return NSK_FALSE;
-                if (usageInfo.owner == NULL)
+                if (usageInfo.owner == nullptr)
                     break;
                 for (cThread = 0; cThread < threads_count; cThread++) {
                     if (jni->IsSameObject(threadList[cThread].thread, usageInfo.owner))
                         break;
                 }
-                if (usageInfo.waiters != NULL) {
+                if (usageInfo.waiters != nullptr) {
                     jvmti->Deallocate((unsigned char*)usageInfo.waiters);
                 }
-                if (usageInfo.notify_waiters != NULL) {
+                if (usageInfo.notify_waiters != nullptr) {
                     jvmti->Deallocate((unsigned char*)usageInfo.notify_waiters);
                 }
                 if (!NSK_VERIFY(cThread != threads_count))
@@ -180,7 +180,7 @@ static int findDeadlockThreads(jvmtiEnv* jvmti, JNIEnv* jni) {
 
     /* deallocate thread names */
     for (i = 0; i < threads_count; i++) {
-        if (threadList[i].name != NULL) {
+        if (threadList[i].name != nullptr) {
             if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threadList[i].name)))
                 return NSK_FALSE;
         }
@@ -228,7 +228,7 @@ JNIEXPORT jint JNI_OnLoad_tc03t002(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
 
     /* init framework and parse options */
@@ -240,7 +240,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capabilities */
@@ -251,7 +251,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC04/tc04t001/tc04t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC04/tc04t001/tc04t001.cpp
index 6000051f1ad..f850b0d89f4 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC04/tc04t001/tc04t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC04/tc04t001/tc04t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,12 +35,12 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jclass object_M = NULL;
+static jclass object_M = nullptr;
 static volatile int waitEventsCount = 0;
 static volatile int waitedEventsCount = 0;
 static volatile int enterEventsCount = 0;
 static volatile int enteredEventsCount = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 
 static jboolean lockSyncLock(jvmtiEnv* jvmti) {
@@ -62,12 +62,12 @@ void JNICALL
 MonitorWait(jvmtiEnv *jvmti, JNIEnv* jni,
         jthread thr, jobject obj, jlong tout) {
 
-    if (!NSK_VERIFY(thr != NULL)) {
+    if (!NSK_VERIFY(thr != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
-    if (!NSK_VERIFY(obj != NULL)) {
+    if (!NSK_VERIFY(obj != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -85,12 +85,12 @@ void JNICALL
 MonitorWaited(jvmtiEnv *jvmti, JNIEnv* jni,
         jthread thr, jobject obj, jboolean timed_out) {
 
-    if (!NSK_VERIFY(thr != NULL)) {
+    if (!NSK_VERIFY(thr != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
-    if (!NSK_VERIFY(obj != NULL)) {
+    if (!NSK_VERIFY(obj != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -107,12 +107,12 @@ MonitorWaited(jvmtiEnv *jvmti, JNIEnv* jni,
 void JNICALL
 MonitorContendedEnter(jvmtiEnv *jvmti, JNIEnv* jni, jthread thr, jobject obj) {
 
-    if (!NSK_VERIFY(thr != NULL)) {
+    if (!NSK_VERIFY(thr != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
-    if (!NSK_VERIFY(obj != NULL)) {
+    if (!NSK_VERIFY(obj != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -129,12 +129,12 @@ MonitorContendedEnter(jvmtiEnv *jvmti, JNIEnv* jni, jthread thr, jobject obj) {
 void JNICALL
 MonitorContendedEntered(jvmtiEnv *jvmti, JNIEnv* jni, jthread thr, jobject obj) {
 
-    if (!NSK_VERIFY(thr != NULL)) {
+    if (!NSK_VERIFY(thr != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
-    if (!NSK_VERIFY(obj != NULL)) {
+    if (!NSK_VERIFY(obj != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -155,10 +155,10 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
 
     NSK_DISPLAY0("Obtain tested object from debugee thread class\n");
 
-    if (!NSK_JNI_VERIFY(jni, (object_M = jni->FindClass(CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (object_M = jni->FindClass(CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (object_M = (jclass)jni->NewGlobalRef(object_M)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (object_M = (jclass)jni->NewGlobalRef(object_M)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock)))
@@ -166,24 +166,24 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
 
     /* enable MonitorWait event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAIT, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAIT, nullptr)))
         nsk_jvmti_setFailStatus();
 
     /* enable MonitorWaited event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAITED, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAITED, nullptr)))
         nsk_jvmti_setFailStatus();
 
     /* enable MonitorContendedEnter event */
     if (!NSK_JVMTI_VERIFY(
             jvmti->SetEventNotificationMode(
-                JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, NULL)))
+                JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, nullptr)))
         nsk_jvmti_setFailStatus();
 
     /* enable MonitorContendedEntered event */
     if (!NSK_JVMTI_VERIFY(
             jvmti->SetEventNotificationMode(
-                JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, NULL)))
+                JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, nullptr)))
         nsk_jvmti_setFailStatus();
 
     return NSK_TRUE;
@@ -193,24 +193,24 @@ static int clean(jvmtiEnv* jvmti, JNIEnv* jni) {
 
     /* disable MonitorWait event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_WAIT, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_WAIT, nullptr)))
         nsk_jvmti_setFailStatus();
 
     /* disable MonitorWaited event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_WAITED, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_WAITED, nullptr)))
         nsk_jvmti_setFailStatus();
 
     /* disable MonitorContendedEnter event */
     if (!NSK_JVMTI_VERIFY(
             jvmti->SetEventNotificationMode(
-                JVMTI_DISABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, NULL)))
+                JVMTI_DISABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, nullptr)))
         nsk_jvmti_setFailStatus();
 
     /* disable MonitorContendedEntered event */
     if (!NSK_JVMTI_VERIFY(
             jvmti->SetEventNotificationMode(
-                JVMTI_DISABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, NULL)))
+                JVMTI_DISABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, nullptr)))
         nsk_jvmti_setFailStatus();
 
     if (!NSK_JVMTI_VERIFY(jvmti->DestroyRawMonitor(syncLock)))
@@ -296,7 +296,7 @@ JNIEXPORT jint JNI_OnLoad_tc04t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -309,7 +309,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capabilities */
@@ -329,7 +329,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC05/tc05t001/tc05t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC05/tc05t001/tc05t001.cpp
index aead5a92589..3c3c0e37703 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC05/tc05t001/tc05t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/contention/TC05/tc05t001/tc05t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,8 +49,8 @@ static const jlong EXPECTED_ACCURACY = 10; // high frequency clock updates expec
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jobject object_M = NULL;
+static jthread thread = nullptr;
+static jobject object_M = nullptr;
 static volatile int waitEventsCount = 0;
 static volatile int waitedEventsCount = 0;
 static jlong waitTime = 0;
@@ -65,12 +65,12 @@ MonitorWait(jvmtiEnv *jvmti, JNIEnv* jni,
         jthread thr, jobject obj, jlong tout) {
     char buffer[32];
 
-    if (!NSK_VERIFY(thr != NULL)) {
+    if (!NSK_VERIFY(thr != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
-    if (!NSK_VERIFY(obj != NULL)) {
+    if (!NSK_VERIFY(obj != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -104,12 +104,12 @@ MonitorWaited(jvmtiEnv *jvmti, JNIEnv* jni,
         jthread thr, jobject obj, jboolean timed_out) {
     char buffer[32];
 
-    if (!NSK_VERIFY(thr != NULL)) {
+    if (!NSK_VERIFY(thr != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
-    if (!NSK_VERIFY(obj != NULL)) {
+    if (!NSK_VERIFY(obj != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -140,10 +140,10 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_NAME = "Debuggee Thread";
     const char* FIELD_SIG = "Ljava/lang/Object;";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
-    jfieldID field = NULL;
-    jclass klass = NULL;
+    jfieldID field = nullptr;
+    jclass klass = nullptr;
     int i;
 
     NSK_DISPLAY0("Prepare: find tested thread\n");
@@ -152,12 +152,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -167,11 +167,11 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
 
-        if (info.name != NULL) {
+        if (info.name != nullptr) {
             if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)info.name)))
                 return NSK_FALSE;
         }
@@ -181,38 +181,38 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threads)))
         return NSK_FALSE;
 
-    if (thread == NULL) {
+    if (thread == nullptr) {
         NSK_COMPLAIN0("Debuggee thread not found");
         return NSK_FALSE;
     }
 
     /* make thread accessable for a long time */
-    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'M' */
-    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "M", FIELD_SIG)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "M", FIELD_SIG)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (object_M = jni->GetObjectField(thread, field)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (object_M = jni->GetObjectField(thread, field)) != nullptr))
         return NSK_FALSE;
 
     /* make object accessable for a long time */
-    if (!NSK_JNI_VERIFY(jni, (object_M = jni->NewGlobalRef(object_M)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (object_M = jni->NewGlobalRef(object_M)) != nullptr))
         return NSK_FALSE;
 
     /* enable MonitorWait event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAIT, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAIT, nullptr)))
         return NSK_FALSE;
 
     /* enable MonitorWaited event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAITED, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAITED, nullptr)))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -222,12 +222,12 @@ static int clean(jvmtiEnv* jvmti, JNIEnv* jni) {
 
     /* disable MonitorWait event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_WAIT, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_WAIT, nullptr)))
         nsk_jvmti_setFailStatus();
 
     /* disable MonitorWaited event */
     if (!NSK_JVMTI_VERIFY(
-            jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_WAITED, NULL)))
+            jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_MONITOR_WAITED, nullptr)))
         nsk_jvmti_setFailStatus();
 
     return NSK_TRUE;
@@ -310,7 +310,7 @@ JNIEXPORT jint JNI_OnLoad_tc05t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -323,7 +323,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capabilities */
@@ -340,7 +340,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM01/em01t001/em01t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM01/em01t001/em01t001.cpp
index 500f4ca655f..55a97693008 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM01/em01t001/em01t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM01/em01t001/em01t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,10 +34,10 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define JVMTI_EVENT_COUNT   (int)(JVMTI_MAX_EVENT_TYPE_VAL - JVMTI_MIN_EVENT_TYPE_VAL + 1)
@@ -127,7 +127,7 @@ classEventsHandler(jvmtiEvent event, jvmtiEnv* jvmti_env, JNIEnv* jni_env,
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)className))) {
         nsk_jvmti_setFailStatus();
     }
-    if (generic != NULL)
+    if (generic != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)generic))) {
             nsk_jvmti_setFailStatus();
         }
@@ -178,7 +178,7 @@ threadEventHandler(jvmtiEvent event, jvmtiEnv* jvmti_env, JNIEnv* jni_env,
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)className))) {
         nsk_jvmti_setFailStatus();
     }
-    if (generic != NULL)
+    if (generic != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)generic))) {
             nsk_jvmti_setFailStatus();
         }
@@ -282,7 +282,7 @@ cbThreadEnd(jvmtiEnv* jvmti_env, JNIEnv* jni_env, jthread thread) {
 static int
 enableEvent(jvmtiEventMode enable, jvmtiEvent event) {
     NSK_DISPLAY1("enabling %s\n", TranslateEvent(event));
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(enable, event, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(enable, event, nullptr))) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -427,7 +427,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     classLoaderCount = nsk_jvmti_findOptionIntValue(CLASS_LOADER_COUNT_PARAM, 10);
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -452,7 +452,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     currentPhase = JVMTI_PHASE_PRIMORDIAL;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM01/em01t002/em01t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM01/em01t002/em01t002.cpp
index d314b16ce2e..7a3700c0863 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM01/em01t002/em01t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM01/em01t002/em01t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,10 +34,10 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define JVMTI_EVENT_COUNT   (int)(JVMTI_MAX_EVENT_TYPE_VAL - JVMTI_MIN_EVENT_TYPE_VAL + 1)
@@ -187,7 +187,7 @@ classEventsHandler(jvmtiEvent event, jvmtiEnv* jvmti_env, JNIEnv* jni_env,
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)className))) {
         nsk_jvmti_setFailStatus();
     }
-    if (generic != NULL)
+    if (generic != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)generic))) {
             nsk_jvmti_setFailStatus();
         }
@@ -239,7 +239,7 @@ threadEventHandler(jvmtiEvent event, jvmtiEnv* jvmti_env, JNIEnv* jni_env,
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)className))) {
         nsk_jvmti_setFailStatus();
     }
-    if (generic != NULL)
+    if (generic != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)generic))) {
             nsk_jvmti_setFailStatus();
         }
@@ -350,7 +350,7 @@ enableEvent(jvmtiEventMode enable, jvmtiEvent event) {
     }
 
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(enable, event, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(enable, event, nullptr))) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -494,7 +494,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     classLoaderCount = nsk_jvmti_findOptionIntValue(CLASS_LOADER_COUNT_PARAM, 10);
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -519,7 +519,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     currentPhase = JVMTI_PHASE_PRIMORDIAL;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t001/em02t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t001/em02t001.cpp
index 0314850e4f7..5bc4a5c7b2f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t001/em02t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t001/em02t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,10 +34,10 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define DEBUGEE_CLASS_NAME      "nsk/jvmti/scenarios/events/EM02/em02t001"
@@ -48,10 +48,10 @@ static jrawMonitorID syncLock = NULL;
 #define OBJECT_FIELD_SIG        "Ljava/lang/Object;"
 #define THREAD_FIELD_SIG        "Ljava/lang/Thread;"
 
-static jthread mainThread = NULL;
-static jthread debuggeeThread = NULL;
-static jobject startObject = NULL;
-static jobject endObject = NULL;
+static jthread mainThread = nullptr;
+static jthread debuggeeThread = nullptr;
+static jobject startObject = nullptr;
+static jobject endObject = nullptr;
 
 #define STEP_AMOUNT 3
 #define JVMTI_EVENT_COUNT   (int)(JVMTI_MAX_EVENT_TYPE_VAL - JVMTI_MIN_EVENT_TYPE_VAL + 1)
@@ -63,21 +63,21 @@ static int newEventCount[JVMTI_EVENT_COUNT];
 static jthread
 findThread(const char *threadName) {
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
-    jthread returnValue = NULL;
+    jthread returnValue = nullptr;
     int i;
 
     /* get all live threads */
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
-        return NULL;
+        return nullptr;
 
-    if (!NSK_VERIFY(threads != NULL))
-        return NULL;
+    if (!NSK_VERIFY(threads != nullptr))
+        return nullptr;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             break;
 
         /* get thread information */
@@ -85,14 +85,14 @@ findThread(const char *threadName) {
             break;
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, threadName) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, threadName) == 0)) {
             returnValue = threads[i];
         }
     }
 
     /* deallocate threads list */
     if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threads)))
-        return NULL;
+        return nullptr;
 
     return returnValue;
 }
@@ -105,7 +105,7 @@ getStaticObjField(const char* className, const char* objFieldName,
 
     ExceptionCheckingJniEnvPtr ec_jni(jni);
     jfieldID fieldID;
-    jclass klass = NULL;
+    jclass klass = nullptr;
 
     klass = ec_jni->FindClass(className, TRACE_JNI_CALL);
     fieldID = ec_jni->GetStaticFieldID(klass, objFieldName, signature, TRACE_JNI_CALL);
@@ -118,7 +118,7 @@ static bool prepare() {
 
     ExceptionCheckingJniEnvPtr ec_jni(jni);
     mainThread = findThread(MAIN_THREAD_NAME);
-    if (!NSK_VERIFY(mainThread != NULL)) {
+    if (!NSK_VERIFY(mainThread != nullptr)) {
         NSK_COMPLAIN1("<%s> thread not found\n", MAIN_THREAD_NAME);
         return false;
     }
@@ -126,14 +126,14 @@ static bool prepare() {
     /* make thread accessable for a long time */
     mainThread = ec_jni->NewGlobalRef(mainThread, TRACE_JNI_CALL);
     startObject = getStaticObjField(DEBUGEE_CLASS_NAME, START_FIELD_NAME, OBJECT_FIELD_SIG);
-    if (!NSK_VERIFY(startObject != NULL))
+    if (!NSK_VERIFY(startObject != nullptr))
         return false;
 
     /*make object accessable for a long time*/
     startObject = ec_jni->NewGlobalRef(startObject, TRACE_JNI_CALL);
 
     endObject = getStaticObjField(DEBUGEE_CLASS_NAME, END_FIELD_NAME, OBJECT_FIELD_SIG);
-    if (!NSK_VERIFY(endObject != NULL))
+    if (!NSK_VERIFY(endObject != nullptr))
         return false;
 
     /*make object accessable for a long time*/
@@ -142,7 +142,7 @@ static bool prepare() {
     debuggeeThread = (jthread) getStaticObjField(DEBUGEE_CLASS_NAME,
                                                  THREAD_FIELD_NAME,
                                                  THREAD_FIELD_SIG);
-    if (!NSK_VERIFY(debuggeeThread != NULL))
+    if (!NSK_VERIFY(debuggeeThread != nullptr))
         return false;
 
     /* make thread accessable for a long time */
@@ -158,7 +158,7 @@ static bool clean() {
     /* disable MonitorContendedEnter event */
     if (!NSK_JVMTI_VERIFY(
             jvmti->SetEventNotificationMode(
-                JVMTI_DISABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, NULL)))
+                JVMTI_DISABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, nullptr)))
         nsk_jvmti_setFailStatus();
 
     /* dispose global references */
@@ -167,10 +167,10 @@ static bool clean() {
     ec_jni->DeleteGlobalRef(debuggeeThread, TRACE_JNI_CALL);
     ec_jni->DeleteGlobalRef(mainThread, TRACE_JNI_CALL);
 
-    startObject = NULL;
-    endObject = NULL;
-    debuggeeThread = NULL;
-    mainThread = NULL;
+    startObject = nullptr;
+    endObject = nullptr;
+    debuggeeThread = nullptr;
+    mainThread = nullptr;
 
     return true;
 }
@@ -396,7 +396,7 @@ handlerMC1(jvmtiEvent event, jvmtiEnv* jvmti, JNIEnv* jni_env,
                             jthread expectedThread, jobject expectedObject) {
     ExceptionCheckingJniEnvPtr ec_jni(jni_env);
 
-    if (expectedThread == NULL || expectedObject == NULL)
+    if (expectedThread == nullptr || expectedObject == nullptr)
         return;
 
     /* check if event is for tested thread and for tested object */
@@ -483,7 +483,7 @@ handlerMC2(jvmtiEvent event, jvmtiEnv* jvmti, JNIEnv* jni_env,
                             jthread expectedThread, jobject expectedObject) {
     ExceptionCheckingJniEnvPtr ec_jni(jni_env);
 
-    if (expectedThread == NULL || expectedObject == NULL)
+    if (expectedThread == nullptr || expectedObject == nullptr)
         return;
 
     /* check if event is for tested thread and for tested object */
@@ -553,13 +553,13 @@ static bool enableEvent(jvmtiEvent event) {
             && (event != JVMTI_EVENT_MONITOR_WAIT)
             && (event != JVMTI_EVENT_MONITOR_WAITED)) {
         if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
-                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
         }
     } else {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
@@ -743,7 +743,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -770,7 +770,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002/em02t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002/em02t002.cpp
index 5f30ac4e1e7..1c6f88ea41a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002/em02t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002/em02t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,9 +33,9 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define STEP_AMOUNT 3
@@ -344,13 +344,13 @@ static bool enableEvent(jvmtiEvent event) {
             && (event != JVMTI_EVENT_GARBAGE_COLLECTION_START)
             && (event != JVMTI_EVENT_GARBAGE_COLLECTION_FINISH)) {
         if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
-                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
         }
     } else {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
@@ -509,7 +509,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -536,7 +536,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t003/em02t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t003/em02t003.cpp
index d5cae3e3a75..a1c1aa85a10 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t003/em02t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t003/em02t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,9 +33,9 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define STEP_AMOUNT 3
@@ -280,7 +280,7 @@ handlerMC1(jvmtiEvent event, jvmtiEnv* jvmti, jmethodID method) {
     if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)sign))) {
         nsk_jvmti_setFailStatus();
     }
-    if (genc != NULL)
+    if (genc != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)genc))) {
             nsk_jvmti_setFailStatus();
         }
@@ -346,7 +346,7 @@ handlerMC2(jvmtiEvent event, jvmtiEnv* jvmti, jmethodID method) {
     if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)sign))) {
         nsk_jvmti_setFailStatus();
     }
-    if (genc != NULL)
+    if (genc != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)genc))) {
             nsk_jvmti_setFailStatus();
         }
@@ -378,13 +378,13 @@ static bool enableEvent(jvmtiEvent event) {
             && (event != JVMTI_EVENT_COMPILED_METHOD_LOAD)
             && (event != JVMTI_EVENT_COMPILED_METHOD_UNLOAD)) {
         if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
-                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
         }
     } else {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
@@ -548,7 +548,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -575,7 +575,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t004/em02t004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t004/em02t004.cpp
index a3ecd17cf1f..b00713b7fe8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t004/em02t004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t004/em02t004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,9 +33,9 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define STEP_AMOUNT 3
@@ -334,7 +334,7 @@ cbNativeMethodBind(jvmtiEnv *jvmti_env, JNIEnv* jni_env,jthread thread,
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)sign))) {
         nsk_jvmti_setFailStatus();
     }
-    if (genc != NULL)
+    if (genc != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)genc))) {
             nsk_jvmti_setFailStatus();
         }
@@ -374,7 +374,7 @@ cbNewNativeMethodBind(jvmtiEnv *jvmti_env, JNIEnv* jni_env,jthread thread,
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)sign))) {
         nsk_jvmti_setFailStatus();
     }
-    if (genc != NULL)
+    if (genc != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)genc))) {
             nsk_jvmti_setFailStatus();
         }
@@ -387,13 +387,13 @@ static bool enableEvent(jvmtiEvent event) {
     if (nsk_jvmti_isOptionalEvent(event)
             && (event != JVMTI_EVENT_NATIVE_METHOD_BIND)) {
         if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
-                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
         }
     } else {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
@@ -554,7 +554,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -581,7 +581,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t005/em02t005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t005/em02t005.cpp
index 66d46a31062..a1b74a56a76 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t005/em02t005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t005/em02t005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,9 +33,9 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define STEP_NUMBER 3
@@ -326,7 +326,7 @@ cbVMObjectAlloc(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)sign_ptr))) {
         nsk_jvmti_setFailStatus();
     }
-    if (gen_ptr != NULL)
+    if (gen_ptr != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)gen_ptr))) {
             nsk_jvmti_setFailStatus();
         }
@@ -366,7 +366,7 @@ cbNewVMObjectAlloc(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)sign_ptr))) {
         nsk_jvmti_setFailStatus();
     }
-    if (gen_ptr != NULL)
+    if (gen_ptr != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)gen_ptr))) {
             nsk_jvmti_setFailStatus();
         }
@@ -379,13 +379,13 @@ static bool enableEvent(jvmtiEvent event) {
     if (nsk_jvmti_isOptionalEvent(event)
             && (event != JVMTI_EVENT_VM_OBJECT_ALLOC)) {
         if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
-                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
         }
     } else {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
@@ -534,7 +534,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
 
@@ -560,7 +560,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006/em02t006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006/em02t006.cpp
index 415cbbcc5ed..c4b65118b1a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006/em02t006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006/em02t006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,9 +33,9 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define STEP_NUMBER 3
@@ -328,13 +328,13 @@ static bool enableEvent(jvmtiEvent event) {
     if (nsk_jvmti_isOptionalEvent(event)
             && (event != JVMTI_EVENT_OBJECT_FREE)) {
         if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
-                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
         }
     } else {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
@@ -485,7 +485,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -511,7 +511,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t007/em02t007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t007/em02t007.cpp
index 0b19c1d0f85..b344a6f438e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t007/em02t007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t007/em02t007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,9 +33,9 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define STEP_NUMBER 3
@@ -200,7 +200,7 @@ cbSingleStep(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)sign))) {
         nsk_jvmti_setFailStatus();
     }
-    if (genc != NULL)
+    if (genc != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)genc))) {
             nsk_jvmti_setFailStatus();
         }
@@ -230,7 +230,7 @@ cbNewSingleStep(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)sign))) {
         nsk_jvmti_setFailStatus();
     }
-    if (genc != NULL)
+    if (genc != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)genc))) {
             nsk_jvmti_setFailStatus();
         }
@@ -357,13 +357,13 @@ static bool enableEvent(jvmtiEvent event) {
     if (nsk_jvmti_isOptionalEvent(event)
             && (event != JVMTI_EVENT_SINGLE_STEP)) {
         if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
-                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
         }
     } else {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
@@ -521,7 +521,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -546,7 +546,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t008/em02t008.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t008/em02t008.cpp
index 5c7edf432d3..89434116744 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t008/em02t008.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t008/em02t008.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,9 +33,9 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define STEP_NUMBER 3
@@ -377,13 +377,13 @@ static bool enableEvent(jvmtiEvent event) {
             && (event != JVMTI_EVENT_EXCEPTION)
             && (event != JVMTI_EVENT_EXCEPTION_CATCH)) {
         if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
-                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
         }
     } else {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
@@ -533,7 +533,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -558,7 +558,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t009/em02t009.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t009/em02t009.cpp
index 1ee810210db..f50cb3388da 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t009/em02t009.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t009/em02t009.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,9 +33,9 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define STEP_NUMBER 3
@@ -243,7 +243,7 @@ void handler1(jvmtiEnv *jvmti_env, jvmtiEvent event, jmethodID method) {
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)sign))) {
         nsk_jvmti_setFailStatus();
     }
-    if (genc != NULL)
+    if (genc != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)genc))) {
             nsk_jvmti_setFailStatus();
         }
@@ -285,7 +285,7 @@ void handler2(jvmtiEnv *jvmti_env, jvmtiEvent event, jmethodID method) {
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)sign))) {
         nsk_jvmti_setFailStatus();
     }
-    if (genc != NULL)
+    if (genc != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)genc))) {
             nsk_jvmti_setFailStatus();
         }
@@ -384,13 +384,13 @@ static bool enableEvent(jvmtiEvent event) {
             && (event != JVMTI_EVENT_METHOD_ENTRY)
             && (event != JVMTI_EVENT_METHOD_EXIT)) {
         if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
-                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
         }
     } else {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
@@ -540,7 +540,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -566,7 +566,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t010/em02t010.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t010/em02t010.cpp
index 5a181180b86..a3257281f0d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t010/em02t010.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t010/em02t010.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,9 +34,9 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define STEP_NUMBER 3
@@ -340,13 +340,13 @@ static bool enableEvent(jvmtiEvent event) {
             && (event != JVMTI_EVENT_FIELD_MODIFICATION)
             && (event != JVMTI_EVENT_FIELD_ACCESS)) {
         if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
-                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
         }
     } else {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
@@ -516,7 +516,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -542,7 +542,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t011/em02t011.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t011/em02t011.cpp
index 626e2500a9a..1e0f043d087 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t011/em02t011.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t011/em02t011.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,9 +34,9 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define STEP_NUMBER 3
@@ -326,13 +326,13 @@ static bool enableEvent(jvmtiEvent event) {
     if (nsk_jvmti_isOptionalEvent(event)
             && (event != JVMTI_EVENT_BREAKPOINT)) {
         if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
-                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
         }
     } else {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
@@ -497,7 +497,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -522,7 +522,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t012/em02t012.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t012/em02t012.cpp
index ad7dfc5e0e8..eb83f542853 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t012/em02t012.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t012/em02t012.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,10 +34,10 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jthread testedThread;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define STEP_NUMBER 3
@@ -330,13 +330,13 @@ static bool enableEvent(jvmtiEvent event) {
     if (nsk_jvmti_isOptionalEvent(event)
             && (event != JVMTI_EVENT_FRAME_POP)) {
         if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
-                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+                jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
         }
     } else {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
             NSK_COMPLAIN1("Unexpected error enabling %s\n",
                 TranslateEvent(event));
             return false;
@@ -503,7 +503,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -529,7 +529,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM04/em04t001/em04t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM04/em04t001/em04t001.cpp
index 86ca654d2cd..825391d9576 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM04/em04t001/em04t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM04/em04t001/em04t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,9 +35,9 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-const void *plist = NULL;
+const void *plist = nullptr;
 
 #define NAME_LENGTH 50
 
@@ -48,7 +48,7 @@ typedef struct nsk_jvmti_DCG_paramsStruct {
     int sign;
 } nsk_jvmti_DCG_params;
 
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 static volatile int callbacksEnabled = NSK_TRUE;
 /* ============================================================================= */
 
@@ -122,7 +122,7 @@ cbDynamicCodeGenerated2(jvmtiEnv *jvmti_env, const char *name,
 
 static int
 enableEvent(jvmtiEventMode enable, jvmtiEvent event) {
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(enable, event, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(enable, event, nullptr))) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -212,7 +212,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved);
-    if (!NSK_VERIFY(jvmti != NULL))
+    if (!NSK_VERIFY(jvmti != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -221,7 +221,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     plist = (const void *)nsk_list_create();
-    if (!NSK_VERIFY(plist != NULL))
+    if (!NSK_VERIFY(plist != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY1("plist = 0x%p\n", plist);
@@ -236,7 +236,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM05/em05t001/em05t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM05/em05t001/em05t001.cpp
index 09646218439..8cd0f4c957f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM05/em05t001/em05t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM05/em05t001/em05t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* constant names */
@@ -65,8 +65,8 @@ typedef struct {
 
 /* descriptions of tested methods */
 static MethodDesc methodsDesc[METHODS_COUNT] = {
-    { "javaMethod", "(I)I", NULL, 0, 0, 0 },
-    { "nativeMethod", "(I)I", NULL, 0, 0, 0 }
+    { "javaMethod", "(I)I", nullptr, 0, 0, 0 },
+    { "nativeMethod", "(I)I", nullptr, 0, 0, 0 }
 };
 
 /* ============================================================================= */
@@ -127,7 +127,7 @@ static int enableEvents(jvmtiEventMode enable) {
     int i;
 
     for (i = 0; i < EVENTS_COUNT; i++) {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(enable, eventsList[i], NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(enable, eventsList[i], nullptr))) {
             nsk_jvmti_setFailStatus();
             return NSK_FALSE;
         }
@@ -142,43 +142,43 @@ static int enableEvents(jvmtiEventMode enable) {
  *    - enable events
  */
 static int prepare() {
-    jclass debugeeClass = NULL;
-    jclass threadClass = NULL;
-    jfieldID threadFieldID = NULL;
-    jthread thread = NULL;
+    jclass debugeeClass = nullptr;
+    jclass threadClass = nullptr;
+    jfieldID threadFieldID = nullptr;
+    jthread thread = nullptr;
     int i;
 
     for (i = 0; i < METHODS_COUNT; i++) {
-        methodsDesc[i].method = (jmethodID)NULL;
+        methodsDesc[i].method = (jmethodID)nullptr;
         methodsDesc[i].loadEvents = 0;
         methodsDesc[i].unloadEvents = 0;
     }
 
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (threadFieldID =
-            jni->GetStaticFieldID(debugeeClass, THREAD_FIELD_NAME, THREAD_FIELD_SIG)) != NULL))
+            jni->GetStaticFieldID(debugeeClass, THREAD_FIELD_NAME, THREAD_FIELD_SIG)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (thread = (jthread)
-            jni->GetStaticObjectField(debugeeClass, threadFieldID)) != NULL))
+            jni->GetStaticObjectField(debugeeClass, threadFieldID)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (threadClass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (threadClass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Find tested methods:\n");
     for (i = 0; i < METHODS_COUNT; i++) {
         if (!NSK_JNI_VERIFY(jni, (methodsDesc[i].method =
-                jni->GetMethodID(threadClass, methodsDesc[i].methodName, methodsDesc[i].methodSig)) != NULL))
+                jni->GetMethodID(threadClass, methodsDesc[i].methodName, methodsDesc[i].methodSig)) != nullptr))
             return NSK_FALSE;
         NSK_DISPLAY3("    method #%d (%s): 0x%p\n",
                                 i, methodsDesc[i].methodName, (void*)methodsDesc[i].method);
     }
 
     NSK_DISPLAY0("Enable events\n");
-    if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL))
+    if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -220,7 +220,7 @@ static int checkEvents() {
  */
 static int clean() {
     NSK_DISPLAY0("Disable events\n");
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL))
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -314,7 +314,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -334,7 +334,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
             return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM05/em05t002/em05t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM05/em05t002/em05t002.cpp
index 9f1b86471b2..01eaf82f214 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM05/em05t002/em05t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM05/em05t002/em05t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* constant names */
@@ -71,8 +71,8 @@ typedef struct {
 
 /* descriptions of tested methods */
 static MethodDesc methodsDesc[METHODS_COUNT] = {
-    { "javaMethod", "(I)I", NULL, 0, {}, {} },
-    { "nativeMethod", "(I)I", NULL, 0, {}, {} }
+    { "javaMethod", "(I)I", nullptr, 0, {}, {} },
+    { "nativeMethod", "(I)I", nullptr, 0, {}, {} }
 };
 
 /* current compilation moment */
@@ -166,15 +166,15 @@ static int generateEvents() {
  *    - enable events
  */
 static int prepare() {
-    jclass debugeeClass = NULL;
-    jclass threadClass = NULL;
-    jfieldID threadFieldID = NULL;
-    jthread thread = NULL;
+    jclass debugeeClass = nullptr;
+    jclass threadClass = nullptr;
+    jfieldID threadFieldID = nullptr;
+    jthread thread = nullptr;
     int i;
 
     for (i = 0; i < METHODS_COUNT; i++) {
         int j;
-        methodsDesc[i].method = (jmethodID)NULL;
+        methodsDesc[i].method = (jmethodID)nullptr;
         methodsDesc[i].compiled = NSK_FALSE;
         for (j = 0; j < MOMENTS_COUNT; j++) {
             methodsDesc[i].loadEvents[j] = 0;
@@ -182,31 +182,31 @@ static int prepare() {
         }
     }
 
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (threadFieldID =
-            jni->GetStaticFieldID(debugeeClass, THREAD_FIELD_NAME, THREAD_FIELD_SIG)) != NULL))
+            jni->GetStaticFieldID(debugeeClass, THREAD_FIELD_NAME, THREAD_FIELD_SIG)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (thread = (jthread)
-            jni->GetStaticObjectField(debugeeClass, threadFieldID)) != NULL))
+            jni->GetStaticObjectField(debugeeClass, threadFieldID)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (threadClass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (threadClass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Find tested methods:\n");
     for (i = 0; i < METHODS_COUNT; i++) {
         if (!NSK_JNI_VERIFY(jni, (methodsDesc[i].method =
-                jni->GetMethodID(threadClass, methodsDesc[i].methodName, methodsDesc[i].methodSig)) != NULL))
+                jni->GetMethodID(threadClass, methodsDesc[i].methodName, methodsDesc[i].methodSig)) != nullptr))
             return NSK_FALSE;
         NSK_DISPLAY3("    method #%d (%s): 0x%p\n",
                                 i, methodsDesc[i].methodName, (void*)methodsDesc[i].method);
     }
 
     NSK_DISPLAY0("Enable events\n");
-    if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL))
+    if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -282,7 +282,7 @@ static int checkEvents() {
  */
 static int clean() {
     NSK_DISPLAY0("Disable events\n");
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL))
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -383,7 +383,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -403,7 +403,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
             return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM06/em06t001/em06t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM06/em06t001/em06t001.cpp
index 87ad1da13f7..ccd0b42a8a6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM06/em06t001/em06t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM06/em06t001/em06t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,10 +33,10 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define JVMTI_EVENT_COUNT   (int)(JVMTI_MAX_EVENT_TYPE_VAL - JVMTI_MIN_EVENT_TYPE_VAL + 1)
@@ -60,13 +60,13 @@ handler(jvmtiEvent event, jvmtiEnv* jvmti, JNIEnv* jni_env,
     jstring jclassName;
     const char *className;
 
-    if (!NSK_JNI_VERIFY(jni_env, (classObject = jni_env->GetObjectClass(klass)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, (classObject = jni_env->GetObjectClass(klass)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
     if (!NSK_JNI_VERIFY(jni_env, (methodID =
-            jni_env->GetMethodID(classObject, "getName", "()Ljava/lang/String;")) != NULL)) {
+            jni_env->GetMethodID(classObject, "getName", "()Ljava/lang/String;")) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -75,7 +75,7 @@ handler(jvmtiEvent event, jvmtiEnv* jvmti, JNIEnv* jni_env,
 
     className = jni_env->GetStringUTFChars(jclassName, 0);
 
-    if (className != NULL && (strcmp(className, EXPECTED_CLASS_NAME) == 0)) {
+    if (className != nullptr && (strcmp(className, EXPECTED_CLASS_NAME) == 0)) {
 
         if (!NSK_JVMTI_VERIFY(jvmti->RawMonitorEnter(syncLock)))
             nsk_jvmti_setFailStatus();
@@ -114,7 +114,7 @@ cbClassPrepare(jvmtiEnv* jvmti, JNIEnv* jni_env, jthread thread, jclass klass) {
 
 static int
 enableEvent(jvmtiEventMode enable, jvmtiEvent event) {
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(enable, event, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(enable, event, nullptr))) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -249,10 +249,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
     classLoaderCount = nsk_jvmti_findOptionIntValue(CLASS_LOADER_COUNT_PARAM, 100);
 
-    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM07/em07t001/em07t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM07/em07t001/em07t001.cpp
index 4aa814611d9..b3236df4208 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM07/em07t001/em07t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM07/em07t001/em07t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,8 +34,8 @@ extern "C" {
 
 /* scaffold objects */
 static jlong timeout = 0;
-static jvmtiEnv *jvmti = NULL;
-static jrawMonitorID syncLock = NULL;
+static jvmtiEnv *jvmti = nullptr;
+static jrawMonitorID syncLock = nullptr;
 
 /* constant names */
 #define JVMTI_EVENT_COUNT   (int)(JVMTI_MAX_EVENT_TYPE_VAL - JVMTI_MIN_EVENT_TYPE_VAL + 1)
@@ -233,7 +233,7 @@ int enableOptionalEvents(jvmtiEnv *jvmti) {
         jvmtiEvent event = (jvmtiEvent)(i + JVMTI_MIN_EVENT_TYPE_VAL);
         if (nsk_jvmti_isOptionalEvent(event))
             if (!NSK_JVMTI_VERIFY_CODE(JVMTI_ERROR_MUST_POSSESS_CAPABILITY,
-                    jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, NULL))) {
+                    jvmti->SetEventNotificationMode(JVMTI_ENABLE, event, nullptr))) {
                 NSK_COMPLAIN1("Unexpected error enabling %s\n",
                     TranslateEvent(event));
                 result = NSK_FALSE;
@@ -355,7 +355,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
-    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -373,7 +373,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM07/em07t002/em07t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM07/em07t002/em07t002.cpp
index 2800ce8116b..a9f0321c3bd 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM07/em07t002/em07t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM07/em07t002/em07t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,15 +35,15 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
-static jrawMonitorID syncLock = NULL;
+static jrawMonitorID syncLock = nullptr;
 
 static int methodLoadCount = 0;
 static int methodUnloadCount = 0;
 
 #define NAME_LENGTH 50
-const void *plist = NULL;
+const void *plist = nullptr;
 static volatile int callbacksEnabled = NSK_TRUE;
 
 typedef struct nsk_jvmti_CompiledMethodIDStruct {
@@ -109,7 +109,7 @@ cbCompiledMethodLoad(jvmtiEnv *jvmti_env, jmethodID method, jint code_size,
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)sign))) {
         nsk_jvmti_setFailStatus();
     }
-    if (genc != NULL)
+    if (genc != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)genc))) {
             nsk_jvmti_setFailStatus();
         }
@@ -155,7 +155,7 @@ cbCompiledMethodUnload(jvmtiEnv *jvmti_env, jmethodID method,
 
 static int
 enableEvent(jvmtiEventMode enable, jvmtiEvent event) {
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(enable, event, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(enable, event, nullptr))) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -264,7 +264,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
-    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("_syncLock", &syncLock))) {
@@ -272,7 +272,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY((plist = (const void *)nsk_list_create()) != NULL))
+    if (!NSK_VERIFY((plist = (const void *)nsk_list_create()) != nullptr))
         return JNI_ERR;
 
     {
@@ -293,7 +293,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/extension/EX03/ex03t001/ex03t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/extension/EX03/ex03t001/ex03t001.cpp
index 810e1b1f47c..a2855dc742a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/extension/EX03/ex03t001/ex03t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/extension/EX03/ex03t001/ex03t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,8 +29,8 @@
 
 extern "C" {
 
-static JNIEnv *jni = NULL;
-static jvmtiEnv* jvmti = NULL;
+static JNIEnv *jni = nullptr;
+static jvmtiEnv* jvmti = nullptr;
 static jlong timeout = 0;
 static jboolean eventEnabled = JNI_FALSE;
 static volatile jboolean eventReceived1 = JNI_FALSE, eventReceived2 = JNI_FALSE;
@@ -42,7 +42,7 @@ static jrawMonitorID eventMon;
 
 static void JNICALL
 ClassUnload(jvmtiEnv* jvmti_env, ...) {
-    JNIEnv *jni_env = NULL;
+    JNIEnv *jni_env = nullptr;
     va_list ap;
 
     va_start(ap, jvmti_env);
@@ -51,9 +51,9 @@ ClassUnload(jvmtiEnv* jvmti_env, ...) {
     va_end(ap);
 
     // The name argument should never be null
-    if (name == NULL) {
+    if (name == nullptr) {
         nsk_jvmti_setFailStatus();
-        NSK_COMPLAIN0("ClassUnload: 'name' input parameter is NULL.\n");
+        NSK_COMPLAIN0("ClassUnload: 'name' input parameter is null.\n");
     } else {
         NSK_DISPLAY1("Class unloaded %s\n", name);
     }
@@ -152,12 +152,12 @@ jboolean enableClassUnloadEvent (jboolean enable) {
 
             if (!NSK_JVMTI_VERIFY(
                     jvmti->SetExtensionEventCallback(extList[i].extension_event_index,
-                                                     enable ? (jvmtiExtensionEvent)ClassUnload : NULL))) {
+                                                     enable ? (jvmtiExtensionEvent)ClassUnload : nullptr))) {
                 nsk_jvmti_setFailStatus();
                 return JNI_FALSE;
             }
             if (!NSK_JVMTI_VERIFY(
-                    jvmti->SetEventNotificationMode(mode, (jvmtiEvent)extList[i].extension_event_index, NULL))) {
+                    jvmti->SetEventNotificationMode(mode, (jvmtiEvent)extList[i].extension_event_index, nullptr))) {
                 nsk_jvmti_setFailStatus();
                 return JNI_FALSE;
             }
@@ -281,14 +281,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("eventMon", &eventMon))) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF01/gf01t001/gf01t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF01/gf01t001/gf01t001.cpp
index 430f8b27160..252cd19b7ac 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF01/gf01t001/gf01t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF01/gf01t001/gf01t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -172,7 +172,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY0("setting event callbacks ...\n");
@@ -185,9 +185,9 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     NSK_DISPLAY0("setting event callbacks done\nenabling events ...\n");
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr)))
         return JNI_ERR;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY0("enabling events done\n\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF04/gf04t001/gf04t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF04/gf04t001/gf04t001.cpp
index a2937f86155..bdd20e8951b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF04/gf04t001/gf04t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF04/gf04t001/gf04t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,7 +36,7 @@ extern "C" {
 /* ============================================================================= */
 
 static jlong timeout = 0;
-static const char* segment = NULL;
+static const char* segment = nullptr;
 static const char* EXP_CLASS_SIGNATURE = "Lnsk/jvmti/scenarios/general_functions/GF04/gf04t001;";
 static jrawMonitorID countLock;
 static jboolean classLoadReceived = JNI_FALSE, classPrepareReceived = JNI_FALSE;
@@ -49,7 +49,7 @@ static jint result = PASSED;
  * @returns NSK_FALSE if any error occured.
  */
 static int addSegment(jvmtiEnv* jvmti, const char segment[], const char where[]) {
-    void* storage = NULL;
+    void* storage = nullptr;
 
     NSK_DISPLAY1("Add segment: %s\n", segment);
     if (!NSK_JVMTI_VERIFY(jvmti->AddToBootstrapClassLoaderSearch(segment))) {
@@ -97,7 +97,7 @@ ClassLoad(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thread, jclass klass) {
             sig);
         classLoadReceived = JNI_TRUE;
 
-        if (!NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_CLASS_LOAD, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_CLASS_LOAD, nullptr))) {
             result = STATUS_FAILED;
         } else {
             NSK_DISPLAY0("ClassLoad event disabled\n");
@@ -123,7 +123,7 @@ ClassPrepare(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thread, jclass klass) {
             sig);
         classPrepareReceived = JNI_TRUE;
 
-        if (!NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_CLASS_PREPARE, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_CLASS_PREPARE, nullptr))) {
             result = STATUS_FAILED;
         } else {
             NSK_DISPLAY0("ClassPrepare event disabled\n");
@@ -148,19 +148,19 @@ JNIEXPORT jint JNI_OnLoad_gf04t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
 
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
-    segment = nsk_jvmti_findOptionStringValue("segment", NULL);
-    if (!NSK_VERIFY(segment != NULL))
+    segment = nsk_jvmti_findOptionStringValue("segment", nullptr);
+    if (!NSK_VERIFY(segment != nullptr))
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("eventLock", &countLock)))
@@ -186,12 +186,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY0("  ... set\n");
 
     NSK_DISPLAY0("Enabling events: \n");
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, nullptr))) {
         return JNI_ERR;
     } else {
         NSK_DISPLAY0("  ... ClassLoad enabled\n");
     }
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_PREPARE, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_PREPARE, nullptr))) {
         return JNI_ERR;
     } else {
         NSK_DISPLAY0("  ... ClassPrepare enabled\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF06/gf06t001/gf06t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF06/gf06t001/gf06t001.cpp
index 355f30c51c6..876b3a8464c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF06/gf06t001/gf06t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF06/gf06t001/gf06t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -72,7 +72,7 @@ static void fillEnvStorage(StorageStructure* storage) {
  * @returns NSK_FALSE if any error occured.
  */
 static int checkEnvStorage(jvmtiEnv* jvmti, const char where[]) {
-    void* storage = NULL;
+    void* storage = nullptr;
 
     NSK_DISPLAY0("Calling GetEnvironmentLocalStorage():");
     if (!NSK_JVMTI_VERIFY(jvmti->GetEnvironmentLocalStorage(&storage))) {
@@ -80,8 +80,8 @@ static int checkEnvStorage(jvmtiEnv* jvmti, const char where[]) {
     }
     NSK_DISPLAY1("  ... got storage: 0x%p\n", (void*)storage);
 
-    if (storage != NULL) {
-        NSK_COMPLAIN2("GetEnvironmentLocalStorage() returned NOT NULL storage in %s:\n"
+    if (storage != nullptr) {
+        NSK_COMPLAIN2("GetEnvironmentLocalStorage() returned NOT null storage in %s:\n"
                       "#   storage pointer: 0x%p\n",
                         where, (void*)storage);
         return NSK_FALSE;
@@ -134,7 +134,7 @@ callbackVMInit(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
     }
 
     NSK_DISPLAY0("Set agentProc for second JVMTI env.\n");
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         nsk_jvmti_setFailStatus();
 }
 
@@ -149,7 +149,7 @@ callbackVMDeath(jvmtiEnv* jvmti, JNIEnv* jni) {
     success = checkEnvStorage(jvmti, "VM_DEATH callback");
 
     NSK_DISPLAY1("Disable events: %d events\n", EVENTS_COUNT);
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, NULL)) {
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, events, nullptr)) {
         success = NSK_FALSE;
     } else {
         NSK_DISPLAY0("  ... disabled\n");
@@ -177,7 +177,7 @@ JNIEXPORT jint JNI_OnLoad_gf06t001(JavaVM *jvm, char *options, void *reserved) {
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
-    jvmtiEnv* jvmti_1 = NULL;
+    jvmtiEnv* jvmti_1 = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -199,7 +199,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* Create second environment */
     if (!NSK_VERIFY((jvmti_2 =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* Set callbacks for second environment */
@@ -226,7 +226,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     NSK_DISPLAY1("Enable events: %d events\n", EVENTS_COUNT);
-    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, NULL)) {
+    if (nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, events, nullptr)) {
         NSK_DISPLAY0("  ... enabled\n");
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF08/gf08t001/gf08t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF08/gf08t001/gf08t001.cpp
index d5d830e6d9b..7dd894afb8d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF08/gf08t001/gf08t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF08/gf08t001/gf08t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -37,7 +37,7 @@ static jlong timeout = 0;
 /* test objects */
 static jrawMonitorID access_lock;
 static jvmtiPhase phase;
-static const char* setVerboseMode = NULL;
+static const char* setVerboseMode = nullptr;
 
 /* ========================================================================== */
 
@@ -54,7 +54,7 @@ JNIEXPORT jint JNI_OnLoad_gf08t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv *jvmti = NULL;
+    jvmtiEnv *jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -64,10 +64,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    setVerboseMode = nsk_jvmti_findOptionStringValue("setVerboseMode", NULL);
+    setVerboseMode = nsk_jvmti_findOptionStringValue("setVerboseMode", nullptr);
 
     if (strcmp(setVerboseMode, "y") == 0 || strcmp(setVerboseMode, "yes") == 0) {
         if (!NSK_JVMTI_VERIFY(jvmti->SetVerboseFlag(JVMTI_VERBOSE_GC, JNI_TRUE))) {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF08/gf08t002/gf08t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF08/gf08t002/gf08t002.cpp
index 4b2455a4f46..ae930eb0805 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF08/gf08t002/gf08t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF08/gf08t002/gf08t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -37,7 +37,7 @@ static jlong timeout = 0;
 /* test objects */
 static jrawMonitorID access_lock;
 static jvmtiPhase phase;
-static const char* setVerboseMode = NULL;
+static const char* setVerboseMode = nullptr;
 
 /* ========================================================================== */
 
@@ -54,7 +54,7 @@ JNIEXPORT jint JNI_OnLoad_gf08t002(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv *jvmti = NULL;
+    jvmtiEnv *jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -64,10 +64,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    setVerboseMode = nsk_jvmti_findOptionStringValue("setVerboseMode", NULL);
+    setVerboseMode = nsk_jvmti_findOptionStringValue("setVerboseMode", nullptr);
 
     if (strcmp(setVerboseMode, "y") == 0 || strcmp(setVerboseMode, "yes") == 0) {
         if (!NSK_JVMTI_VERIFY(jvmti->SetVerboseFlag(JVMTI_VERBOSE_CLASS, JNI_TRUE))) {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF08/gf08t003/gf08t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF08/gf08t003/gf08t003.cpp
index ee6e7bf9f73..5c792635968 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF08/gf08t003/gf08t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/general_functions/GF08/gf08t003/gf08t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -37,7 +37,7 @@ static jlong timeout = 0;
 /* test objects */
 static jrawMonitorID access_lock;
 static jvmtiPhase phase;
-static const char* setVerboseMode = NULL;
+static const char* setVerboseMode = nullptr;
 
 /* ========================================================================== */
 
@@ -54,7 +54,7 @@ JNIEXPORT jint JNI_OnLoad_gf08t003(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv *jvmti = NULL;
+    jvmtiEnv *jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -64,10 +64,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    setVerboseMode = nsk_jvmti_findOptionStringValue("setVerboseMode", NULL);
+    setVerboseMode = nsk_jvmti_findOptionStringValue("setVerboseMode", nullptr);
 
     if (strcmp(setVerboseMode, "y") == 0 || strcmp(setVerboseMode, "yes") == 0) {
         if (!NSK_JVMTI_VERIFY(jvmti->SetVerboseFlag(JVMTI_VERBOSE_JNI, JNI_TRUE))) {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS103/hs103t002/hs103t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS103/hs103t002/hs103t002.cpp
index 634a4d351fa..a903074cd01 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS103/hs103t002/hs103t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS103/hs103t002/hs103t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -57,13 +57,13 @@ JNIEXPORT void JNICALL doRedefineInNativeThread(jvmtiEnv * jvmti,
   testClass = jni->FindClass(MAIN_CLASS);
 
   if (!NSK_JNI_VERIFY(jni, (
-    setRedefinitionFailed = jni->GetStaticMethodID(testClass, "setRedefinitionFailed", "()V")) != NULL))
+    setRedefinitionFailed = jni->GetStaticMethodID(testClass, "setRedefinitionFailed", "()V")) != nullptr))
   {
     jni->FatalError("TEST FAILED: while getting setRedefinitionFailed()\n");
   }
 
   if (!NSK_JNI_VERIFY(jni, (
-    setRedefinitionDone = jni->GetStaticMethodID(testClass, "setRedefinitionDone", "()V")) != NULL))
+    setRedefinitionDone = jni->GetStaticMethodID(testClass, "setRedefinitionDone", "()V")) != nullptr))
   {
     jni->FatalError("TEST FAILED: while getting setRedefinitionDone()\n");
   }
@@ -142,14 +142,14 @@ Java_nsk_jvmti_scenarios_hotswap_HS103_hs103t002_hs103t002_startAgentThread(JNIE
   name = jni->NewStringUTF(threadName);
   clas = jni->FindClass("java/lang/Thread");
 
-  if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(clas, "<init>", "(Ljava/lang/String;)V")) != NULL)) {
+  if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(clas, "<init>", "(Ljava/lang/String;)V")) != nullptr)) {
     jni->FatalError("failed to get ID for the java method\n");
   }
 
   thread = (jthread) jni->NewObject(clas,method,name);
   testAgentThread = jni->NewGlobalRef(thread);
   err = JVMTI_ERROR_NONE;
-  err = jvmti->RunAgentThread(testAgentThread, &doRedefineInNativeThread, NULL,
+  err = jvmti->RunAgentThread(testAgentThread, &doRedefineInNativeThread, nullptr,
                                  JVMTI_THREAD_NORM_PRIORITY);
   if (err == JVMTI_ERROR_INVALID_PRIORITY) {
     nsk_printf(" JVMTI_ERROR_INVALID_PRIORITY ..\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS104/hs104t001/hs104t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS104/hs104t001/hs104t001.cpp
index 72987808f3e..0044aec284e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS104/hs104t001/hs104t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS104/hs104t001/hs104t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,7 +48,7 @@ JNIEXPORT void JNICALL
                         sizeof(fileName)/sizeof(char));
         if (nsk_jvmti_redefineClass(jvmti, klass, fileName)) {
             nsk_printf("Agent:: Successfully redefined..");
-            if (nsk_jvmti_disableNotification(jvmti,JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+            if (nsk_jvmti_disableNotification(jvmti,JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
                 nsk_printf(" Agent :: NOTIFICATIONS ARE DISABLED \n");
             } else {
                 nsk_printf(" Agent :: Failed to disabled \n");
@@ -96,7 +96,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf("Agent :: NOTIFICATIONS ARE ENABLED \n");
         } else {
             nsk_printf(" Error in Eanableing Notifications..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS104/hs104t002/hs104t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS104/hs104t002/hs104t002.cpp
index 5f107e31b90..670b48bfeab 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS104/hs104t002/hs104t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS104/hs104t002/hs104t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -74,7 +74,7 @@ Java_nsk_jvmti_scenarios_hotswap_HS104_hs104t002_hs104t002_redefineClasses(
     jclass cla;
     char fileName[512];
 
-    if (!NSK_JNI_VERIFY(jni, (cla = jni->FindClass(SEARCH_NAME)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (cla = jni->FindClass(SEARCH_NAME)) != nullptr)) {
         nsk_printf(" Agent :: Failed to get class.\n");
         nsk_jvmti_agentFailed();
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS201/hs201t001/hs201t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS201/hs201t001/hs201t001.cpp
index 5883c17f5b4..200df590244 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS201/hs201t001/hs201t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS201/hs201t001/hs201t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* constant names */
@@ -64,7 +64,7 @@ void setCurrentStep(JNIEnv* jni_env, int value) {
     jfieldID fld;
 
     if (!NSK_JNI_VERIFY(jni_env, (fld =
-            jni_env->GetStaticFieldID(testClass, "currentStep", "I")) != NULL)) {
+            jni_env->GetStaticFieldID(testClass, "currentStep", "I")) != nullptr)) {
         jni_env->FatalError("TEST FAILED: while getting currentStep fieldID\n");
     }
 
@@ -102,7 +102,7 @@ void redefineClass(jvmtiEnv *jvmti_env, jclass klass) {
 
     char *className;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &className, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &className, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -165,7 +165,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
 void setBreakPoint(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jclass klass) {
     jmethodID mid;
 
-    if (!NSK_JNI_VERIFY(jni_env, (mid = jni_env->GetMethodID(klass, METHOD_NAME, METHOD_SIG)) != NULL))
+    if (!NSK_JNI_VERIFY(jni_env, (mid = jni_env->GetMethodID(klass, METHOD_NAME, METHOD_SIG)) != nullptr))
         jni_env->FatalError("[agent] failed to get ID for the java method\n");
 
     if (!NSK_JVMTI_VERIFY(jvmti_env->SetBreakpoint(mid, 1)))
@@ -200,7 +200,7 @@ callbackClassLoad(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
         nsk_jvmti_setFailStatus();
     }
 
-    if (generic != NULL)
+    if (generic != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)generic))) {
             nsk_jvmti_setFailStatus();
         }
@@ -232,7 +232,7 @@ callbackSingleStep(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
 
     char *methodName;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &methodName, NULL, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &methodName, nullptr, nullptr))) {
         NSK_COMPLAIN0("TEST FAILED: unable to get method name during Breakpoint callback\n\n");
     }
 
@@ -244,7 +244,7 @@ callbackSingleStep(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
             NSK_COMPLAIN0("TEST FAILED: unable to get method name during Breakpoint callback\n\n");
         }
 
-        if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(declaringClass, &declaringClassName, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(declaringClass, &declaringClassName, nullptr))) {
             NSK_COMPLAIN0("TEST FAILED: unable to get method name during Breakpoint callback\n\n");
         }
 
@@ -335,7 +335,7 @@ callbackException(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
                         className, getThreadName(jni_env, thread));
 
         testStep++;
-        if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != NULL)) {
+        if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != nullptr)) {
             nsk_jvmti_setFailStatus();
             return;
         }
@@ -366,7 +366,7 @@ callbackExceptionCatch(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
                         className, getThreadName(jni_env, thread));
 
         testStep++;
-        if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != NULL)) {
+        if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != nullptr)) {
             nsk_jvmti_setFailStatus();
             return;
         }
@@ -397,7 +397,7 @@ int readNewBytecode(jvmtiEnv* jvmti, int testcase) {
                         filename);
 
     bytecode = fopen(filename, "rb");
-    if (bytecode == NULL) {
+    if (bytecode == nullptr) {
         NSK_COMPLAIN0("TEST FAILED: error opening file\n");
         return NSK_FALSE;
     }
@@ -430,13 +430,13 @@ const char* getThreadName(JNIEnv* jni_env, jthread thread) {
 
     strcpy(chbuffer, "");
 
-    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(thread)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(thread)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return chbuffer;
     }
 
     if (!NSK_JNI_VERIFY(jni_env, (methodID =
-            jni_env->GetMethodID(klass, "getName", "()Ljava/lang/String;")) != NULL)) {
+            jni_env->GetMethodID(klass, "getName", "()Ljava/lang/String;")) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return chbuffer;
     }
@@ -462,7 +462,7 @@ const char* getClassName(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jobject object) {
 
     strcpy(chbuffer, "");
 
-    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(object)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(object)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return chbuffer;
     }
@@ -478,7 +478,7 @@ const char* getClassName(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jobject object) {
         nsk_jvmti_setFailStatus();
     }
 
-    if (generic != NULL)
+    if (generic != nullptr)
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)generic))) {
             nsk_jvmti_setFailStatus();
         }
@@ -491,7 +491,7 @@ const char* getClassName(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jobject object) {
 int getLocalVariableValue(jvmtiEnv *jvmti_env, jthread thread,
                                 jmethodID method) {
 
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLocalVariableEntry *table = nullptr;
     jint entryCount = 0;
     int i;
     jint value = -1;
@@ -501,7 +501,7 @@ int getLocalVariableValue(jvmtiEnv *jvmti_env, jthread thread,
         NSK_COMPLAIN0("TEST FAILED: unable to get local variable table\n\n");
     }
 
-    if (table != NULL) {
+    if (table != nullptr) {
         jvmtiError error;
 
         for (i = 0; i < entryCount; i++) {
@@ -540,10 +540,10 @@ JNIEXPORT void JNICALL
 Java_nsk_jvmti_scenarios_hotswap_HS201_hs201t001_setThread(JNIEnv *env,
                         jclass cls, jthread thread) {
 
-    if (!NSK_JNI_VERIFY(env, (testClass = (jclass) env->NewGlobalRef(cls)) != NULL))
+    if (!NSK_JNI_VERIFY(env, (testClass = (jclass) env->NewGlobalRef(cls)) != nullptr))
         nsk_jvmti_setFailStatus();
 
-    if (!NSK_JNI_VERIFY(env, (testedThread = env->NewGlobalRef(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(env, (testedThread = env->NewGlobalRef(thread)) != nullptr))
         nsk_jvmti_setFailStatus();
 
 }
@@ -632,7 +632,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -670,7 +670,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     enableEvent(jvmti, JVMTI_EVENT_EXCEPTION, testedThread);
     enableEvent(jvmti, JVMTI_EVENT_EXCEPTION_CATCH, testedThread);
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS201/hs201t002/hs201t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS201/hs201t002/hs201t002.cpp
index 43cd4463139..8c369dd1d55 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS201/hs201t002/hs201t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS201/hs201t002/hs201t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* constant names */
@@ -66,7 +66,7 @@ void setCurrentStep(JNIEnv* jni_env, int value) {
     jfieldID fld;
 
     if (!NSK_JNI_VERIFY(jni_env, (fld =
-            jni_env->GetStaticFieldID(testClass, "currentStep", "I")) != NULL)) {
+            jni_env->GetStaticFieldID(testClass, "currentStep", "I")) != nullptr)) {
         jni_env->FatalError("TEST FAILED: while getting currentStep fieldID\n");
     }
 
@@ -105,7 +105,7 @@ void redefineClass(jvmtiEnv *jvmti_env, jclass klass) {
     jint newClassSize;
     unsigned char* newClassBytes;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &className, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &className, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -170,7 +170,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
 void setBreakPoint(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jclass klass) {
     jmethodID mid;
 
-    if (!NSK_JNI_VERIFY(jni_env, (mid = jni_env->GetMethodID(klass, METHOD_NAME, METHOD_SIG)) != NULL))
+    if (!NSK_JNI_VERIFY(jni_env, (mid = jni_env->GetMethodID(klass, METHOD_NAME, METHOD_SIG)) != nullptr))
         jni_env->FatalError("[agent] failed to get ID for the java method\n");
 
     if (!NSK_JVMTI_VERIFY(jvmti_env->SetBreakpoint(mid, 1)))
@@ -189,7 +189,7 @@ callbackClassLoad(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
 
     char *className;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &className, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &className, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -230,7 +230,7 @@ callbackSingleStep(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
 
     char *methodName;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &methodName, NULL, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &methodName, nullptr, nullptr))) {
         NSK_COMPLAIN0("TEST FAILED: unable to get method name during Breakpoint callback\n\n");
     }
 
@@ -242,7 +242,7 @@ callbackSingleStep(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
             NSK_COMPLAIN0("TEST FAILED: unable to get method name during Breakpoint callback\n\n");
         }
 
-        if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(declaringClass, &declaringClassName, NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(declaringClass, &declaringClassName, nullptr))) {
             NSK_COMPLAIN0("TEST FAILED: unable to get method name during Breakpoint callback\n\n");
         }
 
@@ -347,19 +347,19 @@ void handleException(bool isCatch,
                      jobject exception) {
     const char* className = getClassName(jvmti_env, jni_env, exception);
 
-    if (className != NULL && strcmp(EXPECTED_CLASS_SIGN, className) == 0) {
+    if (className != nullptr && strcmp(EXPECTED_CLASS_SIGN, className) == 0) {
         jclass klass;
 
         const char* threadName = getThreadName(jvmti_env, jni_env, thread);
         NSK_DISPLAY3(">>>> %s %s in thread - %s\n", isCatch ? "Caught exception" : "Exception",
-            className, threadName != NULL ? threadName : "NULL");
+            className, threadName != nullptr ? threadName : "null");
         jvmti->Deallocate((unsigned char*)className);
-        if (threadName != NULL) {
+        if (threadName != nullptr) {
             jvmti->Deallocate((unsigned char*)threadName);
         }
 
         testStep++;
-        if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != NULL)) {
+        if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != nullptr)) {
             nsk_jvmti_setFailStatus();
             return;
         }
@@ -390,7 +390,7 @@ int readNewBytecode(jvmtiEnv* jvmti, jint *newClassSize, unsigned char* *newClas
                         filename);
 
     bytecode = fopen(filename, "rb");
-    if (bytecode == NULL) {
+    if (bytecode == nullptr) {
         NSK_COMPLAIN0("TEST FAILED: error opening file\n");
         return NSK_FALSE;
     }
@@ -408,7 +408,7 @@ int readNewBytecode(jvmtiEnv* jvmti, jint *newClassSize, unsigned char* *newClas
     if (read_bytes != *newClassSize) {
         NSK_COMPLAIN0("TEST FAILED: error reading file\n");
         jvmti->Deallocate(*newClassBytes);
-        *newClassBytes = NULL;
+        *newClassBytes = nullptr;
         return NSK_FALSE;
     }
 
@@ -422,18 +422,18 @@ const char* getThreadName(jvmtiEnv* jvmti_env, JNIEnv* jni_env, jthread thread)
     jclass klass;
     jstring jthreadName;
     jsize jthreadNameLen;
-    unsigned char *result = NULL;
+    unsigned char *result = nullptr;
     const char *threadName;
 
-    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(thread)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(thread)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
     if (!NSK_JNI_VERIFY(jni_env, (methodID =
-            jni_env->GetMethodID(klass, "getName", "()Ljava/lang/String;")) != NULL)) {
+            jni_env->GetMethodID(klass, "getName", "()Ljava/lang/String;")) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
     jthreadName = (jstring) jni_env->CallObjectMethod(thread, methodID);
@@ -442,7 +442,7 @@ const char* getThreadName(jvmtiEnv* jvmti_env, JNIEnv* jni_env, jthread thread)
 
     if (!NSK_JVMTI_VERIFY(jvmti_env->Allocate(jthreadNameLen + 1, &result))) {
         NSK_COMPLAIN0("buffer couldn't be allocated\n");
-        return NULL;
+        return nullptr;
     }
 
     threadName = jni_env->GetStringUTFChars(jthreadName, 0);
@@ -461,14 +461,14 @@ const char* getClassName(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jobject object) {
     char *className;
     jclass klass;
 
-    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(object)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(object)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &className, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &className, nullptr))) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
     return className;
@@ -479,7 +479,7 @@ const char* getClassName(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jobject object) {
 int getLocalVariableValue(jvmtiEnv *jvmti_env, jthread thread,
                                 jmethodID method) {
 
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLocalVariableEntry *table = nullptr;
     jint entryCount = 0;
     int i;
     jint value = -1;
@@ -489,7 +489,7 @@ int getLocalVariableValue(jvmtiEnv *jvmti_env, jthread thread,
         NSK_COMPLAIN0("TEST FAILED: unable to get local variable table\n\n");
     }
 
-    if (table != NULL) {
+    if (table != nullptr) {
         jvmtiError error;
 
         for (i = 0; i < entryCount; i++) {
@@ -528,10 +528,10 @@ JNIEXPORT void JNICALL
 Java_nsk_jvmti_scenarios_hotswap_HS201_hs201t002_setThread(JNIEnv *env,
                         jclass cls, jthread thread) {
 
-    if (!NSK_JNI_VERIFY(env, (testClass = (jclass) env->NewGlobalRef(cls)) != NULL))
+    if (!NSK_JNI_VERIFY(env, (testClass = (jclass) env->NewGlobalRef(cls)) != nullptr))
         nsk_jvmti_setFailStatus();
 
-    if (!NSK_JNI_VERIFY(env, (testedThread = env->NewGlobalRef(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(env, (testedThread = env->NewGlobalRef(thread)) != nullptr))
         nsk_jvmti_setFailStatus();
 
     enableEvent(jvmti, JVMTI_EVENT_CLASS_LOAD, testedThread);
@@ -624,7 +624,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -657,7 +657,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     NSK_DISPLAY0("Enable events\n");
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS201/hs201t003/hs201t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS201/hs201t003/hs201t003.cpp
index 97b247a3d62..f848d717183 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS201/hs201t003/hs201t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS201/hs201t003/hs201t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -50,7 +50,7 @@ static jvmtiEvent eventsList[EVENTS_COUNT] = {
     JVMTI_EVENT_FRAME_POP
 };
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 static jint bytesCount; /* number of bytes of a redefining class */
@@ -74,7 +74,7 @@ static int expectedMeth(jvmtiEnv *jvmti_env, const char *event,
     char *sig;
     int methFound = 0;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &sig, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &sig, nullptr))) {
         nsk_jvmti_setFailStatus();
         return 0;
     }
@@ -107,7 +107,7 @@ static void doHotSwap(jvmtiEnv *jvmti_env,
         nsk_jvmti_setFailStatus();
         return;
     }
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(decl_cls, &cls_sig, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(decl_cls, &cls_sig, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -143,7 +143,7 @@ static void doChecks(jvmtiEnv *jvmti_env,
     jint methBytesCount; /* number of bytes of a method */
     unsigned char *methBytes; /* bytes defining a method */
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(tMethodID, &name, &sig, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(tMethodID, &name, &sig, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -196,7 +196,7 @@ void JNICALL MethodEntry(jvmtiEnv *jvmti_env, JNIEnv *env,
                 nsk_jvmti_setFailStatus();
         }
 
-        if (!NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_METHOD_ENTRY, NULL)))
+        if (!NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_METHOD_ENTRY, nullptr)))
             nsk_jvmti_setFailStatus();
     }
 }
@@ -298,7 +298,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add required capabilities */
@@ -324,13 +324,13 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     NSK_DISPLAY0("setting event callbacks done\nenabling events ...\n");
     if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT,
-            eventsList, NULL))
+            eventsList, nullptr))
         return JNI_ERR;
 
     NSK_DISPLAY0("enabling the events done\n\n");
 
     /* register agent proc */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS202/hs202t001/hs202t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS202/hs202t001/hs202t001.cpp
index 6b284a54bbc..e7936fda8c5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS202/hs202t001/hs202t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS202/hs202t001/hs202t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -56,7 +56,7 @@ JNIEXPORT void JNICALL callbackClassPrepare(jvmtiEnv *jvmti,
     if (strcmp(className,CLASS_NAME) == 0) {
         jmethodID method;
         method = jni->GetMethodID(klass, METHOD_NAME, METHOD_SIGN);
-        if (method == NULL) {
+        if (method == nullptr) {
             nsk_printf("Agent:: Method is null ");
         } else {
             jlocation start;
@@ -73,7 +73,7 @@ JNIEXPORT void JNICALL callbackClassPrepare(jvmtiEnv *jvmti,
                     nsk_printf(" ## Error occured %s \n",TranslateError(err));
                 } else  {
                     nsk_printf(" NO ERRORS ");
-                    if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_BREAKPOINT, NULL)) {
+                    if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_BREAKPOINT, nullptr)) {
                         nsk_printf(" Enabled.. notification event ..\n");
                     }
                 }
@@ -116,11 +116,11 @@ void JNICALL callbackBreakpoint(jvmtiEnv *jvmti_env,
         jlocation location) {
     jvmtiError err;
     err = JVMTI_ERROR_NONE;
-    if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_SINGLE_STEP, NULL)) {
+    if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_SINGLE_STEP, nullptr)) {
         nsk_printf(" Enabled.. notification event ..");
     }
     err= jvmti->SetEventNotificationMode(JVMTI_DISABLE,
-            JVMTI_EVENT_BREAKPOINT, NULL);
+            JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err == JVMTI_ERROR_NONE) {
         nsk_printf(" Disabled notification..");
     }
@@ -172,7 +172,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" ## Error occured %s \n",TranslateError(rc));
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf("Agent :: NOTIFICATIONS ARE ENABLED \n");
         } else {
             nsk_printf(" Error in Eanableing Notifications..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS202/hs202t002/hs202t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS202/hs202t002/hs202t002.cpp
index 12f4cc3fb4e..493e23da000 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS202/hs202t002/hs202t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS202/hs202t002/hs202t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,7 +41,7 @@ extern "C" {
 #define METHOD_NAME "display"
 
 static jint redefineNumber = 0;
-static jvmtiEnv * jvmti = NULL;
+static jvmtiEnv * jvmti = nullptr;
 
 static volatile bool thread_suspend_error = false;
 
@@ -119,7 +119,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event callbacks \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_METHOD_EXIT, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_METHOD_EXIT, nullptr)) {
             nsk_printf(" Agent :: NOTIFICATIONS ARE ENABLED \n");
         } else {
             nsk_printf(" Agent :: Error Enabling Notifications..");
@@ -160,7 +160,7 @@ Java_nsk_jvmti_scenarios_hotswap_HS202_hs202t002_hs202t002_resumeThread(JNIEnv *
 
     // disable notifications before resuming thread
     // to avoid recursion on PopFrame issued reinvoke
-    if (nsk_jvmti_disableNotification(jvmti,JVMTI_EVENT_METHOD_EXIT, NULL)) {
+    if (nsk_jvmti_disableNotification(jvmti,JVMTI_EVENT_METHOD_EXIT, nullptr)) {
         nsk_printf("Agent :: nsk_jvmti_disabled notifications..\n");
     } else {
         nsk_printf("Agent :: Failed to disable notifications..");
@@ -194,7 +194,7 @@ Java_nsk_jvmti_scenarios_hotswap_HS202_hs202t002_hs202t002_isThreadSuspended(JNI
     // this again until we see thread_suspend_error is true.
 
     jint state = 0;
-    // No errors possible here: thread is valid, and state is not NULL
+    // No errors possible here: thread is valid, and state is not nullptr
     jvmti->GetThreadState(thread, &state);
     return (state & JVMTI_THREAD_STATE_SUSPENDED) != 0;
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t001/hs203t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t001/hs203t001.cpp
index 2e95e5e7e70..4104656aa25 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t001/hs203t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t001/hs203t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -63,7 +63,7 @@ JNIEXPORT void JNICALL
         if (strcmp(className,CLASS_NAME) == 0) {
             jmethodID method;
             method = jni->GetMethodID(klass,METHOD_NAME,METHOD_SIGN);
-            if (method != NULL) {
+            if (method != nullptr) {
                 jlocation start;
                 jlocation end;
                 jvmtiError err ;
@@ -166,8 +166,8 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_CLASS_LOAD, NULL) &&
-                nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_BREAKPOINT,NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_CLASS_LOAD, nullptr) &&
+                nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_BREAKPOINT,nullptr)) {
             nsk_printf("Agent :: NOTIFICATIONS ARE ENABLED \n");
         } else {
             nsk_printf(" Error in Eanableing Notifications..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t002/hs203t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t002/hs203t002.cpp
index b1b3b42164f..3328e730f08 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t002/hs203t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t002/hs203t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -65,7 +65,7 @@ callbackClassLoad(jvmtiEnv *jvmti,
     if (strcmp(className,CLASS_NAME) == 0) {
         jmethodID method;
         method = jni->GetMethodID(klass,METHOD_NAME,METHOD_SIGN);
-        if (method != NULL) {
+        if (method != nullptr) {
             jlocation start;
             jlocation end;
             jvmtiError err ;
@@ -168,8 +168,8 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_CLASS_LOAD, NULL) &&
-                nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_BREAKPOINT, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_CLASS_LOAD, nullptr) &&
+                nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_BREAKPOINT, nullptr)) {
             nsk_printf("Agent :: NOTIFICATIONS ARE ENABLED \n");
         } else {
             nsk_printf(" Error in Eanableing Notifications..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t003/hs203t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t003/hs203t003.cpp
index a162fa0270c..3f067dd4e9a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t003/hs203t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t003/hs203t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -58,8 +58,8 @@ JNIEXPORT void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
     char * className;
     char * generic;
     redefineNumber=0;
-    className=NULL;
-    generic=NULL;
+    className=nullptr;
+    generic=nullptr;
     if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &className, &generic))) {
         nsk_printf("#error Agent :: while getting classname Signature.\n");
         nsk_jvmti_agentFailed();
@@ -67,7 +67,7 @@ JNIEXPORT void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
         if (strcmp(className,CLASS_NAME) == 0) {
             jfieldID field;
             /* get the field id and set watch on that .*/
-            if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, FIELDNAME, TYPE)) != NULL)) {
+            if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, FIELDNAME, TYPE)) != nullptr)) {
                 nsk_printf(" Agent :: (*JNI)->GetFieldID(jni, ...) returns `null`.\n");
                 nsk_jvmti_agentFailed();
             } else  if (!NSK_JVMTI_VERIFY(jvmti_env->SetFieldAccessWatch(klass, field))) {
@@ -93,7 +93,7 @@ JNIEXPORT void JNICALL callbackFieldAccess(jvmtiEnv *jvmti_env,
         return;
     }
     redefineNumber=0;
-    if (!NSK_JNI_VERIFY(jni, (clas = jni->FindClass(SEARCH_NAME)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (clas = jni->FindClass(SEARCH_NAME)) != nullptr)) {
         nsk_printf(" Agent :: (*JNI)->FindClass(jni, %s) returns `null`.\n",SEARCH_NAME);
         nsk_jvmti_agentFailed();
     } else  {
@@ -155,8 +155,8 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf("#error Agent :: while setting event callbacks.\n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_CLASS_PREPARE, NULL) &&
-                nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_FIELD_ACCESS, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_CLASS_PREPARE, nullptr) &&
+                nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_FIELD_ACCESS, nullptr)) {
             nsk_printf(" Agent :: Notifications are enabled.\n");
         } else {
             nsk_printf("#error Agent :: Eanableing Notifications.\n");
@@ -202,7 +202,7 @@ Java_nsk_jvmti_scenarios_hotswap_HS203_hs203t003_hs203t003_popThreadFrame(JNIEnv
             } else {
                 nsk_printf(" Agent :: poped thread frame.\n");
                 if (!NSK_JVMTI_VERIFY(
-                        jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_FIELD_ACCESS, NULL))) {
+                        jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_FIELD_ACCESS, nullptr))) {
                     nsk_printf("#error Agent :: failed to disable notification JVMTI_EVENT_FIELD ACCESS.\n");
                     nsk_jvmti_agentFailed();
                 } else {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t004/hs203t004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t004/hs203t004.cpp
index e29d7563d43..7a0e59b7206 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t004/hs203t004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS203/hs203t004/hs203t004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -43,14 +43,14 @@ JNIEXPORT void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
                                         jthread thread,
                                         jclass klass) {
     char * className;
-    className=NULL;
+    className=nullptr;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &className, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &className, nullptr))) {
         NSK_COMPLAIN0("#error Agent :: while getting classname.\n");
         nsk_jvmti_agentFailed();
     } else {
         if (strcmp(className, CLASS_NAME) == 0) {
-            if (nsk_jvmti_enableNotification(jvmti_env, JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL)) {
+            if (nsk_jvmti_enableNotification(jvmti_env, JVMTI_EVENT_COMPILED_METHOD_LOAD, nullptr)) {
                 NSK_DISPLAY0(" Agent :: notification enabled for COMPILED_METHOD_LOAD.\n");
                 if (!NSK_JVMTI_VERIFY(jvmti_env->GenerateEvents(JVMTI_EVENT_COMPILED_METHOD_LOAD))) {
                     NSK_COMPLAIN0("#error Agent :: occured while enabling compiled method events.\n");
@@ -83,16 +83,16 @@ JNIEXPORT void JNICALL callbackCompiledMethodLoad(jvmtiEnv *jvmti_env,
             char *className;
             char *methodName;
 
-            className = NULL;
-            methodName = NULL;
+            className = nullptr;
+            methodName = nullptr;
 
-            if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(threadClass, &className, NULL))) {
+            if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(threadClass, &className, nullptr))) {
                 NSK_COMPLAIN0("#error Agent :: while getting classname.\n");
                 nsk_jvmti_agentFailed();
                 return;
             }
 
-            if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &methodName, NULL, NULL))) {
+            if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &methodName, nullptr, nullptr))) {
                 NSK_COMPLAIN0("#error Agent :: while getting methodname.\n");
                 nsk_jvmti_agentFailed();
                 return;
@@ -115,13 +115,13 @@ JNIEXPORT void JNICALL callbackCompiledMethodLoad(jvmtiEnv *jvmti_env,
                 }
             }
 
-            if (className != NULL) {
+            if (className != nullptr) {
                 if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char *)className))) {
                     NSK_COMPLAIN1("#error Agent :: failed to Deallocate className = %s.", className);
                     nsk_jvmti_agentFailed();
                 }
             }
-            if (methodName != NULL) {
+            if (methodName != nullptr) {
                 if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char *)methodName))) {
                     NSK_COMPLAIN1("#error Agent :: failed to Deallocate methodName = %s.", methodName);
                     nsk_jvmti_agentFailed();
@@ -171,7 +171,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             NSK_COMPLAIN0("#error Agent :: occured while setting event callback.\n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             NSK_DISPLAY0(" Agent :: Notifications are enabled.\n");
         } else {
             NSK_COMPLAIN0("#error Agent :: Error in enableing Notifications.\n");
@@ -214,7 +214,7 @@ Java_nsk_jvmti_scenarios_hotswap_HS203_hs203t004_hs203t004_popThreadFrame(JNIEnv
             } else {
                 if (NSK_JVMTI_VERIFY(
                         jvmti->SetEventNotificationMode(JVMTI_DISABLE,
-                                                        JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL))) {
+                                                        JVMTI_EVENT_COMPILED_METHOD_LOAD, nullptr))) {
                     NSK_DISPLAY0(" Agent :: Disabled JVMTI_EVENT_COMPILED_METHOD_LOAD.\n");
                     retvalue = JNI_TRUE;
                 } else {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS204/hs204t002/hs204t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS204/hs204t002/hs204t002.cpp
index 1f1d3f9db09..bc080f2d882 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS204/hs204t002/hs204t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS204/hs204t002/hs204t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -57,12 +57,12 @@ callbackClassPrepare(jvmtiEnv *jvmti,
     if ((strcmp(className, CLASS_NAME) == 0)) {
         jclass cls;
         cls = jni->FindClass(SEARCH_NAME);
-        if (cls == NULL) {
+        if (cls == nullptr) {
             printf("Agent::CLS is null");
         } else {
             jmethodID method;
             method = jni->GetMethodID(cls, METHOD_NAME,METHOD_SIGNATURE);
-            if (method == NULL) {
+            if (method == nullptr) {
                 printf("Agent::Method is null ");
             } else {
                 jlocation start;
@@ -158,8 +158,8 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             return JNI_ERR;
         }
 
-        nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE , NULL);
-        nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_BREAKPOINT, NULL);
+        nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE , nullptr);
+        nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_BREAKPOINT, nullptr);
     }
     return JNI_OK;
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS204/hs204t003/hs204t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS204/hs204t003/hs204t003.cpp
index 4980cd40473..3b182cb616d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS204/hs204t003/hs204t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS204/hs204t003/hs204t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,8 +48,8 @@ JNIEXPORT void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
     char * className;
     char * generic;
 
-    className = NULL;
-    generic   = NULL;
+    className = nullptr;
+    generic   = nullptr;
     redefineNumber=0;
     if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &className, &generic))) {
         NSK_DISPLAY0(" Agent :: Failed get class signature.\n");
@@ -57,7 +57,7 @@ JNIEXPORT void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
     } else {
         if ((strcmp(className, CLASS_NAME) == 0)) {
             jfieldID fieldId;
-            if (!NSK_JNI_VERIFY(jni, (fieldId = jni->GetStaticFieldID(klass, FIELDNAME, TYPE)) != NULL)) {
+            if (!NSK_JNI_VERIFY(jni, (fieldId = jni->GetStaticFieldID(klass, FIELDNAME, TYPE)) != nullptr)) {
                     NSK_DISPLAY0(" Agent :: Failed to get FieldId.\n");
                     nsk_jvmti_agentFailed();
             } else {
@@ -65,8 +65,8 @@ JNIEXPORT void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
                     NSK_DISPLAY0(" Agent :: Failed to set watch point on a field.\n");
                     nsk_jvmti_agentFailed();
                 } else {
-                    nsk_jvmti_enableNotification(jvmti_env, JVMTI_EVENT_FIELD_ACCESS, NULL);
-                    if (!NSK_JNI_VERIFY(jni, (watchFieldClass = (jclass) jni->NewGlobalRef(klass)) != NULL)) {
+                    nsk_jvmti_enableNotification(jvmti_env, JVMTI_EVENT_FIELD_ACCESS, nullptr);
+                    if (!NSK_JNI_VERIFY(jni, (watchFieldClass = (jclass) jni->NewGlobalRef(klass)) != nullptr)) {
                         NSK_DISPLAY0(" Agent :: Failed to get global reference for class.\n");
                         nsk_jvmti_agentFailed();
                     }
@@ -77,14 +77,14 @@ JNIEXPORT void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
         }
     }
 
-    if (className != NULL) {
+    if (className != nullptr) {
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char *)className))) {
             NSK_DISPLAY1(" Agent :: #error failed to Deallocate className = %s.", className);
             nsk_jvmti_agentFailed();
         }
     }
 
-    if (generic != NULL) {
+    if (generic != nullptr) {
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char *)generic))) {
             NSK_DISPLAY1(" Agent :: #error failed to Deallocate class signature = %s.", generic);
             nsk_jvmti_agentFailed();
@@ -105,8 +105,8 @@ JNIEXPORT void JNICALL callbackFieldAccess(jvmtiEnv *jvmti_env,
     char * className;
     char * generic;
 
-    className = NULL;
-    generic   = NULL;
+    className = nullptr;
+    generic   = nullptr;
     if (redefineNumber != 0) {
         return;
     }
@@ -139,14 +139,14 @@ JNIEXPORT void JNICALL callbackFieldAccess(jvmtiEnv *jvmti_env,
         }
     }
 
-    if (className != NULL) {
+    if (className != nullptr) {
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char *)className))) {
             NSK_DISPLAY1(" Agent :: #error failed to Deallocate className = %s.", className);
             nsk_jvmti_agentFailed();
         }
     }
 
-    if (generic != NULL) {
+    if (generic != nullptr) {
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char *)generic))) {
             NSK_DISPLAY1(" Agent :: #error failed to Deallocate class signature = %s.", generic);
             nsk_jvmti_agentFailed();
@@ -192,7 +192,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             NSK_DISPLAY0(" Agent :: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL);
+        nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr);
     }
     return JNI_OK;
 }
@@ -219,7 +219,7 @@ Java_nsk_jvmti_scenarios_hotswap_HS204_hs204t003_hs204t003_popFrame(JNIEnv * jni
                     nsk_jvmti_agentFailed();
                 } else {
                     jfieldID fieldId = jni->GetStaticFieldID(watchFieldClass, FIELDNAME, TYPE);
-                    if (!NSK_JNI_VERIFY(jni, fieldId != NULL)) {
+                    if (!NSK_JNI_VERIFY(jni, fieldId != nullptr)) {
                         NSK_DISPLAY0(" Agent :: Failed to get FieldId before droping watchers.\n");
                         nsk_jvmti_agentFailed();
                     } else {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS204/hs204t004/hs204t004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS204/hs204t004/hs204t004.cpp
index 09178bac4a1..e8141386cb0 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS204/hs204t004/hs204t004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS204/hs204t004/hs204t004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -55,11 +55,11 @@ callbackClassLoad(jvmtiEnv *jvmti_env,
     redefineNumber=0;
     jvmti->GetClassSignature(klass, &className, &generic);
     if (strcmp(className, CLASS_LOADER_CLASS_NAME) == 0) {
-        if (klass != NULL) {
+        if (klass != nullptr) {
             jmethodID method;
             cloader = klass;
             method = jni->GetMethodID(klass,METHOD_NAME,SIGNATURE);
-            if (method != NULL) {
+            if (method != nullptr) {
                 jlocation start;
                 jlocation end;
                 jvmtiError err ;
@@ -158,8 +158,8 @@ jint   Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
               nsk_printf(" Agent:: Error occured while setting event call back \n");
               return JNI_ERR;
           }
-          nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_CLASS_LOAD, NULL);
-          nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_BREAKPOINT, NULL);
+          nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_CLASS_LOAD, nullptr);
+          nsk_jvmti_enableNotification(jvmti,JVMTI_EVENT_BREAKPOINT, nullptr);
       }
       return JNI_OK;
   }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t001/hs301t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t001/hs301t001.cpp
index c98c93e6702..d94ce73a3cf 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t001/hs301t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t001/hs301t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -84,7 +84,7 @@ Java_nsk_jvmti_scenarios_hotswap_HS301_hs301t001_hs301t001_redefine(JNIEnv * jni
 
     redefineNumber=0;
     cls = jni->FindClass(SEARCH_NAME);
-    if (!NSK_JNI_VERIFY(jni, cls != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, cls != nullptr)) {
         nsk_printf("Agent:: (*JNI)->FindClass(jni, %s) returns `null`.\n",SEARCH_NAME);
         return NSK_FALSE;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t002/hs301t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t002/hs301t002.cpp
index 3684e060946..6f84921286a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t002/hs301t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t002/hs301t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -84,7 +84,7 @@ Java_nsk_jvmti_scenarios_hotswap_HS301_hs301t002_hs301t002_redefine(JNIEnv * jni
 
     redefineNumber=0;
     ret = JNI_FALSE;
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(SEARCH_NAME)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(SEARCH_NAME)) != nullptr)) {
         nsk_printf("Agent:: (*JNI)->FindClass(jni, %s) returns `null`.\n", SEARCH_NAME);
         return NSK_FALSE;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t003/hs301t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t003/hs301t003.cpp
index a36ddd49fd2..076c885b622 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t003/hs301t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t003/hs301t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -45,7 +45,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
           nsk_jvmti_getFileName(redefineNumber, FILE_NAME,
                   fileName, sizeof(fileName)/sizeof(char));
           nsk_jvmti_disableNotification(jvmti_env,
-                  JVMTI_EVENT_CLASS_LOAD, NULL);
+                  JVMTI_EVENT_CLASS_LOAD, nullptr);
           if (nsk_jvmti_redefineClass(jvmti_env, klass, fileName)) {
               nsk_printf("\n Redefine successful.\n");
           } else {
@@ -92,7 +92,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back.\n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Agent:: Enabled notification.\n");
         } else {
             nsk_printf(" Agent:: Failed to enable notification.\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t004/hs301t004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t004/hs301t004.cpp
index 0a7ab069738..7c8c6af414c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t004/hs301t004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t004/hs301t004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -44,7 +44,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
         if (strcmp(className, CLASS_NAME) == 0) {
             int redefineNumber =0;
             char fileName[512];
-            nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, NULL);
+            nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, nullptr);
             nsk_jvmti_getFileName(redefineNumber, FILE_NAME, fileName,
                     sizeof(fileName)/sizeof(char));
             if (nsk_jvmti_redefineClass(jvmti_env, klass, fileName)) {
@@ -93,7 +93,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Enabled notification.\n");
         } else {
             nsk_printf(" Failed to enable notifications.\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t005/hs301t005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t005/hs301t005.cpp
index a6bfbae8bd4..7a04fa7c333 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t005/hs301t005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS301/hs301t005/hs301t005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,7 +41,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti,
     if (strcmp(className,CLASS_NAME) == 0) {
         int redefineNumber =0;
         char fileName[512];
-        nsk_jvmti_disableNotification(jvmti, JVMTI_EVENT_CLASS_LOAD, NULL);
+        nsk_jvmti_disableNotification(jvmti, JVMTI_EVENT_CLASS_LOAD, nullptr);
         nsk_jvmti_getFileName(redefineNumber, FILE_NAME, fileName, sizeof(fileName)/sizeof(char));
         if (nsk_jvmti_redefineClass(jvmti, klass, fileName)) {
             nsk_printf("\n Redefine successful ..\n");
@@ -88,7 +88,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Enabled. noftification..");
         } else {
             nsk_printf(" Failed to Enable ..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t001/hs302t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t001/hs302t001.cpp
index cd474e6a71d..883c197533b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t001/hs302t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t001/hs302t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
   if (strcmp(className,CLASS_NAME) == 0) {
     char fileName[512];
     nsk_jvmti_getFileName(redefineNumber, FILE_NAME, fileName, sizeof(fileName)/sizeof(char));
-    nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, NULL);
+    nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, nullptr);
     if (nsk_jvmti_redefineClass(jvmti_env, klass, fileName)) {
       nsk_printf("Redefine successful ..\n");
     } else {
@@ -88,7 +88,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Enabled. noftification..");
         } else {
             nsk_printf(" Failed to Enable ..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t002/hs302t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t002/hs302t002.cpp
index 14fa9aef071..9cd0e4006cc 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t002/hs302t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t002/hs302t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
   jvmti_env->GetClassSignature(klass, &className, &generic);
   if (strcmp(className,CLASS_NAME) == 0) {
       char fileName[512];
-      nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, NULL);
+      nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, nullptr);
       nsk_jvmti_getFileName(redefineNumber, FILE_NAME, fileName, sizeof(fileName)/sizeof(char));
       if (nsk_jvmti_redefineClass(jvmti_env, klass, fileName)) {
           nsk_printf("Redefine successful ..\n");
@@ -94,7 +94,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Enabled. noftification..");
         } else {
             nsk_printf(" Failed to Enable ..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t003/hs302t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t003/hs302t003.cpp
index 2625b7fcb4c..217a27bb5b5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t003/hs302t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t003/hs302t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -43,7 +43,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
       char fileName[512];
 
       nsk_jvmti_getFileName(redefineNumber, FILE_NAME, fileName, sizeof(fileName)/sizeof(char));
-      nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, NULL);
+      nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, nullptr);
       if (nsk_jvmti_redefineClass(jvmti_env, klass, fileName)) {
           nsk_printf("Redefine successful ..\n");
       } else {
@@ -93,7 +93,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Enabled. noftification..");
         } else {
             nsk_printf(" Failed to Enable ..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t004/hs302t004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t004/hs302t004.cpp
index 9c7d26fd543..5cf83fbd4a7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t004/hs302t004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t004/hs302t004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
     char fileName[512];
     nsk_jvmti_getFileName(redefineNumber, FILE_NAME, fileName,
                         sizeof(fileName)/sizeof(char));
-    nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, NULL);
+    nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, nullptr);
     if (nsk_jvmti_redefineClass(jvmti_env, klass,fileName)) {
       nsk_printf("Redefine successful ..\n");
     } else {
@@ -88,7 +88,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Enabled. noftification..");
         } else {
             nsk_printf(" Failed to Enable ..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t005/hs302t005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t005/hs302t005.cpp
index ac0b3ca62e1..c6b9a3d0833 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t005/hs302t005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t005/hs302t005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
   jvmti_env->GetClassSignature(klass, &className, &generic);
   if (strcmp(className,CLASS_NAME) == 0) {
     char fileName[512];
-    nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, NULL);
+    nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, nullptr);
     nsk_jvmti_getFileName(redefineNumber, FILE_NAME, fileName,
                         sizeof(fileName)/sizeof(char));
     if (nsk_jvmti_redefineClass(jvmti_env, klass,fileName)) {
@@ -90,7 +90,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Enabled. noftification..");
         } else {
             nsk_printf(" Failed to Enable ..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t006/hs302t006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t006/hs302t006.cpp
index 4e896c79c5b..ef5d37e6659 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t006/hs302t006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t006/hs302t006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,7 +41,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
     jvmti_env->GetClassSignature(klass, &className, &generic);
     if (strcmp(className,CLASS_NAME) == 0) {
         char fileName[512];
-        nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, NULL);
+        nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, nullptr);
         nsk_jvmti_getFileName(redefineNumber, FILE_NAME, fileName,
                         sizeof(fileName)/sizeof(char));
         if (nsk_jvmti_redefineClass(jvmti_env, klass, fileName)) {
@@ -89,7 +89,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Enabled. noftification..");
         } else {
             nsk_printf(" Failed to Enable ..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t007/hs302t007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t007/hs302t007.cpp
index f1dd8720697..81d83405929 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t007/hs302t007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t007/hs302t007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
     jvmti_env->GetClassSignature(klass, &className, &generic);
     if (strcmp(className,CLASS_NAME) == 0) {
         char fileName[512];
-        nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, NULL);
+        nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, nullptr);
         nsk_jvmti_getFileName(redefineNumber, FILE_NAME, fileName,
                         sizeof(fileName)/sizeof(char));
         if (nsk_jvmti_redefineClass(jvmti_env, klass, fileName)) {
@@ -86,7 +86,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Enabled. noftification..");
         } else {
             nsk_printf(" Failed to Enable ..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t008/hs302t008.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t008/hs302t008.cpp
index 1f11ca27d3b..54506880d09 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t008/hs302t008.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t008/hs302t008.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,7 +41,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
   jvmti_env->GetClassSignature(klass, &className, &generic);
   if (strcmp(className,CLASS_NAME) == 0) {
     char fileName[512];
-    nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, NULL);
+    nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, nullptr);
     nsk_jvmti_getFileName(redefineNumber, FILE_NAME, fileName,
                         sizeof(fileName)/sizeof(char));
     if (nsk_jvmti_redefineClass(jvmti_env, klass, fileName)) {
@@ -89,7 +89,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Enabled. noftification..");
         } else {
             nsk_printf(" Failed to Enable ..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t009/hs302t009.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t009/hs302t009.cpp
index dbcf4290b22..95fce3ff410 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t009/hs302t009.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t009/hs302t009.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
     if (strcmp(className,CLASS_NAME) == 0) {
 
         char fileName[512];
-        nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, NULL);
+        nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, nullptr);
         nsk_jvmti_getFileName(redefineNumber, FILE_NAME, fileName,
                         sizeof(fileName)/sizeof(char));
         if (nsk_jvmti_redefineClass(jvmti_env, klass,fileName)) {
@@ -89,7 +89,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Enabled. noftification..");
         } else {
             nsk_printf(" Failed to Enable ..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t010/hs302t010.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t010/hs302t010.cpp
index fd15976ab42..0d8525c8f6e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t010/hs302t010.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t010/hs302t010.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,7 +41,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
     jvmti_env->GetClassSignature(klass, &className, &generic);
     if (strcmp(className,CLASS_NAME) == 0) {
         char fileName[512];
-        nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, NULL);
+        nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, nullptr);
         nsk_jvmti_getFileName(redefineNumber, FILE_NAME, fileName,
                         sizeof(fileName)/sizeof(char));
         if (nsk_jvmti_redefineClass(jvmti_env, klass, fileName)) {
@@ -88,7 +88,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Enabled. noftification..");
         } else {
             nsk_printf(" Failed to Enable ..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t011/hs302t011.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t011/hs302t011.cpp
index eb9a17c1791..b48aae2a391 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t011/hs302t011.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t011/hs302t011.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,7 +41,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
     jvmti_env->GetClassSignature(klass, &className, &generic);
     if (strcmp(className,CLASS_NAME) == 0) {
         char fileName[512];
-        nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, NULL);
+        nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, nullptr);
         nsk_jvmti_getFileName(redefineNumber, FILE_NAME, fileName,
                         sizeof(fileName)/sizeof(char));
         if (nsk_jvmti_redefineClass(jvmti_env, klass, fileName)) {
@@ -89,7 +89,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Enabled. noftification..");
         } else {
             nsk_printf(" Failed to Enable ..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t012/hs302t012.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t012/hs302t012.cpp
index 4324a18dc73..2bcc8da5020 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t012/hs302t012.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/hotswap/HS302/hs302t012/hs302t012.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -43,7 +43,7 @@ void JNICALL callbackClassPrepare(jvmtiEnv *jvmti_env,
     jvmti_env->GetClassSignature(klass, &className, &generic);
     if (strcmp(className,CLASS_NAME) == 0) {
         char fileName[512];
-        nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, NULL);
+        nsk_jvmti_disableNotification(jvmti_env, JVMTI_EVENT_CLASS_PREPARE, nullptr);
         nsk_jvmti_getFileName(redefineNumber, FILE_NAME, fileName,
                         sizeof(fileName)/sizeof(char));
         if (nsk_jvmti_redefineClass(jvmti_env, klass, fileName)) {
@@ -91,7 +91,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
             nsk_printf(" Agent:: Error occured while setting event call back \n");
             return JNI_ERR;
         }
-        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, NULL)) {
+        if (nsk_jvmti_enableNotification(jvmti, JVMTI_EVENT_CLASS_PREPARE, nullptr)) {
             nsk_printf(" Enabled. noftification..");
         } else {
             nsk_printf(" Failed to Enable ..");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI01/ji01t001/ji01t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI01/ji01t001/ji01t001.cpp
index d3d6ea40c8c..2c9f095737c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI01/ji01t001/ji01t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI01/ji01t001/ji01t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -40,36 +40,36 @@ extern "C" {
 static const char *classSig =
     "Lnsk/jvmti/scenarios/jni_interception/JI01/ji01t001;";
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jrawMonitorID eventLock;
 static jvmtiEventCallbacks callbacks;
 static jint result = NSK_STATUS_PASSED;
 
 // test thread
-static jthread testThread = NULL;
+static jthread testThread = nullptr;
 
 /* the original JNI function table */
-static jniNativeInterface *orig_jni_functions = NULL;
+static jniNativeInterface *orig_jni_functions = nullptr;
 
 /* the redirected JNI function table */
-static jniNativeInterface *redir_jni_functions = NULL;
+static jniNativeInterface *redir_jni_functions = nullptr;
 
 /* number of the redirected JNI function calls */
 static volatile int fnd_calls = 0;
 
 void setTestThread(JNIEnv *env) {
-    jthread curThread = NULL;
+    jthread curThread = nullptr;
     NSK_JVMTI_VERIFY(jvmti->GetCurrentThread(&curThread));
     testThread = env->NewGlobalRef(curThread);
 }
 
 void resetTestThread(JNIEnv *env) {
      env->DeleteGlobalRef(testThread);
-     testThread = NULL;
+     testThread = nullptr;
 }
 
 bool isOnTestThread(JNIEnv *env) {
-    jthread curThread = NULL;
+    jthread curThread = nullptr;
     NSK_JVMTI_VERIFY(jvmti->GetCurrentThread(&curThread));
     return env->IsSameObject(testThread, curThread);
 }
@@ -329,7 +329,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
 
-    if (!NSK_VERIFY(jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1) == JNI_OK && jvmti != NULL))
+    if (!NSK_VERIFY(jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1) == JNI_OK && jvmti != nullptr))
         return JNI_ERR;
 
 
@@ -354,11 +354,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     NSK_DISPLAY0("Event callbacks are set\nEnabling events...\n");
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr)))
         return JNI_ERR;
 
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr)))
         return JNI_ERR;
 
     NSK_DISPLAY0("Events are enabled\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t001/ji03t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t001/ji03t001.cpp
index 1d452892f2c..f55c48c218f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t001/ji03t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t001/ji03t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,15 +35,15 @@ extern "C" {
 #define PASSED  0
 #define STATUS_FAILED  2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static int verbose = 0;
 
 /* the original JNI function table */
-static jniNativeInterface *orig_jni_functions = NULL;
+static jniNativeInterface *orig_jni_functions = nullptr;
 
 /* the redirected JNI function table */
-static jniNativeInterface *redir_jni_functions = NULL;
+static jniNativeInterface *redir_jni_functions = nullptr;
 
 /* number of the redirected JNI function calls */
 int call_count = 0;
@@ -115,7 +115,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_scenarios_jni_1interception_JI03_ji03t001_check(JNIEnv *env, jclass cls) {
     jint ver;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("(%s,%d): TEST FAILURE: JVMTI client was not properly loaded\n",
             __FILE__, __LINE__);
         return STATUS_FAILED;
@@ -183,14 +183,14 @@ JNIEXPORT jint JNI_OnLoad_ji03t001(JavaVM *jvm, char *options, void *reserved) {
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "-verbose") == 0)
+    if (options != nullptr && strcmp(options, "-verbose") == 0)
         verbose = 1;
 
     if (verbose)
         printf("verbose mode on\n");
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("(%s,%d): Failed to call GetEnv\n", __FILE__, __LINE__);
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t002/ji03t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t002/ji03t002.cpp
index 0ed3d60a31e..e7350dac3af 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t002/ji03t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t002/ji03t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,7 +36,7 @@ extern "C" {
 #define PASSED  0
 #define STATUS_FAILED  2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static int verbose = 0;
 
@@ -53,15 +53,15 @@ typedef struct {   /* line numbers of a method */
 } methInfo;
 
 static methInfo meth_info[] = {
-    { 0, "statMeth", "(I)D", NULL, "statMeth_calls", NULL, 0, 0 },
-    { 1, "voidMeth", "()V", NULL, "voidMeth_calls", NULL, 0, 0 }
+    { 0, "statMeth", "(I)D", nullptr, "statMeth_calls", nullptr, 0, 0 },
+    { 1, "voidMeth", "()V", nullptr, "voidMeth_calls", nullptr, 0, 0 }
 };
 
 /* the original JNI function table */
-static jniNativeInterface *orig_jni_functions = NULL;
+static jniNativeInterface *orig_jni_functions = nullptr;
 
 /* the redirected JNI function table */
-static jniNativeInterface *redir_jni_functions = NULL;
+static jniNativeInterface *redir_jni_functions = nullptr;
 
 /** redirected JNI functions **/
 jdouble JNICALL MyCallStaticDoubleMethodV(JNIEnv *env, jclass cls, jmethodID mid, va_list args) {
@@ -127,7 +127,7 @@ void doRedirect(JNIEnv *env, jclass cls) {
             meth_info[i].mid = env->GetStaticMethodID(
                 cls, meth_info[i].m_name, meth_info[i].m_sign);
         }
-        if (meth_info[i].mid == NULL) {
+        if (meth_info[i].mid == nullptr) {
            result = STATUS_FAILED;
            printf("(%s,%d): TEST FAILURE: failed to get the ID for the method \"%s %s\"\n",
                 __FILE__, __LINE__, meth_info[i].m_name, meth_info[i].m_sign);
@@ -270,7 +270,7 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_scenarios_jni_1interception_JI03_ji03t002_check(JNIEnv *env, jobject obj) {
     jclass objCls;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("(%s,%d): TEST FAILURE: JVMTI client was not properly loaded\n",
             __FILE__, __LINE__);
         return STATUS_FAILED;
@@ -309,14 +309,14 @@ JNIEXPORT jint JNI_OnLoad_ji03t002(JavaVM *jvm, char *options, void *reserved) {
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "-verbose") == 0)
+    if (options != nullptr && strcmp(options, "-verbose") == 0)
         verbose = 1;
 
     if (verbose)
         printf("verbose mode on\n");
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("(%s,%d): Failed to call GetEnv\n", __FILE__, __LINE__);
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t003/ji03t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t003/ji03t003.cpp
index 4bb4e45fb07..9b6f70525ea 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t003/ji03t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t003/ji03t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,21 +36,21 @@ extern "C" {
 #define PASSED  0
 #define STATUS_FAILED  2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static int verbose = 0;
 // test thread
-static jthread testThread = NULL;
+static jthread testThread = nullptr;
 
 static const char *javaField = "exc";
 static const char *excClassSig =
     "Lnsk/jvmti/scenarios/jni_interception/JI03/ji03t003Exc;";
 
 /* the original JNI function table */
-static jniNativeInterface *orig_jni_functions = NULL;
+static jniNativeInterface *orig_jni_functions = nullptr;
 
 /* the redirected JNI function table */
-static jniNativeInterface *redir_jni_functions = NULL;
+static jniNativeInterface *redir_jni_functions = nullptr;
 
 /* number of the redirected JNI function calls */
 int throw_calls = 0;
@@ -58,18 +58,18 @@ int thrownew_calls = 0;
 int excoccur_calls = 0;
 
 void setTestThread(JNIEnv *env) {
-    jthread curThread = NULL;
+    jthread curThread = nullptr;
     NSK_JVMTI_VERIFY(jvmti->GetCurrentThread(&curThread));
     testThread = env->NewGlobalRef(curThread);
 }
 
 void resetTestThread(JNIEnv *env) {
      env->DeleteGlobalRef(testThread);
-     testThread = NULL;
+     testThread = nullptr;
 }
 
 bool isOnTestThread(JNIEnv *env) {
-    jthread curThread = NULL;
+    jthread curThread = nullptr;
     NSK_JVMTI_VERIFY(jvmti->GetCurrentThread(&curThread));
     return env->IsSameObject(testThread, curThread);
 }
@@ -290,7 +290,7 @@ Java_nsk_jvmti_scenarios_jni_1interception_JI03_ji03t003_check(JNIEnv *env, jobj
     jclass thrw;
     jclass objCls;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("(%s,%d): TEST FAILURE: JVMTI client was not properly loaded\n",
             __FILE__, __LINE__);
         return STATUS_FAILED;
@@ -357,14 +357,14 @@ JNIEXPORT jint JNI_OnLoad_ji03t003(JavaVM *jvm, char *options, void *reserved) {
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "-verbose") == 0)
+    if (options != nullptr && strcmp(options, "-verbose") == 0)
         verbose = 1;
 
     if (verbose)
         printf("verbose mode on\n");
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("(%s,%d): Failed to call GetEnv\n", __FILE__, __LINE__);
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t004/ji03t004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t004/ji03t004.cpp
index ffbe992669e..d25d2c9fcc1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t004/ji03t004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI03/ji03t004/ji03t004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,7 +36,7 @@ extern "C" {
 #define PASSED  0
 #define STATUS_FAILED  2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static int verbose = 0;
 
@@ -44,10 +44,10 @@ static const char *classSig =
     "Lnsk/jvmti/scenarios/jni_interception/JI03/ji03t004a;";
 
 /* the original JNI function table */
-static jniNativeInterface *orig_jni_functions = NULL;
+static jniNativeInterface *orig_jni_functions = nullptr;
 
 /* the redirected JNI function table */
-static jniNativeInterface *redir_jni_functions = NULL;
+static jniNativeInterface *redir_jni_functions = nullptr;
 
 /* number of the redirected JNI function calls */
 int allobj_calls = 0;
@@ -134,7 +134,7 @@ void doExec(JNIEnv *env, jclass allCls, jmethodID ctorId, const char *msg, ...)
     va_list args;
     va_start(args, msg);
     allObj = env->AllocObject(allCls);
-    if (allObj == NULL) {
+    if (allObj == nullptr) {
         result = STATUS_FAILED;
         printf("(%s,%d): TEST FAILED: failed to call %s AllocObject()\n",
             __FILE__, __LINE__, msg);
@@ -150,7 +150,7 @@ void doExec(JNIEnv *env, jclass allCls, jmethodID ctorId, const char *msg, ...)
     }
 
     newObj = env->NewObjectV(allCls, ctorId, args);
-    if (newObj == NULL) {
+    if (newObj == nullptr) {
         result = STATUS_FAILED;
         printf("(%s,%d): TEST FAILED: failed to call %s NewObjectV()\n",
             __FILE__, __LINE__, msg);
@@ -208,21 +208,21 @@ Java_nsk_jvmti_scenarios_jni_1interception_JI03_ji03t004_check(JNIEnv *env, jobj
     jmethodID ctorId;
     jclass objCls;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("(%s,%d): TEST FAILURE: JVMTI client was not properly loaded\n",
             __FILE__, __LINE__);
         return STATUS_FAILED;
     }
 
     objCls = env->FindClass(classSig);
-    if (objCls == NULL) {
+    if (objCls == nullptr) {
         printf("(%s,%d): TEST FAILED: failed to call FindClass() for \"%s\"\n",
             __FILE__, __LINE__, classSig);
         return STATUS_FAILED;
     }
 
     ctorId = env->GetMethodID(objCls, "<init>", "()V");
-    if (ctorId == NULL) {
+    if (ctorId == nullptr) {
         printf("(%s,%d): TEST FAILED: failed to call GetMethodID() for a constructor\n",
             __FILE__, __LINE__);
         return STATUS_FAILED;
@@ -259,14 +259,14 @@ JNIEXPORT jint JNI_OnLoad_ji03t004(JavaVM *jvm, char *options, void *reserved) {
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "-verbose") == 0)
+    if (options != nullptr && strcmp(options, "-verbose") == 0)
         verbose = 1;
 
     if (verbose)
         printf("verbose mode on\n");
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("(%s,%d): Failed to call GetEnv\n", __FILE__, __LINE__);
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI05/ji05t001/ji05t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI05/ji05t001/ji05t001.cpp
index a38d73ba821..3db35166c6c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI05/ji05t001/ji05t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI05/ji05t001/ji05t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -179,7 +179,7 @@ static int initAgent(int indx) {
 
     NSK_DISPLAY1("\nagent %s initializer: obtaining the JVMTI env ...\n", (indx == 0) ? "A" : "B");
     res = vm->GetEnv((void **) &jvmti[indx], JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti[indx] == NULL) {
+    if (res != JNI_OK || jvmti[indx] == nullptr) {
         NSK_COMPLAIN1("TEST FAILURE: failed to call GetEnv for the agent %s\n",
             (indx == 0) ? "A" : "B");
         result = STATUS_FAILED;
@@ -207,7 +207,7 @@ static int initAgent(int indx) {
 
     NSK_DISPLAY1("\nagent %s initializer: setting event callbacks done\n\tenabling events ...\n",
         (indx == 0) ? "A" : "B");
-    err = jvmti[indx]->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+    err = jvmti[indx]->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
     if (err != JVMTI_ERROR_NONE) { /* enable event globally */
         NSK_COMPLAIN2("TEST FAILURE: failed to enable JVMTI_EVENT_VM_INIT event for the agent %s: %s\n",
             (indx == 0) ? "A" : "B", TranslateError(err));
@@ -227,7 +227,7 @@ static void startAgent(int indx) {
         (indx == 0) ? "A" : "B");
     void* context = (void*) ((indx == 0) ? "agent A" : "agent B");
     agentThr[indx] = THREAD_new((indx == 0) ? agentA : agentB, context);
-    if (THREAD_start(agentThr[indx]) == NULL) {
+    if (THREAD_start(agentThr[indx]) == nullptr) {
         NSK_COMPLAIN1("TEST FAILURE: cannot start the agent %s thread\n",
             (indx == 0) ? "A" : "B");
         exit(STATUS_FAILED);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI06/ji06t001/ji06t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI06/ji06t001/ji06t001.cpp
index d5dfc829d1b..3a2e82c3d3a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI06/ji06t001/ji06t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/jni_interception/JI06/ji06t001/ji06t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -59,7 +59,7 @@ static const char *classSig =
     "Lnsk/jvmti/scenarios/jni_interception/JI06/ji06t001a;";
 
 static JavaVM *vm;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 
 static volatile int verbose = 0;
 
@@ -72,10 +72,10 @@ static volatile jobject clsObj;
 static jrawMonitorID countLock;
 
 /* the original JNI function table */
-static jniNativeInterface *orig_jni_functions = NULL;
+static jniNativeInterface *orig_jni_functions = nullptr;
 
 /* the redirected JNI function table */
-static jniNativeInterface *redir_jni_functions = NULL;
+static jniNativeInterface *redir_jni_functions = nullptr;
 
 /* number of the redirected JNI function calls */
 static volatile int monent_calls = 0;
@@ -315,21 +315,21 @@ Java_nsk_jvmti_scenarios_jni_1interception_JI06_ji06t001_check(JNIEnv *env, jobj
     char *ownContext = (char*) "ownerThr";
     char *redirContext = (char*) "redirectorThr";
     int exitCode = PASSED;
-    void *ownThr = NULL;
-    void *redirThr = NULL;
+    void *ownThr = nullptr;
+    void *redirThr = nullptr;
     void *waitThr[MAX_THREADS];
     int waitContElem[MAX_THREADS]; /* context of a particular waiting thread */
     int i;
     int tries = 0;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         NSK_COMPLAIN0("TEST FAILURE: JVMTI client was not properly loaded\n");
         return STATUS_FAILED;
     }
 
 /* prepare the testing */
     clsObj = env->NewGlobalRef(getObjectFromField(env, obj));
-    if (clsObj == NULL) {
+    if (clsObj == nullptr) {
         NSK_COMPLAIN1("TEST FAILURE: cannot create a new global reference of class \"%s\"\n",
             classSig);
         env->FatalError("failed to create a new global reference");
@@ -337,7 +337,7 @@ Java_nsk_jvmti_scenarios_jni_1interception_JI06_ji06t001_check(JNIEnv *env, jobj
 
     NSK_DISPLAY0("starting monitor owner thread ...\n");
     ownThr = THREAD_new(ownerThread, ownContext);
-    if (THREAD_start(ownThr) == NULL) {
+    if (THREAD_start(ownThr) == nullptr) {
         NSK_COMPLAIN0("TEST FAILURE: cannot start monitor owner thread\n");
         exit(STATUS_FAILED);
     }
@@ -360,7 +360,7 @@ Java_nsk_jvmti_scenarios_jni_1interception_JI06_ji06t001_check(JNIEnv *env, jobj
         waitContElem[i] = i+1;
         /* 4932877 fix in accordance with ANSI C: thread context of type int -> int* -> void*  */
         waitThr[i] = THREAD_new(waitingThread, (void *) &(waitContElem[i]));
-        if (THREAD_start(waitThr[i]) == NULL) {
+        if (THREAD_start(waitThr[i]) == nullptr) {
             NSK_COMPLAIN1("TEST FAILURE: cannot start waiting thread #%d\n",
                 i+1);
             exit(STATUS_FAILED);
@@ -384,7 +384,7 @@ Java_nsk_jvmti_scenarios_jni_1interception_JI06_ji06t001_check(JNIEnv *env, jobj
     NSK_DISPLAY0(">>> TEST CASE a) Trying to redirect the JNI function ...\n\n"
                  "starting redirector thread ...\n");
     redirThr = THREAD_new(redirectorThread, redirContext);
-    if (THREAD_start(redirThr) == NULL) {
+    if (THREAD_start(redirThr) == nullptr) {
         NSK_COMPLAIN0("TEST FAILURE: cannot start redirector thread\n");
         exit(STATUS_FAILED);
     }
@@ -431,7 +431,7 @@ Java_nsk_jvmti_scenarios_jni_1interception_JI06_ji06t001_check(JNIEnv *env, jobj
     /* 4932877 fix in accordance with ANSI C: thread context of type int -> int* -> void*  */
     waitThr[MAX_THREADS-1] = THREAD_new(waitingThread,
         (void *) &(waitContElem[MAX_THREADS-1]));
-    if (THREAD_start(waitThr[MAX_THREADS-1]) == NULL) {
+    if (THREAD_start(waitThr[MAX_THREADS-1]) == nullptr) {
         NSK_COMPLAIN0("TEST FAILURE: cannot start verification thread\n");
         exit(STATUS_FAILED);
     }
@@ -482,7 +482,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     vm = jvm;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA01/ma01t001/ma01t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA01/ma01t001/ma01t001.cpp
index 56bf54b2a94..f0771daa56a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA01/ma01t001/ma01t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA01/ma01t001/ma01t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -69,9 +69,9 @@ JNIEXPORT jint JNI_OnLoad_ma01t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
-    const char* name = NULL;
+    const char* name = nullptr;
     int found = NSK_FALSE;
     int i, count;
 
@@ -97,10 +97,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA01/ma01t001/ma01t001a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA01/ma01t001/ma01t001a.cpp
index 800aebecd87..959a26465e5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA01/ma01t001/ma01t001a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA01/ma01t001/ma01t001a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -69,9 +69,9 @@ JNIEXPORT jint JNI_OnLoad_ma01t001a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
-    const char* name = NULL;
+    const char* name = nullptr;
     int found = NSK_FALSE;
     int i, count;
 
@@ -97,10 +97,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA02/ma02t001/ma02t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA02/ma02t001/ma02t001.cpp
index 464a8186b51..0d7a1f5fe1a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA02/ma02t001/ma02t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA02/ma02t001/ma02t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -91,7 +91,7 @@ JNIEXPORT jint JNI_OnLoad_ma02t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
 
     NSK_DISPLAY0("Agent_OnLoad\n");
@@ -102,10 +102,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
@@ -114,10 +114,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_VERIFY(nsk_jvmti_init_MA(&callbacks)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA02/ma02t001/ma02t001a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA02/ma02t001/ma02t001a.cpp
index 2d850db5d8c..77e0ff05f50 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA02/ma02t001/ma02t001a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA02/ma02t001/ma02t001a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -91,7 +91,7 @@ JNIEXPORT jint JNI_OnLoad_ma02t001a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
 
     NSK_DISPLAY0("Agent_OnLoad\n");
@@ -102,10 +102,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
@@ -114,10 +114,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_VERIFY(nsk_jvmti_init_MA(&callbacks)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA03/ma03t001/ma03t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA03/ma03t001/ma03t001.cpp
index cb10b246b30..6b1d29f4991 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA03/ma03t001/ma03t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA03/ma03t001/ma03t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -102,7 +102,7 @@ JNIEXPORT jint JNI_OnLoad_ma03t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
 
     NSK_DISPLAY0("Agent_OnLoad\n");
@@ -113,10 +113,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
@@ -126,13 +126,13 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_VERIFY(nsk_jvmti_init_MA(&callbacks)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA03/ma03t001/ma03t001a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA03/ma03t001/ma03t001a.cpp
index ec744e3bdde..38fa0bb8e1f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA03/ma03t001/ma03t001a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA03/ma03t001/ma03t001a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -103,7 +103,7 @@ JNIEXPORT jint JNI_OnLoad_ma03t001a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
 
     NSK_DISPLAY0("Agent_OnLoad\n");
@@ -114,10 +114,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t001/ma04t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t001/ma04t001.cpp
index 937daddbd39..a3f28659bae 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t001/ma04t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t001/ma04t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,7 +39,7 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jobject testedObject = NULL;
+static jobject testedObject = nullptr;
 
 /* ========================================================================== */
 
@@ -47,24 +47,24 @@ static int prepare(JNIEnv* jni) {
     const char* CLASS_NAME = "nsk/jvmti/scenarios/multienv/MA04/ma04t001";
     const char* FIELD_NAME = "testedObject";
     const char* FIELD_SIGNATURE = "Ljava/lang/Object;";
-    jclass cls = NULL;
-    jfieldID fid = NULL;
+    jclass cls = nullptr;
+    jfieldID fid = nullptr;
 
     NSK_DISPLAY0("Obtain tested object from a static field of debugee class\n");
 
     NSK_DISPLAY1("Find class: %s\n", CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY2("Find field: %s:%s\n", FIELD_NAME, FIELD_SIGNATURE);
     if (!NSK_JNI_VERIFY(jni, (fid =
-            jni->GetStaticFieldID(cls, FIELD_NAME, FIELD_SIGNATURE)) != NULL))
+            jni->GetStaticFieldID(cls, FIELD_NAME, FIELD_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->GetStaticObjectField(cls, fid)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->GetStaticObjectField(cls, fid)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewGlobalRef(testedObject)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewGlobalRef(testedObject)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -200,7 +200,7 @@ JNIEXPORT jint JNI_OnLoad_ma04t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
     jvmtiCapabilities caps;
 
@@ -212,7 +212,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -221,7 +221,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t001/ma04t001a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t001/ma04t001a.cpp
index cbc5bc9054f..1f07af5da4e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t001/ma04t001a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t001/ma04t001a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,7 +39,7 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jobject testedObject = NULL;
+static jobject testedObject = nullptr;
 
 /* ========================================================================== */
 
@@ -47,24 +47,24 @@ static int prepare(JNIEnv* jni) {
     const char* CLASS_NAME = "nsk/jvmti/scenarios/multienv/MA04/ma04t001";
     const char* FIELD_NAME = "testedObject";
     const char* FIELD_SIGNATURE = "Ljava/lang/Object;";
-    jclass cls = NULL;
-    jfieldID fid = NULL;
+    jclass cls = nullptr;
+    jfieldID fid = nullptr;
 
     NSK_DISPLAY0("Obtain tested object from a static field of debugee class\n");
 
     NSK_DISPLAY1("Find class: %s\n", CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY2("Find field: %s:%s\n", FIELD_NAME, FIELD_SIGNATURE);
     if (!NSK_JNI_VERIFY(jni, (fid =
-            jni->GetStaticFieldID(cls, FIELD_NAME, FIELD_SIGNATURE)) != NULL))
+            jni->GetStaticFieldID(cls, FIELD_NAME, FIELD_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->GetStaticObjectField(cls, fid)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->GetStaticObjectField(cls, fid)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewGlobalRef(testedObject)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewGlobalRef(testedObject)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -200,7 +200,7 @@ JNIEXPORT jint JNI_OnLoad_ma04t001a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
     jvmtiCapabilities caps;
 
@@ -212,7 +212,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -221,7 +221,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t002/ma04t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t002/ma04t002.cpp
index 2091ef57ca6..c4bff40748c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t002/ma04t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t002/ma04t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,9 +39,9 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jobject testedObject = NULL;
-static jobject testedInstance = NULL;
-static jclass testedClass = NULL;
+static jobject testedObject = nullptr;
+static jobject testedInstance = nullptr;
+static jclass testedClass = nullptr;
 static int ObjectsCount = 0;
 
 /* ========================================================================== */
@@ -76,33 +76,33 @@ static int prepare(JNIEnv* jni) {
     const char* FIELD_SIGNATURE = "Ljava/lang/Object;";
     const char* INSTANCE_NAME = "testedInstance1";
     const char* INSTANCE_SIGNATURE = "Lnsk/jvmti/scenarios/multienv/MA04/ma04t002;";
-    jfieldID fid = NULL;
+    jfieldID fid = nullptr;
 
     NSK_DISPLAY0("Obtain tested object from a static field of debugee class\n");
 
     NSK_DISPLAY1("Find class: %s\n", CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (testedClass = jni->FindClass(CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = jni->FindClass(CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass) jni->NewGlobalRef(testedClass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass) jni->NewGlobalRef(testedClass)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY2("Find field: %s:%s\n", FIELD_NAME, FIELD_SIGNATURE);
     if (!NSK_JNI_VERIFY(jni, (fid =
-            jni->GetStaticFieldID(testedClass, FIELD_NAME, FIELD_SIGNATURE)) != NULL))
+            jni->GetStaticFieldID(testedClass, FIELD_NAME, FIELD_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->GetStaticObjectField(testedClass, fid)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->GetStaticObjectField(testedClass, fid)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY2("Find class instance: %s:%s\n",
         INSTANCE_NAME, INSTANCE_SIGNATURE);
     if (!NSK_JNI_VERIFY(jni, (fid =
-            jni->GetStaticFieldID(testedClass, INSTANCE_NAME, INSTANCE_SIGNATURE)) != NULL))
+            jni->GetStaticFieldID(testedClass, INSTANCE_NAME, INSTANCE_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (testedInstance =
-            jni->GetStaticObjectField(testedClass, fid)) != NULL))
+            jni->GetStaticObjectField(testedClass, fid)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -305,7 +305,7 @@ JNIEXPORT jint JNI_OnLoad_ma04t002(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
     jvmtiCapabilities caps;
 
@@ -317,7 +317,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -327,14 +327,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
     if (!NSK_VERIFY(nsk_jvmti_init_MA(&callbacks)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t002/ma04t002a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t002/ma04t002a.cpp
index cd639c1fd78..0834d306a1c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t002/ma04t002a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t002/ma04t002a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,9 +39,9 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jobject testedObject = NULL;
-static jobject testedInstance = NULL;
-static jclass testedClass = NULL;
+static jobject testedObject = nullptr;
+static jobject testedInstance = nullptr;
+static jclass testedClass = nullptr;
 static int ObjectsCount = 0;
 
 /* ========================================================================== */
@@ -76,33 +76,33 @@ static int prepare(JNIEnv* jni) {
     const char* FIELD_SIGNATURE = "Ljava/lang/Object;";
     const char* INSTANCE_NAME = "testedInstance2";
     const char* INSTANCE_SIGNATURE = "Lnsk/jvmti/scenarios/multienv/MA04/ma04t002;";
-    jfieldID fid = NULL;
+    jfieldID fid = nullptr;
 
     NSK_DISPLAY0("Obtain tested object from a static field of debugee class\n");
 
     NSK_DISPLAY1("Find class: %s\n", CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (testedClass = jni->FindClass(CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = jni->FindClass(CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass) jni->NewGlobalRef(testedClass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass) jni->NewGlobalRef(testedClass)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY2("Find field: %s:%s\n", FIELD_NAME, FIELD_SIGNATURE);
     if (!NSK_JNI_VERIFY(jni, (fid =
-            jni->GetStaticFieldID(testedClass, FIELD_NAME, FIELD_SIGNATURE)) != NULL))
+            jni->GetStaticFieldID(testedClass, FIELD_NAME, FIELD_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->GetStaticObjectField(testedClass, fid)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->GetStaticObjectField(testedClass, fid)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY2("Find class instance: %s:%s\n",
         INSTANCE_NAME, INSTANCE_SIGNATURE);
     if (!NSK_JNI_VERIFY(jni, (fid =
-            jni->GetStaticFieldID(testedClass, INSTANCE_NAME, INSTANCE_SIGNATURE)) != NULL))
+            jni->GetStaticFieldID(testedClass, INSTANCE_NAME, INSTANCE_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (testedInstance =
-            jni->GetStaticObjectField(testedClass, fid)) != NULL))
+            jni->GetStaticObjectField(testedClass, fid)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -303,7 +303,7 @@ JNIEXPORT jint JNI_OnLoad_ma04t002a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
     jvmtiCapabilities caps;
 
@@ -315,7 +315,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -325,14 +325,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
     if (!NSK_VERIFY(nsk_jvmti_init_MA(&callbacks)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t003/ma04t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t003/ma04t003.cpp
index af2922e055b..d6eb01b18b8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t003/ma04t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t003/ma04t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,7 +39,7 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jobject testedObject = NULL;
+static jobject testedObject = nullptr;
 static int ObjectFreeEventsCount = 0;
 
 /* ========================================================================== */
@@ -82,24 +82,24 @@ static int prepare(JNIEnv* jni) {
     const char* CLASS_NAME = "nsk/jvmti/scenarios/multienv/MA04/ma04t003";
     const char* FIELD_NAME = "testedObject1";
     const char* FIELD_SIGNATURE = "Ljava/lang/Object;";
-    jclass cls = NULL;
-    jfieldID fid = NULL;
+    jclass cls = nullptr;
+    jfieldID fid = nullptr;
 
     NSK_DISPLAY0("Obtain tested object from a static field of debugee class\n");
 
     NSK_DISPLAY1("Find class: %s\n", CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY2("Find field: %s:%s\n", FIELD_NAME, FIELD_SIGNATURE);
     if (!NSK_JNI_VERIFY(jni, (fid =
-            jni->GetStaticFieldID(cls, FIELD_NAME, FIELD_SIGNATURE)) != NULL))
+            jni->GetStaticFieldID(cls, FIELD_NAME, FIELD_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->GetStaticObjectField(cls, fid)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->GetStaticObjectField(cls, fid)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewGlobalRef(testedObject)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewGlobalRef(testedObject)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -146,7 +146,7 @@ JNIEXPORT jint JNI_OnLoad_ma04t003(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
     jvmtiCapabilities caps;
 
@@ -158,7 +158,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -168,7 +168,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
@@ -177,10 +177,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_VERIFY(nsk_jvmti_init_MA(&callbacks)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, nullptr)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t003/ma04t003a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t003/ma04t003a.cpp
index 3df2bf2c0b9..5a42cd21e95 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t003/ma04t003a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA04/ma04t003/ma04t003a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,7 +39,7 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jobject testedObject = NULL;
+static jobject testedObject = nullptr;
 static int ObjectFreeEventsCount = 0;
 
 /* ========================================================================== */
@@ -82,24 +82,24 @@ static int prepare(JNIEnv* jni) {
     const char* CLASS_NAME = "nsk/jvmti/scenarios/multienv/MA04/ma04t003";
     const char* FIELD_NAME = "testedObject2";
     const char* FIELD_SIGNATURE = "Ljava/lang/Object;";
-    jclass cls = NULL;
-    jfieldID fid = NULL;
+    jclass cls = nullptr;
+    jfieldID fid = nullptr;
 
     NSK_DISPLAY0("Obtain tested object from a static field of debugee class\n");
 
     NSK_DISPLAY1("Find class: %s\n", CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY2("Find field: %s:%s\n", FIELD_NAME, FIELD_SIGNATURE);
     if (!NSK_JNI_VERIFY(jni, (fid =
-            jni->GetStaticFieldID(cls, FIELD_NAME, FIELD_SIGNATURE)) != NULL))
+            jni->GetStaticFieldID(cls, FIELD_NAME, FIELD_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->GetStaticObjectField(cls, fid)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->GetStaticObjectField(cls, fid)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewGlobalRef(testedObject)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedObject = jni->NewGlobalRef(testedObject)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -146,7 +146,7 @@ JNIEXPORT jint JNI_OnLoad_ma04t003a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
     jvmtiCapabilities caps;
 
@@ -158,7 +158,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -168,7 +168,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
@@ -177,10 +177,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_VERIFY(nsk_jvmti_init_MA(&callbacks)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, nullptr)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA05/ma05t001/ma05t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA05/ma05t001/ma05t001.cpp
index 6c07c02a5d1..c57c7cebb4d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA05/ma05t001/ma05t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA05/ma05t001/ma05t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,8 +38,8 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jmethodID method = NULL;
+static jthread thread = nullptr;
+static jmethodID method = nullptr;
 static int BreakpointEventsCount = 0;
 static int FramePopEventsCount = 0;
 
@@ -50,19 +50,19 @@ static int FramePopEventsCount = 0;
 static void JNICALL
 Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method, jlocation location) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     BreakpointEventsCount++;
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
     }
 
     NSK_DISPLAY2("Breakpoint event: %s%s\n", name, signature);
 
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 
     switch (BreakpointEventsCount) {
@@ -93,20 +93,20 @@ static void JNICALL
 FramePop(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method,
         jboolean wasPopedByException) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     FramePopEventsCount++;
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
     NSK_DISPLAY2("FramePop event: %s%s\n", name, signature);
 
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -115,8 +115,8 @@ FramePop(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
-    jclass klass = NULL;
+    jthread *threads = nullptr;
+    jclass klass = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -126,12 +126,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -141,11 +141,11 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
 
-        if (info.name != NULL) {
+        if (info.name != nullptr) {
             if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)info.name)))
                 return NSK_FALSE;
         }
@@ -155,29 +155,29 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threads)))
         return NSK_FALSE;
 
-    if (thread == NULL) {
+    if (thread == nullptr) {
         NSK_COMPLAIN0("Debuggee thread not found");
         return NSK_FALSE;
     }
 
-    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'checkPoint' */
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "checkPoint", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "checkPoint", "()V")) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JVMTI_VERIFY(jvmti->SetBreakpoint(method, 0)))
         return NSK_FALSE;
 
     /* enable events */
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr)))
         return NSK_FALSE;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, nullptr)))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -212,7 +212,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         nsk_jvmti_setFailStatus();
     }
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_FRAME_POP, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_FRAME_POP, nullptr)))
         nsk_jvmti_setFailStatus();
 
     NSK_TRACE(jvmti->ClearBreakpoint(method, 0));
@@ -237,7 +237,7 @@ JNIEXPORT jint JNI_OnLoad_ma05t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
     jvmtiCapabilities caps;
 
@@ -249,7 +249,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -258,7 +258,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_JVMTI_VERIFY(jvmti->AddCapabilities(&caps)))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA05/ma05t001/ma05t001a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA05/ma05t001/ma05t001a.cpp
index 785cdeb6018..19f6e52837e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA05/ma05t001/ma05t001a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA05/ma05t001/ma05t001a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,8 +38,8 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jmethodID midCheckPoint = NULL;
+static jthread thread = nullptr;
+static jmethodID midCheckPoint = nullptr;
 static int MethodEntryEventsCount = 0;
 static int FramePopEventsCount = 0;
 
@@ -50,23 +50,23 @@ static int FramePopEventsCount = 0;
 static void JNICALL
 MethodEntry(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     if (method != midCheckPoint)
         return;
 
     MethodEntryEventsCount++;
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
     NSK_DISPLAY2("MethodEntry event: %s%s\n", name, signature);
 
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 
     switch (MethodEntryEventsCount) {
@@ -82,7 +82,7 @@ MethodEntry(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
 
     case 3:
         NSK_DISPLAY0("Testcase #3: FramePop disabled in 2nd agent\n");
-        if (!NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_FRAME_POP, NULL)))
+        if (!NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_FRAME_POP, nullptr)))
             nsk_jvmti_setFailStatus();
         if (!NSK_JVMTI_VERIFY(jvmti_env->NotifyFramePop(thread, 0)))
             nsk_jvmti_setFailStatus();
@@ -99,20 +99,20 @@ static void JNICALL
 FramePop(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method,
         jboolean wasPopedByException) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     FramePopEventsCount++;
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
     NSK_DISPLAY2("FramePop event: %s%s\n", name, signature);
 
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 
     switch (MethodEntryEventsCount) {
@@ -142,8 +142,8 @@ FramePop(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
-    jclass klass = NULL;
+    jthread *threads = nullptr;
+    jclass klass = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -153,12 +153,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -168,11 +168,11 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
 
-        if (info.name != NULL) {
+        if (info.name != nullptr) {
             if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)info.name)))
                 return NSK_FALSE;
         }
@@ -182,26 +182,26 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threads)))
         return NSK_FALSE;
 
-    if (thread == NULL) {
+    if (thread == nullptr) {
         NSK_COMPLAIN0("Debuggee thread not found");
         return NSK_FALSE;
     }
 
-    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'checkPoint' */
-    if (!NSK_JNI_VERIFY(jni, (midCheckPoint = jni->GetMethodID(klass, "checkPoint", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (midCheckPoint = jni->GetMethodID(klass, "checkPoint", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* enable events */
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, nullptr)))
         return NSK_FALSE;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, nullptr)))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -233,7 +233,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     NSK_TRACE(jni->DeleteGlobalRef(thread));
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_METHOD_ENTRY, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_METHOD_ENTRY, nullptr)))
         nsk_jvmti_setFailStatus();
 
     if (!nsk_jvmti_resumeSync())
@@ -255,7 +255,7 @@ JNIEXPORT jint JNI_OnLoad_ma05t001a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
     jvmtiCapabilities caps;
 
@@ -267,7 +267,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -276,7 +276,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_JVMTI_VERIFY(jvmti->AddCapabilities(&caps)))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA06/ma06t001/ma06t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA06/ma06t001/ma06t001.cpp
index 812d8e09ab9..6d6be2d9b8a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA06/ma06t001/ma06t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA06/ma06t001/ma06t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,9 +38,9 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jclass testedClass = NULL;
+static jclass testedClass = nullptr;
 static jint klass_byte_count = 0;
-static unsigned char *klass_bytes = NULL;
+static unsigned char *klass_bytes = nullptr;
 static int magicIndex = 0;
 static int ClassFileLoadHookEventFlag = NSK_FALSE;
 
@@ -59,11 +59,11 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jint *new_class_data_len, unsigned char** new_class_data) {
     jint i;
 
-    if (name != NULL && (strcmp(name, CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, CLASS_NAME) == 0)) {
         ClassFileLoadHookEventFlag = NSK_TRUE;
         NSK_DISPLAY0("ClassFileLoadHook event\n");
 
-        if (class_being_redefined == NULL) {
+        if (class_being_redefined == nullptr) {
             /* sent by class load */
             if (!NSK_JVMTI_VERIFY(jvmti_env->Allocate(class_data_len, &klass_bytes)))
                 nsk_jvmti_setFailStatus();
@@ -93,10 +93,10 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
 
     NSK_DISPLAY1("Find class: %s\n", CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (testedClass = jni->FindClass(CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = jni->FindClass(CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass) jni->NewGlobalRef(testedClass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass) jni->NewGlobalRef(testedClass)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -107,7 +107,7 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
 static int redefine(jvmtiEnv* jvmti, jint value) {
     jvmtiClassDefinition class_def;
 
-    if (!NSK_VERIFY(klass_byte_count != 0 && klass_bytes != NULL))
+    if (!NSK_VERIFY(klass_byte_count != 0 && klass_bytes != nullptr))
         return NSK_FALSE;
 
     if (!NSK_VERIFY(magicIndex != 0))
@@ -178,7 +178,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         nsk_jvmti_setFailStatus();
     }
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         nsk_jvmti_setFailStatus();
 
     NSK_TRACE(jni->DeleteGlobalRef(testedClass));
@@ -202,7 +202,7 @@ JNIEXPORT jint JNI_OnLoad_ma06t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
     jvmtiCapabilities caps;
 
@@ -214,7 +214,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -222,7 +222,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_JVMTI_VERIFY(jvmti->AddCapabilities(&caps)))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
@@ -230,7 +230,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_VERIFY(nsk_jvmti_init_MA(&callbacks)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA06/ma06t001/ma06t001a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA06/ma06t001/ma06t001a.cpp
index 9d97aa5f2cb..daf92c53ac4 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA06/ma06t001/ma06t001a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA06/ma06t001/ma06t001a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,9 +38,9 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jclass testedClass = NULL;
+static jclass testedClass = nullptr;
 static jint klass_byte_count = 0;
-static unsigned char *klass_bytes = NULL;
+static unsigned char *klass_bytes = nullptr;
 static int magicIndex = 0;
 static int ClassFileLoadHookEventFlag = NSK_FALSE;
 
@@ -59,11 +59,11 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jint *new_class_data_len, unsigned char** new_class_data) {
     jint i;
 
-    if (name != NULL && (strcmp(name, CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, CLASS_NAME) == 0)) {
         ClassFileLoadHookEventFlag = NSK_TRUE;
         NSK_DISPLAY0("ClassFileLoadHook event\n");
 
-        if (class_being_redefined == NULL) {
+        if (class_being_redefined == nullptr) {
             /* sent by class load */
             if (!NSK_JVMTI_VERIFY(jvmti_env->Allocate(class_data_len, &klass_bytes)))
                 nsk_jvmti_setFailStatus();
@@ -93,10 +93,10 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
 
     NSK_DISPLAY1("Find class: %s\n", CLASS_NAME);
-    if (!NSK_JNI_VERIFY(jni, (testedClass = jni->FindClass(CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = jni->FindClass(CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass) jni->NewGlobalRef(testedClass)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (testedClass = (jclass) jni->NewGlobalRef(testedClass)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -107,7 +107,7 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
 static int redefine(jvmtiEnv* jvmti, jint value) {
     jvmtiClassDefinition class_def;
 
-    if (!NSK_VERIFY(klass_byte_count != 0 && klass_bytes != NULL))
+    if (!NSK_VERIFY(klass_byte_count != 0 && klass_bytes != nullptr))
         return NSK_FALSE;
 
     if (!NSK_VERIFY(magicIndex != 0))
@@ -178,7 +178,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         nsk_jvmti_setFailStatus();
     }
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         nsk_jvmti_setFailStatus();
 
     NSK_TRACE(jni->DeleteGlobalRef(testedClass));
@@ -202,7 +202,7 @@ JNIEXPORT jint JNI_OnLoad_ma06t001a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
     jvmtiCapabilities caps;
 
@@ -214,7 +214,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -222,7 +222,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_JVMTI_VERIFY(jvmti->AddCapabilities(&caps)))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
@@ -230,7 +230,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_VERIFY(nsk_jvmti_init_MA(&callbacks)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA07/ma07t001/ma07t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA07/ma07t001/ma07t001.cpp
index 0fa045ead94..cb21bce2ee7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA07/ma07t001/ma07t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA07/ma07t001/ma07t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,7 +39,7 @@ static jlong timeout = 0;
 
 /* test objects */
 static jint klass_byte_count = 0;
-static unsigned char *klass_bytes = NULL;
+static unsigned char *klass_bytes = nullptr;
 static int ClassFileLoadHookEventFlag = NSK_FALSE;
 
 const char* CLASS_NAME = "nsk/jvmti/scenarios/multienv/MA07/ma07t001a";
@@ -62,11 +62,11 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
     jint magicIndex = 0;
     jint i;
 
-    if (name != NULL && (strcmp(name, CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, CLASS_NAME) == 0)) {
         ClassFileLoadHookEventFlag = NSK_TRUE;
         NSK_DISPLAY0("ClassFileLoadHook event\n");
 
-        if (!NSK_VERIFY(class_being_redefined == NULL)) {
+        if (!NSK_VERIFY(class_being_redefined == nullptr)) {
             nsk_jvmti_setFailStatus();
             return;
         }
@@ -151,7 +151,7 @@ JNIEXPORT jint JNI_OnLoad_ma07t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
 
     NSK_DISPLAY0("Agent_OnLoad\n");
@@ -162,10 +162,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
@@ -173,7 +173,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_VERIFY(nsk_jvmti_init_MA(&callbacks)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA07/ma07t001/ma07t001a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA07/ma07t001/ma07t001a.cpp
index fe5965ba627..e5410c9394c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA07/ma07t001/ma07t001a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA07/ma07t001/ma07t001a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,7 +39,7 @@ static jlong timeout = 0;
 
 /* test objects */
 static jint klass_byte_count = 0;
-static unsigned char *klass_bytes = NULL;
+static unsigned char *klass_bytes = nullptr;
 static int ClassFileLoadHookEventFlag = NSK_FALSE;
 
 const char* CLASS_NAME = "nsk/jvmti/scenarios/multienv/MA07/ma07t001a";
@@ -62,11 +62,11 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
     jint magicIndex = 0;
     jint i;
 
-    if (name != NULL && (strcmp(name, CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, CLASS_NAME) == 0)) {
         ClassFileLoadHookEventFlag = NSK_TRUE;
         NSK_DISPLAY0("ClassFileLoadHook event\n");
 
-        if (!NSK_VERIFY(class_being_redefined == NULL)) {
+        if (!NSK_VERIFY(class_being_redefined == nullptr)) {
             nsk_jvmti_setFailStatus();
             return;
         }
@@ -152,7 +152,7 @@ JNIEXPORT jint JNI_OnLoad_ma07t001a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiEventCallbacks callbacks;
 
     NSK_DISPLAY0("Agent_OnLoad\n");
@@ -163,10 +163,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&callbacks, 0, sizeof(callbacks));
@@ -174,7 +174,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_VERIFY(nsk_jvmti_init_MA(&callbacks)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA08/ma08t001/ma08t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA08/ma08t001/ma08t001.cpp
index fd6d56029d3..375a1c944b2 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA08/ma08t001/ma08t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA08/ma08t001/ma08t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,9 +38,9 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jobject threadDeath = NULL;
-static jthread threadForStop = NULL;
-static jthread threadForInterrupt = NULL;
+static jobject threadDeath = nullptr;
+static jthread threadForStop = nullptr;
+static jthread threadForInterrupt = nullptr;
 
 /* ========================================================================== */
 
@@ -51,10 +51,10 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_DEATH_CTOR_NAME = "<init>";
     const char* THREAD_DEATH_CTOR_SIGNATURE = "()V";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
-    jclass cls = NULL;
-    jmethodID ctor = NULL;
+    jclass cls = nullptr;
+    jmethodID ctor = nullptr;
     int i;
 
     NSK_DISPLAY0("Prepare: find tested thread\n");
@@ -63,12 +63,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -78,7 +78,7 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL) {
+        if (info.name != nullptr) {
             if (strcmp(info.name, STOP_THREAD_NAME) == 0) {
                 threadForStop = threads[i];
             } else if (strcmp(info.name, INTERRUPT_THREAD_NAME) == 0) {
@@ -91,26 +91,26 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threads)))
         return NSK_FALSE;
 
-    if (threadForStop == NULL) {
+    if (threadForStop == nullptr) {
         NSK_COMPLAIN0("DebuggeeThreadForStop not found");
         return NSK_FALSE;
     }
 
-    if (threadForInterrupt == NULL) {
+    if (threadForInterrupt == nullptr) {
         NSK_COMPLAIN0("DebuggeeThreadForInterrupt not found");
         return NSK_FALSE;
     }
 
     NSK_DISPLAY0("Prepare: create new instance of ThreadDeath exception\n");
 
-    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (cls = jni->FindClass(THREAD_DEATH_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JNI_VERIFY(jni, (ctor =
-            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != NULL))
+            jni->GetMethodID(cls, THREAD_DEATH_CTOR_NAME, THREAD_DEATH_CTOR_SIGNATURE)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (threadDeath = jni->NewObject(cls, ctor)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (threadDeath = jni->NewObject(cls, ctor)) != nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -131,7 +131,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     NSK_DISPLAY0("Testcase #1: call StopThread\n");
-    if (!NSK_VERIFY(threadForStop != NULL)) {
+    if (!NSK_VERIFY(threadForStop != nullptr)) {
         nsk_jvmti_setFailStatus();
     } else {
         if (!NSK_JVMTI_VERIFY(jvmti->StopThread(threadForStop, threadDeath)))
@@ -139,7 +139,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     NSK_DISPLAY0("Testcase #2: call InterruptThread\n");
-    if (!NSK_VERIFY(threadForInterrupt != NULL)) {
+    if (!NSK_VERIFY(threadForInterrupt != nullptr)) {
         nsk_jvmti_setFailStatus();
     } else {
         if (!NSK_JVMTI_VERIFY(jvmti->InterruptThread(threadForInterrupt)))
@@ -171,7 +171,7 @@ JNIEXPORT jint JNI_OnLoad_ma08t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -183,10 +183,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA08/ma08t001/ma08t001a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA08/ma08t001/ma08t001a.cpp
index 2253e5a088d..c77b118941a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA08/ma08t001/ma08t001a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA08/ma08t001/ma08t001a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,8 +38,8 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jthread threadForStop = NULL;
-static jthread threadForInterrupt = NULL;
+static jthread threadForStop = nullptr;
+static jthread threadForInterrupt = nullptr;
 static int ThreadDeathFlag = 0;
 static int InterruptedExceptionFlag = 0;
 
@@ -53,20 +53,20 @@ static void JNICALL
 Exception(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jthread thread,
         jmethodID method, jlocation location, jobject exception,
         jmethodID catch_method, jlocation catch_location) {
-    jclass klass = NULL;
-    char *signature = NULL;
+    jclass klass = nullptr;
+    char *signature = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
-    if (!NSK_VERIFY(signature != NULL)) {
+    if (!NSK_VERIFY(signature != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -100,7 +100,7 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* STOP_THREAD_NAME = "DebuggeeThreadForStop";
     const char* INTERRUPT_THREAD_NAME = "DebuggeeThreadForInterrupt";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -110,12 +110,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -125,7 +125,7 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL) {
+        if (info.name != nullptr) {
             if (strcmp(info.name, STOP_THREAD_NAME) == 0) {
                 threadForStop = threads[i];
             } else if (strcmp(info.name, INTERRUPT_THREAD_NAME) == 0) {
@@ -138,24 +138,24 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threads)))
         return NSK_FALSE;
 
-    if (threadForStop == NULL) {
+    if (threadForStop == nullptr) {
         NSK_COMPLAIN0("DebuggeeThreadForStop not found");
         return NSK_FALSE;
     }
 
-    if (threadForInterrupt == NULL) {
+    if (threadForInterrupt == nullptr) {
         NSK_COMPLAIN0("DebuggeeThreadForInterrupt not found");
         return NSK_FALSE;
     }
 
-    if (!NSK_JNI_VERIFY(jni, (threadForStop = jni->NewGlobalRef(threadForStop)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (threadForStop = jni->NewGlobalRef(threadForStop)) != nullptr))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (threadForInterrupt = jni->NewGlobalRef(threadForInterrupt)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (threadForInterrupt = jni->NewGlobalRef(threadForInterrupt)) != nullptr))
         return NSK_FALSE;
 
     /* enable event */
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION, nullptr)))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -191,7 +191,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         nsk_jvmti_setFailStatus();
 
     /* disable event */
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_EXCEPTION, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_EXCEPTION, nullptr)))
         nsk_jvmti_setFailStatus();
 
     NSK_TRACE(jni->DeleteGlobalRef(threadForStop));
@@ -216,7 +216,7 @@ JNIEXPORT jint JNI_OnLoad_ma08t001a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -228,10 +228,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t001/ma10t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t001/ma10t001.cpp
index 330b7b713a6..5c45e75a167 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t001/ma10t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t001/ma10t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,10 +48,10 @@ static const char *testThreadName = "Debuggee Thread";
 
 void releaseThreadInfo(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jvmtiThreadInfo *info) {
     jvmti_env->Deallocate((unsigned char *)info->name);
-    if (info->thread_group != NULL) {
+    if (info->thread_group != nullptr) {
         jni_env->DeleteLocalRef(info->thread_group);
     }
-    if (info->context_class_loader != NULL) {
+    if (info->context_class_loader != nullptr) {
         jni_env->DeleteLocalRef(info->context_class_loader);
     }
 }
@@ -80,8 +80,8 @@ static void JNICALL
 Exception(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jthread thread,
         jmethodID method, jlocation location, jobject exception,
         jmethodID catch_method, jlocation catch_location) {
-    jclass klass = NULL;
-    char *signature = NULL;
+    jclass klass = nullptr;
+    char *signature = nullptr;
 
     if (!isTestThread("Exception", jvmti_env, jni_env, thread)) {
         return;
@@ -89,24 +89,24 @@ Exception(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jthread thread,
 
     ExceptionEventsCount++;
 
-    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY1("Exception event: %s\n", signature);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
 void JNICALL
 ExceptionCatch(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jthread thread,
         jmethodID method, jlocation location, jobject exception) {
-    jclass klass = NULL;
-    char *signature = NULL;
+    jclass klass = nullptr;
+    char *signature = nullptr;
 
     if (!isTestThread("ExceptionCatch", jvmti_env, jni_env, thread)) {
         return;
@@ -114,16 +114,16 @@ ExceptionCatch(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jthread thread,
 
     ExceptionCatchEventsCount++;
 
-    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY1("ExceptionCatch event: %s\n", signature);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -136,9 +136,9 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     if (!nsk_jvmti_waitForSync(timeout))
         return;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION, nullptr)))
         nsk_jvmti_setFailStatus();
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION_CATCH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION_CATCH, nullptr)))
         nsk_jvmti_setFailStatus();
 
     /* resume debugee and wait for sync */
@@ -147,9 +147,9 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     if (!nsk_jvmti_waitForSync(timeout))
         return;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_EXCEPTION, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_EXCEPTION, nullptr)))
         nsk_jvmti_setFailStatus();
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_EXCEPTION_CATCH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_EXCEPTION_CATCH, nullptr)))
         nsk_jvmti_setFailStatus();
 
     NSK_DISPLAY1("Exception events received: %d\n",
@@ -181,7 +181,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -193,10 +193,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t001/ma10t001a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t001/ma10t001a.cpp
index 29863b2c2c1..8ce327c18a0 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t001/ma10t001a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t001/ma10t001a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,42 +49,42 @@ static void JNICALL
 Exception(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jthread thread,
         jmethodID method, jlocation location, jobject exception,
         jmethodID catch_method, jlocation catch_location) {
-    jclass klass = NULL;
-    char *signature = NULL;
+    jclass klass = nullptr;
+    char *signature = nullptr;
 
     ExceptionEventsCount++;
 
-    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY1("Exception event: %s\n", signature);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
 void JNICALL
 ExceptionCatch(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jthread thread,
         jmethodID method, jlocation location, jobject exception) {
-    jclass klass = NULL;
-    char *signature = NULL;
+    jclass klass = nullptr;
+    char *signature = nullptr;
 
     ExceptionCatchEventsCount++;
 
-    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY1("ExceptionCatch event: %s\n", signature);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -132,7 +132,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t001a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -144,10 +144,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t002/ma10t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t002/ma10t002.cpp
index c9b34e0eb49..3e9e15d92f1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t002/ma10t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t002/ma10t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
+static jthread thread = nullptr;
 
 /* event counts */
 static int MethodEntryEventsCount = 0;
@@ -50,18 +50,18 @@ static int MethodEntryEventsCount = 0;
 static void JNICALL
 MethodEntry(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     MethodEntryEventsCount++;
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY2("MethodEntry event: %s%s\n", name, signature);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -70,7 +70,7 @@ MethodEntry(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -80,12 +80,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -95,12 +95,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
 
-    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != nullptr))
         return NSK_FALSE;
 
     /* deallocate threads list */
@@ -159,7 +159,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t002(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -171,10 +171,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t002/ma10t002a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t002/ma10t002a.cpp
index e8256ff6dc1..9bf090dbbc4 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t002/ma10t002a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t002/ma10t002a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -47,18 +47,18 @@ static int MethodEntryEventsCount = 0;
 static void JNICALL
 MethodEntry(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     MethodEntryEventsCount++;
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY2("MethodEntry event: %s%s\n", name, signature);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -101,7 +101,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t002a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -113,10 +113,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t003/ma10t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t003/ma10t003.cpp
index 2b75f45a6ae..78857457350 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t003/ma10t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t003/ma10t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
+static jthread thread = nullptr;
 
 /* event counts */
 static int MethodExitEventsCount = 0;
@@ -51,18 +51,18 @@ static void JNICALL
 MethodExit(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method,
         jboolean was_poped_by_exception, jvalue return_value) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     MethodExitEventsCount++;
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY2("MethodExit event: %s%s\n", name, signature);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -71,7 +71,7 @@ MethodExit(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -81,12 +81,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -96,12 +96,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
 
-    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != nullptr))
         return NSK_FALSE;
 
     /* deallocate threads list */
@@ -160,7 +160,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t003(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -172,10 +172,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t003/ma10t003a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t003/ma10t003a.cpp
index 98a8f8287fb..356d71c7202 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t003/ma10t003a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t003/ma10t003a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,18 +48,18 @@ static void JNICALL
 MethodExit(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jthread thread, jmethodID method,
         jboolean was_poped_by_exception, jvalue return_value) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     MethodExitEventsCount++;
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY2("MethodExit event: %s%s\n", name, signature);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -102,7 +102,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t003a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -114,10 +114,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t004/ma10t004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t004/ma10t004.cpp
index 329da7c919c..578d167a15c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t004/ma10t004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t004/ma10t004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ extern "C" {
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
+static jthread thread = nullptr;
 
 /* event counts */
 static int SingleStepEventsCount = 0;
@@ -50,23 +50,23 @@ static int SingleStepEventsCount = 0;
 static void JNICALL
 SingleStep(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
         jmethodID method, jlocation location) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
     char buffer[32];
 
     SingleStepEventsCount++;
 
-    NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, NULL));
+    NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, nullptr));
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY3("SingleStep event: %s%s, location=%s\n", name, signature,
         jlong_to_string(location, buffer));
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -75,7 +75,7 @@ SingleStep(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -85,12 +85,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -100,12 +100,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
     }
 
-    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != nullptr))
         return NSK_FALSE;
 
     /* deallocate threads list */
@@ -164,7 +164,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t004(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -176,10 +176,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t004/ma10t004a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t004/ma10t004a.cpp
index 4f97e7c7926..15819c71e54 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t004/ma10t004a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t004/ma10t004a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -47,23 +47,23 @@ static int SingleStepEventsCount = 0;
 static void JNICALL
 SingleStep(jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread,
         jmethodID method, jlocation location) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
     char buffer[32];
 
     SingleStepEventsCount++;
 
-    NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, NULL));
+    NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, nullptr));
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY3("SingleStep event: %s%s, location=%s\n", name, signature,
         jlong_to_string(location, buffer));
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -106,7 +106,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t004a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -118,10 +118,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t005/ma10t005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t005/ma10t005.cpp
index 2f49fe219f4..c736ec86063 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t005/ma10t005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t005/ma10t005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,12 +52,12 @@ VMObjectAlloc(jvmtiEnv *jvmti_env, JNIEnv* jni_env,
 
     VMObjectAllocEventsCount++;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(object_klass, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(object_klass, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY2("VMObjectAlloc: \"%s\", size=%d\n", signature, size);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -94,7 +94,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t005(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -106,10 +106,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -123,7 +123,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_VERIFY(nsk_jvmti_init_MA(&callbacks)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t005/ma10t005a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t005/ma10t005a.cpp
index 418f082f280..592f9d6af07 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t005/ma10t005a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t005/ma10t005a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,12 +52,12 @@ VMObjectAlloc(jvmtiEnv *jvmti_env, JNIEnv* jni_env,
 
     VMObjectAllocEventsCount++;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(object_klass, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(object_klass, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY2("VMObjectAlloc: \"%s\", size=%d\n", signature, size);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -94,7 +94,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t005a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -106,10 +106,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t006/ma10t006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t006/ma10t006.cpp
index ac2d54a16ab..886675712c0 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t006/ma10t006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t006/ma10t006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,34 +49,34 @@ static void JNICALL
 CompiledMethodLoad(jvmtiEnv *jvmti_env, jmethodID method,
         jint code_size, const void* code_addr, jint map_length,
         const jvmtiAddrLocationMap* map, const void* compile_info) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     CompiledMethodLoadEventsCount++;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY3("CompiledMethodLoad event: %s%s (0x%p)\n",
         name, signature, code_addr);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
 static void JNICALL
 CompiledMethodUnload(jvmtiEnv *jvmti_env, jmethodID method,
         const void* code_addr) {
-    char *name = NULL;
-    char *sig = NULL;
+    char *name = nullptr;
+    char *sig = nullptr;
     jvmtiError err;
     CompiledMethodUnloadEventsCount++;
 
     NSK_DISPLAY0("CompiledMethodUnload event received\n");
     // Check for the case that the class has been unloaded
-    err = jvmti_env->GetMethodName(method, &name, &sig, NULL);
+    err = jvmti_env->GetMethodName(method, &name, &sig, nullptr);
     if (err == JVMTI_ERROR_NONE) {
         NSK_DISPLAY3("for: \tmethod: name=\"%s\" signature=\"%s\"\n\tnative address=0x%p\n",
           name, sig, code_addr);
@@ -127,7 +127,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t006(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -139,10 +139,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -157,9 +157,9 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_VERIFY(nsk_jvmti_init_MA(&callbacks)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, nullptr)))
         return JNI_ERR;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_UNLOAD, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_UNLOAD, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t006/ma10t006a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t006/ma10t006a.cpp
index 2ddf7ec6d9c..96993ef79cc 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t006/ma10t006a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t006/ma10t006a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,35 +49,35 @@ static void JNICALL
 CompiledMethodLoad(jvmtiEnv *jvmti_env, jmethodID method,
         jint code_size, const void* code_addr, jint map_length,
         const jvmtiAddrLocationMap* map, const void* compile_info) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     CompiledMethodLoadEventsCount++;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY3("CompiledMethodLoad event: %s%s (0x%p)\n",
         name, signature, code_addr);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
 static void JNICALL
 CompiledMethodUnload(jvmtiEnv *jvmti_env, jmethodID method,
         const void* code_addr) {
-    char *name = NULL;
-    char *sig = NULL;
+    char *name = nullptr;
+    char *sig = nullptr;
     jvmtiError err;
 
     CompiledMethodUnloadEventsCount++;
 
     NSK_DISPLAY0("CompiledMethodUnload event received\n");
     // Check for the case that the class has been unloaded
-    err = jvmti_env->GetMethodName(method, &name, &sig, NULL);
+    err = jvmti_env->GetMethodName(method, &name, &sig, nullptr);
     if (err == JVMTI_ERROR_NONE) {
         NSK_DISPLAY3("for: \tmethod: name=\"%s\" signature=\"%s\"\n\tnative address=0x%p\n",
           name, sig, code_addr);
@@ -124,7 +124,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t006a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -136,10 +136,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t007/ma10t007.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t007/ma10t007.cpp
index cee84708ed6..4f94aa4c430 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t007/ma10t007.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t007/ma10t007.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -95,7 +95,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t007(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -107,10 +107,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -125,9 +125,9 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_VERIFY(nsk_jvmti_init_MA(&callbacks)))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, nullptr)))
         return JNI_ERR;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t007/ma10t007a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t007/ma10t007a.cpp
index e86e00fbc23..ebd5a6569d9 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t007/ma10t007a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t007/ma10t007a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -95,7 +95,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t007a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -107,10 +107,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t008/ma10t008.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t008/ma10t008.cpp
index 449f94e64b0..ebf76643958 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t008/ma10t008.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t008/ma10t008.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -165,7 +165,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t008(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -177,10 +177,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -198,13 +198,13 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     /* enable events */
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, nullptr)))
         return JNI_ERR;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, nullptr)))
         return JNI_ERR;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAIT, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAIT, nullptr)))
         return JNI_ERR;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAITED, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAITED, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t008/ma10t008a.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t008/ma10t008a.cpp
index 9d4c0d81c07..9638dfdd48b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t008/ma10t008a.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/multienv/MA10/ma10t008/ma10t008a.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -165,7 +165,7 @@ JNIEXPORT jint JNI_OnLoad_ma10t008a(JavaVM *jvm, char *options, void *reserved)
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
 
@@ -177,10 +177,10 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP01/sp01t001/sp01t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP01/sp01t001/sp01t001.cpp
index f0f3bc4a0a3..d3779929295 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP01/sp01t001/sp01t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP01/sp01t001/sp01t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,8 +39,8 @@ extern "C" {
 #define THREADS_FIELD_SIG       "[L" THREAD_CLASS_NAME ";"
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* number of tested threads */
@@ -114,24 +114,24 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
  *    - make global refs
  */
 static int prepare() {
-    jclass debugeeClass = NULL;
-    jfieldID threadsFieldID = NULL;
-    jobjectArray threadsArray = NULL;
+    jclass debugeeClass = nullptr;
+    jfieldID threadsFieldID = nullptr;
+    jobjectArray threadsArray = nullptr;
     jsize threadsArrayLength = 0;
     jsize i;
 
     /* find debugee class */
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     /* find static field with threads array */
     if (!NSK_JNI_VERIFY(jni, (threadsFieldID =
-            jni->GetStaticFieldID(debugeeClass, THREADS_FIELD_NAME, THREADS_FIELD_SIG)) != NULL))
+            jni->GetStaticFieldID(debugeeClass, THREADS_FIELD_NAME, THREADS_FIELD_SIG)) != nullptr))
         return NSK_FALSE;
 
     /* get threads array from static field */
     if (!NSK_JNI_VERIFY(jni, (threadsArray = (jobjectArray)
-            jni->GetStaticObjectField(debugeeClass, threadsFieldID)) != NULL))
+            jni->GetStaticObjectField(debugeeClass, threadsFieldID)) != nullptr))
         return NSK_FALSE;
 
     /* check array length */
@@ -142,14 +142,14 @@ static int prepare() {
     /* get each thread from array */
     for (i = 0; i < THREADS_COUNT; i++) {
         if (!NSK_JNI_VERIFY(jni, (threadsList[i] = (jthread)
-                jni->GetObjectArrayElement(threadsArray, i)) != NULL))
+                jni->GetObjectArrayElement(threadsArray, i)) != nullptr))
             return NSK_FALSE;
     }
 
     /* make global references to threads */
     for (i = 0; i < THREADS_COUNT; i++) {
         if (!NSK_JNI_VERIFY(jni, (threadsList[i] = (jthread)
-                jni->NewGlobalRef(threadsList[i])) != NULL))
+                jni->NewGlobalRef(threadsList[i])) != nullptr))
             return NSK_FALSE;
     }
 
@@ -260,11 +260,11 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP01/sp01t002/sp01t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP01/sp01t002/sp01t002.cpp
index 99b3dcc7a38..4fe02129060 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP01/sp01t002/sp01t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP01/sp01t002/sp01t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* number of tested threads */
@@ -142,7 +142,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
  *    - make global refs
  */
 static int prepare() {
-    jthread *allThreadsList = NULL;
+    jthread *allThreadsList = nullptr;
     jint allThreadsCount = 0;
     int found = 0;
     int i;
@@ -151,21 +151,21 @@ static int prepare() {
 
     /* clean threads list */
     for (i = 0; i < THREADS_COUNT; i++) {
-        threadsList[i] = NULL;
+        threadsList[i] = nullptr;
     }
 
     /* get all live threads */
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&allThreadsCount, &allThreadsList)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != NULL))
+    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != nullptr))
         return NSK_FALSE;
 
     /* find tested threads */
     for (i = 0; i < allThreadsCount; i++) {
         jvmtiThreadInfo threadInfo;
 
-        if (!NSK_VERIFY(allThreadsList[i] != NULL))
+        if (!NSK_VERIFY(allThreadsList[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread name (info) */
@@ -173,7 +173,7 @@ static int prepare() {
             return NSK_FALSE;
 
         /* find by name */
-        if (threadInfo.name != NULL) {
+        if (threadInfo.name != nullptr) {
             int j;
 
             for (j = 0; j < THREADS_COUNT; j++) {
@@ -193,7 +193,7 @@ static int prepare() {
     /* check if all tested threads found */
     found = 0;
     for (i = 0; i < THREADS_COUNT; i++) {
-        if (threadsList[i] == NULL) {
+        if (threadsList[i] == nullptr) {
             NSK_COMPLAIN2("Not found tested thread #%d (%s)\n", i, threadsName[i]);
         } else {
             found++;
@@ -205,7 +205,7 @@ static int prepare() {
 
     /* make global refs */
     for (i = 0; i < THREADS_COUNT; i++) {
-        if (!NSK_JNI_VERIFY(jni, (threadsList[i] = jni->NewGlobalRef(threadsList[i])) != NULL))
+        if (!NSK_JNI_VERIFY(jni, (threadsList[i] = jni->NewGlobalRef(threadsList[i])) != nullptr))
             return NSK_FALSE;
     }
 
@@ -434,7 +434,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -447,7 +447,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP01/sp01t003/sp01t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP01/sp01t003/sp01t003.cpp
index 814b4bf3a1e..504f965adca 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP01/sp01t003/sp01t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP01/sp01t003/sp01t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* number of tested threads */
@@ -142,7 +142,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
  *    - make global refs
  */
 static int prepare() {
-    jthread *allThreadsList = NULL;
+    jthread *allThreadsList = nullptr;
     jint allThreadsCount = 0;
     int found = 0;
     int i;
@@ -151,21 +151,21 @@ static int prepare() {
 
     /* clean threads list */
     for (i = 0; i < THREADS_COUNT; i++) {
-        threadsList[i] = NULL;
+        threadsList[i] = nullptr;
     }
 
     /* get all live threads */
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&allThreadsCount, &allThreadsList)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != NULL))
+    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != nullptr))
         return NSK_FALSE;
 
     /* find tested threads */
     for (i = 0; i < allThreadsCount; i++) {
         jvmtiThreadInfo threadInfo;
 
-        if (!NSK_VERIFY(allThreadsList[i] != NULL))
+        if (!NSK_VERIFY(allThreadsList[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread name (info) */
@@ -173,7 +173,7 @@ static int prepare() {
             return NSK_FALSE;
 
         /* find by name */
-        if (threadInfo.name != NULL) {
+        if (threadInfo.name != nullptr) {
             int j;
 
             for (j = 0; j < THREADS_COUNT; j++) {
@@ -193,7 +193,7 @@ static int prepare() {
     /* check if all tested threads found */
     found = 0;
     for (i = 0; i < THREADS_COUNT; i++) {
-        if (threadsList[i] == NULL) {
+        if (threadsList[i] == nullptr) {
             NSK_COMPLAIN2("Not found tested thread #%d (%s)\n", i, threadsName[i]);
         } else {
             found++;
@@ -205,7 +205,7 @@ static int prepare() {
 
     /* make global refs */
     for (i = 0; i < THREADS_COUNT; i++) {
-        if (!NSK_JNI_VERIFY(jni, (threadsList[i] = jni->NewGlobalRef(threadsList[i])) != NULL))
+        if (!NSK_JNI_VERIFY(jni, (threadsList[i] = jni->NewGlobalRef(threadsList[i])) != nullptr))
             return NSK_FALSE;
     }
 
@@ -445,7 +445,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -458,7 +458,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t001/sp02t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t001/sp02t001.cpp
index 491d7f04928..9dc696c7d88 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t001/sp02t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t001/sp02t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* constants */
@@ -50,12 +50,12 @@ typedef struct {
 
 /* descriptions of tested threads */
 static ThreadDesc threadsDesc[THREADS_COUNT] = {
-    { "threadRunning", 2, NULL },
-    { "threadEntering", 2, NULL },
-    { "threadWaiting", 2, NULL },
-    { "threadSleeping", 2, NULL },
-    { "threadRunningInterrupted", 2, NULL },
-    { "threadRunningNative", 2, NULL }
+    { "threadRunning", 2, nullptr },
+    { "threadEntering", 2, nullptr },
+    { "threadWaiting", 2, nullptr },
+    { "threadSleeping", 2, nullptr },
+    { "threadRunningInterrupted", 2, nullptr },
+    { "threadRunningNative", 2, nullptr }
 };
 
 /* ============================================================================= */
@@ -123,7 +123,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
  *    - make global refs
  */
 static int prepare() {
-    jthread *allThreadsList = NULL;
+    jthread *allThreadsList = nullptr;
     jint allThreadsCount = 0;
     int found = 0;
     int i;
@@ -132,21 +132,21 @@ static int prepare() {
 
     /* clean threads list */
     for (i = 0; i < THREADS_COUNT; i++) {
-        threadsDesc[i].thread = (jthread)NULL;
+        threadsDesc[i].thread = (jthread)nullptr;
     }
 
     /* get all live threads */
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&allThreadsCount, &allThreadsList)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != NULL))
+    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != nullptr))
         return NSK_FALSE;
 
     /* find tested threads */
     for (i = 0; i < allThreadsCount; i++) {
         jvmtiThreadInfo threadInfo;
 
-        if (!NSK_VERIFY(allThreadsList[i] != NULL))
+        if (!NSK_VERIFY(allThreadsList[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread name (info) */
@@ -154,7 +154,7 @@ static int prepare() {
             return NSK_FALSE;
 
         /* find by name */
-        if (threadInfo.name != NULL) {
+        if (threadInfo.name != nullptr) {
             int j;
 
             for (j = 0; j < THREADS_COUNT; j++) {
@@ -174,7 +174,7 @@ static int prepare() {
     /* check if all tested threads found */
     found = 0;
     for (i = 0; i < THREADS_COUNT; i++) {
-        if (threadsDesc[i].thread == NULL) {
+        if (threadsDesc[i].thread == nullptr) {
             NSK_COMPLAIN2("Not found tested thread #%d (%s)\n", i, threadsDesc[i].threadName);
         } else {
             found++;
@@ -187,7 +187,7 @@ static int prepare() {
     /* make global refs */
     for (i = 0; i < THREADS_COUNT; i++) {
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].thread = (jthread)
-                jni->NewGlobalRef(threadsDesc[i].thread)) != NULL))
+                jni->NewGlobalRef(threadsDesc[i].thread)) != nullptr))
             return NSK_FALSE;
     }
 
@@ -356,7 +356,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -369,7 +369,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t002/sp02t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t002/sp02t002.cpp
index 00aa34f3fdb..eadc3fa3cc6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t002/sp02t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t002/sp02t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* constants */
@@ -54,12 +54,12 @@ typedef struct {
 
 /* descriptions of tested threads */
 static ThreadDesc threadsDesc[THREADS_COUNT] = {
-    { "threadRunning", "testedMethod", "()V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION },
-    { "threadEntering", "testedMethod", "()V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION },
-    { "threadWaiting", "testedMethod", "()V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION },
-    { "threadSleeping", "testedMethod", "()V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION },
-    { "threadRunningInterrupted", "testedMethod", "()V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION },
-    { "threadRunningNative", "testedMethod", "()V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION }
+    { "threadRunning", "testedMethod", "()V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION },
+    { "threadEntering", "testedMethod", "()V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION },
+    { "threadWaiting", "testedMethod", "()V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION },
+    { "threadSleeping", "testedMethod", "()V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION },
+    { "threadRunningInterrupted", "testedMethod", "()V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION },
+    { "threadRunningNative", "testedMethod", "()V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION }
 };
 
 /* indexes of known threads */
@@ -143,7 +143,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
  *    - make global refs
  */
 static int prepare() {
-    jthread *allThreadsList = NULL;
+    jthread *allThreadsList = nullptr;
     jint allThreadsCount = 0;
     int found = 0;
     int i;
@@ -152,8 +152,8 @@ static int prepare() {
 
     /* clean threads list */
     for (i = 0; i < THREADS_COUNT; i++) {
-        threadsDesc[i].thread = (jthread)NULL;
-        threadsDesc[i].method = (jmethodID)NULL;
+        threadsDesc[i].thread = (jthread)nullptr;
+        threadsDesc[i].method = (jmethodID)nullptr;
         threadsDesc[i].location = NSK_JVMTI_INVALID_JLOCATION;
     }
 
@@ -161,14 +161,14 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&allThreadsCount, &allThreadsList)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != NULL))
+    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != nullptr))
         return NSK_FALSE;
 
     /* find tested threads */
     for (i = 0; i < allThreadsCount; i++) {
         jvmtiThreadInfo threadInfo;
 
-        if (!NSK_VERIFY(allThreadsList[i] != NULL))
+        if (!NSK_VERIFY(allThreadsList[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread name (info) */
@@ -176,7 +176,7 @@ static int prepare() {
             return NSK_FALSE;
 
         /* find by name */
-        if (threadInfo.name != NULL) {
+        if (threadInfo.name != nullptr) {
             int j;
 
             for (j = 0; j < THREADS_COUNT; j++) {
@@ -196,7 +196,7 @@ static int prepare() {
     /* check if all tested threads found */
     found = 0;
     for (i = 0; i < THREADS_COUNT; i++) {
-        if (threadsDesc[i].thread == NULL) {
+        if (threadsDesc[i].thread == nullptr) {
             NSK_COMPLAIN2("Not found tested thread #%d (%s)\n", i, threadsDesc[i].threadName);
         } else {
             found++;
@@ -211,11 +211,11 @@ static int prepare() {
     for (i = 0; i < THREADS_COUNT; i++) {
         /* get thread class */
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].cls =
-                jni->GetObjectClass(threadsDesc[i].thread)) != NULL))
+                jni->GetObjectClass(threadsDesc[i].thread)) != nullptr))
             return NSK_FALSE;
         /* get frame method */
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].method =
-                jni->GetMethodID(threadsDesc[i].cls, threadsDesc[i].methodName, threadsDesc[i].methodSig)) != NULL))
+                jni->GetMethodID(threadsDesc[i].cls, threadsDesc[i].methodName, threadsDesc[i].methodSig)) != nullptr))
             return NSK_FALSE;
 
         NSK_DISPLAY4("    thread #%d (%s): %p (%s)\n",
@@ -227,10 +227,10 @@ static int prepare() {
     /* make global refs */
     for (i = 0; i < THREADS_COUNT; i++) {
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].thread = (jthread)
-                jni->NewGlobalRef(threadsDesc[i].thread)) != NULL))
+                jni->NewGlobalRef(threadsDesc[i].thread)) != nullptr))
             return NSK_FALSE;
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].cls = (jclass)
-                jni->NewGlobalRef(threadsDesc[i].cls)) != NULL))
+                jni->NewGlobalRef(threadsDesc[i].cls)) != nullptr))
             return NSK_FALSE;
     }
 
@@ -313,8 +313,8 @@ static int checkThreads(int suspended, const char* kind) {
                                         j, (void*)frameStack[j].method,
                                         (long)frameStack[j].location);
             /* check frame method */
-            if (frameStack[j].method == NULL) {
-                NSK_COMPLAIN3("NULL methodID in stack for %s thread #%d (%s)\n",
+            if (frameStack[j].method == nullptr) {
+                NSK_COMPLAIN3("null methodID in stack for %s thread #%d (%s)\n",
                             kind, i, threadsDesc[i].threadName);
                 nsk_jvmti_setFailStatus();
             } else if (frameStack[j].method == threadsDesc[i].method) {
@@ -419,7 +419,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -432,7 +432,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t003/sp02t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t003/sp02t003.cpp
index 20c758aed6c..0916f392a8b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t003/sp02t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t003/sp02t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* constants */
@@ -54,12 +54,12 @@ typedef struct {
 
 /* descriptions of tested threads */
 static ThreadDesc threadsDesc[THREADS_COUNT] = {
-    { "threadRunning", "testedMethod", "()V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION },
-    { "threadEntering", "testedMethod", "()V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION },
-    { "threadWaiting", "testedMethod", "()V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION },
-    { "threadSleeping", "testedMethod", "()V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION },
-    { "threadRunningInterrupted", "testedMethod", "()V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION },
-    { "threadRunningNative", "testedMethod", "()V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION }
+    { "threadRunning", "testedMethod", "()V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION },
+    { "threadEntering", "testedMethod", "()V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION },
+    { "threadWaiting", "testedMethod", "()V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION },
+    { "threadSleeping", "testedMethod", "()V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION },
+    { "threadRunningInterrupted", "testedMethod", "()V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION },
+    { "threadRunningNative", "testedMethod", "()V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION }
 };
 
 /* indexes of known threads */
@@ -144,7 +144,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
  *    - make global refs
  */
 static int prepare() {
-    jthread *allThreadsList = NULL;
+    jthread *allThreadsList = nullptr;
     jint allThreadsCount = 0;
     int found = 0;
     int i;
@@ -153,8 +153,8 @@ static int prepare() {
 
     /* clean threads list */
     for (i = 0; i < THREADS_COUNT; i++) {
-        threadsDesc[i].thread = (jthread)NULL;
-        threadsDesc[i].method = (jmethodID)NULL;
+        threadsDesc[i].thread = (jthread)nullptr;
+        threadsDesc[i].method = (jmethodID)nullptr;
         threadsDesc[i].location = NSK_JVMTI_INVALID_JLOCATION;
     }
 
@@ -162,14 +162,14 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&allThreadsCount, &allThreadsList)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != NULL))
+    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != nullptr))
         return NSK_FALSE;
 
     /* find tested threads */
     for (i = 0; i < allThreadsCount; i++) {
         jvmtiThreadInfo threadInfo;
 
-        if (!NSK_VERIFY(allThreadsList[i] != NULL))
+        if (!NSK_VERIFY(allThreadsList[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread name (info) */
@@ -177,7 +177,7 @@ static int prepare() {
             return NSK_FALSE;
 
         /* find by name */
-        if (threadInfo.name != NULL) {
+        if (threadInfo.name != nullptr) {
             int j;
 
             for (j = 0; j < THREADS_COUNT; j++) {
@@ -197,7 +197,7 @@ static int prepare() {
     /* check if all tested threads found */
     found = 0;
     for (i = 0; i < THREADS_COUNT; i++) {
-        if (threadsDesc[i].thread == NULL) {
+        if (threadsDesc[i].thread == nullptr) {
             NSK_COMPLAIN2("Not found tested thread #%d (%s)\n", i, threadsDesc[i].threadName);
         } else {
             found++;
@@ -212,11 +212,11 @@ static int prepare() {
     for (i = 0; i < THREADS_COUNT; i++) {
         /* get thread class */
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].cls =
-                jni->GetObjectClass(threadsDesc[i].thread)) != NULL))
+                jni->GetObjectClass(threadsDesc[i].thread)) != nullptr))
             return NSK_FALSE;
         /* get frame method */
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].method =
-                jni->GetMethodID(threadsDesc[i].cls, threadsDesc[i].methodName, threadsDesc[i].methodSig)) != NULL))
+                jni->GetMethodID(threadsDesc[i].cls, threadsDesc[i].methodName, threadsDesc[i].methodSig)) != nullptr))
             return NSK_FALSE;
 
         NSK_DISPLAY4("    thread #%d (%s): %p (%s)\n",
@@ -228,10 +228,10 @@ static int prepare() {
     /* make global refs */
     for (i = 0; i < THREADS_COUNT; i++) {
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].thread = (jthread)
-                jni->NewGlobalRef(threadsDesc[i].thread)) != NULL))
+                jni->NewGlobalRef(threadsDesc[i].thread)) != nullptr))
             return NSK_FALSE;
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].cls = (jclass)
-                jni->NewGlobalRef(threadsDesc[i].cls)) != NULL))
+                jni->NewGlobalRef(threadsDesc[i].cls)) != nullptr))
             return NSK_FALSE;
     }
 
@@ -297,7 +297,7 @@ static int checkThreads(int suspended, const char* kind) {
 
         found = 0;
         for (j = 0; j < frameStackSize; j++) {
-            jmethodID qMethod = (jmethodID)NULL;
+            jmethodID qMethod = (jmethodID)nullptr;
             jlocation qLocation = NSK_JVMTI_INVALID_JLOCATION;
 
             NSK_DISPLAY3("      %d frame: method: %p, location: %ld\n",
@@ -432,7 +432,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */    {
@@ -444,7 +444,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP03/sp03t001/sp03t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP03/sp03t001/sp03t001.cpp
index b0560a13a1f..8ce99cf73a1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP03/sp03t001/sp03t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP03/sp03t001/sp03t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* number of tested threads */
@@ -146,7 +146,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
  *    - make global refs
  */
 static int prepare() {
-    jthread *allThreadsList = NULL;
+    jthread *allThreadsList = nullptr;
     jint allThreadsCount = 0;
     int notfound = 0;
     int i, j;
@@ -156,14 +156,14 @@ static int prepare() {
     /* allocate and clean threads list */
     for (i = 0; i < THREADS_KINDS; i++) {
         threadsCounts[i] = 0;
-        threadsList[i] = NULL;
+        threadsList[i] = nullptr;
 
         if (!NSK_JVMTI_VERIFY(jvmti->Allocate(threadsCount * sizeof(jthread),
                                               (unsigned char**)&threadsList[i])))
             return NSK_FALSE;
 
         for (j = 0; j < threadsCount; j++) {
-            threadsList[i][j] = NULL;
+            threadsList[i][j] = nullptr;
         }
     }
 
@@ -171,14 +171,14 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&allThreadsCount, &allThreadsList)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != NULL))
+    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != nullptr))
         return NSK_FALSE;
 
     /* find tested threads */
     for (i = 0; i < allThreadsCount; i++) {
         jvmtiThreadInfo threadInfo;
 
-        if (!NSK_VERIFY(allThreadsList[i] != NULL))
+        if (!NSK_VERIFY(allThreadsList[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread name (info) */
@@ -186,7 +186,7 @@ static int prepare() {
             return NSK_FALSE;
 
         /* find by name */
-        if (threadInfo.name != NULL) {
+        if (threadInfo.name != nullptr) {
             for (j = 0; j < THREADS_KINDS; j++) {
                 if (strcmp(threadInfo.name, threadsName[j]) == 0) {
                     int k = threadsCounts[j];
@@ -222,7 +222,7 @@ static int prepare() {
     for (i = 0; i < THREADS_KINDS; i++) {
         for (j = 0; j < threadsCount; j++) {
             if (!NSK_JNI_VERIFY(jni, (threadsList[i][j] =
-                    jni->NewGlobalRef(threadsList[i][j])) != NULL))
+                    jni->NewGlobalRef(threadsList[i][j])) != nullptr))
                 return NSK_FALSE;
         }
     }
@@ -235,7 +235,7 @@ static int prepare() {
  */
 static int suspendThreadsList(int suspend) {
     jlong resultsSize = threadsCount * sizeof(jvmtiError);
-    jvmtiError* results = NULL;
+    jvmtiError* results = nullptr;
     const char* kind = (suspend ? "suspending" : "resuming");
     int i, j;
 
@@ -368,7 +368,7 @@ static int clean() {
     for (i = 0; i < THREADS_KINDS; i++) {
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threadsList[i])))
             return NSK_FALSE;
-        threadsList[i] = NULL;
+        threadsList[i] = nullptr;
     }
 
     return NSK_TRUE;
@@ -443,7 +443,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -456,7 +456,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP03/sp03t002/sp03t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP03/sp03t002/sp03t002.cpp
index 986d1113fc6..3001cb25902 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP03/sp03t002/sp03t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP03/sp03t002/sp03t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* number of tested threads */
@@ -149,7 +149,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
  *    - make global refs
  */
 static int prepare() {
-    jthread *allThreadsList = NULL;
+    jthread *allThreadsList = nullptr;
     jint allThreadsCount = 0;
     int notfound = 0;
     int i, j;
@@ -159,14 +159,14 @@ static int prepare() {
     /* allocate and clean threads list */
     for (i = 0; i < THREADS_KINDS; i++) {
         threadsCounts[i] = 0;
-        threadsList[i] = NULL;
+        threadsList[i] = nullptr;
 
         if (!NSK_JVMTI_VERIFY(jvmti->Allocate(threadsCount * sizeof(jthread),
                                               (unsigned char**)&threadsList[i])))
             return NSK_FALSE;
 
         for (j = 0; j < threadsCount; j++) {
-            threadsList[i][j] = NULL;
+            threadsList[i][j] = nullptr;
         }
     }
 
@@ -174,14 +174,14 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&allThreadsCount, &allThreadsList)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != NULL))
+    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != nullptr))
         return NSK_FALSE;
 
     /* find tested threads */
     for (i = 0; i < allThreadsCount; i++) {
         jvmtiThreadInfo threadInfo;
 
-        if (!NSK_VERIFY(allThreadsList[i] != NULL))
+        if (!NSK_VERIFY(allThreadsList[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread name (info) */
@@ -189,7 +189,7 @@ static int prepare() {
             return NSK_FALSE;
 
         /* find by name */
-        if (threadInfo.name != NULL) {
+        if (threadInfo.name != nullptr) {
             for (j = 0; j < THREADS_KINDS; j++) {
                 if (strcmp(threadInfo.name, threadsName[j]) == 0) {
                     int k = threadsCounts[j];
@@ -225,7 +225,7 @@ static int prepare() {
     for (i = 0; i < THREADS_KINDS; i++) {
         for (j = 0; j < threadsCount; j++) {
             if (!NSK_JNI_VERIFY(jni, (threadsList[i][j] =
-                    jni->NewGlobalRef(threadsList[i][j])) != NULL))
+                    jni->NewGlobalRef(threadsList[i][j])) != nullptr))
                 return NSK_FALSE;
         }
     }
@@ -238,7 +238,7 @@ static int prepare() {
  */
 static int suspendThreadsList(int suspend) {
     jlong resultsSize = threadsCount * sizeof(jvmtiError);
-    jvmtiError* results = NULL;
+    jvmtiError* results = nullptr;
     const char* kind = (suspend ? "suspending" : "resuming");
     int i, j;
 
@@ -371,7 +371,7 @@ static int clean() {
     for (i = 0; i < THREADS_KINDS; i++) {
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threadsList[i])))
             return NSK_FALSE;
-        threadsList[i] = NULL;
+        threadsList[i] = nullptr;
     }
 
     return NSK_TRUE;
@@ -446,7 +446,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -459,7 +459,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP04/sp04t001/sp04t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP04/sp04t001/sp04t001.cpp
index 45657600f9e..f05ae7e81f8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP04/sp04t001/sp04t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP04/sp04t001/sp04t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* number of tested threads */
@@ -146,7 +146,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
  *    - make global refs
  */
 static int prepare() {
-    jthread *allThreadsList = NULL;
+    jthread *allThreadsList = nullptr;
     jint allThreadsCount = 0;
     int notfound = 0;
     int i, j;
@@ -156,14 +156,14 @@ static int prepare() {
     /* allocate and clean threads list */
     for (i = 0; i < THREADS_KINDS; i++) {
         threadsCounts[i] = 0;
-        threadsList[i] = NULL;
+        threadsList[i] = nullptr;
 
         if (!NSK_JVMTI_VERIFY(jvmti->Allocate(threadsCount * sizeof(jthread),
                                               (unsigned char**)&threadsList[i])))
             return NSK_FALSE;
 
         for (j = 0; j < threadsCount; j++) {
-            threadsList[i][j] = NULL;
+            threadsList[i][j] = nullptr;
         }
     }
 
@@ -171,14 +171,14 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&allThreadsCount, &allThreadsList)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != NULL))
+    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != nullptr))
         return NSK_FALSE;
 
     /* find tested threads */
     for (i = 0; i < allThreadsCount; i++) {
         jvmtiThreadInfo threadInfo;
 
-        if (!NSK_VERIFY(allThreadsList[i] != NULL))
+        if (!NSK_VERIFY(allThreadsList[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread name (info) */
@@ -186,7 +186,7 @@ static int prepare() {
             return NSK_FALSE;
 
         /* find by name */
-        if (threadInfo.name != NULL) {
+        if (threadInfo.name != nullptr) {
             for (j = 0; j < THREADS_KINDS; j++) {
                 if (strcmp(threadInfo.name, threadsName[j]) == 0) {
                     int k = threadsCounts[j];
@@ -222,7 +222,7 @@ static int prepare() {
     for (i = 0; i < THREADS_KINDS; i++) {
         for (j = 0; j < threadsCount; j++) {
             if (!NSK_JNI_VERIFY(jni, (threadsList[i][j] =
-                    jni->NewGlobalRef(threadsList[i][j])) != NULL))
+                    jni->NewGlobalRef(threadsList[i][j])) != nullptr))
                 return NSK_FALSE;
         }
     }
@@ -235,7 +235,7 @@ static int prepare() {
  */
 static int suspendThreadsList(int suspend) {
     jlong resultsSize = threadsCount * sizeof(jvmtiError);
-    jvmtiError* results = NULL;
+    jvmtiError* results = nullptr;
     const char* kind = (suspend ? "suspending" : "resuming");
     int i, j;
 
@@ -368,7 +368,7 @@ static int clean() {
     for (i = 0; i < THREADS_KINDS; i++) {
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threadsList[i])))
             return NSK_FALSE;
-        threadsList[i] = NULL;
+        threadsList[i] = nullptr;
     }
 
     return NSK_TRUE;
@@ -443,7 +443,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -456,7 +456,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP04/sp04t002/sp04t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP04/sp04t002/sp04t002.cpp
index 5122bd4fe55..dcd2cdfb176 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP04/sp04t002/sp04t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP04/sp04t002/sp04t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* number of tested threads */
@@ -146,7 +146,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
  *    - make global refs
  */
 static int prepare() {
-    jthread *allThreadsList = NULL;
+    jthread *allThreadsList = nullptr;
     jint allThreadsCount = 0;
     int notfound = 0;
     int i, j;
@@ -156,14 +156,14 @@ static int prepare() {
     /* allocate and clean threads list */
     for (i = 0; i < THREADS_KINDS; i++) {
         threadsCounts[i] = 0;
-        threadsList[i] = NULL;
+        threadsList[i] = nullptr;
 
         if (!NSK_JVMTI_VERIFY(jvmti->Allocate(threadsCount * sizeof(jthread),
                                               (unsigned char**)&threadsList[i])))
             return NSK_FALSE;
 
         for (j = 0; j < threadsCount; j++) {
-            threadsList[i][j] = NULL;
+            threadsList[i][j] = nullptr;
         }
     }
 
@@ -171,14 +171,14 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&allThreadsCount, &allThreadsList)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != NULL))
+    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != nullptr))
         return NSK_FALSE;
 
     /* find tested threads */
     for (i = 0; i < allThreadsCount; i++) {
         jvmtiThreadInfo threadInfo;
 
-        if (!NSK_VERIFY(allThreadsList[i] != NULL))
+        if (!NSK_VERIFY(allThreadsList[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread name (info) */
@@ -186,7 +186,7 @@ static int prepare() {
             return NSK_FALSE;
 
         /* find by name */
-        if (threadInfo.name != NULL) {
+        if (threadInfo.name != nullptr) {
             for (j = 0; j < THREADS_KINDS; j++) {
                 if (strcmp(threadInfo.name, threadsName[j]) == 0) {
                     int k = threadsCounts[j];
@@ -222,7 +222,7 @@ static int prepare() {
     for (i = 0; i < THREADS_KINDS; i++) {
         for (j = 0; j < threadsCount; j++) {
             if (!NSK_JNI_VERIFY(jni, (threadsList[i][j] =
-                    jni->NewGlobalRef(threadsList[i][j])) != NULL))
+                    jni->NewGlobalRef(threadsList[i][j])) != nullptr))
                 return NSK_FALSE;
         }
     }
@@ -235,7 +235,7 @@ static int prepare() {
  */
 static int suspendThreadsList(int suspend) {
     jlong resultsSize = threadsCount * sizeof(jvmtiError);
-    jvmtiError* results = NULL;
+    jvmtiError* results = nullptr;
     const char* kind = (suspend ? "suspending" : "resuming");
     int i, j;
 
@@ -368,7 +368,7 @@ static int clean() {
     for (i = 0; i < THREADS_KINDS; i++) {
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threadsList[i])))
             return NSK_FALSE;
-        threadsList[i] = NULL;
+        threadsList[i] = nullptr;
     }
 
     return NSK_TRUE;
@@ -443,7 +443,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add specific capabilities for suspending thread */
@@ -456,7 +456,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP05/sp05t002/sp05t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP05/sp05t002/sp05t002.cpp
index 04a3b498e3f..94dfb9ead45 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP05/sp05t002/sp05t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP05/sp05t002/sp05t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,8 +38,8 @@ extern "C" {
 #define THREADS_FIELD_SIG       "[L" THREAD_CLASS_NAME ";"
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* number of tested threads and events */
@@ -143,7 +143,7 @@ static int enableEvents(jvmtiEventMode enable) {
     int i;
 
     for (i = 0; i < EVENTS_COUNT; i++) {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(enable, eventsList[i], NULL))) {
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(enable, eventsList[i], nullptr))) {
             nsk_jvmti_setFailStatus();
             return NSK_FALSE;
         }
@@ -159,24 +159,24 @@ static int enableEvents(jvmtiEventMode enable) {
  *    - enable events
  */
 static int prepare() {
-    jclass debugeeClass = NULL;
-    jfieldID threadsFieldID = NULL;
-    jobjectArray threadsArray = NULL;
+    jclass debugeeClass = nullptr;
+    jfieldID threadsFieldID = nullptr;
+    jobjectArray threadsArray = nullptr;
     jsize threadsArrayLength = 0;
     jsize i;
 
     /* find debugee class */
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     /* find static field with threads array */
     if (!NSK_JNI_VERIFY(jni, (threadsFieldID =
-            jni->GetStaticFieldID(debugeeClass, THREADS_FIELD_NAME, THREADS_FIELD_SIG)) != NULL))
+            jni->GetStaticFieldID(debugeeClass, THREADS_FIELD_NAME, THREADS_FIELD_SIG)) != nullptr))
         return NSK_FALSE;
 
     /* get threads array from static field */
     if (!NSK_JNI_VERIFY(jni, (threadsArray = (jobjectArray)
-            jni->GetStaticObjectField(debugeeClass, threadsFieldID)) != NULL))
+            jni->GetStaticObjectField(debugeeClass, threadsFieldID)) != nullptr))
         return NSK_FALSE;
 
     /* check array length */
@@ -187,14 +187,14 @@ static int prepare() {
     /* get each thread from array */
     for (i = 0; i < THREADS_COUNT; i++) {
         if (!NSK_JNI_VERIFY(jni, (threadsList[i] = (jthread)
-                jni->GetObjectArrayElement(threadsArray, i)) != NULL))
+                jni->GetObjectArrayElement(threadsArray, i)) != nullptr))
             return NSK_FALSE;
     }
 
     /* make global references to threads */
     for (i = 0; i < THREADS_COUNT; i++) {
         if (!NSK_JNI_VERIFY(jni, (threadsList[i] = (jthread)
-                jni->NewGlobalRef(threadsList[i])) != NULL))
+                jni->NewGlobalRef(threadsList[i])) != nullptr))
             return NSK_FALSE;
     }
 
@@ -279,8 +279,8 @@ JNIEXPORT void JNICALL
 callbackThreadStart(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
     int i;
 
-    /* check if thread is not NULL */
-    if (!NSK_VERIFY(thread != NULL)) {
+    /* check if thread is not nullptr */
+    if (!NSK_VERIFY(thread != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -306,8 +306,8 @@ JNIEXPORT void JNICALL
 callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
     int i;
 
-    /* check if thread is not NULL */
-    if (!NSK_VERIFY(thread != NULL)) {
+    /* check if thread is not nullptr */
+    if (!NSK_VERIFY(thread != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -388,7 +388,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* set events callbacks */
@@ -402,7 +402,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP05/sp05t003/sp05t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP05/sp05t003/sp05t003.cpp
index 455f88db20c..392ff86cb21 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP05/sp05t003/sp05t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP05/sp05t003/sp05t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,8 +41,8 @@ extern "C" {
 #define TIMEOUT_DELTA  1000
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* number of tested threads and events */
@@ -100,7 +100,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
         {
             eventsStart = 0;
             if (!NSK_JVMTI_VERIFY(
-                    jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, NULL))) {
+                    jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, nullptr))) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -121,7 +121,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
             }
 
             if (!NSK_JVMTI_VERIFY(
-                    jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_THREAD_START, NULL))) {
+                    jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_THREAD_START, nullptr))) {
                 nsk_jvmti_setFailStatus();
             }
 
@@ -150,7 +150,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
         {
             eventsEnd = 0;
             if (!NSK_JVMTI_VERIFY(
-                    jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_END, NULL))) {
+                    jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_END, nullptr))) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
@@ -171,7 +171,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* agentJNI, void* arg) {
             }
 
             if (!NSK_JVMTI_VERIFY(
-                    jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_THREAD_END, NULL))) {
+                    jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_THREAD_END, nullptr))) {
                 nsk_jvmti_setFailStatus();
             }
 
@@ -231,24 +231,24 @@ static int resumeThreads(const char* kind) {
  *    - make global refs
  */
 static int prepare() {
-    jclass debugeeClass = NULL;
-    jfieldID threadsFieldID = NULL;
-    jobjectArray threadsArray = NULL;
+    jclass debugeeClass = nullptr;
+    jfieldID threadsFieldID = nullptr;
+    jobjectArray threadsArray = nullptr;
     jsize threadsArrayLength = 0;
     jsize i;
 
     /* find debugee class */
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr))
         return NSK_FALSE;
 
     /* find static field with threads array */
     if (!NSK_JNI_VERIFY(jni, (threadsFieldID =
-            jni->GetStaticFieldID(debugeeClass, THREADS_FIELD_NAME, THREADS_FIELD_SIG)) != NULL))
+            jni->GetStaticFieldID(debugeeClass, THREADS_FIELD_NAME, THREADS_FIELD_SIG)) != nullptr))
         return NSK_FALSE;
 
     /* get threads array from static field */
     if (!NSK_JNI_VERIFY(jni, (threadsArray = (jobjectArray)
-            jni->GetStaticObjectField(debugeeClass, threadsFieldID)) != NULL))
+            jni->GetStaticObjectField(debugeeClass, threadsFieldID)) != nullptr))
         return NSK_FALSE;
 
     /* check array length */
@@ -259,14 +259,14 @@ static int prepare() {
     /* get each thread from array */
     for (i = 0; i < THREADS_COUNT; i++) {
         if (!NSK_JNI_VERIFY(jni, (threadsList[i] = (jthread)
-                jni->GetObjectArrayElement(threadsArray, i)) != NULL))
+                jni->GetObjectArrayElement(threadsArray, i)) != nullptr))
             return NSK_FALSE;
     }
 
     /* make global references to threads */
     for (i = 0; i < THREADS_COUNT; i++) {
         if (!NSK_JNI_VERIFY(jni, (threadsList[i] = (jthread)
-                jni->NewGlobalRef(threadsList[i])) != NULL))
+                jni->NewGlobalRef(threadsList[i])) != nullptr))
             return NSK_FALSE;
     }
 
@@ -362,8 +362,8 @@ JNIEXPORT void JNICALL
 callbackThreadStart(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
     int i;
 
-    /* check if thread is not NULL */
-    if (!NSK_VERIFY(thread != NULL)) {
+    /* check if thread is not nullptr */
+    if (!NSK_VERIFY(thread != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -397,8 +397,8 @@ JNIEXPORT void JNICALL
 callbackThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
     int i;
 
-    /* check if thread is not NULL */
-    if (!NSK_VERIFY(thread != NULL)) {
+    /* check if thread is not nullptr */
+    if (!NSK_VERIFY(thread != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
@@ -487,7 +487,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* add capabilities for suspending thread */
@@ -510,7 +510,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t001/sp06t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t001/sp06t001.cpp
index 4f46a0fd08e..cde5a717c8c 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t001/sp06t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t001/sp06t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* constants */
@@ -62,12 +62,12 @@ typedef struct {
 
 /* descriptions of tested threads */
 static ThreadDesc threadsDesc[THREADS_COUNT] = {
-    { "threadRunning", "testedMethod", "(ZI)V", 2, NULL, NULL, NULL, NSK_FALSE },
-    { "threadEntering", "testedMethod", "(ZI)V", 2, NULL, NULL, NULL, NSK_FALSE },
-    { "threadWaiting", "testedMethod", "(ZI)V", 2, NULL, NULL, NULL, NSK_FALSE },
-    { "threadSleeping", "testedMethod", "(ZI)V", 2, NULL, NULL, NULL, NSK_FALSE },
-    { "threadRunningInterrupted", "testedMethod", "(ZI)V", 2, NULL, NULL, NULL, NSK_FALSE },
-    { "threadRunningNative", "testedMethod", "(ZI)V", 2, NULL, NULL, NULL, NSK_FALSE }
+    { "threadRunning", "testedMethod", "(ZI)V", 2, nullptr, nullptr, nullptr, NSK_FALSE },
+    { "threadEntering", "testedMethod", "(ZI)V", 2, nullptr, nullptr, nullptr, NSK_FALSE },
+    { "threadWaiting", "testedMethod", "(ZI)V", 2, nullptr, nullptr, nullptr, NSK_FALSE },
+    { "threadSleeping", "testedMethod", "(ZI)V", 2, nullptr, nullptr, nullptr, NSK_FALSE },
+    { "threadRunningInterrupted", "testedMethod", "(ZI)V", 2, nullptr, nullptr, nullptr, NSK_FALSE },
+    { "threadRunningNative", "testedMethod", "(ZI)V", 2, nullptr, nullptr, nullptr, NSK_FALSE }
 };
 
 /* indexes of known threads */
@@ -152,7 +152,7 @@ static int generateEvents() {
  *    - enable events
  */
 static int prepare() {
-    jthread *allThreadsList = NULL;
+    jthread *allThreadsList = nullptr;
     jint allThreadsCount = 0;
     int found = 0;
     int i;
@@ -161,8 +161,8 @@ static int prepare() {
 
     /* clean threads list */
     for (i = 0; i < THREADS_COUNT; i++) {
-        threadsDesc[i].thread = (jthread)NULL;
-        threadsDesc[i].method = (jmethodID)NULL;
+        threadsDesc[i].thread = (jthread)nullptr;
+        threadsDesc[i].method = (jmethodID)nullptr;
         threadsDesc[i].methodCompiled = NSK_FALSE;
     }
 
@@ -170,20 +170,20 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&allThreadsCount, &allThreadsList)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != NULL))
+    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != nullptr))
         return NSK_FALSE;
 
     /* find tested threads */
     for (i = 0; i < allThreadsCount; i++) {
         jvmtiThreadInfo threadInfo;
 
-        if (!NSK_VERIFY(allThreadsList[i] != NULL))
+        if (!NSK_VERIFY(allThreadsList[i] != nullptr))
             return NSK_FALSE;
 
         if (!NSK_JVMTI_VERIFY(jvmti->GetThreadInfo(allThreadsList[i], &threadInfo)))
             return NSK_FALSE;
 
-        if (threadInfo.name != NULL) {
+        if (threadInfo.name != nullptr) {
             int j;
 
             for (j = 0; j < THREADS_COUNT; j++) {
@@ -203,7 +203,7 @@ static int prepare() {
     /* check if all tested threads found */
     found = 0;
     for (i = 0; i < THREADS_COUNT; i++) {
-        if (threadsDesc[i].thread == NULL) {
+        if (threadsDesc[i].thread == nullptr) {
             NSK_COMPLAIN2("Not found tested thread #%d (%s)\n", i, threadsDesc[i].threadName);
         } else {
             found++;
@@ -218,11 +218,11 @@ static int prepare() {
     for (i = 0; i < THREADS_COUNT; i++) {
 
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].cls =
-                jni->GetObjectClass(threadsDesc[i].thread)) != NULL))
+                jni->GetObjectClass(threadsDesc[i].thread)) != nullptr))
             return NSK_FALSE;
 
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].method =
-                jni->GetMethodID(threadsDesc[i].cls, threadsDesc[i].methodName, threadsDesc[i].methodSig)) != NULL))
+                jni->GetMethodID(threadsDesc[i].cls, threadsDesc[i].methodName, threadsDesc[i].methodSig)) != nullptr))
             return NSK_FALSE;
 
         NSK_DISPLAY4("    thread #%d (%s): 0x%p (%s)\n",
@@ -234,15 +234,15 @@ static int prepare() {
     /* make global refs */
     for (i = 0; i < THREADS_COUNT; i++) {
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].thread = (jthread)
-                jni->NewGlobalRef(threadsDesc[i].thread)) != NULL))
+                jni->NewGlobalRef(threadsDesc[i].thread)) != nullptr))
             return NSK_FALSE;
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].cls = (jclass)
-                jni->NewGlobalRef(threadsDesc[i].cls)) != NULL))
+                jni->NewGlobalRef(threadsDesc[i].cls)) != nullptr))
             return NSK_FALSE;
     }
 
     NSK_DISPLAY0("Enable tested events\n");
-    if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL))
+    if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -343,7 +343,7 @@ static int clean() {
     int i;
 
     NSK_DISPLAY0("Disable events\n");
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL))
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Dispose global references to threads\n");
@@ -474,7 +474,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -495,7 +495,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
             return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t002/sp06t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t002/sp06t002.cpp
index d8600af0d67..43e55d53988 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t002/sp06t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t002/sp06t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* constants */
@@ -62,12 +62,12 @@ typedef struct {
 
 /* descriptions of tested threads */
 static ThreadDesc threadsDesc[THREADS_COUNT] = {
-    { "threadRunning", "testedMethod", "(ZI)V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
-    { "threadEntering", "testedMethod", "(ZI)V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
-    { "threadWaiting", "testedMethod", "(ZI)V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
-    { "threadSleeping", "testedMethod", "(ZI)V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
-    { "threadRunningInterrupted", "testedMethod", "(ZI)V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
-    { "threadRunningNative", "testedMethod", "(ZI)V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE }
+    { "threadRunning", "testedMethod", "(ZI)V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
+    { "threadEntering", "testedMethod", "(ZI)V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
+    { "threadWaiting", "testedMethod", "(ZI)V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
+    { "threadSleeping", "testedMethod", "(ZI)V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
+    { "threadRunningInterrupted", "testedMethod", "(ZI)V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
+    { "threadRunningNative", "testedMethod", "(ZI)V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE }
 };
 
 /* indexes of known threads */
@@ -160,7 +160,7 @@ static int generateEvents() {
  *    - enable events
  */
 static int prepare() {
-    jthread *allThreadsList = NULL;
+    jthread *allThreadsList = nullptr;
     jint allThreadsCount = 0;
     int found = 0;
     int i;
@@ -169,8 +169,8 @@ static int prepare() {
 
     /* clean threads list */
     for (i = 0; i < THREADS_COUNT; i++) {
-        threadsDesc[i].thread = (jthread)NULL;
-        threadsDesc[i].method = (jmethodID)NULL;
+        threadsDesc[i].thread = (jthread)nullptr;
+        threadsDesc[i].method = (jmethodID)nullptr;
         threadsDesc[i].location = NSK_JVMTI_INVALID_JLOCATION;
         threadsDesc[i].methodCompiled = NSK_FALSE;
     }
@@ -179,20 +179,20 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&allThreadsCount, &allThreadsList)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != NULL))
+    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != nullptr))
         return NSK_FALSE;
 
     /* find tested threads */
     for (i = 0; i < allThreadsCount; i++) {
         jvmtiThreadInfo threadInfo;
 
-        if (!NSK_VERIFY(allThreadsList[i] != NULL))
+        if (!NSK_VERIFY(allThreadsList[i] != nullptr))
             return NSK_FALSE;
 
         if (!NSK_JVMTI_VERIFY(jvmti->GetThreadInfo(allThreadsList[i], &threadInfo)))
             return NSK_FALSE;
 
-        if (threadInfo.name != NULL) {
+        if (threadInfo.name != nullptr) {
             int j;
 
             for (j = 0; j < THREADS_COUNT; j++) {
@@ -212,7 +212,7 @@ static int prepare() {
     /* check if all tested threads found */
     found = 0;
     for (i = 0; i < THREADS_COUNT; i++) {
-        if (threadsDesc[i].thread == NULL) {
+        if (threadsDesc[i].thread == nullptr) {
             NSK_COMPLAIN2("Not found tested thread #%d (%s)\n", i, threadsDesc[i].threadName);
         } else {
             found++;
@@ -227,11 +227,11 @@ static int prepare() {
     for (i = 0; i < THREADS_COUNT; i++) {
 
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].cls =
-                jni->GetObjectClass(threadsDesc[i].thread)) != NULL))
+                jni->GetObjectClass(threadsDesc[i].thread)) != nullptr))
             return NSK_FALSE;
 
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].method =
-                jni->GetMethodID(threadsDesc[i].cls, threadsDesc[i].methodName, threadsDesc[i].methodSig)) != NULL))
+                jni->GetMethodID(threadsDesc[i].cls, threadsDesc[i].methodName, threadsDesc[i].methodSig)) != nullptr))
             return NSK_FALSE;
 
         NSK_DISPLAY4("    thread #%d (%s): 0x%p (%s)\n",
@@ -243,15 +243,15 @@ static int prepare() {
     /* make global refs */
     for (i = 0; i < THREADS_COUNT; i++) {
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].thread = (jthread)
-                jni->NewGlobalRef(threadsDesc[i].thread)) != NULL))
+                jni->NewGlobalRef(threadsDesc[i].thread)) != nullptr))
             return NSK_FALSE;
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].cls = (jclass)
-                jni->NewGlobalRef(threadsDesc[i].cls)) != NULL))
+                jni->NewGlobalRef(threadsDesc[i].cls)) != nullptr))
             return NSK_FALSE;
     }
 
     NSK_DISPLAY0("Enable tested events\n");
-    if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL))
+    if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -337,8 +337,8 @@ static int checkThreads(int suspended, const char* kind0) {
                                         j, (void*)frameStack[j].method,
                                         (long)frameStack[j].location);
             /* check frame method */
-            if (frameStack[j].method == NULL) {
-                NSK_COMPLAIN3("NULL methodID in stack for %s thread #%d (%s)\n",
+            if (frameStack[j].method == nullptr) {
+                NSK_COMPLAIN3("null methodID in stack for %s thread #%d (%s)\n",
                             kind, i, threadsDesc[i].threadName);
                 nsk_jvmti_setFailStatus();
             } else if (frameStack[j].method == threadsDesc[i].method) {
@@ -372,7 +372,7 @@ static int clean() {
     int i;
 
     NSK_DISPLAY0("Disable events\n");
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL))
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Dispose global references to threads\n");
@@ -503,7 +503,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -524,7 +524,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
             return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t003/sp06t003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t003/sp06t003.cpp
index 5c06270a977..c396f623610 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t003/sp06t003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t003/sp06t003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,8 +32,8 @@ extern "C" {
 /* ============================================================================= */
 
 /* scaffold objects */
-static JNIEnv* jni = NULL;
-static jvmtiEnv *jvmti = NULL;
+static JNIEnv* jni = nullptr;
+static jvmtiEnv *jvmti = nullptr;
 static jlong timeout = 0;
 
 /* constants */
@@ -62,12 +62,12 @@ typedef struct {
 
 /* descriptions of tested threads */
 static ThreadDesc threadsDesc[THREADS_COUNT] = {
-    { "threadRunning", "testedMethod", "(ZI)V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
-    { "threadEntering", "testedMethod", "(ZI)V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
-    { "threadWaiting", "testedMethod", "(ZI)V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
-    { "threadSleeping", "testedMethod", "(ZI)V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
-    { "threadRunningInterrupted", "testedMethod", "(ZI)V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
-    { "threadRunningNative", "testedMethod", "(ZI)V", NULL, NULL, NULL, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE }
+    { "threadRunning", "testedMethod", "(ZI)V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
+    { "threadEntering", "testedMethod", "(ZI)V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
+    { "threadWaiting", "testedMethod", "(ZI)V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
+    { "threadSleeping", "testedMethod", "(ZI)V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
+    { "threadRunningInterrupted", "testedMethod", "(ZI)V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE },
+    { "threadRunningNative", "testedMethod", "(ZI)V", nullptr, nullptr, nullptr, NSK_JVMTI_INVALID_JLOCATION, NSK_FALSE }
 };
 
 /* indexes of known threads */
@@ -160,7 +160,7 @@ static int generateEvents() {
  *    - enable events
  */
 static int prepare() {
-    jthread *allThreadsList = NULL;
+    jthread *allThreadsList = nullptr;
     jint allThreadsCount = 0;
     int found = 0;
     int i;
@@ -169,8 +169,8 @@ static int prepare() {
 
     /* clean threads list */
     for (i = 0; i < THREADS_COUNT; i++) {
-        threadsDesc[i].thread = (jthread)NULL;
-        threadsDesc[i].method = (jmethodID)NULL;
+        threadsDesc[i].thread = (jthread)nullptr;
+        threadsDesc[i].method = (jmethodID)nullptr;
         threadsDesc[i].location = NSK_JVMTI_INVALID_JLOCATION;
         threadsDesc[i].methodCompiled = NSK_FALSE;
     }
@@ -179,20 +179,20 @@ static int prepare() {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&allThreadsCount, &allThreadsList)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != NULL))
+    if (!NSK_VERIFY(allThreadsCount > 0 && allThreadsList != nullptr))
         return NSK_FALSE;
 
     /* find tested threads */
     for (i = 0; i < allThreadsCount; i++) {
         jvmtiThreadInfo threadInfo;
 
-        if (!NSK_VERIFY(allThreadsList[i] != NULL))
+        if (!NSK_VERIFY(allThreadsList[i] != nullptr))
             return NSK_FALSE;
 
         if (!NSK_JVMTI_VERIFY(jvmti->GetThreadInfo(allThreadsList[i], &threadInfo)))
             return NSK_FALSE;
 
-        if (threadInfo.name != NULL) {
+        if (threadInfo.name != nullptr) {
             int j;
 
             for (j = 0; j < THREADS_COUNT; j++) {
@@ -212,7 +212,7 @@ static int prepare() {
     /* check if all tested threads found */
     found = 0;
     for (i = 0; i < THREADS_COUNT; i++) {
-        if (threadsDesc[i].thread == NULL) {
+        if (threadsDesc[i].thread == nullptr) {
             NSK_COMPLAIN2("Not found tested thread #%d (%s)\n", i, threadsDesc[i].threadName);
         } else {
             found++;
@@ -227,11 +227,11 @@ static int prepare() {
     for (i = 0; i < THREADS_COUNT; i++) {
 
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].cls =
-                jni->GetObjectClass(threadsDesc[i].thread)) != NULL))
+                jni->GetObjectClass(threadsDesc[i].thread)) != nullptr))
             return NSK_FALSE;
 
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].method =
-                jni->GetMethodID(threadsDesc[i].cls, threadsDesc[i].methodName, threadsDesc[i].methodSig)) != NULL))
+                jni->GetMethodID(threadsDesc[i].cls, threadsDesc[i].methodName, threadsDesc[i].methodSig)) != nullptr))
             return NSK_FALSE;
 
         NSK_DISPLAY4("    thread #%d (%s): 0x%p (%s)\n",
@@ -243,15 +243,15 @@ static int prepare() {
     /* make global refs */
     for (i = 0; i < THREADS_COUNT; i++) {
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].thread = (jthread)
-                jni->NewGlobalRef(threadsDesc[i].thread)) != NULL))
+                jni->NewGlobalRef(threadsDesc[i].thread)) != nullptr))
             return NSK_FALSE;
         if (!NSK_JNI_VERIFY(jni, (threadsDesc[i].cls = (jclass)
-                jni->NewGlobalRef(threadsDesc[i].cls)) != NULL))
+                jni->NewGlobalRef(threadsDesc[i].cls)) != nullptr))
             return NSK_FALSE;
     }
 
     NSK_DISPLAY0("Enable tested events\n");
-    if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, NULL))
+    if (!nsk_jvmti_enableEvents(JVMTI_ENABLE, EVENTS_COUNT, eventsList, nullptr))
         return NSK_FALSE;
 
     return NSK_TRUE;
@@ -320,7 +320,7 @@ static int checkThreads(int suspended, const char* kind0) {
 
         found = 0;
         for (j = 0; j < frameStackSize; j++) {
-            jmethodID qMethod = (jmethodID)NULL;
+            jmethodID qMethod = (jmethodID)nullptr;
             jlocation qLocation = NSK_JVMTI_INVALID_JLOCATION;
 
             NSK_DISPLAY3("      %d frame: method: 0x%p, location: %ld\n",
@@ -384,7 +384,7 @@ static int clean() {
     int i;
 
     NSK_DISPLAY0("Disable events\n");
-    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, NULL))
+    if (!nsk_jvmti_enableEvents(JVMTI_DISABLE, EVENTS_COUNT, eventsList, nullptr))
         return NSK_FALSE;
 
     NSK_DISPLAY0("Dispose global references to threads\n");
@@ -515,7 +515,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -536,7 +536,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
             return JNI_ERR;
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP07/sp07t001/sp07t001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP07/sp07t001/sp07t001.cpp
index 0a9125332e0..eaf871eb405 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP07/sp07t001/sp07t001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP07/sp07t001/sp07t001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,9 +41,9 @@ static const jlong SAMPLING_INTERVAL = 10;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jrawMonitorID waitLock = NULL;
-static jrawMonitorID frameLock = NULL;
+static jthread thread = nullptr;
+static jrawMonitorID waitLock = nullptr;
+static jrawMonitorID frameLock = nullptr;
 static int sampleCount = 0;
 static volatile int depth = 0;
 static jvmtiFrameInfo sampleStack[MAX_DEPTH];
@@ -55,7 +55,7 @@ static jvmtiFrameInfo frameBuffer[MAX_DEPTH];
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
     int i;
 
@@ -65,12 +65,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -80,11 +80,11 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
 
-        if (info.name != NULL) {
+        if (info.name != nullptr) {
             if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)info.name)))
                 return NSK_FALSE;
         }
@@ -94,7 +94,7 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threads)))
         return NSK_FALSE;
 
-    if (thread == NULL) {
+    if (thread == nullptr) {
         NSK_COMPLAIN0("Debuggee thread not found");
         return NSK_FALSE;
     }
@@ -123,27 +123,27 @@ static int wait_for(jvmtiEnv* jvmti, jlong millis) {
 
 static int displayFrameInfo(jvmtiEnv* jvmti, jint i) {
     char buffer[32];
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(frameBuffer[frameCount-1-i].method, &name, &signature, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(frameBuffer[frameCount-1-i].method, &name, &signature, nullptr)))
         return NSK_FALSE;
 
     NSK_DISPLAY4("    got[%d] method: %s%s, location: %s\n", i, name,
         signature, jlong_to_string(frameBuffer[frameCount-1-i].location, buffer));
-    if (name != NULL)
+    if (name != nullptr)
         jvmti->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti->Deallocate((unsigned char*)signature);
 
-    if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(sampleStack[i].method, &name, &signature, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(sampleStack[i].method, &name, &signature, nullptr)))
         return NSK_FALSE;
 
     NSK_DISPLAY4("    exp[%d] method: %s%s, location: %s\n", i, name,
         signature, jlong_to_string(sampleStack[i].location, buffer));
-    if (name != NULL)
+    if (name != nullptr)
         jvmti->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti->Deallocate((unsigned char*)signature);
 
     return NSK_TRUE;
@@ -151,27 +151,27 @@ static int displayFrameInfo(jvmtiEnv* jvmti, jint i) {
 
 static int complainFrameInfo(jvmtiEnv* jvmti, jint i) {
     char buffer[32];
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(frameBuffer[frameCount-1-i].method, &name, &signature, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(frameBuffer[frameCount-1-i].method, &name, &signature, nullptr)))
         return NSK_FALSE;
 
     NSK_COMPLAIN3("    got: method=%s%s, location=%s\n", name, signature,
         jlong_to_string(frameBuffer[frameCount-1-i].location, buffer));
-    if (name != NULL)
+    if (name != nullptr)
         jvmti->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti->Deallocate((unsigned char*)signature);
 
-    if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(sampleStack[i].method, &name, &signature, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(sampleStack[i].method, &name, &signature, nullptr)))
         return NSK_FALSE;
 
     NSK_COMPLAIN3("    expected: method=%s%s, location=%s\n", name, signature,
         jlong_to_string(sampleStack[i].location, buffer));
-    if (name != NULL)
+    if (name != nullptr)
         jvmti->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti->Deallocate((unsigned char*)signature);
 
     return NSK_TRUE;
@@ -257,8 +257,8 @@ JNIEXPORT jint JNICALL
 Java_nsk_jvmti_scenarios_sampling_SP07_sp07t001Thread_wrapper(JNIEnv* jni,
         jobject obj, jint i) {
     jint result = 0;
-    jclass klass = NULL;
-    jmethodID method = NULL;
+    jclass klass = nullptr;
+    jmethodID method = nullptr;
     jvmtiEnv* jvmti = nsk_jvmti_getAgentJVMTIEnv();
 
     if (!NSK_VERIFY(depth < MAX_DEPTH)) {
@@ -269,14 +269,14 @@ Java_nsk_jvmti_scenarios_sampling_SP07_sp07t001Thread_wrapper(JNIEnv* jni,
     if (!NSK_JVMTI_VERIFY(jvmti->RawMonitorEnter(frameLock)))
         return NSK_FALSE;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->GetFrameLocation(NULL, 1, &sampleStack[depth].method, &sampleStack[depth].location))) {
+    if (!NSK_JVMTI_VERIFY(jvmti->GetFrameLocation(nullptr, 1, &sampleStack[depth].method, &sampleStack[depth].location))) {
         nsk_jvmti_setFailStatus();
         return 0;
     }
 
     depth++;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->GetFrameLocation(NULL, 0, &sampleStack[depth].method, &sampleStack[depth].location))) {
+    if (!NSK_JVMTI_VERIFY(jvmti->GetFrameLocation(nullptr, 0, &sampleStack[depth].method, &sampleStack[depth].location))) {
         nsk_jvmti_setFailStatus();
         return 0;
     }
@@ -286,12 +286,12 @@ Java_nsk_jvmti_scenarios_sampling_SP07_sp07t001Thread_wrapper(JNIEnv* jni,
     if (!NSK_JVMTI_VERIFY(jvmti->RawMonitorExit(frameLock)))
         return NSK_FALSE;
 
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(obj)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(obj)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return 0;
     }
 
-    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "fibonacci", "(I)I")) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (method = jni->GetMethodID(klass, "fibonacci", "(I)I")) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return 0;
     }
@@ -325,7 +325,7 @@ JNIEXPORT jint JNI_OnLoad_sp07t001(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     /* init framework and parse options */
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
@@ -336,14 +336,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("frameLock", &frameLock)))
         return NSK_FALSE;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP07/sp07t002/sp07t002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP07/sp07t002/sp07t002.cpp
index a83af49dc47..d256d87bdff 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP07/sp07t002/sp07t002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP07/sp07t002/sp07t002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,12 +41,12 @@ static const jlong SAMPLING_INTERVAL = 10;
 static jlong timeout = 0;
 
 /* test objects */
-static jthread thread = NULL;
-static jrawMonitorID waitLock = NULL;
-static jfieldID field = NULL;
-static jmethodID methodRun = NULL;
-static jmethodID methodCatcher = NULL;
-static jmethodID methodThrower = NULL;
+static jthread thread = nullptr;
+static jrawMonitorID waitLock = nullptr;
+static jfieldID field = nullptr;
+static jmethodID methodRun = nullptr;
+static jmethodID methodCatcher = nullptr;
+static jmethodID methodThrower = nullptr;
 static jint MAX_LADDER = 0;
 static int sampleCount = 0;
 static jint frameCount = 0;
@@ -57,10 +57,10 @@ static jvmtiFrameInfo frameBuffer[MAX_DEPTH];
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     const char* THREAD_NAME = "Debuggee Thread";
     jvmtiThreadInfo info;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
     jint threads_count = 0;
-    jclass klass = NULL;
-    jfieldID fid = NULL;
+    jclass klass = nullptr;
+    jfieldID fid = nullptr;
     int i;
 
     NSK_DISPLAY0("Prepare: find tested thread\n");
@@ -69,12 +69,12 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->GetAllThreads(&threads_count, &threads)))
         return NSK_FALSE;
 
-    if (!NSK_VERIFY(threads_count > 0 && threads != NULL))
+    if (!NSK_VERIFY(threads_count > 0 && threads != nullptr))
         return NSK_FALSE;
 
     /* find tested thread */
     for (i = 0; i < threads_count; i++) {
-        if (!NSK_VERIFY(threads[i] != NULL))
+        if (!NSK_VERIFY(threads[i] != nullptr))
             return NSK_FALSE;
 
         /* get thread information */
@@ -84,11 +84,11 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
         NSK_DISPLAY3("    thread #%d (%s): %p\n", i, info.name, threads[i]);
 
         /* find by name */
-        if (info.name != NULL && (strcmp(info.name, THREAD_NAME) == 0)) {
+        if (info.name != nullptr && (strcmp(info.name, THREAD_NAME) == 0)) {
             thread = threads[i];
         }
 
-        if (info.name != NULL) {
+        if (info.name != nullptr) {
             if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)info.name)))
                 return NSK_FALSE;
         }
@@ -98,37 +98,37 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)threads)))
         return NSK_FALSE;
 
-    if (thread == NULL) {
+    if (thread == nullptr) {
         NSK_COMPLAIN0("Debuggee thread not found");
         return NSK_FALSE;
     }
 
     /* get tested thread class */
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->GetObjectClass(thread)) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread field 'MAX_LADDER' */
-    if (!NSK_JNI_VERIFY(jni, (fid = jni->GetStaticFieldID(klass, "MAX_LADDER", "I")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (fid = jni->GetStaticFieldID(klass, "MAX_LADDER", "I")) != nullptr))
         return NSK_FALSE;
 
     MAX_LADDER = jni->GetStaticIntField(klass, fid);
     NSK_DISPLAY1("MAX_LADDER: %d\n", MAX_LADDER);
 
     /* get tested thread field 'depth' */
-    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "depth", "I")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (field = jni->GetFieldID(klass, "depth", "I")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'run' */
-    if (!NSK_JNI_VERIFY(jni, (methodRun = jni->GetMethodID(klass, "run", "()V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (methodRun = jni->GetMethodID(klass, "run", "()V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'catcher' */
     if (!NSK_JNI_VERIFY(jni, (methodCatcher =
-            jni->GetMethodID(klass, "catcher", "(II)V")) != NULL))
+            jni->GetMethodID(klass, "catcher", "(II)V")) != nullptr))
         return NSK_FALSE;
 
     /* get tested thread method 'thrower' */
-    if (!NSK_JNI_VERIFY(jni, (methodThrower= jni->GetMethodID(klass, "thrower", "(I)V")) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (methodThrower= jni->GetMethodID(klass, "thrower", "(I)V")) != nullptr))
         return NSK_FALSE;
 
     if (!NSK_JVMTI_VERIFY(jvmti->CreateRawMonitor("waitLock", &waitLock)))
@@ -155,17 +155,17 @@ static int wait_for(jvmtiEnv* jvmti, jlong millis) {
 
 static int displayFrameInfo(jvmtiEnv* jvmti, jint i) {
     char buffer[32];
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(frameBuffer[frameCount-1-i].method, &name, &signature, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(frameBuffer[frameCount-1-i].method, &name, &signature, nullptr)))
         return NSK_FALSE;
 
     NSK_DISPLAY4("    [%d] method: %s%s, location: %s\n", i, name,
         signature, jlong_to_string(frameBuffer[frameCount-1-i].location, buffer));
-    if (name != NULL)
+    if (name != nullptr)
         jvmti->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti->Deallocate((unsigned char*)signature);
 
     return NSK_TRUE;
@@ -173,20 +173,20 @@ static int displayFrameInfo(jvmtiEnv* jvmti, jint i) {
 
 static int complainFrameInfo(jvmtiEnv* jvmti, jint i, jmethodID method) {
     char buffer[32];
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(frameBuffer[frameCount-1-i].method, &name, &signature, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(frameBuffer[frameCount-1-i].method, &name, &signature, nullptr)))
         return NSK_FALSE;
 
     NSK_COMPLAIN3("    got method: %s%s, location: %s\n", name, signature,
         jlong_to_string(frameBuffer[frameCount-1-i].location, buffer));
-    if (name != NULL)
+    if (name != nullptr)
         jvmti->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti->Deallocate((unsigned char*)signature);
 
-    if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(method, &name, &signature, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->GetMethodName(method, &name, &signature, nullptr)))
         return NSK_FALSE;
 
     NSK_COMPLAIN2("    expected method: %s%s\n", name, signature);
@@ -196,7 +196,7 @@ static int complainFrameInfo(jvmtiEnv* jvmti, jint i, jmethodID method) {
 
 static int checkStackTrace(jvmtiEnv* jvmti, JNIEnv* jni) {
     int res = NSK_TRUE;
-    jmethodID method = NULL;
+    jmethodID method = nullptr;
     jint depth;
     jint i;
     int displayFlag =
@@ -288,7 +288,7 @@ JNIEXPORT jint JNI_OnLoad_sp07t002(JavaVM *jvm, char *options, void *reserved) {
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
 
     /* init framework and parse options */
@@ -300,7 +300,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(caps));
@@ -309,7 +309,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref001/followref001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref001/followref001.cpp
index 08661336a14..e09e0040823 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref001/followref001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref001/followref001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -62,7 +62,7 @@ static int objectsCount  = 0;
 static int fakeUserData  = 0;
 static int userDataError = 0;
 
-static ObjectDesc* objectDescList = NULL;
+static ObjectDesc* objectDescList = nullptr;
 
 static const jlong ROOT_CLASS_TAG   = 9;
 static const jlong CHAIN_CLASS_TAG  = 99;
@@ -95,8 +95,6 @@ static const char* ref_kind_str[28] = {
    "JVMTI_HEAP_REFERENCE_OTHER"
 };
 
-#define DEREF(ptr) (((ptr) == NULL ? 0 : *(ptr)))
-
 
 /* ============================================================================= */
 
@@ -175,7 +173,7 @@ static bool getAndTagClasses(jvmtiEnv*    jvmti,
                              jclass*      rootObjectClass,
                              jclass*      chainObjectClass) {
 
-    if (!NSK_JNI_VERIFY(jni, (*debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (*debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return false;
     }
@@ -184,7 +182,7 @@ static bool getAndTagClasses(jvmtiEnv*    jvmti,
     fflush(0);
 
     if (!NSK_JNI_VERIFY(jni, (*rootObjectClass =
-            jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return false;
     }
@@ -200,7 +198,7 @@ static bool getAndTagClasses(jvmtiEnv*    jvmti,
 
 
     if (!NSK_JNI_VERIFY(jni, (*chainObjectClass =
-            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return false;
     }
@@ -227,10 +225,10 @@ static bool getFieldsAndObjects(jvmtiEnv*  jvmti,
                                 jfieldID*  reachableChainField,
                                 jfieldID*  unreachableChainField,
                                 jfieldID*  nextField) {
-    jfieldID rootObjectField = NULL;
+    jfieldID rootObjectField = nullptr;
 
     if (!NSK_JNI_VERIFY(jni, (rootObjectField =
-            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return false;
     }
@@ -239,7 +237,7 @@ static bool getFieldsAndObjects(jvmtiEnv*  jvmti,
     fflush(0);
 
     if (!NSK_JNI_VERIFY(jni, (*reachableChainField =
-            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return false;
     }
@@ -248,7 +246,7 @@ static bool getFieldsAndObjects(jvmtiEnv*  jvmti,
     fflush(0);
 
     if (!NSK_JNI_VERIFY(jni, (*unreachableChainField =
-            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return false;
     }
@@ -258,7 +256,7 @@ static bool getFieldsAndObjects(jvmtiEnv*  jvmti,
     fflush(0);
 
     if (!NSK_JNI_VERIFY(jni, (*nextField =
-            jni->GetFieldID(chainObjectClass, NEXT_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(chainObjectClass, NEXT_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return false;
     }
@@ -267,14 +265,14 @@ static bool getFieldsAndObjects(jvmtiEnv*  jvmti,
     fflush(0);
 
     if (!NSK_JNI_VERIFY(jni, (*rootObjectPtr =
-            jni->GetStaticObjectField(debugeeClass, rootObjectField)) != NULL)) {
+            jni->GetStaticObjectField(debugeeClass, rootObjectField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return false;
     }
     printf("\nFound root object: 0x%p\n", (void*) *rootObjectPtr);
     fflush(0);
 
-    if (!NSK_JNI_VERIFY(jni, (*rootObjectPtr = jni->NewGlobalRef(*rootObjectPtr)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (*rootObjectPtr = jni->NewGlobalRef(*rootObjectPtr)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return false;
     }
@@ -296,7 +294,7 @@ static bool getAndTagChainObjects(
     ObjectDesc objectDescList[],
     jlong      tag,
     bool       reachable) {
-    jobject nextObj = NULL;
+    jobject nextObj = nullptr;
     jlong objTag = (reachable ? tag : -tag);
 
     if (count <= 0) {
@@ -306,7 +304,7 @@ static bool getAndTagChainObjects(
     count--;
     tag++;
 
-    if (!NSK_JNI_VERIFY(jni, (nextObj = jni->GetObjectField(currObj, refField)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (nextObj = jni->GetObjectField(currObj, refField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return false;
     }
@@ -350,13 +348,13 @@ static int getAndTagTestedObjects(
     ObjectDesc** objectDescList,
     jobject*     rootObjectPtr)
 {
-    jclass   debugeeClass          = NULL;
-    jclass   rootObjectClass       = NULL;
-    jclass   chainObjectClass      = NULL;
+    jclass   debugeeClass          = nullptr;
+    jclass   rootObjectClass       = nullptr;
+    jclass   chainObjectClass      = nullptr;
 
-    jfieldID reachableChainField   = NULL;
-    jfieldID unreachableChainField = NULL;
-    jfieldID nextField             = NULL;
+    jfieldID reachableChainField   = nullptr;
+    jfieldID unreachableChainField = nullptr;
+    jfieldID nextField             = nullptr;
 
     if (!initObjectDescList(jvmti,
                             chainLength,
@@ -504,12 +502,12 @@ static void releaseTestedObjects(jvmtiEnv*   jvmti,
                                  ObjectDesc* objectDescList,
                                  jobject     rootObject)
 {
-    if (rootObject != NULL) {
+    if (rootObject != nullptr) {
         printf("Release object reference to root tested object: 0x%p\n", rootObject);
         NSK_TRACE(jni->DeleteGlobalRef(rootObject));
     }
 
-    if (objectDescList != NULL) {
+    if (objectDescList != nullptr) {
         printf("Deallocate objects list: 0x%p\n", (void*)objectDescList);
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)objectDescList))) {
             nsk_jvmti_setFailStatus();
@@ -577,7 +575,7 @@ jint JNICALL heapReferenceCallback(
         nsk_jvmti_setFailStatus();
     }
 
-    if (tag_ptr != NULL && *tag_ptr != 0) {
+    if (tag_ptr != nullptr && *tag_ptr != 0) {
         int found = 0;
         int i;
 
@@ -724,7 +722,7 @@ jint JNICALL stringPrimitiveValueCallback(
 /** Agent algorithm. */
 static void JNICALL
 agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
-    jobject rootObject = NULL;
+    jobject rootObject = nullptr;
 
     printf("Wait for tested objects created\n");
     fflush(0);
@@ -760,7 +758,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     fflush(0);
 
     if (!NSK_JVMTI_VERIFY(jvmti->FollowReferences((jint)   0,    /* heap_filter    */
-                                                  (jclass) NULL, /* class          */
+                                                  (jclass) nullptr, /* class          */
                                                   rootObject,    /* initial_object */
                                                   &heapCallbacks,
                                                   (const void *) &fakeUserData))) {
@@ -803,7 +801,7 @@ JNIEXPORT jint JNI_OnLoad_followref001(JavaVM *jvm, char *options, void *reserve
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options))) {
         return JNI_ERR;
@@ -814,7 +812,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_VERIFY(chainLength > 0))
         return JNI_ERR;
 
-    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL)) {
+    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr)) {
         return JNI_ERR;
     }
 
@@ -829,13 +827,13 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* Setting Heap Callbacks */
-    heapCallbacks.heap_iteration_callback         = NULL;
+    heapCallbacks.heap_iteration_callback         = nullptr;
     heapCallbacks.heap_reference_callback         = heapReferenceCallback;
     heapCallbacks.primitive_field_callback        = primitiveFieldCallback;
     heapCallbacks.array_primitive_value_callback  = arrayPrimitiveValueCallback;
     heapCallbacks.string_primitive_value_callback = stringPrimitiveValueCallback;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL))) {
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr))) {
         return JNI_ERR;
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref002/followref002.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref002/followref002.cpp
index ee1eff158d6..d84b3b37624 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref002/followref002.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref002/followref002.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -60,7 +60,7 @@ static int objectsCount  = 0;
 static int fakeUserData  = 0;
 static int userDataError = 0;
 
-static ObjectDesc* objectDescList = NULL;
+static ObjectDesc* objectDescList = nullptr;
 
 static jlong rootClassTag   = 9;
 static jlong chainClassTag  = 99;
@@ -92,8 +92,6 @@ static const char* ref_kind_str[28] = {
    "JVMTI_HEAP_REFERENCE_OTHER"
 };
 
-#define DEREF(ptr) (((ptr) == NULL ? 0 : *(ptr)))
-
 /* ============================================================================= */
 
 /** Obtain chain of tested objects and tag them recursively. */
@@ -110,7 +108,7 @@ static int getAndTagChainObjects(
     jlong      tag,
     int        reachable)
 {
-    jobject obj = NULL;
+    jobject obj = nullptr;
     jlong objTag = (reachable ? tag : -tag);
 
     if (count <= 0)
@@ -119,7 +117,7 @@ static int getAndTagChainObjects(
     count--;
     tag++;
 
-    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetObjectField(firstObject, firstField)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetObjectField(firstObject, firstField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -159,14 +157,14 @@ static int getAndTagTestedObjects(
     ObjectDesc** objectDescList,
     jobject*     rootObject)
 {
-    jclass debugeeClass = NULL;
-    jclass rootObjectClass = NULL;
-    jclass chainObjectClass = NULL;
+    jclass debugeeClass = nullptr;
+    jclass rootObjectClass = nullptr;
+    jclass chainObjectClass = nullptr;
 
-    jfieldID objectField = NULL;
-    jfieldID reachableChainField = NULL;
-    jfieldID unreachableChainField = NULL;
-    jfieldID tailField = NULL;
+    jfieldID objectField = nullptr;
+    jfieldID reachableChainField = nullptr;
+    jfieldID unreachableChainField = nullptr;
+    jfieldID tailField = nullptr;
 
     /* root object + reachable and unreachable object chains */
     *objectsCount = 1 + 2 * chainLength;
@@ -194,7 +192,7 @@ static int getAndTagTestedObjects(
 
     printf("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
     fflush(0);
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -202,7 +200,7 @@ static int getAndTagTestedObjects(
 
     printf("Find root object class: %s\n", ROOT_OBJECT_CLASS_NAME);
     fflush(0);
-    if (!NSK_JNI_VERIFY(jni, (rootObjectClass = jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (rootObjectClass = jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -216,7 +214,7 @@ static int getAndTagTestedObjects(
     printf("Find chain object class: %s\n", CHAIN_OBJECT_CLASS_NAME);
     fflush(0);
     if (!NSK_JNI_VERIFY(jni, (chainObjectClass =
-            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -230,7 +228,7 @@ static int getAndTagTestedObjects(
     printf("Find static field in debugee class: %s\n", OBJECT_FIELD_NAME);
     fflush(0);
     if (!NSK_JNI_VERIFY(jni, (objectField =
-            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -239,7 +237,7 @@ static int getAndTagTestedObjects(
     printf("Find instance field in root object class: %s\n", REACHABLE_CHAIN_FIELD_NAME);
     fflush(0);
     if (!NSK_JNI_VERIFY(jni, (reachableChainField =
-            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -248,7 +246,7 @@ static int getAndTagTestedObjects(
     printf("Find instance field in root object class: %s\n", UNREACHABLE_CHAIN_FIELD_NAME);
     fflush(0);
     if (!NSK_JNI_VERIFY(jni, (unreachableChainField =
-            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -257,7 +255,7 @@ static int getAndTagTestedObjects(
     printf("Find instance field in chain object class: %s\n", TAIL_FIELD_NAME);
     fflush(0);
     if (!NSK_JNI_VERIFY(jni, (tailField =
-            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -266,14 +264,14 @@ static int getAndTagTestedObjects(
     printf("Get root object from static field: %s\n", OBJECT_FIELD_NAME);
     fflush(0);
     if (!NSK_JNI_VERIFY(jni, (*rootObject =
-            jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+            jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
     printf("  ... got object: 0x%p\n", (void*)*rootObject);
     fflush(0);
 
-    if (!NSK_JNI_VERIFY(jni, (*rootObject = jni->NewGlobalRef(*rootObject)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (*rootObject = jni->NewGlobalRef(*rootObject)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -394,12 +392,12 @@ static int checkTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni,
 /** Release references to the tested objects and free allocated memory. */
 static int releaseTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                 ObjectDesc* objectDescList, jobject rootObject) {
-    if (rootObject != NULL) {
+    if (rootObject != nullptr) {
         printf("Release object reference to root tested object: 0x%p\n", rootObject);
         NSK_TRACE(jni->DeleteGlobalRef(rootObject));
     }
 
-    if (objectDescList != NULL) {
+    if (objectDescList != nullptr) {
         printf("Deallocate objects list: 0x%p\n", (void*)objectDescList);
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)objectDescList))) {
             nsk_jvmti_setFailStatus();
@@ -460,13 +458,13 @@ jint JNICALL heapReferenceCallback(
            (int) referrer_index);
     fflush(0);
 
-    if (tag_ptr == NULL) {
-        NSK_COMPLAIN1("NULL tag_ptr is passed to heapReferenceCallback:"
+    if (tag_ptr == nullptr) {
+        NSK_COMPLAIN1("null tag_ptr is passed to heapReferenceCallback:"
                       " tag_ptr=0x%p\n", (void*)tag_ptr);
         nsk_jvmti_setFailStatus();
     }
 
-    if (tag_ptr != NULL && *tag_ptr != 0) {
+    if (tag_ptr != nullptr && *tag_ptr != 0) {
         int found = 0;
         int i;
 
@@ -601,7 +599,7 @@ jint JNICALL stringPrimitiveValueCallback(
 /** Agent algorithm. */
 static void JNICALL
 agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
-    jobject rootObject = NULL;
+    jobject rootObject = nullptr;
 
     printf("Wait for tested objects created\n");
     fflush(0);
@@ -635,7 +633,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     {
         jint heap_filter = JVMTI_HEAP_FILTER_UNTAGGED | JVMTI_HEAP_FILTER_CLASS_UNTAGGED;
         if (!NSK_JVMTI_VERIFY(jvmti->FollowReferences(heap_filter,
-                                                      (jclass) NULL, /* class          */
+                                                      (jclass) nullptr, /* class          */
                                                       rootObject,    /* initial_object */
                                                       &heapCallbacks,
                                                       (const void *) &fakeUserData))) {
@@ -668,7 +666,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         jint heap_filter = JVMTI_HEAP_FILTER_UNTAGGED | JVMTI_HEAP_FILTER_CLASS_UNTAGGED |
                            JVMTI_HEAP_FILTER_TAGGED   | JVMTI_HEAP_FILTER_CLASS_TAGGED;
         if (!NSK_JVMTI_VERIFY(jvmti->FollowReferences(heap_filter,
-                                                      (jclass) NULL, /* class          */
+                                                      (jclass) nullptr, /* class          */
                                                       rootObject,    /* initial_object */
                                                       &heapCallbacks,
                                                       (const void *) &fakeUserData))) {
@@ -714,7 +712,7 @@ JNIEXPORT jint JNI_OnLoad_followref002(JavaVM *jvm, char *options, void *reserve
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -726,7 +724,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -740,13 +738,13 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* Setting Heap Callbacks */
-    heapCallbacks.heap_iteration_callback         = NULL;
+    heapCallbacks.heap_iteration_callback         = nullptr;
     heapCallbacks.heap_reference_callback         = heapReferenceCallback;
     heapCallbacks.primitive_field_callback        = primitiveFieldCallback;
     heapCallbacks.array_primitive_value_callback  = arrayPrimitiveValueCallback;
     heapCallbacks.string_primitive_value_callback = stringPrimitiveValueCallback;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref003/followref003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref003/followref003.cpp
index 22892f71a36..197a50cea1f 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref003/followref003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref003/followref003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -71,7 +71,7 @@ static int objectsCount  = 0;
 static int fakeUserData  = 0;
 static int userDataError = 0;
 
-static ObjectDesc* objectDescList = NULL;
+static ObjectDesc* objectDescList = nullptr;
 
 #define TARG_THREAD_TAG  11
 #define FIRST_THREAD_TAG (TARG_THREAD_TAG + 1)
@@ -118,9 +118,6 @@ static const char* ref_kind_str[28] = {
 };
 
 
-#define DEREF(ptr) (((ptr) == NULL ? 0 : *(ptr)))
-
-
 /* ============================================================================= */
 
 /** Obtain chain of tested objects and tag them recursively. */
@@ -129,7 +126,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
                            jfieldID nextField, const char nextFieldName[],
                            int count, ObjectDesc objectDescList[],
                            jlong tag, int reachable) {
-    jobject obj = NULL;
+    jobject obj = nullptr;
     jlong objTag = (reachable ? tag : -tag);
 
     if (count <= 0)
@@ -138,7 +135,7 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
     count--;
     tag++;
 
-    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetObjectField(firstObject, firstField)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (obj = jni->GetObjectField(firstObject, firstField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -164,14 +161,14 @@ static int getChainObjects(jvmtiEnv* jvmti, JNIEnv* jni, jobject firstObject,
 static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                             int *objectsCount, ObjectDesc* *objectDescList,
                             jobject* rootObject) {
-    jclass debugeeClass = NULL;
-    jclass rootObjectClass = NULL;
-    jclass chainObjectClass = NULL;
+    jclass debugeeClass = nullptr;
+    jclass rootObjectClass = nullptr;
+    jclass chainObjectClass = nullptr;
 
-    jfieldID objectField = NULL;
-    jfieldID reachableChainField = NULL;
-    jfieldID unreachableChainField = NULL;
-    jfieldID tailField = NULL;
+    jfieldID objectField = nullptr;
+    jfieldID reachableChainField = nullptr;
+    jfieldID unreachableChainField = nullptr;
+    jfieldID tailField = nullptr;
 
     *objectsCount = 1 + 2 * chainLength;
 
@@ -198,7 +195,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     printf("Find debugee class: %s\n", DEBUGEE_CLASS_NAME);
     fflush(0);
-    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (debugeeClass = jni->FindClass(DEBUGEE_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -206,7 +203,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
 
     printf("Find root object class: %s\n", ROOT_OBJECT_CLASS_NAME);
     fflush(0);
-    if (!NSK_JNI_VERIFY(jni, (rootObjectClass = jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (rootObjectClass = jni->FindClass(ROOT_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -221,7 +218,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
     printf("Find chain object class: %s\n", CHAIN_OBJECT_CLASS_NAME);
     fflush(0);
     if (!NSK_JNI_VERIFY(jni, (chainObjectClass =
-            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != NULL)) {
+            jni->FindClass(CHAIN_OBJECT_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -237,7 +234,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
     printf("Find static field in debugee class: %s\n", OBJECT_FIELD_NAME);
     fflush(0);
     if (!NSK_JNI_VERIFY(jni, (objectField =
-            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetStaticFieldID(debugeeClass, OBJECT_FIELD_NAME, ROOT_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -246,7 +243,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
     printf("Find instance field in root object class: %s\n", REACHABLE_CHAIN_FIELD_NAME);
     fflush(0);
     if (!NSK_JNI_VERIFY(jni, (reachableChainField =
-            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, REACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -255,7 +252,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
     printf("Find instance field in root object class: %s\n", UNREACHABLE_CHAIN_FIELD_NAME);
     fflush(0);
     if (!NSK_JNI_VERIFY(jni, (unreachableChainField =
-            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(rootObjectClass, UNREACHABLE_CHAIN_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -264,7 +261,7 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
     printf("Find instance field in chain object class: %s\n", TAIL_FIELD_NAME);
     fflush(0);
     if (!NSK_JNI_VERIFY(jni, (tailField =
-            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != NULL)) {
+            jni->GetFieldID(chainObjectClass, TAIL_FIELD_NAME, CHAIN_OBJECT_CLASS_SIG)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -273,14 +270,14 @@ static int getTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
     printf("Get root object from static field: %s\n", OBJECT_FIELD_NAME);
     fflush(0);
     if (!NSK_JNI_VERIFY(jni, (*rootObject =
-            jni->GetStaticObjectField(debugeeClass, objectField)) != NULL)) {
+            jni->GetStaticObjectField(debugeeClass, objectField)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
     printf("  ... got object: 0x%p\n", (void*)*rootObject);
     fflush(0);
 
-    if (!NSK_JNI_VERIFY(jni, (*rootObject = jni->NewGlobalRef(*rootObject)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (*rootObject = jni->NewGlobalRef(*rootObject)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -394,12 +391,12 @@ static int checkTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni,
 /** Release references to the tested objects and free allocated memory. */
 static int releaseTestedObjects(jvmtiEnv* jvmti, JNIEnv* jni, int chainLength,
                                 ObjectDesc* objectDescList, jobject rootObject) {
-    if (rootObject != NULL) {
+    if (rootObject != nullptr) {
         printf("Release object reference to root tested object: 0x%p\n", rootObject);
         NSK_TRACE(jni->DeleteGlobalRef(rootObject));
     }
 
-    if (objectDescList != NULL) {
+    if (objectDescList != nullptr) {
         printf("Deallocate objects list: 0x%p\n", (void*)objectDescList);
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*)objectDescList))) {
             nsk_jvmti_setFailStatus();
@@ -469,8 +466,8 @@ static int registerFrame(jlong thr_id, jint depth, jmethodID method,
      * (Do we have to clarify this in the JVMTI spec?)
      * Do not consider the test as failing in such a case.
      */
-    if (method == NULL && ref_kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL) {
-        NSK_COMPLAIN0("methodID must not be NULL\n");
+    if (method == nullptr && ref_kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL) {
+        NSK_COMPLAIN0("methodID must not be null\n");
         failed = 1;
     }
     if (failed) {
@@ -590,7 +587,7 @@ jint JNICALL heapReferenceCallback(
     jint depth         = -1;
     jint slot          = -1;
     jint index         = -1;
-    jmethodID method   = (jmethodID) NULL;
+    jmethodID method   = (jmethodID) nullptr;
     jlocation location = (jlocation)(-1);
     jlong tag          = DEREF(tag_ptr);
     jlong ref_tag      = DEREF(referrer_tag_ptr);
@@ -670,13 +667,13 @@ jint JNICALL heapReferenceCallback(
            (int) index);
     fflush(0);
 
-    if (tag_ptr == NULL) {
-        NSK_COMPLAIN1("NULL tag_ptr is passed to heapReferenceCallback:"
+    if (tag_ptr == nullptr) {
+        NSK_COMPLAIN1("null tag_ptr is passed to heapReferenceCallback:"
                       " tag_ptr=0x%p\n", (void*)tag_ptr);
         nsk_jvmti_setFailStatus();
     }
 
-    if (tag_ptr != NULL && tag != 0) {
+    if (tag_ptr != nullptr && tag != 0) {
         int found = 0;
         int i;
 
@@ -878,7 +875,7 @@ static jthread getTargetThread(jvmtiEnv *jvmti) {
     static const char *target_thread_name = "main";
     jint i;
     jint thread_count = -1;
-    jthread *threads = NULL;
+    jthread *threads = nullptr;
 
     jvmti->GetAllThreads(&thread_count, &threads);
 
@@ -891,7 +888,7 @@ static jthread getTargetThread(jvmtiEnv *jvmti) {
         }
     }
 
-    return NULL;
+    return nullptr;
 }
 
 static jvmtiError setTagForTargetThread(jvmtiEnv *jvmti, jlong tag) {
@@ -902,7 +899,7 @@ static jvmtiError setTagForTargetThread(jvmtiEnv *jvmti, jlong tag) {
 /** Agent algorithm. */
 static void JNICALL
 agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
-    jobject rootObject = NULL;
+    jobject rootObject = nullptr;
 
     printf("Wait for tested objects created\n");
     fflush(0);
@@ -939,8 +936,8 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     fflush(0);
     {
         if (!NSK_JVMTI_VERIFY(jvmti->FollowReferences((jint)   0,     /* heap_filter    */
-                                                      (jclass)  NULL, /* class          */
-                                                      (jobject) NULL, /* initial_object */
+                                                      (jclass)  nullptr, /* class          */
+                                                      (jobject) nullptr, /* initial_object */
                                                       &heapCallbacks,
                                                       (const void *) &fakeUserData))) {
              nsk_jvmti_setFailStatus();
@@ -977,8 +974,8 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         jint heap_filter = JVMTI_HEAP_FILTER_UNTAGGED
                          | JVMTI_HEAP_FILTER_CLASS_UNTAGGED;
         if (!NSK_JVMTI_VERIFY(jvmti->FollowReferences(heap_filter,
-                                                      (jclass)  NULL, /* class          */
-                                                      (jobject) NULL, /* initial_object */
+                                                      (jclass)  nullptr, /* class          */
+                                                      (jobject) nullptr, /* initial_object */
                                                       &heapCallbacks,
                                                       (const void *) &fakeUserData))) {
              nsk_jvmti_setFailStatus();
@@ -1026,7 +1023,7 @@ JNIEXPORT jint JNI_OnLoad_followref003(JavaVM *jvm, char *options, void *reserve
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
@@ -1035,7 +1032,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     {
         const char* infoOpt = nsk_jvmti_findOptionValue("info");
-        if (infoOpt != NULL) {
+        if (infoOpt != nullptr) {
             if (strcmp(infoOpt, "none") == 0)
                 info = INFO_NONE;
             else if (strcmp(infoOpt, "all") == 0)
@@ -1061,7 +1058,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     {
@@ -1075,13 +1072,13 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* Setting Heap Callbacks */
-    heapCallbacks.heap_iteration_callback         = NULL;
+    heapCallbacks.heap_iteration_callback         = nullptr;
     heapCallbacks.heap_reference_callback         = heapReferenceCallback;
     heapCallbacks.primitive_field_callback        = primitiveFieldCallback;
     heapCallbacks.array_primitive_value_callback  = arrayPrimitiveValueCallback;
     heapCallbacks.string_primitive_value_callback = stringPrimitiveValueCallback;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref004/followref004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref004/followref004.cpp
index a1831044057..c6c24999441 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref004/followref004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref004/followref004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -146,16 +146,16 @@ static void createGlobalRefs(JNIEnv * jni)
 {
     jclass klass;
 
-    if  (!NSK_JNI_VERIFY(jni, (klass = jni->FindClass(JAVA_LANG_STRING_CLASS_NAME)) != NULL)) {
+    if  (!NSK_JNI_VERIFY(jni, (klass = jni->FindClass(JAVA_LANG_STRING_CLASS_NAME)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
-    if (!NSK_JNI_VERIFY(jni, (g_jniGlobalRef = jni->NewGlobalRef(klass)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (g_jniGlobalRef = jni->NewGlobalRef(klass)) != nullptr)) {
         nsk_jvmti_setFailStatus();
     }
 
-    if (!NSK_JNI_VERIFY(jni, (g_jniWeakGlobalRef = jni->NewWeakGlobalRef(klass)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (g_jniWeakGlobalRef = jni->NewWeakGlobalRef(klass)) != nullptr)) {
         nsk_jvmti_setFailStatus();
     }
 
@@ -180,8 +180,8 @@ static void JNICALL agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg)
     createGlobalRefs(jni);
 
     retCode = jvmti->FollowReferences((jint) 0,                 /* heap filter */
-                                      NULL,                     /* class */
-                                      NULL,                     /* inital object */
+                                      nullptr,                     /* class */
+                                      nullptr,                     /* inital object */
                                       &g_heapCallbacks,
                                       (const void *) &g_fakeUserData);
 
@@ -218,7 +218,7 @@ JNIEXPORT jint JNI_OnLoad_followref004(JavaVM *jvm, char *options, void *reserve
 #endif
 jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved)
 {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options))) {
         return JNI_ERR;
@@ -226,13 +226,13 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved)
 
     g_timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
-    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL)) {
+    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr)) {
         return JNI_ERR;
     }
 
     /* Setting Heap Callbacks */
     memset(&g_heapCallbacks, 0, sizeof(g_heapCallbacks));
-    g_heapCallbacks.heap_iteration_callback         = NULL;
+    g_heapCallbacks.heap_iteration_callback         = nullptr;
     g_heapCallbacks.heap_reference_callback         = heapReferenceCallback;
     g_heapCallbacks.primitive_field_callback        = primitiveFieldCallback;
     g_heapCallbacks.array_primitive_value_callback  = arrayPrimitiveValueCallback;
@@ -250,7 +250,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved)
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL))) {
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr))) {
         return JNI_ERR;
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref005/followref005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref005/followref005.cpp
index 52b313b51c4..a8df86c3273 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref005/followref005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref005/followref005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -46,8 +46,8 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
            "    return an error if env. doesn't possess can_tag_objects capability\n");
 
     retCode = jvmti->FollowReferences((jint) 0,                 /* heap filter */
-                                      NULL,                     /* class */
-                                      NULL,                     /* inital object */
+                                      nullptr,                     /* class */
+                                      nullptr,                     /* inital object */
                                       &g_wrongHeapCallbacks,
                                       (const void *) &g_fakeUserData);
 
@@ -57,7 +57,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     retCode = jvmti->IterateThroughHeap((jint) 0,                 /* heap filter */
-                                        NULL,                     /* class */
+                                        nullptr,                     /* class */
                                         &g_wrongHeapCallbacks,
                                         (const void *) &g_fakeUserData);
 
@@ -115,7 +115,7 @@ JNIEXPORT jint JNI_OnLoad_followref005(JavaVM *jvm, char *options, void *reserve
 }
 #endif
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options))) {
         return JNI_ERR;
@@ -123,7 +123,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     g_timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
-    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL)) {
+    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr)) {
         return JNI_ERR;
     }
 
@@ -137,7 +137,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL))) {
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr))) {
         return JNI_ERR;
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref006/followref006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref006/followref006.cpp
index cabd4696827..d161739de62 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref006/followref006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/FollowReferences/followref006/followref006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -51,7 +51,7 @@ static void verifyReturnCodes(JNIEnv* jni, jvmtiEnv* jvmti)
 
     retCode = jvmti->FollowReferences((jint) 0,                 /* heap filter */
                                       (jclass) &g_wrongHeapCallbacks ,   /* invalid class, but valid memory address */
-                                      NULL,                     /* inital object */
+                                      nullptr,                     /* inital object */
                                       &g_wrongHeapCallbacks,
                                       (const void *) &g_fakeUserData);
 
@@ -63,18 +63,18 @@ static void verifyReturnCodes(JNIEnv* jni, jvmtiEnv* jvmti)
     // When FollowReferences() is called with an invalid initial object
     // the behaviour according to the jvmti spec is optional.
     // It may return JVMTI_ERROR_INVALID_OBJECT and not follow any references.
-    // Or it may treat the object as NULL, and follow all references.
+    // Or it may treat the object as nullptr, and follow all references.
     //
     // We will accept both behaviours. We use empty callbacks since the existing
     // callback marks the test as failed.
 
-    emptyHeapCallbacks.heap_iteration_callback = NULL;
-    emptyHeapCallbacks.heap_reference_callback = NULL;
-    emptyHeapCallbacks.primitive_field_callback = NULL;
-    emptyHeapCallbacks.array_primitive_value_callback = NULL;
-    emptyHeapCallbacks.string_primitive_value_callback = NULL;
+    emptyHeapCallbacks.heap_iteration_callback = nullptr;
+    emptyHeapCallbacks.heap_reference_callback = nullptr;
+    emptyHeapCallbacks.primitive_field_callback = nullptr;
+    emptyHeapCallbacks.array_primitive_value_callback = nullptr;
+    emptyHeapCallbacks.string_primitive_value_callback = nullptr;
     retCode = jvmti->FollowReferences((jint) 0,               // heap filter
-                                      NULL,                   // class
+                                      nullptr,                   // class
                                       (jobject) &g_wrongHeapCallbacks,  // invalid inital object
                                       &emptyHeapCallbacks,    // No callbacks
                                       (const void *) &g_fakeUserData);
@@ -87,9 +87,9 @@ static void verifyReturnCodes(JNIEnv* jni, jvmtiEnv* jvmti)
     NSK_DISPLAY0("FollowReferences: Invalid callbacks:");
 
     retCode = jvmti->FollowReferences((jint) 0,     /* heap filter */
-                                      NULL,         /* class */
-                                      NULL,         /* inital object */
-                                      NULL,
+                                      nullptr,         /* class */
+                                      nullptr,         /* inital object */
+                                      nullptr,
                                       (const void *) &g_fakeUserData);
 
     if (!NSK_VERIFY(retCode == JVMTI_ERROR_NULL_POINTER)) {
@@ -105,17 +105,17 @@ static void verifyReturnCodes(JNIEnv* jni, jvmtiEnv* jvmti)
         nsk_jvmti_setFailStatus();
     }
 
-    NSK_DISPLAY0("GetTag: NULL object pointer:");
+    NSK_DISPLAY0("GetTag: null object pointer:");
 
-    retCode = jvmti->GetTag(NULL, &tag);
+    retCode = jvmti->GetTag(nullptr, &tag);
 
     if (!NSK_VERIFY(retCode == JVMTI_ERROR_INVALID_OBJECT)) {
         nsk_jvmti_setFailStatus();
     }
 
-    NSK_DISPLAY0("GetTag: NULL tag pointer:");
+    NSK_DISPLAY0("GetTag: null tag pointer:");
 
-    retCode = jvmti->GetTag((jobject) &g_wrongHeapCallbacks, NULL);
+    retCode = jvmti->GetTag((jobject) &g_wrongHeapCallbacks, nullptr);
 
     if (!NSK_VERIFY(retCode == JVMTI_ERROR_NULL_POINTER)) {
         nsk_jvmti_setFailStatus();
@@ -131,15 +131,15 @@ static void verifyReturnCodes(JNIEnv* jni, jvmtiEnv* jvmti)
         nsk_jvmti_setFailStatus();
     }
 
-    NSK_DISPLAY0("SetTag: NULL object pointer:");
+    NSK_DISPLAY0("SetTag: null object pointer:");
 
-    retCode = jvmti->GetTag(NULL, &tag);
+    retCode = jvmti->GetTag(nullptr, &tag);
 
     if (!NSK_VERIFY(retCode == JVMTI_ERROR_INVALID_OBJECT)) {
         nsk_jvmti_setFailStatus();
     }
 
-    NSK_DISPLAY0("GetTag: NULL tag pointer:");
+    NSK_DISPLAY0("GetTag: null tag pointer:");
 
 } /* verifyReturnCodes */
 
@@ -151,14 +151,14 @@ static void checkNoObjIterated(JNIEnv* jni, jvmtiEnv* jvmti, const char * szClas
     jclass klass;
 
     NSK_DISPLAY1("Verify, that no objects are returned if initial object is %s", szClassName);
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->FindClass(szClassName)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->FindClass(szClassName)) != nullptr)) {
         nsk_jvmti_setFailStatus();
         return;
     }
 
     retCode = jvmti->FollowReferences((jint) 0,     /* heap filter */
                                       klass, /* class */
-                                      NULL,         /* inital object */
+                                      nullptr,         /* inital object */
                                       &g_wrongHeapCallbacks,
                                       (const void *) &g_fakeUserData);
 
@@ -211,7 +211,7 @@ JNIEXPORT jint JNI_OnLoad_followref006(JavaVM *jvm, char *options, void *reserve
 #endif
 jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved)
 {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options))) {
         return JNI_ERR;
@@ -219,7 +219,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved)
 
     g_timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
-    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL)) {
+    if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr)) {
         return JNI_ERR;
     }
 
@@ -235,7 +235,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved)
         }
     }
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL))) {
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr))) {
         return JNI_ERR;
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretbase/earlyretbase.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretbase/earlyretbase.cpp
index 9bca3a9c004..faa370694b4 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretbase/earlyretbase.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretbase/earlyretbase.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,7 +35,7 @@ extern "C" {
 
 #define RETURN_FAILED errCode = STATUS_FAILED; fflush(0); return errCode
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 
@@ -51,7 +51,7 @@ static int errCode = PASSED;
 
 static const char *sig_exp       = "()J";
 static const char *name_exp      = "activeMethod";
-static jmethodID midActiveMethod = NULL;
+static jmethodID midActiveMethod = nullptr;
 
 void JNICALL
 MethodExit(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thr,
@@ -84,13 +84,13 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretbase_suspThread(JNIEnv *env,
     }
 
     jclass clazz = env->GetObjectClass(earlyretThr);
-    if (clazz == NULL) {
+    if (clazz == nullptr) {
         printf("Cannot get class of thread object\n");
         RETURN_FAILED;
     }
 
     midActiveMethod = env->GetMethodID(clazz, name_exp, sig_exp);
-    if (midActiveMethod == NULL) {
+    if (midActiveMethod == nullptr) {
         printf("Cannot find Method ID for method %s\n", name_exp);
         RETURN_FAILED;
     }
@@ -137,7 +137,7 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretbase_doForceEarlyReturn(JNIEnv *env
      * that ForceEarlyReturn correctly generates them */
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_METHOD_EXIT, NULL);
+        JVMTI_EVENT_METHOD_EXIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable METHOD_EXIT event: %s (%d)\n",
                TranslateError(err), err);
@@ -147,7 +147,7 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretbase_doForceEarlyReturn(JNIEnv *env
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_FRAME_POP, NULL);
+        JVMTI_EVENT_FRAME_POP, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable FRAME_POP event: %s (%d)\n",
                TranslateError(err), err);
@@ -197,7 +197,7 @@ jint  Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong error code from a valid call to GetEnv!\n");
         return JNI_ERR;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretfp/earlyretfp.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretfp/earlyretfp.cpp
index 0feb076932d..d4353eb9dce 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretfp/earlyretfp.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretfp/earlyretfp.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,15 +36,15 @@ extern "C" {
 #define RETURN_FAILED errCode = STATUS_FAILED; fflush(0); return
 
 #define METHCNT 2
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint errCode = PASSED;
 static jboolean printdump = JNI_TRUE;
-static jmethodID midCheckPoint      = NULL;
-static jmethodID midRun             = NULL;
-static jmethodID midCountDownFloat  = NULL;
-static jmethodID midCountDownDouble = NULL;
+static jmethodID midCheckPoint      = nullptr;
+static jmethodID midRun             = nullptr;
+static jmethodID midCountDownFloat  = nullptr;
+static jmethodID midCountDownDouble = nullptr;
 
 /* There is no synchronization for the counters because
  * they are incremented in single threaded mode.
@@ -70,7 +70,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
     jclass cls;
     jlocation loc_exp = (i == 0) ? 0x16 : 0xd;
     char *sigClass, *name, *sig, *generic;
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLocalVariableEntry *table = nullptr;
     jint entryCount = 0;
     jint argValue;
     jint j;
@@ -105,7 +105,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
                i, TranslateError(err), err);
         RETURN_FAILED;
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             if (strcmp(table[j].name, argName) == 0) {
                 err = jvmti_env->GetLocalInt(thr, 0,
@@ -125,17 +125,17 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
         printf(", arg value: %d\n", argValue);
     }
 
-    if (sigClass == NULL || strcmp(sigClass, cls_exp) != 0) {
+    if (sigClass == nullptr || strcmp(sigClass, cls_exp) != 0) {
         printf("(step %d) wrong class sig: \"%s\",\n", i, sigClass);
         printf(" expected: \"%s\"\n", cls_exp);
         RETURN_FAILED;
     }
-    if (name == NULL || strcmp(name, name_exp[methidx]) != 0) {
+    if (name == nullptr || strcmp(name, name_exp[methidx]) != 0) {
         printf("(step %d) wrong method name: \"%s\",", i, name);
         printf(" expected: \"%s\"\n", name_exp[methidx]);
         RETURN_FAILED;
     }
-    if (sig == NULL || strcmp(sig, sig_exp[methidx]) != 0) {
+    if (sig == nullptr || strcmp(sig, sig_exp[methidx]) != 0) {
         printf("(step %d) wrong method sig: \"%s\",", i, sig);
         printf(" expected: \"%s\"\n", sig_exp[methidx]);
         RETURN_FAILED;
@@ -153,16 +153,16 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
         RETURN_FAILED;
     }
 
-    if (sigClass != NULL) {
+    if (sigClass != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sigClass);
     }
-    if (name != NULL) {
+    if (name != nullptr) {
         jvmti_env->Deallocate((unsigned char*)name);
     }
-    if (sig != NULL) {
+    if (sig != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sig);
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             jvmti_env->Deallocate((unsigned char*)(table[j].name));
             jvmti_env->Deallocate((unsigned char*)(table[j].signature));
@@ -307,14 +307,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printf("Printdump is turned on!\n");
 
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong error code from a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -370,7 +370,7 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretfp_getReady(
     JNIEnv *env, jclass c, jclass cls, jint depth, jdouble retval) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         RETURN_FAILED;
     }
@@ -383,25 +383,25 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretfp_getReady(
     }
 
     midRun = env->GetMethodID(cls, "run", "()V");
-    if (midRun == NULL) {
+    if (midRun == nullptr) {
         printf("Cannot find Method ID for method run\n");
         RETURN_FAILED;
     }
 
     midCheckPoint = env->GetMethodID(cls, "checkPoint", "()V");
-    if (midCheckPoint == NULL) {
+    if (midCheckPoint == nullptr) {
         printf("Cannot find Method ID for method checkPoint\n");
         RETURN_FAILED;
     }
 
     midCountDownFloat = env->GetMethodID(cls, "countDownFloat", "(I)F");
-    if (midCountDownFloat == NULL) {
+    if (midCountDownFloat == nullptr) {
         printf("Cannot find Method ID for method countDownFloat\n");
         RETURN_FAILED;
     }
 
     midCountDownDouble = env->GetMethodID(cls, "countDownDouble", "(I)D");
-    if (midCountDownDouble == NULL) {
+    if (midCountDownDouble == nullptr) {
         printf("Cannot find Method ID for method countDownDouble\n");
         RETURN_FAILED;
     }
@@ -414,7 +414,7 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretfp_getReady(
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretint/earlyretint.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretint/earlyretint.cpp
index 071aa1db1f3..81c0a1e5ec8 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretint/earlyretint.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretint/earlyretint.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,20 +35,20 @@ extern "C" {
 
 #define RETURN_FAILED errCode = STATUS_FAILED; fflush(0); return
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint errCode = PASSED;
 static jboolean printdump = JNI_TRUE;
 
-static jmethodID midCheckPoint = NULL;
-static jmethodID midRun        = NULL;
+static jmethodID midCheckPoint = nullptr;
+static jmethodID midRun        = nullptr;
 
-static jmethodID midCountDownInt     = NULL;
-static jmethodID midCountDownShort   = NULL;
-static jmethodID midCountDownChar    = NULL;
-static jmethodID midCountDownByte    = NULL;
-static jmethodID midCountDownBoolean = NULL;
+static jmethodID midCountDownInt     = nullptr;
+static jmethodID midCountDownShort   = nullptr;
+static jmethodID midCountDownChar    = nullptr;
+static jmethodID midCountDownByte    = nullptr;
+static jmethodID midCountDownBoolean = nullptr;
 
 static jint framesExpected = 0;
 static jint framesCount = 0;
@@ -78,7 +78,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
     jclass cls;
     jlocation loc_exp = (i == 0) ? 0x21 : 0xd;
     char *sigClass, *name, *sig, *generic;
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLocalVariableEntry *table = nullptr;
     jint entryCount = 0;
     jint argValue = -i;
     jint j;
@@ -106,17 +106,17 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
         RETURN_FAILED;
     }
 
-    if (sigClass == NULL || strcmp(sigClass, cls_exp) != 0) {
+    if (sigClass == nullptr || strcmp(sigClass, cls_exp) != 0) {
         printf("(step %d) Wrong class sig: \"%s\",\n", i, sigClass);
         printf(" expected: \"%s\"\n", cls_exp);
         RETURN_FAILED;
     }
-    if (name == NULL || strcmp(name, name_exp[methidx]) != 0) {
+    if (name == nullptr || strcmp(name, name_exp[methidx]) != 0) {
         printf("(step %d) wrong method name: \"%s\",", i, name);
         printf(" expected: \"%s\"\n", name_exp[methidx]);
         RETURN_FAILED;
     }
-    if (sig == NULL || strcmp(sig, sign_exp[methidx]) != 0) {
+    if (sig == nullptr || strcmp(sig, sign_exp[methidx]) != 0) {
         printf("(step %d) wrong method sig: \"%s\",", i, sig);
         printf(" expected: \"%s\"\n", sign_exp[methidx]);
         RETURN_FAILED;
@@ -136,7 +136,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
                i, TranslateError(err), err);
         RETURN_FAILED;
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             if (strcmp(table[j].name, argName) == 0) {
                 err = jvmti_env->GetLocalInt(thr, 0,
@@ -162,16 +162,16 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
         RETURN_FAILED;
     }
 
-    if (sigClass != NULL) {
+    if (sigClass != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sigClass);
     }
-    if (name != NULL) {
+    if (name != nullptr) {
         jvmti_env->Deallocate((unsigned char*)name);
     }
-    if (sig != NULL) {
+    if (sig != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sig);
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             jvmti_env->Deallocate((unsigned char*)(table[j].name));
             jvmti_env->Deallocate((unsigned char*)(table[j].signature));
@@ -313,14 +313,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printf("Printdump is turned on!\n");
 
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong error code from a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -375,7 +375,7 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretint_getReady(
     JNIEnv *env, jclass c, jclass cls, jint depth) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         RETURN_FAILED;
     }
@@ -388,43 +388,43 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretint_getReady(
     }
 
     midRun = env->GetMethodID(cls, "run", "()V");
-    if (midRun == NULL) {
+    if (midRun == nullptr) {
         printf("Cannot find Method ID for method run\n");
         RETURN_FAILED;
     }
 
     midCheckPoint = env->GetMethodID(cls, "checkPoint", "()V");
-    if (midCheckPoint == NULL) {
+    if (midCheckPoint == nullptr) {
         printf("Cannot find Method ID for method checkPoint\n");
         RETURN_FAILED;
     }
 
     midCountDownInt = env->GetMethodID(cls, "countDownInt", "(I)I");
-    if (midCheckPoint == NULL) {
+    if (midCheckPoint == nullptr) {
         printf("Cannot find Method ID for method countDownInt\n");
         RETURN_FAILED;
     }
 
     midCountDownShort = env->GetMethodID(cls, "countDownShort", "(I)S");
-    if (midCountDownShort == NULL) {
+    if (midCountDownShort == nullptr) {
         printf("Cannot find Method ID for method countDownShort\n");
         RETURN_FAILED;
     }
 
     midCountDownChar = env->GetMethodID(cls, "countDownChar", "(I)C");
-    if (midCountDownChar == NULL) {
+    if (midCountDownChar == nullptr) {
         printf("Cannot find Method ID for method countDownChar\n");
         RETURN_FAILED;
     }
 
     midCountDownByte = env->GetMethodID(cls, "countDownByte", "(I)B");
-    if (midCountDownByte == NULL) {
+    if (midCountDownByte == nullptr) {
         printf("Cannot find Method ID for method countDownByte\n");
         RETURN_FAILED;
     }
 
     midCountDownBoolean = env->GetMethodID(cls, "countDownBoolean", "(I)Z");
-    if (midCountDownBoolean == NULL) {
+    if (midCountDownBoolean == nullptr) {
         printf("Cannot find Method ID for method countDownBoolean\n");
         RETURN_FAILED;
     }
@@ -437,7 +437,7 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretint_getReady(
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretlong/earlyretlong.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretlong/earlyretlong.cpp
index 74f358e924b..7261fe3f621 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretlong/earlyretlong.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretlong/earlyretlong.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,15 +36,15 @@ extern "C" {
 
 #define RETURN_FAILED errCode = STATUS_FAILED; fflush(0); return
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint errCode = PASSED;
 static jboolean printdump = JNI_TRUE;
 
-static jmethodID midRun            = NULL;
-static jmethodID midCountDownLong  = NULL;
-static jmethodID midCheckPoint     = NULL;
+static jmethodID midRun            = nullptr;
+static jmethodID midCountDownLong  = nullptr;
+static jmethodID midCheckPoint     = nullptr;
 
 static jint framesExpected = 0;
 static jint framesCount = 0;
@@ -64,7 +64,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
     jclass cls;
     jlocation loc_exp = (frame_no == 0) ? 0x15 : 0xd;
     char *sigClass, *name, *sig, *generic;
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLocalVariableEntry *table = nullptr;
     jint entryCount = 0;
     jint argValue;
     jint j;
@@ -99,7 +99,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
                frame_no, TranslateError(err), err);
         RETURN_FAILED;
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             if (strcmp(table[j].name, argName) == 0) {
                 err = jvmti_env->GetLocalInt(thr, 0,
@@ -119,17 +119,17 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
         printf(", arg value: %d\n", argValue);
     }
 
-    if (sigClass == NULL || strcmp(sigClass, cls_exp) != 0) {
+    if (sigClass == nullptr || strcmp(sigClass, cls_exp) != 0) {
         printf("(step %d) Wrong class sig: \"%s\",\n", frame_no, sigClass);
         printf(" expected: \"%s\"\n", cls_exp);
         RETURN_FAILED;
     }
-    if (name == NULL || strcmp(name, name_exp) != 0) {
+    if (name == nullptr || strcmp(name, name_exp) != 0) {
         printf("(step %d) wrong method name: \"%s\",", frame_no, name);
         printf(" expected: \"%s\"\n", name_exp);
         RETURN_FAILED;
     }
-    if (sig == NULL || strcmp(sig, sig_exp) != 0) {
+    if (sig == nullptr || strcmp(sig, sig_exp) != 0) {
         printf("(step %d) wrong method sig: \"%s\",", frame_no, sig);
         printf(" expected: \"%s\"\n", sig_exp);
         RETURN_FAILED;
@@ -146,16 +146,16 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
         RETURN_FAILED;
     }
 
-    if (sigClass != NULL) {
+    if (sigClass != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sigClass);
     }
-    if (name != NULL) {
+    if (name != nullptr) {
         jvmti_env->Deallocate((unsigned char*)name);
     }
-    if (sig != NULL) {
+    if (sig != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sig);
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             jvmti_env->Deallocate((unsigned char*)(table[j].name));
             jvmti_env->Deallocate((unsigned char*)(table[j].signature));
@@ -294,14 +294,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printf("Printdump is turned on!\n");
 
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong error code from a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -357,7 +357,7 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretlong_getReady(
     jvmtiError err;
 
     val_exp = retval_base;
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         RETURN_FAILED;
     }
@@ -370,19 +370,19 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretlong_getReady(
     }
 
     midRun = env->GetMethodID(cls, "run", "()V");
-    if (midRun == NULL) {
+    if (midRun == nullptr) {
         printf("Cannot find Method ID for method run\n");
         RETURN_FAILED;
     }
 
     midCheckPoint = env->GetMethodID(cls, "checkPoint", "()V");
-    if (midCheckPoint == NULL) {
+    if (midCheckPoint == nullptr) {
         printf("Cannot find Method ID for method checkPoint\n");
         RETURN_FAILED;
     }
 
     midCountDownLong = env->GetMethodID(cls, "countDownLong", "(I)J");
-    if (midCountDownLong == NULL) {
+    if (midCountDownLong == nullptr) {
         printf("Cannot find Method ID for method countDownLong\n");
         RETURN_FAILED;
     }
@@ -395,7 +395,7 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretlong_getReady(
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretobj/earlyretobj.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretobj/earlyretobj.cpp
index 0cdbcb18029..b5f6a60f4c3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretobj/earlyretobj.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretobj/earlyretobj.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,15 +36,15 @@ extern "C" {
 
 #define RETURN_FAILED errCode = STATUS_FAILED; fflush(0); return
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint errCode = PASSED;
 static jboolean printdump = JNI_TRUE;
 
-static jmethodID midRun             = NULL;
-static jmethodID midCountDownObject = NULL;
-static jmethodID midCheckPoint      = NULL;
+static jmethodID midRun             = nullptr;
+static jmethodID midCountDownObject = nullptr;
+static jmethodID midCheckPoint      = nullptr;
 
 static jint framesExpected = 0;
 static jint framesCount = 0;
@@ -52,7 +52,7 @@ static jint methodExitEventCount = 0;
 
 static const char *cls_exp = "Lnsk/jvmti/unit/ForceEarlyReturn/earlyretobj$earlyretThread;";
 
-static jobject val_exp = NULL;
+static jobject val_exp = nullptr;
 static const char  *sig_exp = "(I)Lnsk/jvmti/unit/ForceEarlyReturn/earlyretobj$RetObj;";
 static const char *name_exp = "countDownObject";
 
@@ -64,7 +64,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
     jclass cls;
     jlocation loc_exp = (frame_no == 0) ? 0x15 : 0xd;
     char *sigClass, *name, *sig, *generic;
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLocalVariableEntry *table = nullptr;
     jint entryCount = 0;
     jint argValue;
     jint j;
@@ -99,7 +99,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
                frame_no, TranslateError(err), err);
         RETURN_FAILED;
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             if (strcmp(table[j].name, argName) == 0) {
                 err = jvmti_env->GetLocalInt(thr, 0,
@@ -119,17 +119,17 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
         printf(", arg value: %d\n", argValue);
     }
 
-    if (sigClass == NULL || strcmp(sigClass, cls_exp) != 0) {
+    if (sigClass == nullptr || strcmp(sigClass, cls_exp) != 0) {
         printf("(step %d) Wrong class sig: \"%s\",\n", frame_no, sigClass);
         printf(" expected: \"%s\"\n", cls_exp);
         RETURN_FAILED;
     }
-    if (name == NULL || strcmp(name, name_exp) != 0) {
+    if (name == nullptr || strcmp(name, name_exp) != 0) {
         printf("(step %d) wrong method name: \"%s\",", frame_no, name);
         printf(" expected: \"%s\"\n", name_exp);
         RETURN_FAILED;
     }
-    if (sig == NULL || strcmp(sig, sig_exp) != 0) {
+    if (sig == nullptr || strcmp(sig, sig_exp) != 0) {
         printf("(step %d) wrong method sig: \"%s\",", frame_no, sig);
         printf(" expected: \"%s\"\n", sig_exp);
         RETURN_FAILED;
@@ -146,16 +146,16 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
         RETURN_FAILED;
     }
 
-    if (sigClass != NULL) {
+    if (sigClass != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sigClass);
     }
-    if (name != NULL) {
+    if (name != nullptr) {
         jvmti_env->Deallocate((unsigned char*)name);
     }
-    if (sig != NULL) {
+    if (sig != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sig);
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             jvmti_env->Deallocate((unsigned char*)(table[j].name));
             jvmti_env->Deallocate((unsigned char*)(table[j].signature));
@@ -292,14 +292,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printf("Printdump is turned on!\n");
 
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong error code from a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -354,7 +354,7 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretobj_getReady(
     JNIEnv *env, jclass c, jclass cls, jint depth, jobject ret_obj) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         RETURN_FAILED;
     }
@@ -367,19 +367,19 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretobj_getReady(
     }
 
     midRun = env->GetMethodID(cls, "run", "()V");
-    if (midRun == NULL) {
+    if (midRun == nullptr) {
         printf("Cannot find Method ID for method run\n");
         RETURN_FAILED;
     }
 
     midCheckPoint = env->GetMethodID(cls, "checkPoint", "()V");
-    if (midCheckPoint == NULL) {
+    if (midCheckPoint == nullptr) {
         printf("Cannot find Method ID for method checkPoint\n");
         RETURN_FAILED;
     }
 
     midCountDownObject = env->GetMethodID(cls, "countDownObject", sig_exp);
-    if (midCountDownObject == NULL) {
+    if (midCountDownObject == nullptr) {
         printf("Cannot find Method ID for method countDownObject\n");
         RETURN_FAILED;
     }
@@ -392,7 +392,7 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretobj_getReady(
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretstr/earlyretstr.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretstr/earlyretstr.cpp
index 7622d1065b0..9629ebf46dc 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretstr/earlyretstr.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretstr/earlyretstr.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,15 +35,15 @@ extern "C" {
 
 #define RETURN_FAILED errCode = STATUS_FAILED; fflush(0); return
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint errCode = PASSED;
 static jboolean printdump = JNI_TRUE;
 
-static jmethodID midRun             = NULL;
-static jmethodID midCountDownString = NULL;
-static jmethodID midCheckPoint      = NULL;
+static jmethodID midRun             = nullptr;
+static jmethodID midCountDownString = nullptr;
+static jmethodID midCheckPoint      = nullptr;
 
 static jint framesExpected = 0;
 static jint framesCount = 0;
@@ -51,7 +51,7 @@ static jint methodExitEventCount = 0;
 
 static const char *cls_exp = "Lnsk/jvmti/unit/ForceEarlyReturn/earlyretstr$earlyretThread;";
 
-static jstring str_exp = NULL;
+static jstring str_exp = nullptr;
 static const char  *sig_exp = "(I)Ljava/lang/String;";
 static const char *name_exp = "countDownString";
 
@@ -63,7 +63,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
     jclass cls;
     jlocation loc_exp = (frame_no == 0) ? 0x15 : 0xd;
     char *sigClass, *name, *sig, *generic;
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLocalVariableEntry *table = nullptr;
     jint entryCount = 0;
     jint argValue;
     jint j;
@@ -98,7 +98,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
                frame_no, TranslateError(err), err);
         RETURN_FAILED;
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             if (strcmp(table[j].name, argName) == 0) {
                 err = jvmti_env->GetLocalInt(thr, 0,
@@ -118,17 +118,17 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
         printf(", arg value: %d\n", argValue);
     }
 
-    if (sigClass == NULL || strcmp(sigClass, cls_exp) != 0) {
+    if (sigClass == nullptr || strcmp(sigClass, cls_exp) != 0) {
         printf("(step %d) Wrong class sig: \"%s\",\n", frame_no, sigClass);
         printf(" expected: \"%s\"\n", cls_exp);
         RETURN_FAILED;
     }
-    if (name == NULL || strcmp(name, name_exp) != 0) {
+    if (name == nullptr || strcmp(name, name_exp) != 0) {
         printf("(step %d) wrong method name: \"%s\",", frame_no, name);
         printf(" expected: \"%s\"\n", name_exp);
         RETURN_FAILED;
     }
-    if (sig == NULL || strcmp(sig, sig_exp) != 0) {
+    if (sig == nullptr || strcmp(sig, sig_exp) != 0) {
         printf("(step %d) wrong method sig: \"%s\",", frame_no, sig);
         printf(" expected: \"%s\"\n", sig_exp);
         RETURN_FAILED;
@@ -145,16 +145,16 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
         RETURN_FAILED;
     }
 
-    if (sigClass != NULL) {
+    if (sigClass != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sigClass);
     }
-    if (name != NULL) {
+    if (name != nullptr) {
         jvmti_env->Deallocate((unsigned char*)name);
     }
-    if (sig != NULL) {
+    if (sig != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sig);
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             jvmti_env->Deallocate((unsigned char*)(table[j].name));
             jvmti_env->Deallocate((unsigned char*)(table[j].signature));
@@ -291,14 +291,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printf("Printdump is turned on!\n");
 
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong error code of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -353,7 +353,7 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretstr_getReady(
     JNIEnv *env, jclass c, jclass cls, jint depth, jstring expected_str) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         RETURN_FAILED;
     }
@@ -366,19 +366,19 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretstr_getReady(
     }
 
     midRun = env->GetMethodID(cls, "run", "()V");
-    if (midRun == NULL) {
+    if (midRun == nullptr) {
         printf("Cannot find Method ID for method run\n");
         RETURN_FAILED;
     }
 
     midCheckPoint = env->GetMethodID(cls, "checkPoint", "()V");
-    if (midCheckPoint == NULL) {
+    if (midCheckPoint == nullptr) {
         printf("Cannot find Method ID for method checkPoint\n");
         RETURN_FAILED;
     }
 
     midCountDownString = env->GetMethodID(cls, "countDownString", sig_exp);
-    if (midCountDownString == NULL) {
+    if (midCountDownString == nullptr) {
         printf("Cannot find Method ID for method countDownString\n");
         RETURN_FAILED;
     }
@@ -391,7 +391,7 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretstr_getReady(
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretvoid/earlyretvoid.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretvoid/earlyretvoid.cpp
index 2a50307dc25..567ed23a543 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretvoid/earlyretvoid.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/ForceEarlyReturn/earlyretvoid/earlyretvoid.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,13 +35,13 @@ extern "C" {
 
 #define RETURN_FAILED errCode = STATUS_FAILED; fflush(0); return
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint errCode = PASSED;
 static jboolean printdump = JNI_TRUE;
-static jmethodID midCheckPoint = NULL;
-static jmethodID midRun = NULL;
+static jmethodID midCheckPoint = nullptr;
+static jmethodID midRun = nullptr;
 
 static jint framesExpected = 0;
 static jint framesCount = 0;
@@ -57,7 +57,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
     jclass cls;
     jlocation loc_exp = (frame_no == 0) ? 25 : 11;
     char *sigClass, *name, *sig, *generic;
-    jvmtiLocalVariableEntry *table = NULL;
+    jvmtiLocalVariableEntry *table = nullptr;
     jint entryCount = 0;
     jint argValue;
     jint j;
@@ -92,7 +92,7 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
                frame_no, TranslateError(err), err);
         RETURN_FAILED;
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             if (strcmp(table[j].name, argName) == 0) {
                 err = jvmti_env->GetLocalInt(thr, 0,
@@ -112,17 +112,17 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
         printf(", arg value: %d\n", argValue);
     }
 
-    if (sigClass == NULL || strcmp(sigClass, cls_exp) != 0) {
+    if (sigClass == nullptr || strcmp(sigClass, cls_exp) != 0) {
         printf("(step %d) wrong class sig: \"%s\",\n", frame_no, sigClass);
         printf(" expected: \"%s\"\n", cls_exp);
         RETURN_FAILED;
     }
-    if (name == NULL || strcmp(name, name_exp) != 0) {
+    if (name == nullptr || strcmp(name, name_exp) != 0) {
         printf("(step %d) wrong method name: \"%s\",", frame_no, name);
         printf(" expected: \"%s\"\n", name_exp);
         RETURN_FAILED;
     }
-    if (sig == NULL || strcmp(sig, sig_exp) != 0) {
+    if (sig == nullptr || strcmp(sig, sig_exp) != 0) {
         printf("(step %d) wrong method sig: \"%s\",", frame_no, sig);
         printf(" expected: \"%s\"\n", sig_exp);
         RETURN_FAILED;
@@ -139,16 +139,16 @@ void check(jvmtiEnv *jvmti_env, jthread thr, jmethodID mid,
         RETURN_FAILED;
     }
 
-    if (sigClass != NULL) {
+    if (sigClass != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sigClass);
     }
-    if (name != NULL) {
+    if (name != nullptr) {
         jvmti_env->Deallocate((unsigned char*)name);
     }
-    if (sig != NULL) {
+    if (sig != nullptr) {
         jvmti_env->Deallocate((unsigned char*)sig);
     }
-    if (table != NULL) {
+    if (table != nullptr) {
         for (j = 0; j < entryCount; j++) {
             jvmti_env->Deallocate((unsigned char*)(table[j].name));
             jvmti_env->Deallocate((unsigned char*)(table[j].signature));
@@ -241,14 +241,14 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printf("Printdump is turned on!\n");
 
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong error code from a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -300,7 +300,7 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretvoid_getReady(
     JNIEnv *env, jclass c, jclass cls, jint depth) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         RETURN_FAILED;
     }
@@ -312,13 +312,13 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretvoid_getReady(
     }
 
     midRun = env->GetMethodID(cls, "run", "()V");
-    if (midRun == NULL) {
+    if (midRun == nullptr) {
         printf("Cannot find Method ID for method run\n");
         RETURN_FAILED;
     }
 
     midCheckPoint = env->GetMethodID(cls, "checkPoint", "()V");
-    if (midCheckPoint == NULL) {
+    if (midCheckPoint == nullptr) {
         printf("Cannot find Method ID for method checkPoint\n");
         RETURN_FAILED;
     }
@@ -331,7 +331,7 @@ Java_nsk_jvmti_unit_ForceEarlyReturn_earlyretvoid_getReady(
     }
 
     err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
-        JVMTI_EVENT_BREAKPOINT, NULL);
+        JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetAllStackTraces/getallstktr001/getallstktr001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetAllStackTraces/getallstktr001/getallstktr001.cpp
index 82fa5dfdfa7..a6d2804ba76 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetAllStackTraces/getallstktr001/getallstktr001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetAllStackTraces/getallstktr001/getallstktr001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -64,10 +64,10 @@ static jrawMonitorID jraw_monitor;
 
 
 #define MAX_FRAMES_CNT  30
-static jvmtiStackInfo  *stack_buf1    = NULL;
-static jvmtiStackInfo  *stack_buf2    = NULL;
-static jthread         *thread_list   = NULL;
-static jvmtiThreadInfo *thread_info   = NULL;
+static jvmtiStackInfo  *stack_buf1    = nullptr;
+static jvmtiStackInfo  *stack_buf2    = nullptr;
+static jthread         *thread_list   = nullptr;
+static jvmtiThreadInfo *thread_info   = nullptr;
 static jint             threads_count = 0;
 
 
@@ -191,10 +191,10 @@ void compare_one_stack_trace(int ti,
     static const char* TEST_THREAD_NAME_PREFIX = "getallstktr001-";
     size_t PFX_LEN = strlen(TEST_THREAD_NAME_PREFIX);
 
-    if (thr_info->name != NULL) {
+    if (thr_info->name != nullptr) {
         printf("compare stack #%d: thread: %s\n", ti, thr_info->name);
     } else {
-        printf("compare stack #%d: thread is NULL\n", ti);
+        printf("compare stack #%d: thread is null\n", ti);
         return;
     }
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetConstantPool/getcpool001/getcpool001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetConstantPool/getcpool001/getcpool001.cpp
index feafa26dde2..0514a46224d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetConstantPool/getcpool001/getcpool001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetConstantPool/getcpool001/getcpool001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -39,8 +39,8 @@ static jvmtiEventCallbacks callbacks;
 #define RETURN_FAILED errCode = STATUS_FAILED; fflush(0); return
 
 static jint      errCode       = PASSED;
-static jvmtiEnv *jvmti         = NULL;
-static jmethodID midCheckPoint = NULL;
+static jvmtiEnv *jvmti         = nullptr;
+static jmethodID midCheckPoint = nullptr;
 
 
 JNIEXPORT void JNICALL
@@ -51,7 +51,7 @@ Java_nsk_jvmti_unit_GetConstantPool_getcpool001_getCP(
     int           rep          = 0;
     jint          cp_cnt       = 0;
     jint          cp_bytes_cnt = 0;
-    unsigned char *cp_bytes    = NULL;
+    unsigned char *cp_bytes    = nullptr;
 
     err = jvmti->GetConstantPool(cls, &cp_cnt, &cp_bytes_cnt, &cp_bytes);
     if (err != JVMTI_ERROR_NONE) {
@@ -102,7 +102,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -151,7 +151,7 @@ Java_nsk_jvmti_unit_GetConstantPool_getcpool001_getReady(
     JNIEnv *env, jclass c, jclass cls) {
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         RETURN_FAILED;
     }
@@ -163,7 +163,7 @@ Java_nsk_jvmti_unit_GetConstantPool_getcpool001_getReady(
     }
 
     midCheckPoint = env->GetMethodID(cls, "checkPoint", "()V");
-    if (midCheckPoint == NULL) {
+    if (midCheckPoint == nullptr) {
         printf("Cannot find Method ID for method checkPoint\n");
         RETURN_FAILED;
     }
@@ -175,7 +175,7 @@ Java_nsk_jvmti_unit_GetConstantPool_getcpool001_getReady(
         RETURN_FAILED;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable BREAKPOINT event: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetLineNumberTable/linetab004/linetab004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetLineNumberTable/linetab004/linetab004.cpp
index fb3db7f4be7..9f40468f433 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetLineNumberTable/linetab004/linetab004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetLineNumberTable/linetab004/linetab004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,7 +36,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -56,12 +56,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -97,7 +97,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 void checkGetLineNumberTable(jmethodID mid, const char *methName,
         int abstract, jvmtiError exp) {
     jint entryCount = -1;
-    jvmtiLineNumberEntry *table = NULL;
+    jvmtiLineNumberEntry *table = nullptr;
     jvmtiError err;
     int i;
 
@@ -132,7 +132,7 @@ Java_nsk_jvmti_unit_GetLineNumberTable_linetab004_check(JNIEnv *env, jclass cls)
     jclass abstr;
     jclass interf;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -145,13 +145,13 @@ Java_nsk_jvmti_unit_GetLineNumberTable_linetab004_check(JNIEnv *env, jclass cls)
         printf("\n Check methods of interface:\n");
     }
     interf = env->FindClass("nsk/jvmti/unit/GetLineNumberTable/Interface004");
-    if (interf == NULL) {
+    if (interf == nullptr) {
         printf("Cannot get Interface class!\n");
         return STATUS_FAILED;
     }
 
     mid = env->GetMethodID(cls, "instanceMeth0", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
@@ -159,7 +159,7 @@ Java_nsk_jvmti_unit_GetLineNumberTable_linetab004_check(JNIEnv *env, jclass cls)
         JVMTI_ERROR_ABSENT_INFORMATION);
 
     mid = env->GetMethodID(cls, "instanceMeth1", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
@@ -170,13 +170,13 @@ Java_nsk_jvmti_unit_GetLineNumberTable_linetab004_check(JNIEnv *env, jclass cls)
         printf("\n Check methods of abstract class:\n");
     }
     abstr = env->GetSuperclass(cls);
-    if (abstr == NULL) {
+    if (abstr == nullptr) {
         printf("Cannot get super class!\n");
         return STATUS_FAILED;
     }
 
     mid = env->GetMethodID(abstr, "instanceMeth0", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
@@ -184,7 +184,7 @@ Java_nsk_jvmti_unit_GetLineNumberTable_linetab004_check(JNIEnv *env, jclass cls)
         JVMTI_ERROR_ABSENT_INFORMATION);
 
     mid = env->GetMethodID(abstr, "instanceMeth1", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
@@ -195,7 +195,7 @@ Java_nsk_jvmti_unit_GetLineNumberTable_linetab004_check(JNIEnv *env, jclass cls)
         printf("\n Check methods of regular class:\n");
     }
     mid = env->GetMethodID(cls, "instanceMeth0", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
@@ -203,7 +203,7 @@ Java_nsk_jvmti_unit_GetLineNumberTable_linetab004_check(JNIEnv *env, jclass cls)
         JVMTI_ERROR_ABSENT_INFORMATION);
 
     mid = env->GetMethodID(cls, "instanceMeth1", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
@@ -211,7 +211,7 @@ Java_nsk_jvmti_unit_GetLineNumberTable_linetab004_check(JNIEnv *env, jclass cls)
         JVMTI_ERROR_ABSENT_INFORMATION);
 
     mid = env->GetMethodID(cls, "instanceMeth2", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
@@ -222,7 +222,7 @@ Java_nsk_jvmti_unit_GetLineNumberTable_linetab004_check(JNIEnv *env, jclass cls)
         printf("\n Check native methods of regular class:\n");
     }
     mid = env->GetMethodID(cls, "instanceNativeMeth", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
@@ -230,7 +230,7 @@ Java_nsk_jvmti_unit_GetLineNumberTable_linetab004_check(JNIEnv *env, jclass cls)
         JVMTI_ERROR_NATIVE_METHOD);
 
     mid = env->GetStaticMethodID(cls, "staticNativeMeth", "()I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot get method ID!\n");
         return STATUS_FAILED;
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetLocalVariable/getlocal003/getlocal003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetLocalVariable/getlocal003/getlocal003.cpp
index 1688cd1b723..4361f6df756 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetLocalVariable/getlocal003/getlocal003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetLocalVariable/getlocal003/getlocal003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,12 +34,12 @@ extern "C" {
 #define STATUS_PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = STATUS_PASSED;
 static jboolean printdump = JNI_FALSE;
-static jmethodID mid = NULL;
-static jvmtiLocalVariableEntry *table = NULL;
+static jmethodID mid = nullptr;
+static jvmtiLocalVariableEntry *table = nullptr;
 static jint entryCount = 0;
 static jint methodExitCnt = -1;
 
@@ -140,7 +140,7 @@ MethodExit(jvmtiEnv *jvmti_env,
 
     jvmtiError err;
     jlocation location;
-    jmethodID frame_method = NULL;
+    jmethodID frame_method = nullptr;
 
     if (mid != method) {
         return;
@@ -181,12 +181,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     static jvmtiCapabilities caps;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -233,12 +233,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 JNIEXPORT void JNICALL
 Java_nsk_jvmti_unit_GetLocalVariable_getlocal003_instMeth(JNIEnv *env, jobject inst) {
     jvmtiError err;
-    jobject obj = NULL;
+    jobject obj = nullptr;
 
     printf("\n Native instMeth: started\n");
 
     // Test GetLocalInstance with native instance method instMeth() frame
-    err = jvmti->GetLocalInstance(NULL, 0, &obj);
+    err = jvmti->GetLocalInstance(nullptr, 0, &obj);
     printf(" Native instMeth: GetLocalInstance: %s (%d)\n", TranslateError(err), err);
     if (err != JVMTI_ERROR_NONE) {
         printf("FAIL: GetLocalInstance failed to get instance for native instance method frame\n");
@@ -250,7 +250,7 @@ Java_nsk_jvmti_unit_GetLocalVariable_getlocal003_instMeth(JNIEnv *env, jobject i
     }
 
     // Test GetLocalInstance with java instance method meth01() frame
-    err = jvmti->GetLocalInstance(NULL, 1, &obj);
+    err = jvmti->GetLocalInstance(nullptr, 1, &obj);
     printf(" Native instMeth: GetLocalInstance: %s (%d)\n", TranslateError(err), err);
     if (err != JVMTI_ERROR_NONE) {
         printf("FAIL: GetLocalInstance failed to get instance for java instance method frame\n");
@@ -266,18 +266,18 @@ Java_nsk_jvmti_unit_GetLocalVariable_getlocal003_instMeth(JNIEnv *env, jobject i
 JNIEXPORT void JNICALL
 Java_nsk_jvmti_unit_GetLocalVariable_getlocal003_getMeth(JNIEnv *env, jclass cls) {
     jvmtiError err;
-    jobject obj = NULL;
+    jobject obj = nullptr;
 
     printf("\n Native getMeth: started\n");
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
     }
 
     mid = env->GetStaticMethodID(cls, "staticMeth", "(I)I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find Method ID for staticMeth\n");
         result = STATUS_FAILED;
         return;
@@ -291,7 +291,7 @@ Java_nsk_jvmti_unit_GetLocalVariable_getlocal003_getMeth(JNIEnv *env, jclass cls
         return;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_EXIT, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_EXIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable metod exit event: %s (%d)\n",
                TranslateError(err), err);
@@ -299,7 +299,7 @@ Java_nsk_jvmti_unit_GetLocalVariable_getlocal003_getMeth(JNIEnv *env, jclass cls
     }
 
     // Test GetLocalInstance with native static method getMeth() frame
-    err = jvmti->GetLocalInstance(NULL, 0, &obj);
+    err = jvmti->GetLocalInstance(nullptr, 0, &obj);
     printf(" Native getMeth: GetLocalInstance: %s (%d)\n", TranslateError(err), err);
     if (err != JVMTI_ERROR_INVALID_SLOT) {
         printf("FAIL: GetLocalInstance failed to return JVMTI_ERROR_INVALID_SLOT for native static method frame\n");
@@ -307,7 +307,7 @@ Java_nsk_jvmti_unit_GetLocalVariable_getlocal003_getMeth(JNIEnv *env, jclass cls
     }
 
     // Test GetLocalInstance with java static method run() frame
-    err = jvmti->GetLocalInstance(NULL, 1, &obj);
+    err = jvmti->GetLocalInstance(nullptr, 1, &obj);
     printf(" Native getMeth: GetLocalInstance: %s (%d)\n", TranslateError(err), err);
     if (err != JVMTI_ERROR_INVALID_SLOT) {
         printf("FAIL: GetLocalInstance failed to return JVMTI_ERROR_INVALID_SLOT for java static method frame\n");
@@ -329,7 +329,7 @@ Java_nsk_jvmti_unit_GetLocalVariable_getlocal003_checkLoc(JNIEnv *env,
     jint i, j;
     int  overlap = 0;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
@@ -337,7 +337,7 @@ Java_nsk_jvmti_unit_GetLocalVariable_getlocal003_checkLoc(JNIEnv *env,
     printf("\n checkLoc: START\n");
 
     mid = env->GetStaticMethodID(cls, "staticMeth", "(I)I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find Method ID for staticMeth\n");
         result = STATUS_FAILED;
         return;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetLocalVariable/getlocal004/getlocal004.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetLocalVariable/getlocal004/getlocal004.cpp
index c63875c7da5..a74ca32f27b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetLocalVariable/getlocal004/getlocal004.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/GetLocalVariable/getlocal004/getlocal004.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = STATUS_PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -61,12 +61,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     static jvmtiCapabilities caps;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -105,16 +105,16 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
 JNIEXPORT void JNICALL
 Java_nsk_jvmti_unit_GetLocalVariable_getlocal004_getMeth(JNIEnv *env, jclass cls) {
-    jmethodID mid = NULL;
+    jmethodID mid = nullptr;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         result = STATUS_FAILED;
         return;
     }
 
     mid = env->GetStaticMethodID(cls, "staticMeth", "(I)I");
-    if (mid == NULL) {
+    if (mid == nullptr) {
         printf("Cannot find Method ID for staticMeth\n");
         result = STATUS_FAILED;
         return;
@@ -156,7 +156,7 @@ Java_nsk_jvmti_unit_GetLocalVariable_getlocal004_checkLoc(JNIEnv *env,
     jlong      locLong   = 0L;
     jdouble    locDouble = 0.0f;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         return;
     }
     printf("\n ----------------- checkLoc: %d -----------------\n\n", scope_no);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/IsSynthetic/issynth001/issynth001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/IsSynthetic/issynth001/issynth001.cpp
index 7587d47178b..8ebe8508577 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/IsSynthetic/issynth001/issynth001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/IsSynthetic/issynth001/issynth001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define JVM_ACC_SYNTHETIC     0x1000
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -54,12 +54,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -102,9 +102,9 @@ checkClassMethods(jclass klass) {
     jmethodID mid;
     jboolean isSynthetic;
     jint meth_cnt = 0;
-    jmethodID* methods_ptr = NULL;
-    char* name_ptr = NULL;
-    char* sign_ptr = NULL;
+    jmethodID* methods_ptr = nullptr;
+    char* name_ptr = nullptr;
+    char* sign_ptr = nullptr;
     int i;
 
     err = jvmti->GetClassMethods(klass, &meth_cnt, &methods_ptr);
@@ -118,7 +118,7 @@ checkClassMethods(jclass klass) {
         jint mods;
         mid = methods_ptr[i];
         err = jvmti->GetMethodName(mid, &name_ptr,
-                                    &sign_ptr, (char **) NULL);
+                                    &sign_ptr, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("(GetMethodName#%d) unexpected error: %s (%d)\n",
                    i, TranslateError(err), err);
@@ -160,12 +160,12 @@ checkClassFields(jclass klass) {
     jfieldID fid;
     jboolean isSynthetic;
     jint fld_cnt = 0;
-    jfieldID* fields_ptr = NULL;
-    char* name_ptr = NULL;
-    char* sign_ptr = NULL;
+    jfieldID* fields_ptr = nullptr;
+    char* name_ptr = nullptr;
+    char* sign_ptr = nullptr;
     int i;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -181,7 +181,7 @@ checkClassFields(jclass klass) {
         jint mods;
         fid = fields_ptr[i];
         err = jvmti->GetFieldName(klass, fid, &name_ptr,
-                                    &sign_ptr, (char **) NULL);
+                                    &sign_ptr, nullptr);
         if (err != JVMTI_ERROR_NONE) {
             printf("(GetFieldName#%d) unexpected error: %s (%d)\n",
                    i, TranslateError(err), err);
@@ -222,13 +222,13 @@ Java_nsk_jvmti_unit_IsSynthetic_issynth001_check(JNIEnv *env,
         jclass cls, jclass klass) {
 
     jvmtiError err;
-    char* class_sign = NULL;
+    char* class_sign = nullptr;
 
     if (!caps.can_get_synthetic_attribute) {
         return result;
     }
 
-    err = jvmti->GetClassSignature(cls, &class_sign, (char **) NULL);
+    err = jvmti->GetClassSignature(cls, &class_sign, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("GetSourceFileName unexpected error: %s (%d)\n",
                TranslateError(err), err);
@@ -249,7 +249,7 @@ Java_nsk_jvmti_unit_IsSynthetic_issynth001_check(JNIEnv *env,
         return result;
     }
 
-    err = jvmti->GetClassSignature(klass, &class_sign, (char **) NULL);
+    err = jvmti->GetClassSignature(klass, &class_sign, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("GetSourceFileName unexpected error: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/MethodBind/JvmtiTest/JvmtiTest.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/MethodBind/JvmtiTest/JvmtiTest.cpp
index a70807450d6..b68e220470b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/MethodBind/JvmtiTest/JvmtiTest.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/MethodBind/JvmtiTest/JvmtiTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -77,7 +77,7 @@ findLoadClass_type findLoadedClass_func;
 
 JNIEXPORT jclass JNICALL
 my_findLoadedClass(JNIEnv *env, jobject loader, jstring name) {
-  const char* sname = env->GetStringUTFChars(name, NULL);
+  const char* sname = env->GetStringUTFChars(name, nullptr);
   debug_printf("Intercepted findLoadedClass, name = %s\n", sname);
   return (*findLoadedClass_func)(env, loader, name);
 }
@@ -102,7 +102,7 @@ void JNICALL testNativeMethodBind(jvmtiEnv* jvmti_env, JNIEnv *jni_env,
     debug_printf("bind event: \n");
     print_method_name(mid);
 
-    ret = jvmti_env->GetMethodName(mid, &mname, &signature, NULL);
+    ret = jvmti_env->GetMethodName(mid, &mname, &signature, nullptr);
     if (ret == JVMTI_ERROR_NONE) {
       if (strcmp(mname, "findLoadedClass") == 0) {
         findLoadedClass_func = (findLoadClass_type)func;
@@ -161,13 +161,13 @@ jint Agent_Initialize(JavaVM * jvm, char *options, void *reserved) {
     res = jvmti->SetEventCallbacks(&callbacks, sizeof(callbacks));
     JVMTI_ERROR_CHECK("SetEventCallbacks returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for VM_INIT returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for vm death event returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for native method bind event returned error", res);
 
     return JNI_OK;
@@ -275,14 +275,14 @@ print_method_name(jmethodID mid) {
       return;
     }
 
-    ret = jvmti->GetClassSignature(klass, &clname, NULL);
+    ret = jvmti->GetClassSignature(klass, &clname, nullptr);
     if (ret != JVMTI_ERROR_NONE) {
       printf("Error: GetClassSignature %d  \n", ret);
       iGlobalStatus = 2;
       return;
     }
 
-    ret = jvmti->GetMethodName(mid, &mname, &signature, NULL);
+    ret = jvmti->GetMethodName(mid, &mname, &signature, nullptr);
     if (ret != JVMTI_ERROR_NONE) {
       printf("Error: GetMethodName %d  \n", ret);
       iGlobalStatus = 2;
@@ -296,7 +296,7 @@ print_method_name(jmethodID mid) {
 JNIEXPORT void JNICALL
 Java_nsk_jvmti_unit_MethodBind_JvmtiTest_GetStackTrace(JNIEnv * env, jclass cls, jobject thr) {
     jvmtiError ret;
-    jvmtiFrameInfo *stack_buffer = NULL;
+    jvmtiFrameInfo *stack_buffer = nullptr;
     jint max_count = 20;
     jint count;
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/StackTrace/JvmtiTest/JvmtiTest.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/StackTrace/JvmtiTest/JvmtiTest.cpp
index 572ff53c5ef..fbaf0fa1816 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/StackTrace/JvmtiTest/JvmtiTest.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/StackTrace/JvmtiTest/JvmtiTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -195,8 +195,8 @@ Java_nsk_jvmti_unit_StackTrace_JvmtiTest_GetFrameCount(JNIEnv * env, jclass cls,
 JNIEXPORT void JNICALL
 Java_nsk_jvmti_unit_StackTrace_JvmtiTest_GetStackTrace(JNIEnv * env, jclass cls, jobject thr) {
     jvmtiError ret;
-    jvmtiFrameInfo *stack_buffer = NULL;
-    jvmtiFrameInfo *compare_buffer = NULL;
+    jvmtiFrameInfo *stack_buffer = nullptr;
+    jvmtiFrameInfo *compare_buffer = nullptr;
     jint max_count = 20;
     jint count;
     jclass klass;
@@ -291,14 +291,14 @@ Java_nsk_jvmti_unit_StackTrace_JvmtiTest_GetStackTrace(JNIEnv * env, jclass cls,
             return;
         }
 
-        ret = jvmti->GetClassSignature(klass, &clname, NULL);
+        ret = jvmti->GetClassSignature(klass, &clname, nullptr);
         if (ret != JVMTI_ERROR_NONE) {
             printf("Error: GetClassSignature %d  \n", ret);
             iGlobalStatus = 2;
             return;
         }
 
-        ret = jvmti->GetMethodName(stack_buffer[i].method, &mname, &signature, NULL);
+        ret = jvmti->GetMethodName(stack_buffer[i].method, &mname, &signature, nullptr);
         if (ret != JVMTI_ERROR_NONE) {
             printf("Error: GetMethodName %d  \n", ret);
             iGlobalStatus = 2;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/agentthr/agentthr.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/agentthr/agentthr.cpp
index 58e2cfe9498..17e7f517923 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/agentthr/agentthr.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/agentthr/agentthr.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@ extern "C" {
 #define STATUS_FAILED 2
 
 static JavaVM *jvm_ins;
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
@@ -121,13 +121,13 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiError err;
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     jvm_ins = jvm;
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -140,7 +140,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable JVMTI_EVENT_THREAD_START: %s (%d)\n",
                TranslateError(err), err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/clsldrclss00x/clsldrclss00x.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/clsldrclss00x/clsldrclss00x.cpp
index 2efbf140649..c1adeb386ff 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/clsldrclss00x/clsldrclss00x.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/clsldrclss00x/clsldrclss00x.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 
@@ -51,12 +51,12 @@ JNIEXPORT jint JNI_OnLoad_clsldrclss00x(JavaVM *jvm, char *options, void *reserv
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jint res;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-    if (res != JNI_OK || jvmti == NULL) {
+    if (res != JNI_OK || jvmti == nullptr) {
         printf("Wrong result of a valid call to GetEnv!\n");
         return JNI_ERR;
     }
@@ -74,7 +74,7 @@ Java_nsk_jvmti_unit_clsldrclss00x_check(JNIEnv *env, jclass appCls, jclass objCl
     jboolean found;
     jint i;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -86,8 +86,8 @@ Java_nsk_jvmti_unit_clsldrclss00x_check(JNIEnv *env, jclass appCls, jclass objCl
         result = STATUS_FAILED;
         return result;
     }
-    if (appClassloader == NULL) {
-        printf("(GetClassLoader app) unexpected loader - NULL\n");
+    if (appClassloader == nullptr) {
+        printf("(GetClassLoader app) unexpected loader - null\n");
         result = STATUS_FAILED;
         return result;
     }
@@ -99,8 +99,8 @@ Java_nsk_jvmti_unit_clsldrclss00x_check(JNIEnv *env, jclass appCls, jclass objCl
         result = STATUS_FAILED;
         return result;
     }
-    if (objClassloader != NULL) {
-        printf("(GetClassLoader obj) unexpected loader - !NULL\n");
+    if (objClassloader != nullptr) {
+        printf("(GetClassLoader obj) unexpected loader - !null\n");
         result = STATUS_FAILED;
         return result;
     }
@@ -117,7 +117,7 @@ Java_nsk_jvmti_unit_clsldrclss00x_check(JNIEnv *env, jclass appCls, jclass objCl
         for (i = 0; i < classCount; ++i) {
           char *classSig;
           jclass k = classes[i];
-          err = jvmti->GetClassSignature(k, &classSig, NULL);
+          err = jvmti->GetClassSignature(k, &classSig, nullptr);
           if (err != JVMTI_ERROR_NONE) {
             printf("Error (getClassSignature): %s (%d)\n", TranslateError(err), err);
             result = STATUS_FAILED;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/events/redefineCFLH/JvmtiTest/JvmtiTest.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/events/redefineCFLH/JvmtiTest/JvmtiTest.cpp
index 37ba70728c1..59ed1561bb2 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/events/redefineCFLH/JvmtiTest/JvmtiTest.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/events/redefineCFLH/JvmtiTest/JvmtiTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@ extern "C" {
 #define STATUS_FAILED 2
 #define PASSED 0
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jvmtiCapabilities caps;
 static jvmtiEventCallbacks callbacks;
 static jint result = PASSED;
@@ -63,12 +63,12 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *env,
     char *sig;
     char *gen;
 
-    if (name != NULL && (strcmp(name, CLASS_NAME) == 0)) {
+    if (name != nullptr && (strcmp(name, CLASS_NAME) == 0)) {
         if (printdump == JNI_TRUE) {
             printf("Received class file load hook event for class %s\n", name);
         }
 
-        if (redefined_class != NULL) {
+        if (redefined_class != nullptr) {
             err = jvmti->GetClassSignature(redefined_class, &sig, &gen);
             if (err != JVMTI_ERROR_NONE) {
                 printf("(GetClassSignature) unexpected error: %s (%d)\n",
@@ -106,7 +106,7 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
     jint res;
     jvmtiError err;
 
-    if (options != NULL && strcmp(options, "printdump") == 0) {
+    if (options != nullptr && strcmp(options, "printdump") == 0) {
         printdump = JNI_TRUE;
     }
 
@@ -150,14 +150,14 @@ jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
         return JNI_ERR;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable event JVMTI_EVENT_VM_INIT: %s (%d)\n",
                TranslateError(err), err);
         return JNI_ERR;
     }
 
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         printf("Failed to enable event JVMTI_EVENT_CLASS_FILE_LOAD_HOOK: %s (%d)\n",
                TranslateError(err), err);
@@ -173,7 +173,7 @@ Java_nsk_jvmti_unit_events_redefineCFLH_JvmtiTest_makeRedefinition(JNIEnv *env,
     jvmtiClassDefinition classDef;
     jvmtiError err;
 
-    if (jvmti == NULL) {
+    if (jvmti == nullptr) {
         printf("JVMTI client was not properly loaded!\n");
         return STATUS_FAILED;
     }
@@ -185,7 +185,7 @@ Java_nsk_jvmti_unit_events_redefineCFLH_JvmtiTest_makeRedefinition(JNIEnv *env,
 /* filling the structure jvmtiClassDefinition */
     classDef.klass = redefCls;
     classDef.class_byte_count = env->GetArrayLength(classBytes);
-    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);
+    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, nullptr);
 
     if (fl == 2) {
         printf(">>>>>>>> Invoke RedefineClasses():\n");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/extmech/extmech.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/extmech/extmech.cpp
index 4d7b9868670..3dfa394efc5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/extmech/extmech.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/extmech/extmech.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -100,7 +100,7 @@ Java_nsk_jvmti_unit_extmech_enableClassUnloadEvent
         if (strcmp(ext_events[i].id, (char*)"com.sun.hotspot.events.ClassUnload") == 0) {
 
             err = jvmti->SetExtensionEventCallback(ext_events[i].extension_event_index,
-                enable ? (jvmtiExtensionEvent)ClassUnload : NULL);
+                enable ? (jvmtiExtensionEvent)ClassUnload : nullptr);
 
             if (err != JVMTI_ERROR_NONE) {
                 fprintf(stderr, "SetExtenionEventCallback failed: %d\n", err);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/AddToBootstrapClassLoaderSearch/JvmtiTest/JvmtiTest.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/AddToBootstrapClassLoaderSearch/JvmtiTest/JvmtiTest.cpp
index 4d38e540d87..1ef592cd959 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/AddToBootstrapClassLoaderSearch/JvmtiTest/JvmtiTest.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/AddToBootstrapClassLoaderSearch/JvmtiTest/JvmtiTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -143,13 +143,13 @@ classFileLoadEvent(jvmtiEnv *jvmti_env, JNIEnv *env,
                         jint* new_class_data_len,
                         unsigned char** new_class_data) {
 
-    if (name != NULL && (strcmp(name, BOOT_CLASS) == 0)) {
+    if (name != nullptr && (strcmp(name, BOOT_CLASS) == 0)) {
         debug_printf("Received class file load hook event for class: \n\t%s\n",
             name);
         debug_printf("Received class loader: 0x%p \n", loader);
         /* Check to make sure Boot class got loaded from bootstrap class path.*/
 
-      if (loader == NULL) {
+      if (loader == nullptr) {
          boot_class_count++;
       }
    }
@@ -192,7 +192,7 @@ jint Agent_Initialize(JavaVM * jvm, char *options, void *reserved) {
         strncpy(segment, options, (size_t) sizeof(segment)/sizeof(char));
         segment[(size_t) sizeof(segment)/sizeof(char) - 1] = 0;
         idx = strchr(segment, ',');
-        if (idx != NULL) *idx = 0;
+        if (idx != nullptr) *idx = 0;
     }
 
     res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
@@ -214,19 +214,19 @@ jint Agent_Initialize(JavaVM * jvm, char *options, void *reserved) {
     res = jvmti->SetEventCallbacks(&callbacks, sizeof(callbacks));
     JVMTI_ERROR_CHECK("SetEventCallbacks returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_START, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_START, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for VM_START returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for VM_INIT returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for NATIVE_METHOD_BIND returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for VM_DEATH returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode CLASS_FILE_LOAD_HOOK returned error", res);
 
     strcat(segment, "/newclass");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/Dispose/JvmtiTest/JvmtiTest.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/Dispose/JvmtiTest/JvmtiTest.cpp
index f85d438a68a..24066525e63 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/Dispose/JvmtiTest/JvmtiTest.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/Dispose/JvmtiTest/JvmtiTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -115,7 +115,7 @@ jint Agent_Initialize(JavaVM * jvm, char *options, void *reserved) {
     JVMTI_ERROR_CHECK("GetAddCapabilities returned error", res);
 
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for VM_INIT returned error", res);
 
     res = jvmti->GetSystemProperties(&count, &properties);
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/ForceGarbageCollection/gc/gc.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/ForceGarbageCollection/gc/gc.cpp
index f3ff582ea8d..e1c57fa08d2 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/ForceGarbageCollection/gc/gc.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/ForceGarbageCollection/gc/gc.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -134,16 +134,16 @@ jint Agent_Initialize(JavaVM * jvm, char *options, void *reserved) {
     res = jvmti->SetEventCallbacks(&callbacks, sizeof(callbacks));
     JVMTI_ERROR_CHECK("SetEventCallbacks returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for VM_INIT returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for vm death event returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for gc start returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for gc finish returned error", res);
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/nosuspendMonitorInfo/JvmtiTest/JvmtiTest.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/nosuspendMonitorInfo/JvmtiTest/JvmtiTest.cpp
index 4c0e6fbbc6b..66799c3d004 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/nosuspendMonitorInfo/JvmtiTest/JvmtiTest.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/nosuspendMonitorInfo/JvmtiTest/JvmtiTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -134,10 +134,10 @@ jint Agent_Initialize(JavaVM * jvm, char *options, void *reserved) {
     res = jvmti->SetEventCallbacks(&callbacks, sizeof(callbacks));
     JVMTI_ERROR_CHECK("SetEventCallbacks returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for VM_INIT returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for vm death event returned error", res);
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/nosuspendStackTrace/JvmtiTest/JvmtiTest.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/nosuspendStackTrace/JvmtiTest/JvmtiTest.cpp
index c3934dd0b90..432045f98e2 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/nosuspendStackTrace/JvmtiTest/JvmtiTest.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/nosuspendStackTrace/JvmtiTest/JvmtiTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -133,10 +133,10 @@ jint Agent_Initialize(JavaVM * jvm, char *options, void *reserved) {
     res = jvmti->SetEventCallbacks(&callbacks, sizeof(callbacks));
     JVMTI_ERROR_CHECK("SetEventCallbacks returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for VM_INIT returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for vm death event returned error", res);
 
     return JNI_OK;
@@ -233,7 +233,7 @@ Java_nsk_jvmti_unit_functions_nosuspendStackTrace_JvmtiTest_GetFrameCount(JNIEnv
 JNIEXPORT void JNICALL
 Java_nsk_jvmti_unit_functions_nosuspendStackTrace_JvmtiTest_GetStackTrace(JNIEnv * env, jclass cls, jobject thr) {
     jvmtiError ret;
-    jvmtiFrameInfo *stack_buffer = NULL;
+    jvmtiFrameInfo *stack_buffer = nullptr;
     jint count = 20;
     jclass klass;
     char *mname;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/rawmonitor/rawmonitor.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/rawmonitor/rawmonitor.cpp
index b7df38f8ecc..55267f99ead 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/rawmonitor/rawmonitor.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/rawmonitor/rawmonitor.cpp
@@ -1,6 +1,6 @@
 /*
 s
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -222,13 +222,13 @@ jint Agent_Initialize(JavaVM * jvm, char *options, void *reserved) {
     res = jvmti->SetEventCallbacks(&callbacks, sizeof(callbacks));
     JVMTI_ERROR_CHECK("SetEventCallbacks returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for VM_INIT returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for vm death event returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode CLASS_FILE_LOAD_HOOK returned error", res);
 
      /* acquire lock in onload */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/heapref/heapref.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/heapref/heapref.cpp
index 640779eb75c..bab6bfbbfca 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/heapref/heapref.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/heapref/heapref.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,7 +35,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static jvmtiCapabilities jvmti_caps;
@@ -70,8 +70,8 @@ typedef struct _refLink {
   struct _refLink *next;
 } refLink;
 
-static MyTag *fakeRoot = NULL;
-static MyTag *missed = NULL;
+static MyTag *fakeRoot = nullptr;
+static MyTag *missed = nullptr;
 
 static void breakpoint() {
   printf("Continuing from BREAKPOINT\n");
@@ -82,10 +82,10 @@ static MyTag *newTag(refKind kind,
                      jlong size,
                      const char* name) {
   static jlong seq_num = 0;
-  MyTag* new_tag = NULL;
+  MyTag* new_tag = nullptr;
 
   new_tag = (MyTag*) malloc(sizeof(MyTag));
-  if (NULL == new_tag) {
+  if (nullptr == new_tag) {
     printf("Error (newTag malloc): failed\n");
     result = STATUS_FAILED;
   }
@@ -95,7 +95,7 @@ static MyTag *newTag(refKind kind,
   new_tag->sequence = ++seq_num;
   new_tag->visited = JNI_FALSE;
   new_tag->name = name;
-  new_tag->ref = NULL;
+  new_tag->ref = nullptr;
   return new_tag;
 }
 
@@ -103,11 +103,11 @@ static void setTag(JNIEnv *env,
                    jobject obj,
                    refKind kind,
                    const char* name) {
-  MyTag *new_tag = NULL;
-  MyTag *class_tag = NULL;
+  MyTag *new_tag = nullptr;
+  MyTag *class_tag = nullptr;
   jvmtiError err;
   jlong size = 0;
-  jclass obj_class = NULL;
+  jclass obj_class = nullptr;
   jlong haba = 0;
 
   err = jvmti->GetObjectSize(obj, &size);
@@ -124,7 +124,7 @@ static void setTag(JNIEnv *env,
     printf("Error (GetTag): %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
   }
-  if (class_tag != NULL && class_tag->kind != rclass) {
+  if (class_tag != nullptr && class_tag->kind != rclass) {
     printf("Error class tag which is not a class\n");
     result = STATUS_FAILED;
   }
@@ -142,7 +142,7 @@ static void addRef(MyTag *from, int reference_kind, MyTag *to) {
   refLink *new_ref;
 
   new_ref = (refLink*) malloc(sizeof(refLink));
-  if (NULL == new_ref) {
+  if (nullptr == new_ref) {
     printf("Error (addRef malloc): failed\n");
     result = STATUS_FAILED;
   }
@@ -215,7 +215,7 @@ static void walk(MyTag* tag, jint depth, const char* ref_label) {
   const char *indent = spaces + (len - 2 * depth);
 
   const MyTag* const ctag = tag->class_tag;
-  const char* const cname = ctag != NULL ? ctag->name : "";
+  const char* const cname = ctag != nullptr ? ctag->name : "";
 
   printf("%s", indent);
 
@@ -258,12 +258,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
   jvmtiError err;
 
-  if (options != NULL && strcmp(options, "printdump") == 0) {
+  if (options != nullptr && strcmp(options, "printdump") == 0) {
     printdump = JNI_TRUE;
   }
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     printf("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -281,7 +281,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
 jvmtiIterationControl JNICALL
 heapMarkCallback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data) {
-  const MyTag* const tag = newTag(rmark, (const MyTag*)(intptr_t)class_tag, size, NULL);
+  const MyTag* const tag = newTag(rmark, (const MyTag*)(intptr_t)class_tag, size, nullptr);
   *tag_ptr = (intptr_t)tag;
 
   if (user_data != &dummy_user_data && user_data_error_flag == JNI_FALSE) {
@@ -300,7 +300,7 @@ heapRootCallback(jvmtiHeapRootKind root_kind,
 
   if (0 == *tag_ptr) {
     /* new tag */
-    MyTag* tag = newTag(kind, (MyTag*)(intptr_t)class_tag, size, NULL);
+    MyTag* tag = newTag(kind, (MyTag*)(intptr_t)class_tag, size, nullptr);
     addRef(fakeRoot, HEAP_ROOT_REF_KIND_BASE+root_kind, tag);
     *tag_ptr = (intptr_t)tag;
   } else {
@@ -326,7 +326,7 @@ stackReferenceCallback(jvmtiHeapRootKind root_kind,
 
   if (0 == *tag_ptr) {
     /* new tag */
-    MyTag* tag = newTag(kind, (MyTag*)(intptr_t)class_tag, size, NULL);
+    MyTag* tag = newTag(kind, (MyTag*)(intptr_t)class_tag, size, nullptr);
     addRef(fakeRoot, HEAP_ROOT_REF_KIND_BASE+root_kind, tag);
     *tag_ptr = (intptr_t)tag;
   } else {
@@ -347,7 +347,7 @@ objectReferenceCallback(jvmtiObjectReferenceKind reference_kind,
                         jlong* tag_ptr, jlong referrer_tag,
                         jint referrer_index, void* user_data) {
   refKind kind = rother;
-  MyTag* referrer = NULL;
+  MyTag* referrer = nullptr;
 
   if (0 == referrer_tag) {
     referrer = missed;
@@ -357,7 +357,7 @@ objectReferenceCallback(jvmtiObjectReferenceKind reference_kind,
 
   if (0 == *tag_ptr) {
     /* new tag */
-    MyTag* tag = newTag(kind, (MyTag*)(intptr_t)class_tag, size, NULL);
+    MyTag* tag = newTag(kind, (MyTag*)(intptr_t)class_tag, size, nullptr);
     addRef(referrer, reference_kind, tag);
     *tag_ptr = (intptr_t) tag;
   } else {
@@ -382,13 +382,13 @@ Java_nsk_jvmti_unit_heapref_check(JNIEnv *env, jclass cls) {
   jint threadCount = 0;
   jint i;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     printf("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
 
-  fakeRoot = newTag(rother, (const MyTag *)NULL, 0, "FAKE_ROOT");
-  missed = newTag(rother, (const MyTag *)NULL, 0, "MISSED");
+  fakeRoot = newTag(rother, nullptr, 0, "FAKE_ROOT");
+  missed = newTag(rother, nullptr, 0, "MISSED");
 
   if (env->PushLocalFrame(500) != 0) {
     printf("Error (PushLocalFrame): failed\n");
@@ -404,7 +404,7 @@ Java_nsk_jvmti_unit_heapref_check(JNIEnv *env, jclass cls) {
   for (i = 0; i < classCount; ++i) {
     char *classSig;
     jclass k = classes[i];
-    err = jvmti->GetClassSignature(k, &classSig, NULL);
+    err = jvmti->GetClassSignature(k, &classSig, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       printf("Error (getClassSignature): %s (%d)\n", TranslateError(err), err);
       result = STATUS_FAILED;
@@ -414,7 +414,7 @@ Java_nsk_jvmti_unit_heapref_check(JNIEnv *env, jclass cls) {
       if (classSig[len-1] == ';') {
         classSig[len-1] = 0;
       }
-      if (*classSig == 'L' && slash != NULL) {
+      if (*classSig == 'L' && slash != nullptr) {
         classSig = slash + 1;
       }
       setTag(env, k, rclass, (const char*)classSig);
@@ -439,7 +439,7 @@ Java_nsk_jvmti_unit_heapref_check(JNIEnv *env, jclass cls) {
     }
   }
 
-  env->PopLocalFrame(NULL);
+  env->PopLocalFrame(nullptr);
 
   user_data_error_flag = JNI_FALSE;
   err = jvmti->IterateOverHeap(
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/refignore/refignore.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/refignore/refignore.cpp
index bdf8f3b368d..eb840e39061 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/refignore/refignore.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/refignore/refignore.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,7 +35,7 @@ extern "C" {
 #define PASSED 0
 #define STATUS_FAILED 2
 
-static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *jvmti = nullptr;
 static jint result = PASSED;
 static jboolean printdump = JNI_FALSE;
 static jvmtiCapabilities jvmti_caps;
@@ -70,8 +70,8 @@ typedef struct _refLink {
   struct _refLink *next;
 } refLink;
 
-static MyTag *fakeRoot = NULL;
-static MyTag *missed = NULL;
+static MyTag *fakeRoot = nullptr;
+static MyTag *missed = nullptr;
 
 static void breakpoint() {
   printf("Continuing from BREAKPOINT\n");
@@ -82,10 +82,10 @@ static MyTag *newTag(refKind kind,
                      jlong size,
                      const char* name) {
   static jlong seq_num = 0;
-  MyTag* new_tag = NULL;
+  MyTag* new_tag = nullptr;
 
   new_tag = (MyTag*) malloc(sizeof(MyTag));
-  if (NULL == new_tag) {
+  if (nullptr == new_tag) {
     printf("Error (newTag malloc): failed\n");
     result = STATUS_FAILED;
   }
@@ -95,7 +95,7 @@ static MyTag *newTag(refKind kind,
   new_tag->sequence = ++seq_num;
   new_tag->visited = JNI_FALSE;
   new_tag->name = name;
-  new_tag->ref = NULL;
+  new_tag->ref = nullptr;
   return new_tag;
 }
 
@@ -103,11 +103,11 @@ static void setTag(JNIEnv *env,
                    jobject obj,
                    refKind kind,
                    const char* name) {
-  MyTag *new_tag = NULL;
-  MyTag *class_tag = NULL;
+  MyTag *new_tag = nullptr;
+  MyTag *class_tag = nullptr;
   jvmtiError err;
   jlong size = 0;
-  jclass obj_class = NULL;
+  jclass obj_class = nullptr;
   jlong haba = 0;
 
   err = jvmti->GetObjectSize(obj, &size);
@@ -124,7 +124,7 @@ static void setTag(JNIEnv *env,
     printf("Error (GetTag): %s (%d)\n", TranslateError(err), err);
     result = STATUS_FAILED;
   }
-  if (class_tag != NULL && class_tag->kind != rclass) {
+  if (class_tag != nullptr && class_tag->kind != rclass) {
     printf("Error class tag which is not a class\n");
     result = STATUS_FAILED;
   }
@@ -142,7 +142,7 @@ static void addRef(MyTag *from, int reference_kind, MyTag *to) {
   refLink *new_ref;
 
   new_ref = (refLink*) malloc(sizeof(refLink));
-  if (NULL == new_ref) {
+  if (nullptr == new_ref) {
     printf("Error (addRef malloc): failed\n");
     result = STATUS_FAILED;
   }
@@ -215,7 +215,7 @@ static void walk(MyTag* tag, jint depth, const char* ref_label) {
   const char *indent = spaces + (len - 2 * depth);
 
   const MyTag* const ctag = tag->class_tag;
-  const char* const cname = ctag != NULL ? ctag->name : "";
+  const char* const cname = ctag != nullptr ? ctag->name : "";
 
   printf("%s", indent);
 
@@ -256,12 +256,12 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
   jint res;
   jvmtiError err;
 
-  if (options != NULL && strcmp(options, "printdump") == 0) {
+  if (options != nullptr && strcmp(options, "printdump") == 0) {
     printdump = JNI_TRUE;
   }
 
   res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
-  if (res != JNI_OK || jvmti == NULL) {
+  if (res != JNI_OK || jvmti == nullptr) {
     printf("Wrong result of a valid call to GetEnv!\n");
     return JNI_ERR;
   }
@@ -279,7 +279,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
 jvmtiIterationControl JNICALL
 heapMarkCallback(jlong class_tag, jlong size, jlong* tag_ptr, void* user_data) {
-  const MyTag* const tag = newTag(rmark, (const MyTag*)(intptr_t)class_tag, size, NULL);
+  const MyTag* const tag = newTag(rmark, (const MyTag*)(intptr_t)class_tag, size, nullptr);
   *tag_ptr = (intptr_t)tag;
 
   if (user_data != &dummy_user_data && user_data_error_flag == JNI_FALSE) {
@@ -298,7 +298,7 @@ heapRootCallback(jvmtiHeapRootKind root_kind,
 
   if (0 == *tag_ptr) {
     /* new tag */
-    MyTag* tag = newTag(kind, (MyTag*)(intptr_t)class_tag, size, NULL);
+    MyTag* tag = newTag(kind, (MyTag*)(intptr_t)class_tag, size, nullptr);
     addRef(fakeRoot, HEAP_ROOT_REF_KIND_BASE+root_kind, tag);
     *tag_ptr = (intptr_t)tag;
   } else {
@@ -324,7 +324,7 @@ stackReferenceCallback(jvmtiHeapRootKind root_kind,
 
   if (0 == *tag_ptr) {
     /* new tag */
-    MyTag* tag = newTag(kind, (MyTag*)(intptr_t)class_tag, size, NULL);
+    MyTag* tag = newTag(kind, (MyTag*)(intptr_t)class_tag, size, nullptr);
     addRef(fakeRoot, HEAP_ROOT_REF_KIND_BASE+root_kind, tag);
     *tag_ptr = (intptr_t)tag;
   } else {
@@ -345,7 +345,7 @@ objectReferenceCallback(jvmtiObjectReferenceKind reference_kind,
                         jlong* tag_ptr, jlong referrer_tag,
                         jint referrer_index, void* user_data) {
   refKind kind = rother;
-  MyTag* referrer = NULL;
+  MyTag* referrer = nullptr;
 
   if (0 == referrer_tag) {
     referrer = missed;
@@ -355,7 +355,7 @@ objectReferenceCallback(jvmtiObjectReferenceKind reference_kind,
 
   if (0 == *tag_ptr) {
     /* new tag */
-    MyTag* tag = newTag(kind, (MyTag*)(intptr_t)class_tag, size, NULL);
+    MyTag* tag = newTag(kind, (MyTag*)(intptr_t)class_tag, size, nullptr);
     addRef(referrer, reference_kind, tag);
     *tag_ptr = (intptr_t) tag;
   } else {
@@ -380,13 +380,13 @@ Java_nsk_jvmti_unit_refignore_check(JNIEnv *env, jclass cls) {
   jint threadCount = 0;
   jint i;
 
-  if (jvmti == NULL) {
+  if (jvmti == nullptr) {
     printf("JVMTI client was not properly loaded!\n");
     return STATUS_FAILED;
   }
 
-  fakeRoot = newTag(rother, (const MyTag *)NULL, 0, "FAKE_ROOT");
-  missed = newTag(rother, (const MyTag *)NULL, 0, "MISSED");
+  fakeRoot = newTag(rother, nullptr, 0, "FAKE_ROOT");
+  missed = newTag(rother, nullptr, 0, "MISSED");
 
   if (env->PushLocalFrame(500) != 0) {
     printf("Error (PushLocalFrame): failed\n");
@@ -402,7 +402,7 @@ Java_nsk_jvmti_unit_refignore_check(JNIEnv *env, jclass cls) {
   for (i = 0; i < classCount; ++i) {
     char *classSig;
     jclass k = classes[i];
-    err = jvmti->GetClassSignature(k, &classSig, NULL);
+    err = jvmti->GetClassSignature(k, &classSig, nullptr);
     if (err != JVMTI_ERROR_NONE) {
       printf("Error (getClassSignature): %s (%d)\n", TranslateError(err), err);
       result = STATUS_FAILED;
@@ -412,7 +412,7 @@ Java_nsk_jvmti_unit_refignore_check(JNIEnv *env, jclass cls) {
       if (classSig[len-1] == ';') {
         classSig[len-1] = 0;
       }
-      if (*classSig == 'L' && slash != NULL) {
+      if (*classSig == 'L' && slash != nullptr) {
         classSig = slash + 1;
       }
       setTag(env, k, rclass, (const char*)classSig);
@@ -437,7 +437,7 @@ Java_nsk_jvmti_unit_refignore_check(JNIEnv *env, jclass cls) {
     }
   }
 
-  env->PopLocalFrame(NULL);
+  env->PopLocalFrame(nullptr);
 
   user_data_error_flag = JNI_FALSE;
   err = jvmti->IterateOverHeap(
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/setNullVMInit/JvmtiTest/JvmtiTest.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/setNullVMInit/JvmtiTest/JvmtiTest.cpp
index f670dfafbb5..1ce5facd4eb 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/setNullVMInit/JvmtiTest/JvmtiTest.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/setNullVMInit/JvmtiTest/JvmtiTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,7 +26,7 @@
 
            VMInit initial thread arg.
            SetThreadLocalStorage and SetEnvironmentLocalStorage should allow
-           value to be set to NULL.
+           value to be set to nullptr.
  */
 
 #include <stdio.h>
@@ -105,13 +105,13 @@ void check_val(intptr_t x, intptr_t y, const char* msg) {
 
 void JNICALL vmInit(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jthread thread) {
   check_val(get_thread_local(thread), 0, "thread initial");
-  check_val(get_thread_local(NULL), 0, "thread initial");
+  check_val(get_thread_local(nullptr), 0, "thread initial");
   set_thread_local(thread, 35);
   check_val(get_thread_local(thread), 35, "thread set non-zero");
-  check_val(get_thread_local(NULL), 35, "thread set non-zero");
-  set_thread_local(NULL, 0);
+  check_val(get_thread_local(nullptr), 35, "thread set non-zero");
+  set_thread_local(nullptr, 0);
   check_val(get_thread_local(thread), 0, "thread set zero");
-  check_val(get_thread_local(NULL), 0, "thread set zero");
+  check_val(get_thread_local(nullptr), 0, "thread set zero");
 
   check_val(get_env_local(), 14, "env set non-zero");
   set_env_local(77);
@@ -161,7 +161,7 @@ jint Agent_Initialize(JavaVM * jvm, char *options, void *reserved) {
     res = jvmti->SetEventCallbacks(&callbacks, sizeof(callbacks));
     JVMTI_ERROR_CHECK("SetEventCallbacks returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT,NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT,nullptr);
     JVMTI_ERROR_CHECK("SetEventNotificationMode for VM_INIT returned error", res);
 
     return JNI_OK;
@@ -175,7 +175,7 @@ Java_nsk_jvmti_unit_setNullVMInit_JvmtiTest_check(JNIEnv *env, jclass cls) {
   set_env_local(0);
   check_val(get_env_local(), 0, "env reset to zero");
 
-  check_val(get_thread_local(NULL), 0, "thread check");
+  check_val(get_thread_local(nullptr), 0, "thread check");
 
   return iGlobalStatus;
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/timers/JvmtiTest/JvmtiTest.cpp b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/timers/JvmtiTest/JvmtiTest.cpp
index d9be94340e7..b903de9b7ec 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/timers/JvmtiTest/JvmtiTest.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/timers/JvmtiTest/JvmtiTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -143,10 +143,10 @@ jint Agent_Initialize(JavaVM * jvm, char *options, void *reserved) {
     res = jvmti->SetEventCallbacks(&callbacks, sizeof(callbacks));
     JVMTI_ERROR_CHECK_DURING_ONLOAD("SetEventCallbacks returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr);
     JVMTI_ERROR_CHECK_DURING_ONLOAD("SetEventNotificationMode for VM_INIT returned error", res);
 
-    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL);
+    res = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr);
     JVMTI_ERROR_CHECK_DURING_ONLOAD("SetEventNotificationMode for vm death event returned error", res);
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/StackTraceController.cpp b/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/StackTraceController.cpp
index 5b907b42a7e..3e46cc25368 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/StackTraceController.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/StackTraceController.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,7 +29,7 @@ extern "C" {
 
 #define GET_OBJECT_CLASS(_class, _obj)\
     if (!NSK_JNI_VERIFY(env, (_class = \
-            env->GetObjectClass(_obj)) != NULL))\
+            env->GetObjectClass(_obj)) != nullptr))\
         return 2
 
 #define CALL_STATIC_VOID_NOPARAM(_class, _methodName)\
@@ -39,12 +39,12 @@ extern "C" {
 
 #define GET_STATIC_METHOD_ID(_methodID, _class, _methodName, _sig)\
     if (!NSK_JNI_VERIFY(env, (_methodID = \
-            env->GetStaticMethodID(_class, _methodName, _sig)) != NULL))\
+            env->GetStaticMethodID(_class, _methodName, _sig)) != nullptr))\
         return 2
 
 #define GET_METHOD_ID(_methodID, _class, _methodName, _sig)\
     if (!NSK_JNI_VERIFY(env, (_methodID = \
-            env->GetMethodID(_class, _methodName, _sig)) != NULL))\
+            env->GetMethodID(_class, _methodName, _sig)) != nullptr))\
         return 2
 
 #define CALL_VOID_NOPARAM(_obj, _class, _methodName)\
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/ThreadController.cpp b/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/ThreadController.cpp
index 3e8530d0ecc..e5fbc02b46d 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/ThreadController.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/ThreadController.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -31,17 +31,17 @@ extern "C" {
 
 #define FIND_CLASS(_class, _className)\
     if (!NSK_JNI_VERIFY(env, (_class = \
-            env->FindClass(_className)) != NULL))\
+            env->FindClass(_className)) != nullptr))\
         return
 
 #define GET_OBJECT_CLASS(_class, _obj)\
     if (!NSK_JNI_VERIFY(env, (_class = \
-            env->GetObjectClass(_obj)) != NULL))\
+            env->GetObjectClass(_obj)) != nullptr))\
         return
 
 #define GET_STATIC_FIELD_ID(_fieldID, _class, _fieldName, _fieldSig)\
     if (!NSK_JNI_VERIFY(env, (_fieldID = \
-            env->GetStaticFieldID(_class, _fieldName, _fieldSig)) != NULL))\
+            env->GetStaticFieldID(_class, _fieldName, _fieldSig)) != nullptr))\
         return
 
 #define GET_STATIC_OBJ_FIELD(_value, _class, _fieldName, _fieldSig)\
@@ -54,7 +54,7 @@ extern "C" {
 
 #define GET_FIELD_ID(_fieldID, _class, _fieldName, _fieldSig)\
     if (!NSK_JNI_VERIFY(env, (_fieldID = \
-            env->GetFieldID(_class, _fieldName, _fieldSig)) != NULL))\
+            env->GetFieldID(_class, _fieldName, _fieldSig)) != nullptr))\
         return
 
 #define GET_INT_FIELD(_value, _obj, _class, _fieldName)\
@@ -90,12 +90,12 @@ extern "C" {
 
 #define GET_STATIC_METHOD_ID(_methodID, _class, _methodName, _sig)\
     if (!NSK_JNI_VERIFY(env, (_methodID = \
-            env->GetStaticMethodID(_class, _methodName, _sig)) != NULL))\
+            env->GetStaticMethodID(_class, _methodName, _sig)) != nullptr))\
         return
 
 #define GET_METHOD_ID(_methodID, _class, _methodName, _sig)\
     if (!NSK_JNI_VERIFY(env, (_methodID = \
-            env->GetMethodID(_class, _methodName, _sig)) != NULL))\
+            env->GetMethodID(_class, _methodName, _sig)) != nullptr))\
         return
 
 #define CALL_STATIC_VOID_NOPARAM(_class, _methodName)\
@@ -134,7 +134,7 @@ extern "C" {
 #define NEW_OBJ(_obj, _class, _constructorName, _sig, _params)\
     GET_METHOD_ID(method, _class, _constructorName, _sig);\
     if (!NSK_JNI_VERIFY(env, (_obj = \
-            env->NewObject(_class, method, _params)) != NULL))\
+            env->NewObject(_class, method, _params)) != nullptr))\
         return
 
 #define MONITOR_ENTER(x) \
@@ -487,23 +487,23 @@ extern "C" {
         jint state;
 
         if (!NSK_VERIFY(env->GetJavaVM(&vm) == 0)) {
-            return NULL;
+            return nullptr;
         }
 
         if (!NSK_VERIFY(vm->GetEnv((void **)&jvmti, JVMTI_VERSION_1) == JNI_OK)) {
-            return NULL;
+            return nullptr;
         }
 
         if (!NSK_VERIFY(jvmti->GetThreadState((jthread)thread, &state) == JVMTI_ERROR_NONE)) {
-            return NULL;
+            return nullptr;
         }
 
         stateName = getStateName(env, state);
-        if (!NSK_JNI_VERIFY(env, (ThreadState = env->FindClass("java/lang/Thread$State")) != NULL))
-            return NULL;
+        if (!NSK_JNI_VERIFY(env, (ThreadState = env->FindClass("java/lang/Thread$State")) != nullptr))
+            return nullptr;
 
-        if (!NSK_JNI_VERIFY(env, (method = env->GetStaticMethodID(ThreadState, "valueOf", "(Ljava/lang/String;)Ljava/lang/Thread$State;")) != NULL))
-            return NULL;
+        if (!NSK_JNI_VERIFY(env, (method = env->GetStaticMethodID(ThreadState, "valueOf", "(Ljava/lang/String;)Ljava/lang/Thread$State;")) != nullptr))
+            return nullptr;
         threadState = env->CallStaticObjectMethod(ThreadState, method, stateName);
 
         return threadState;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/thread/Deadlock.cpp b/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/thread/Deadlock.cpp
index 6e2c066b94e..5c9a22e2464 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/thread/Deadlock.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/thread/Deadlock.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,12 +27,12 @@ extern "C" {
 
 #define FIND_CLASS(_class, _className)\
         if (!NSK_JNI_VERIFY(env, (_class = \
-             env->FindClass(_className)) != NULL))\
+             env->FindClass(_className)) != nullptr))\
                 return
 
 #define GET_OBJECT_CLASS(_class, _obj)\
         if (!NSK_JNI_VERIFY(env, (_class = \
-             env->GetObjectClass(_obj)) != NULL))\
+             env->GetObjectClass(_obj)) != nullptr))\
                 return
 
 #define GET_OBJ_FIELD(_value, _obj, _class, _fieldName, _fieldSig)\
@@ -41,12 +41,12 @@ extern "C" {
 
 #define GET_FIELD_ID(_fieldID, _class, _fieldName, _fieldSig)\
         if (!NSK_JNI_VERIFY(env, (_fieldID = \
-             env->GetFieldID(_class, _fieldName, _fieldSig)) != NULL))\
+             env->GetFieldID(_class, _fieldName, _fieldSig)) != nullptr))\
                 return
 
 #define GET_METHOD_ID(_methodID, _class, _methodName, _sig)\
         if (!NSK_JNI_VERIFY(env, (_methodID = \
-             env->GetMethodID(_class, _methodName, _sig)) != NULL)) \
+             env->GetMethodID(_class, _methodName, _sig)) != nullptr)) \
                 return
 
 #define CALL_VOID_NOPARAM(_obj, _class, _methodName)\
@@ -72,23 +72,23 @@ JNIEXPORT void JNICALL Java_nsk_monitoring_share_thread_Deadlock_00024NativeLock
         FIND_CLASS(testBugClass, "nsk/share/TestBug");
         GET_OBJ_FIELD(lock, o, nativeLockerClass, "lock", "Ljava/lang/Object;");
         GET_OBJ_FIELD(step1, o, nativeLockerClass, "step1", "Lnsk/share/Wicket;");
-        if (step1 == NULL) {
+        if (step1 == nullptr) {
                 env->ThrowNew(testBugClass, "step1 field is null");
                 return;
         }
         GET_OBJ_FIELD(step2, o, nativeLockerClass, "step2", "Lnsk/share/Wicket;");
-        if (step2 == NULL) {
+        if (step2 == nullptr) {
                 env->ThrowNew(testBugClass, "step2 field is null");
                 return;
         }
         GET_OBJ_FIELD(step3, o, nativeLockerClass, "step3", "Lnsk/share/Wicket;");
-        if (step3 == NULL) {
+        if (step3 == nullptr) {
                 env->ThrowNew(testBugClass, "step3 field is null");
                 return;
         }
         GET_OBJ_FIELD(inner, o, lockerClass, "inner", "Lnsk/monitoring/share/thread/Deadlock$Locker;");
         if (env->MonitorEnter(lock) == JNI_OK) {
-                if (inner == NULL) {
+                if (inner == nullptr) {
                         env->ThrowNew(testBugClass, "Should not reach here");
                 } else {
                         CALL_VOID_NOPARAM(step1, wicketClass, "unlock");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/thread/LockingThreads.cpp b/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/thread/LockingThreads.cpp
index c8870989fa6..604b0620c5b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/thread/LockingThreads.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/thread/LockingThreads.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,12 +27,12 @@ extern "C" {
 
 #define FIND_CLASS(_class, _className)\
         if (!NSK_JNI_VERIFY(env, (_class = \
-             env->FindClass(_className)) != NULL))\
+             env->FindClass(_className)) != nullptr))\
                 return
 
 #define GET_OBJECT_CLASS(_class, _obj)\
         if (!NSK_JNI_VERIFY(env, (_class = \
-             env->GetObjectClass(_obj)) != NULL))\
+             env->GetObjectClass(_obj)) != nullptr))\
                 return
 
 #define GET_OBJ_FIELD(_value, _obj, _class, _fieldName, _fieldSig)\
@@ -41,12 +41,12 @@ extern "C" {
 
 #define GET_FIELD_ID(_fieldID, _class, _fieldName, _fieldSig)\
         if (!NSK_JNI_VERIFY(env, (_fieldID = \
-             env->GetFieldID(_class, _fieldName, _fieldSig)) != NULL))\
+             env->GetFieldID(_class, _fieldName, _fieldSig)) != nullptr))\
                 return
 
 #define GET_METHOD_ID(_methodID, _class, _methodName, _sig)\
         if (!NSK_JNI_VERIFY(env, (_methodID = \
-             env->GetMethodID(_class, _methodName, _sig)) != NULL))\
+             env->GetMethodID(_class, _methodName, _sig)) != nullptr))\
                 return
 
 #define CALL_VOID_NOPARAM(_obj, _class, _methodName)\
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/thread/RecursiveMonitoringThread.cpp b/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/thread/RecursiveMonitoringThread.cpp
index d5349b037ff..6926c8f712e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/thread/RecursiveMonitoringThread.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/monitoring/share/thread/RecursiveMonitoringThread.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,17 +29,17 @@ extern "C" {
 
 #define FIND_CLASS(_class, _className)\
     if (!NSK_JNI_VERIFY(env, (_class = \
-            env->FindClass(_className)) != NULL))\
+            env->FindClass(_className)) != nullptr))\
         return
 
 #define GET_OBJECT_CLASS(_class, _obj)\
     if (!NSK_JNI_VERIFY(env, (_class = \
-            env->GetObjectClass(_obj)) != NULL))\
+            env->GetObjectClass(_obj)) != nullptr))\
         return
 
 #define GET_STATIC_FIELD_ID(_fieldID, _class, _fieldName, _fieldSig)\
     if (!NSK_JNI_VERIFY(env, (_fieldID = \
-            env->GetStaticFieldID(_class, _fieldName, _fieldSig)) != NULL))\
+            env->GetStaticFieldID(_class, _fieldName, _fieldSig)) != nullptr))\
         return
 
 #define GET_STATIC_OBJ_FIELD(_value, _class, _fieldName, _fieldSig)\
@@ -52,7 +52,7 @@ extern "C" {
 
 #define GET_FIELD_ID(_fieldID, _class, _fieldName, _fieldSig)\
     if (!NSK_JNI_VERIFY(env, (_fieldID = \
-            env->GetFieldID(_class, _fieldName, _fieldSig)) != NULL))\
+            env->GetFieldID(_class, _fieldName, _fieldSig)) != nullptr))\
         return
 
 #define GET_INT_FIELD(_value, _obj, _class, _fieldName)\
@@ -84,12 +84,12 @@ extern "C" {
 
 #define GET_STATIC_METHOD_ID(_methodID, _class, _methodName, _sig)\
     if (!NSK_JNI_VERIFY(env, (_methodID = \
-            env->GetStaticMethodID(_class, _methodName, _sig)) != NULL))\
+            env->GetStaticMethodID(_class, _methodName, _sig)) != nullptr))\
         return
 
 #define GET_METHOD_ID(_methodID, _class, _methodName, _sig)\
     if (!NSK_JNI_VERIFY(env, (_methodID = \
-            env->GetMethodID(_class, _methodName, _sig)) != NULL))\
+            env->GetMethodID(_class, _methodName, _sig)) != nullptr))\
         return
 
 #define CALL_STATIC_VOID_NOPARAM(_class, _methodName)\
@@ -124,7 +124,7 @@ extern "C" {
 #define NEW_OBJ(_obj, _class, _constructorName, _sig, _params)\
     GET_METHOD_ID(method, _class, _constructorName, _sig);\
     if (!NSK_JNI_VERIFY(env, (_obj = \
-            env->NewObject(_class, method, _params)) != NULL))\
+            env->NewObject(_class, method, _params)) != nullptr))\
         return
 
 #define MONITOR_ENTER(x) \
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/ExceptionCheckingJniEnv/exceptionjni001/exceptionjni001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/ExceptionCheckingJniEnv/exceptionjni001/exceptionjni001.cpp
index 342ef4d2ccd..1c70c90388e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/ExceptionCheckingJniEnv/exceptionjni001/exceptionjni001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/ExceptionCheckingJniEnv/exceptionjni001/exceptionjni001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2018, 2019, Google and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -33,9 +33,9 @@
 // methods.
 static bool is_error_called;
 static const char* const null_return_expected_message_start =
-    "JNI method GetFieldID : Return is NULL from exceptionjni001.cpp : ";
+    "JNI method GetFieldID : Return is null from exceptionjni001.cpp : ";
 static const char* const null_file_expected_message_start =
-    "JNI method GetFieldID : Return is NULL from Unknown File : ";
+    "JNI method GetFieldID : Return is null from Unknown File : ";
 
 // Used by the ErrorCheckerMessage and the tests to determine test success.
 static long expected_line_number;
@@ -52,11 +52,11 @@ static bool CheckMessage(JNIEnv* env, const char* message, const char* expected_
 
   size_t len = strlen(expected_message);
 
-  char* end_ptr = NULL;
+  char* end_ptr = nullptr;
   long actual_line = strtol(message + len, &end_ptr, 0);
 
-  if (end_ptr == NULL || *end_ptr != '\0') {
-    fprintf(stderr, "end_ptr == NULL or *end_ptr terminating from %s\n", message);
+  if (end_ptr == nullptr || *end_ptr != '\0') {
+    fprintf(stderr, "end_ptr == null or *end_ptr terminating from %s\n", message);
     return false;
   }
 
@@ -101,7 +101,7 @@ static bool checkFailureMessageEmptyFile(JNIEnv* env, jclass cls) {
 
   expected_message_start = null_file_expected_message_start;
   expected_line_number = __LINE__ + 1;
-  ec_jni->GetFieldID(cls, "whatever", "does not matter", __LINE__, NULL);
+  ec_jni->GetFieldID(cls, "whatever", "does not matter", __LINE__, nullptr);
 
   return is_error_called && error_message_ok;
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/JVMTIagent.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/JVMTIagent.cpp
index 69dc2da5b57..59395c6fcf6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/JVMTIagent.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/JVMTIagent.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -41,7 +41,7 @@
 
 extern "C" {
 
-static jvmtiEnv *jvmti = NULL; /* JVMTI env */
+static jvmtiEnv *jvmti = nullptr; /* JVMTI env */
 static jvmtiEventCallbacks callbacks;
 static jrawMonitorID eventLock; /* raw monitor used for exclusive ownership of HotSwap function */
 
@@ -106,9 +106,9 @@ typedef struct {   /* test class info */
 } class_info;
 
 
-static const char *shortTestName = NULL; /* name of the test without package prefix */
+static const char *shortTestName = nullptr; /* name of the test without package prefix */
 static jclass rasCls; /* reference to the auxiliary class RASagent used for HotSwap */
-static class_info *clsInfo = NULL, *clsInfoFst = NULL;
+static class_info *clsInfo = nullptr, *clsInfoFst = nullptr;
 
 static void lock(JNIEnv*);
 static void unlock(JNIEnv*);
@@ -160,11 +160,11 @@ ClassLoad(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jthread thread, jclass klass) {
         lock(jni_env);
         display(0, "#### JVMTIagent: ClassLoad: >>>>>>>> entered the raw monitor \"eventLock\" ####\n");
 
-        if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &cls_sig, /*&generic*/NULL)))
+        if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &cls_sig, /*&generic*/nullptr)))
             jni_env->FatalError("JVMTIagent: failed to get class signature\n");
         else {
-            if (shortTestName != NULL) {
-                if (strstr((const char*) cls_sig, shortTestName) != NULL) {
+            if (shortTestName != nullptr) {
+                if (strstr((const char*) cls_sig, shortTestName) != nullptr) {
                     display(0,
                             "#### JVMTIagent: found test class matched with \"%s\"\n"
                             "<JVMTIagent>\tsignature=%s\n",
@@ -198,7 +198,7 @@ CompiledMethodLoad(jvmtiEnv *jvmti_env, jmethodID method, jint code_size,
 
     display(1, "#### JVMTIagent: CompiledMethodLoad occurred ####\n");
 
-    getVerdict(NULL, "CompiledMethodLoad");
+    getVerdict(nullptr, "CompiledMethodLoad");
 }
 
 void JNICALL
@@ -207,7 +207,7 @@ CompiledMethodUnload(jvmtiEnv *jvmti_env, jmethodID method,
 
     display(1, "#### JVMTIagent: CompiledMethodUnload occurred ####\n");
 
-    getVerdict(NULL, "CompiledMethodUnload");
+    getVerdict(nullptr, "CompiledMethodUnload");
 }
 
 void JNICALL
@@ -215,7 +215,7 @@ DataDumpRequest(jvmtiEnv *jvmti_env) {
 
     display(1, "#### JVMTIagent: DataDumpRequest occurred ####\n");
 
-    getVerdict(NULL, "DataDumpRequest");
+    getVerdict(nullptr, "DataDumpRequest");
 }
 
 void JNICALL
@@ -226,7 +226,7 @@ DynamicCodeGenerated(jvmtiEnv *jvmti_env,
 
     display(1, "#### JVMTIagent: DynamicCodeGenerated occurred ####\n");
 
-    getVerdict(NULL, "DynamicCodeGenerated");
+    getVerdict(nullptr, "DynamicCodeGenerated");
 }
 
 void JNICALL
@@ -286,7 +286,7 @@ GarbageCollectionFinish(jvmtiEnv *jvmti_env) {
 
     display(1, "#### JVMTIagent: GarbageCollectionFinish occurred ####\n");
 
-    getVerdict(NULL, "GarbageCollectionFinish");
+    getVerdict(nullptr, "GarbageCollectionFinish");
 }
 
 void JNICALL
@@ -294,7 +294,7 @@ GarbageCollectionStart(jvmtiEnv *jvmti_env) {
 
     display(1, "#### JVMTIagent: GarbageCollectionStart occurred ####\n");
 
-    getVerdict(NULL, "GarbageCollectionStart");
+    getVerdict(nullptr, "GarbageCollectionStart");
 }
 
 void JNICALL
@@ -347,7 +347,7 @@ ObjectFree(jvmtiEnv *jvmti_env, jlong tag) {
 
     display(1, "#### JVMTIagent: ObjectFree occurred ####\n");
 
-    getVerdict(NULL, "ObjectFree");
+    getVerdict(nullptr, "ObjectFree");
 }
 
 void JNICALL
@@ -489,10 +489,10 @@ JNIEXPORT jint JNICALL
 Java_nsk_share_RASagent_setHotSwapMode(JNIEnv *jni_env, jclass cls,
         jboolean vrb, jint level, jstring shortName) {
     jvmtiCapabilities capabil;
-    jmethodID mid = NULL;
+    jmethodID mid = nullptr;
 
-    if (jvmti == NULL) {
-        printf("ERROR(%s,%d): JVMTIagent was not properly loaded: JVMTI env = NULL\n",
+    if (jvmti == nullptr) {
+        printf("ERROR(%s,%d): JVMTIagent was not properly loaded: JVMTI env = null\n",
                __FILE__, __LINE__);
         return 1;
     }
@@ -554,14 +554,14 @@ Java_nsk_share_RASagent_setHotSwapMode(JNIEnv *jni_env, jclass cls,
             return 1;
     }
 
-    if (!NSK_JNI_VERIFY(jni_env, (shortTestName = jni_env->GetStringUTFChars(shortName, NULL)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, (shortTestName = jni_env->GetStringUTFChars(shortName, nullptr)) != nullptr)) {
         printf("ERROR: JVMTIagent: unable to get UTF-8 characters of the string\n");
         return 1;
     }
     display(0, "#### JVMTIagent: short name of current test is \"%s\"\n",
         shortTestName);
 
-    if (!NSK_JNI_VERIFY(jni_env, (rasCls = jni_env->NewGlobalRef(cls)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, (rasCls = jni_env->NewGlobalRef(cls)) != nullptr)) {
         printf("ERROR JVMTIagent: unable to create a new global reference of the class \"RASagent\"\n");
         return 1;
     }
@@ -576,19 +576,19 @@ Java_nsk_share_RASagent_setHotSwapMode(JNIEnv *jni_env, jclass cls,
 }
 
 static jint allocClsInfo(JNIEnv *jni_env, char *cls_sig, jclass clazz) {
-    class_info *_clsInfo = NULL;
-    jmethodID mid = NULL;
+    class_info *_clsInfo = nullptr;
+    jmethodID mid = nullptr;
     jbyteArray classBytes;
     jboolean isCopy;
 
     _clsInfo = (class_info*) malloc(sizeof(class_info));
-    if (_clsInfo == NULL)
+    if (_clsInfo == nullptr)
         jni_env->FatalError("JVMTIagent: cannot allocate memory for class_info\n");
 
     /* fill the structure class_info */
     _clsInfo->clazzsig = cls_sig;
 
-    if (!NSK_JNI_VERIFY(jni_env, ((*_clsInfo).cls = jni_env->NewGlobalRef(clazz)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni_env, ((*_clsInfo).cls = jni_env->NewGlobalRef(clazz)) != nullptr)) {
         printf("ERROR: JVMTIagent: unable to create a new global reference of class \"%s\"\n",
             _clsInfo->clazzsig);
         free(_clsInfo);
@@ -597,7 +597,7 @@ static jint allocClsInfo(JNIEnv *jni_env, char *cls_sig, jclass clazz) {
     }
 
     if (!NSK_JNI_VERIFY(jni_env, (mid =
-        jni_env->GetStaticMethodID(rasCls, "loadFromClassFile", "(Ljava/lang/String;)[B")) != NULL))
+        jni_env->GetStaticMethodID(rasCls, "loadFromClassFile", "(Ljava/lang/String;)[B")) != nullptr))
         jni_env->FatalError("JVMTIagent: unable to get ID of the method \"loadFromClassFile\"\n");
 
     classBytes = (jbyteArray) jni_env->CallStaticObjectMethod(rasCls, mid, jni_env->NewStringUTF(cls_sig));
@@ -609,9 +609,9 @@ static jint allocClsInfo(JNIEnv *jni_env, char *cls_sig, jclass clazz) {
     (*_clsInfo).clsBytes =
         jni_env->GetByteArrayElements(classBytes, &isCopy);
 
-    _clsInfo->next = NULL;
+    _clsInfo->next = nullptr;
 
-    if (clsInfo != NULL) {
+    if (clsInfo != nullptr) {
         clsInfo->next = (struct class_info*) _clsInfo;
     }
     else {
@@ -627,7 +627,7 @@ static void deallocClsInfo(JNIEnv *jni_env) {
 
     NSK_TRACE(jni_env->DeleteGlobalRef(rasCls));
 
-    while (clsInfoCurr != NULL) {
+    while (clsInfoCurr != nullptr) {
         class_info *_clsInfo = clsInfoCurr;
 
         if (!NSK_JVMTI_VERIFY(jvmti->Deallocate((unsigned char*) clsInfoCurr->clazzsig)))
@@ -640,16 +640,16 @@ static void deallocClsInfo(JNIEnv *jni_env) {
         free(_clsInfo);
     }
     /* fix for 4756585: indicate that stucture class_info is empty now */
-    clsInfoFst = NULL;
+    clsInfoFst = nullptr;
 }
 
 static int findAndHotSwap(JNIEnv *jni_env, jclass clazz) {
     int ret_code = 0;
-    char *clazzsig = NULL;
+    char *clazzsig = nullptr;
     class_info *clsInfoCurr = clsInfoFst;
 
     display(1, "\n#### JVMTIagent: findAndHotSwap: obtaining class signature of class to be hotswap ...\n");
-    if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(clazz, &clazzsig, /*&generic*/NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(clazz, &clazzsig, /*&generic*/nullptr)))
         jni_env->FatalError("JVMTIagent: findAndHotSwap: failed to get class signature\n");
     else {
         display(1, "#### JVMTIagent: findAndHotSwap: ... class signature obtained: \"%s\"\n",
@@ -659,7 +659,7 @@ static int findAndHotSwap(JNIEnv *jni_env, jclass clazz) {
         lock(jni_env);
         display(0, "#### JVMTIagent: findAndHotSwap: >>>>>>>> entered the raw monitor \"eventLock\" ####\n");
 
-        while (clsInfoCurr != NULL) {
+        while (clsInfoCurr != nullptr) {
             if (hotswap == HOTSWAP_EVERY_METHOD_ENTRY_FOR_EVERY_CLASS ||
                     hotswap == HOTSWAP_EVERY_EXCEPTION_FOR_EVERY_CLASS) {
                 display(1, "\n#### JVMTIagent: findAndHotSwap: going to hotswap tested class \"%s\" during execution of class \"%s\" ...\n",
@@ -735,7 +735,7 @@ static int addStressEvents() {
 
             callbacks.SingleStep = &SingleStep;
 
-            if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, NULL)))
+            if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, nullptr)))
                 return JNI_ERR;
 
             stepEventSet = JNI_TRUE;
@@ -751,7 +751,7 @@ static int addStressEvents() {
 
             callbacks.MethodEntry = &MethodEntry;
 
-            if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, NULL)))
+            if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, nullptr)))
                 return JNI_ERR;
 
             display(0, "#### JVMTIagent: ... setting MethodEntry events done\n");
@@ -761,7 +761,7 @@ static int addStressEvents() {
 
             callbacks.MethodExit = &MethodExit;
 
-            if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_EXIT, NULL)))
+            if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_EXIT, nullptr)))
                 return JNI_ERR;
 
             display(0, "#### JVMTIagent: ... setting MethodExit events done\n");
@@ -777,7 +777,7 @@ static int addStressEvents() {
 
             callbacks.ExceptionCatch = &ExceptionCatch;
 
-            if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION_CATCH, NULL)))
+            if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION_CATCH, nullptr)))
                 return JNI_ERR;
 
             excCatchEventSet = JNI_TRUE;
@@ -822,7 +822,7 @@ static int enableEventsCaps() {
 
     callbacks.Breakpoint = &Breakpoint;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting Breakpoint events done\n");
 
@@ -831,7 +831,7 @@ static int enableEventsCaps() {
 
     callbacks.ClassFileLoadHook = &ClassFileLoadHook;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting ClassFileLoadHook events done\n");
 
@@ -840,7 +840,7 @@ static int enableEventsCaps() {
 
     callbacks.ClassLoad = &ClassLoad;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_LOAD, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting ClassLoad events done\n");
 
@@ -849,7 +849,7 @@ static int enableEventsCaps() {
 
     callbacks.ClassPrepare = &ClassPrepare;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_PREPARE, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_PREPARE, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting ClassPrepare events done\n");
 
@@ -858,7 +858,7 @@ static int enableEventsCaps() {
 
     callbacks.CompiledMethodLoad = &CompiledMethodLoad;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting CompiledMethodLoad events done\n");
 
@@ -867,7 +867,7 @@ static int enableEventsCaps() {
 
     callbacks.CompiledMethodUnload = &CompiledMethodUnload;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_UNLOAD, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_UNLOAD, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting CompiledMethodUnload events done\n");
 
@@ -876,7 +876,7 @@ static int enableEventsCaps() {
 
     callbacks.DataDumpRequest = &DataDumpRequest;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_DATA_DUMP_REQUEST, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_DATA_DUMP_REQUEST, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting DataDumpRequest events done\n");
 
@@ -885,7 +885,7 @@ static int enableEventsCaps() {
 
     callbacks.DynamicCodeGenerated = &DynamicCodeGenerated;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_DYNAMIC_CODE_GENERATED, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_DYNAMIC_CODE_GENERATED, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting DynamicCodeGenerated events done\n");
 
@@ -894,7 +894,7 @@ static int enableEventsCaps() {
 
     callbacks.Exception = &Exception;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting Exception events done\n");
 
@@ -903,7 +903,7 @@ static int enableEventsCaps() {
 
     callbacks.FieldAccess = &FieldAccess;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_ACCESS, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_ACCESS, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting FieldAccess events done\n");
 
@@ -912,7 +912,7 @@ static int enableEventsCaps() {
 
     callbacks.FieldModification = &FieldModification;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_MODIFICATION, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FIELD_MODIFICATION, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting FieldModification events done\n");
 
@@ -921,7 +921,7 @@ static int enableEventsCaps() {
 
     callbacks.FramePop = &FramePop;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_FRAME_POP, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting FramePop events done\n");
 
@@ -930,7 +930,7 @@ static int enableEventsCaps() {
 
     callbacks.GarbageCollectionFinish = &GarbageCollectionFinish;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting GarbageCollectionFinish events done\n");
 
@@ -939,7 +939,7 @@ static int enableEventsCaps() {
 
     callbacks.GarbageCollectionStart = &GarbageCollectionStart;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_START, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting GarbageCollectionStart events done\n");
 
@@ -948,7 +948,7 @@ static int enableEventsCaps() {
 
     callbacks.MonitorContendedEnter = &MonitorContendedEnter;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTER, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting MonitorContendedEnter events done\n");
 
@@ -957,7 +957,7 @@ static int enableEventsCaps() {
 
     callbacks.MonitorContendedEntered = &MonitorContendedEntered;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting MonitorContendedEntered events done\n");
 
@@ -966,7 +966,7 @@ static int enableEventsCaps() {
 
     callbacks.MonitorWait = &MonitorWait;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAIT, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAIT, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting MonitorWait events done\n");
 
@@ -975,7 +975,7 @@ static int enableEventsCaps() {
 
     callbacks.MonitorWaited = &MonitorWaited;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAITED, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_MONITOR_WAITED, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting MonitorWaited events done\n");
 
@@ -984,7 +984,7 @@ static int enableEventsCaps() {
 
     callbacks.NativeMethodBind = &NativeMethodBind;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting NativeMethodBind events done\n");
 
@@ -993,7 +993,7 @@ static int enableEventsCaps() {
 
     callbacks.ObjectFree = &ObjectFree;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting ObjectFree events done\n");
 
@@ -1002,7 +1002,7 @@ static int enableEventsCaps() {
 
     callbacks.ThreadEnd = &ThreadEnd;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_END, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_END, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting ThreadEnd events done\n");
 
@@ -1011,7 +1011,7 @@ static int enableEventsCaps() {
 
     callbacks.ThreadStart = &ThreadStart;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting ThreadStart events done\n");
 
@@ -1020,7 +1020,7 @@ static int enableEventsCaps() {
 
     callbacks.VMDeath = &VMDeath;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_DEATH, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting VMDeath events done\n");
 
@@ -1029,7 +1029,7 @@ static int enableEventsCaps() {
 
     callbacks.VMInit = &VMInit;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting VMInit events done\n");
 
@@ -1038,7 +1038,7 @@ static int enableEventsCaps() {
 
     callbacks.VMStart = &VMStart;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_START, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_START, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting VMStart events done\n");
 
@@ -1047,7 +1047,7 @@ static int enableEventsCaps() {
 
     callbacks.VMObjectAlloc = &VMObjectAlloc;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, nullptr)))
         return JNI_ERR;
     display(0, "#### JVMTIagent: ... setting VMObjectAlloc events done\n");
 
@@ -1153,7 +1153,7 @@ static void getVerdict(JNIEnv *jni_env, const char *evnt) {
         snprintf(error_msg, sizeof(error_msg), "JVMTIagent: getVerdict: %s event occured after VMDeath",
             evnt);
 
-        if (jni_env == NULL) { /* some event callbacks have no pointer to jni */
+        if (jni_env == nullptr) { /* some event callbacks have no pointer to jni */
             printf("ERROR: %s\n", error_msg);
             exit(97);
         }
@@ -1181,7 +1181,7 @@ JNIEXPORT jint JNICALL
 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     doSetup(options);
@@ -1198,7 +1198,7 @@ Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
     }
 
     /* register agent proc and arg */
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/aod/aod.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/aod/aod.cpp
index 4219ad9a0f4..b3b076b2ef7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/aod/aod.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/aod/aod.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -44,13 +44,13 @@ void nsk_aod_internal_error() {
 }
 
 void nsk_free_options(Options* options) {
-  if (options != NULL) {
+  if (options != nullptr) {
     int i;
     for (i = 0; i < NSK_AOD_MAX_OPTIONS; i++) {
-      if (options->names[i] != NULL) {
+      if (options->names[i] != nullptr) {
         free(options->names[i]);
       }
-      if (options->values[i] != NULL) {
+      if (options->values[i] != nullptr) {
         free(options->values[i]);
       }
     }
@@ -71,20 +71,20 @@ static Options* nsk_aod_createOptionsObject(char* optionsString) {
     char* value;
     char* sep;
 
-    if (optionsString == NULL) {
+    if (optionsString == nullptr) {
       NSK_COMPLAIN0("options were not passed to the native agent\n");
-      return NULL;
+      return nullptr;
     }
     options = (Options*) malloc(sizeof(Options));
     memset(options, 0, sizeof(Options));
     options->size = 0;
     name = optionsString;
-    while (name != NULL && i < NSK_AOD_MAX_OPTIONS) {
+    while (name != nullptr && i < NSK_AOD_MAX_OPTIONS) {
       sep = strchr(name, '=');
-      if (sep == NULL) { // name not found
+      if (sep == nullptr) { // name not found
         NSK_COMPLAIN1("Invalid options format: '%s'\n", optionsString);
         nsk_free_options(options);
-        return NULL;
+        return nullptr;
       }
       *sep = '\0';
       options->names[i] =  strdup(name);
@@ -92,10 +92,10 @@ static Options* nsk_aod_createOptionsObject(char* optionsString) {
       if (*value == '\0') { // value not found
         NSK_COMPLAIN1("Option '%s' is empty\n", options->names[i]);
         nsk_free_options(options);
-        return NULL;
+        return nullptr;
       }
       sep = strchr(value, ' ');
-      if (sep != NULL) {
+      if (sep != nullptr) {
         *sep = '\0';
         name = sep + 1;
       } else {
@@ -105,10 +105,10 @@ static Options* nsk_aod_createOptionsObject(char* optionsString) {
       i++;
 
       if (*name == '\0') {
-        name = NULL;
+        name = nullptr;
       }
     }
-    if (name != NULL) {
+    if (name != nullptr) {
       NSK_COMPLAIN1("WARNING: not all options were parsed, only %d options can be specified\n",
                     NSK_AOD_MAX_OPTIONS);
     }
@@ -119,12 +119,12 @@ static Options* nsk_aod_createOptionsObject(char* optionsString) {
 Options* nsk_aod_createOptions(char* optionsString) {
     Options* options;
 
-    if (!NSK_VERIFY((options = (Options*) nsk_aod_createOptionsObject(optionsString)) != NULL))
-        return NULL;
+    if (!NSK_VERIFY((options = (Options*) nsk_aod_createOptionsObject(optionsString)) != nullptr))
+        return nullptr;
 
     if (!NSK_VERIFY(nsk_aod_optionSpecified(options, NSK_AOD_AGENT_NAME_OPTION))) {
         NSK_COMPLAIN0("Agent name wasn't specified\n");
-        return NULL;
+        return nullptr;
     }
 
     /*
@@ -143,9 +143,9 @@ Options* nsk_aod_createOptions(char* optionsString) {
 const char* nsk_aod_getOptionValue(Options* options, const char* option) {
     int i;
 
-    if (!NSK_VERIFY(options != NULL)) {
-        NSK_COMPLAIN0("Options NULL\n");
-        return NULL;
+    if (!NSK_VERIFY(options != nullptr)) {
+        NSK_COMPLAIN0("Options null\n");
+        return nullptr;
     }
 
     for (i = 0; i < options->size; i++) {
@@ -156,14 +156,14 @@ const char* nsk_aod_getOptionValue(Options* options, const char* option) {
 
     NSK_COMPLAIN1("Option '%s' isn't defined\n", option);
 
-    return NULL;
+    return nullptr;
 }
 
 int nsk_aod_optionSpecified(Options* options, const char* option) {
     int i;
 
-    if (!NSK_VERIFY(options != NULL)) {
-        NSK_COMPLAIN0("Options NULL\n");
+    if (!NSK_VERIFY(options != nullptr)) {
+        NSK_COMPLAIN0("Options null\n");
         return NSK_FALSE;
     }
 
@@ -188,9 +188,9 @@ static const char* AGENT_LOADED_METHOD_SIGNATURE = "(Ljava/lang/String;)V";
 static const char* AGENT_FINISHED_METHOD_NAME = "agentFinished";
 static const char* AGENT_FINISHED_METHOD_SIGNATURE = "(Ljava/lang/String;Z)V";
 
-static jclass targetAppClass = NULL;
-static jmethodID agentLoadedMethod = NULL;
-static jmethodID agentFinishedMethod = NULL;
+static jclass targetAppClass = nullptr;
+static jmethodID agentLoadedMethod = nullptr;
+static jmethodID agentFinishedMethod = nullptr;
 
 // this function is used to notify target application that native agent has been loaded
 int nsk_aod_agentLoaded(JNIEnv* jni, const char* agentName) {
@@ -198,31 +198,31 @@ int nsk_aod_agentLoaded(JNIEnv* jni, const char* agentName) {
 
     NSK_DISPLAY1("Agent %s is loaded\n", agentName);
 
-    if (targetAppClass == NULL) {
+    if (targetAppClass == nullptr) {
         /*
          * FindClass returns local reference, to cache reference to target application class
          * global reference should be created
          */
         jclass localTargetAppClass;
         if (!NSK_JNI_VERIFY(jni, (localTargetAppClass =
-            jni->FindClass(TARGET_APP_CLASS_NAME)) != NULL)) {
+            jni->FindClass(TARGET_APP_CLASS_NAME)) != nullptr)) {
             return NSK_FALSE;
         }
 
         if (!NSK_JNI_VERIFY(jni, (targetAppClass = (jclass)
-            jni->NewGlobalRef(localTargetAppClass)) != NULL)) {
+            jni->NewGlobalRef(localTargetAppClass)) != nullptr)) {
             return NSK_FALSE;
         }
     }
 
-    if (agentLoadedMethod == NULL) {
+    if (agentLoadedMethod == nullptr) {
         if (!NSK_JNI_VERIFY(jni, (agentLoadedMethod =
-            jni->GetStaticMethodID(targetAppClass, AGENT_LOADED_METHOD_NAME, AGENT_LOADED_METHOD_SIGNATURE)) != NULL))
+            jni->GetStaticMethodID(targetAppClass, AGENT_LOADED_METHOD_NAME, AGENT_LOADED_METHOD_SIGNATURE)) != nullptr))
             return NSK_FALSE;
     }
 
     if (!NSK_JNI_VERIFY(jni, (agentNameString =
-        jni->NewStringUTF(agentName)) != NULL))
+        jni->NewStringUTF(agentName)) != nullptr))
         return NSK_FALSE;
 
     jni->CallStaticVoidMethod(targetAppClass, agentLoadedMethod, agentNameString);
@@ -252,13 +252,13 @@ int nsk_aod_agentFinished(JNIEnv* jni, const char* agentName, int success) {
 
     NSK_DISPLAY2("Agent %s finished (success: %d)\n", agentName, success);
 
-    if (agentFinishedMethod == NULL) {
+    if (agentFinishedMethod == nullptr) {
         if (!NSK_JNI_VERIFY(jni, (agentFinishedMethod =
-            jni->GetStaticMethodID(targetAppClass, AGENT_FINISHED_METHOD_NAME, AGENT_FINISHED_METHOD_SIGNATURE)) != NULL))
+            jni->GetStaticMethodID(targetAppClass, AGENT_FINISHED_METHOD_NAME, AGENT_FINISHED_METHOD_SIGNATURE)) != nullptr))
             return NSK_FALSE;
     }
 
-    if (!NSK_JNI_VERIFY(jni, (agentNameString = jni->NewStringUTF(agentName)) != NULL))
+    if (!NSK_JNI_VERIFY(jni, (agentNameString = jni->NewStringUTF(agentName)) != nullptr))
         return NSK_FALSE;
 
     jni->CallStaticVoidMethod(targetAppClass, agentFinishedMethod, agentNameString, success ? JNI_TRUE : JNI_FALSE);
@@ -276,7 +276,7 @@ JNIEnv* nsk_aod_createJNIEnv(JavaVM* vm) {
     JNIEnv* jni;
     vm->GetEnv((void**)&jni, JNI_VERSION_1_2);
 
-    NSK_VERIFY(jni != NULL);
+    NSK_VERIFY(jni != nullptr);
 
     return jni;
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/BooleanArrayCriticalLocker.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/BooleanArrayCriticalLocker.cpp
index a64f108222f..2ad70dfe076 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/BooleanArrayCriticalLocker.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/BooleanArrayCriticalLocker.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,7 +28,7 @@
 
 extern "C" {
 
-static jfieldID objFieldId = NULL;
+static jfieldID objFieldId = nullptr;
 
 /*
  * Class:     nsk_share_gc_lock_jni_BooleanArrayCriticalLocker
@@ -45,31 +45,31 @@ JNIEXPORT jboolean JNICALL Java_nsk_share_gc_lock_jni_BooleanArrayCriticalLocker
   jboolean hash = JNI_TRUE;
   time_t start_time, current_time;
 
-  if (objFieldId == NULL) {
+  if (objFieldId == nullptr) {
     jclass klass = ec_jni->GetObjectClass(o, TRACE_JNI_CALL);
     objFieldId = ec_jni->GetFieldID(klass, "obj", "Ljava/lang/Object;", TRACE_JNI_CALL);
   }
   arr = (jbooleanArray) ec_jni->GetObjectField(o, objFieldId, TRACE_JNI_CALL);
-  ec_jni->SetObjectField(o, objFieldId, NULL, TRACE_JNI_CALL);
+  ec_jni->SetObjectField(o, objFieldId, nullptr, TRACE_JNI_CALL);
 
   size = ec_jni->GetArrayLength(arr, TRACE_JNI_CALL);
-  start_time = time(NULL);
+  start_time = time(nullptr);
   enterTime /= 1000;
   current_time = 0;
   while (difftime(current_time, start_time) < enterTime) {
     hash = JNI_TRUE;
-    pa = (jboolean*) ec_jni->GetPrimitiveArrayCritical(arr, NULL, TRACE_JNI_CALL);
-    if (pa != NULL) {
+    pa = (jboolean*) ec_jni->GetPrimitiveArrayCritical(arr, nullptr, TRACE_JNI_CALL);
+    if (pa != nullptr) {
       for (i = 0; i < size; ++i) {
         hash ^= pa[i];
       }
     } else {
-      jni_env->FatalError("GetPrimitiveArrayCritical returned NULL");
+      jni_env->FatalError("GetPrimitiveArrayCritical returned null");
     }
     mssleep((long) sleepTime);
     ec_jni->ReleasePrimitiveArrayCritical(arr, pa, 0, TRACE_JNI_CALL);
     mssleep((long) sleepTime);
-    current_time = time(NULL);
+    current_time = time(nullptr);
   }
   ec_jni->SetObjectField(o, objFieldId, arr, TRACE_JNI_CALL);
   return hash;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/ByteArrayCriticalLocker.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/ByteArrayCriticalLocker.cpp
index ae13774efee..1feb98d9ef5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/ByteArrayCriticalLocker.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/ByteArrayCriticalLocker.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,7 +28,7 @@
 
 extern "C" {
 
-static jfieldID objFieldId = NULL;
+static jfieldID objFieldId = nullptr;
 
 /*
  * Class:     nsk_share_gc_lock_jni_ByteArrayCriticalLocker
@@ -44,31 +44,31 @@ JNIEXPORT jbyte JNICALL Java_nsk_share_gc_lock_jni_ByteArrayCriticalLocker_criti
   jbyte hash = 0;
   time_t start_time, current_time;
 
-  if (objFieldId == NULL) {
+  if (objFieldId == nullptr) {
     jclass klass = ec_jni->GetObjectClass(o, TRACE_JNI_CALL);
     objFieldId = ec_jni->GetFieldID(klass, "obj", "Ljava/lang/Object;", TRACE_JNI_CALL);
   }
   arr = (jbyteArray) ec_jni->GetObjectField(o, objFieldId, TRACE_JNI_CALL);
-  ec_jni->SetObjectField(o, objFieldId, NULL, TRACE_JNI_CALL);
+  ec_jni->SetObjectField(o, objFieldId, nullptr, TRACE_JNI_CALL);
 
   size = ec_jni->GetArrayLength(arr, TRACE_JNI_CALL);
-  start_time = time(NULL);
+  start_time = time(nullptr);
   enterTime /= 1000;
   current_time = 0;
   while (difftime(current_time, start_time) < enterTime) {
     hash = 0;
-    pa = (jbyte*) ec_jni->GetPrimitiveArrayCritical(arr, NULL, TRACE_JNI_CALL);
-    if (pa != NULL) {
+    pa = (jbyte*) ec_jni->GetPrimitiveArrayCritical(arr, nullptr, TRACE_JNI_CALL);
+    if (pa != nullptr) {
       for (i = 0; i < size; ++i) {
         hash ^= pa[i];
       }
     } else {
-      jni_env->FatalError("GetPrimitiveArrayCritical returned NULL");
+      jni_env->FatalError("GetPrimitiveArrayCritical returned null");
     }
     mssleep((long) sleepTime);
     ec_jni->ReleasePrimitiveArrayCritical(arr, pa, 0, TRACE_JNI_CALL);
     mssleep((long) sleepTime);
-    current_time = time(NULL);
+    current_time = time(nullptr);
   }
   ec_jni->SetObjectField(o, objFieldId, arr, TRACE_JNI_CALL);
   return hash;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/CharArrayCriticalLocker.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/CharArrayCriticalLocker.cpp
index 8c46de5dd42..9c6231a0a16 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/CharArrayCriticalLocker.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/CharArrayCriticalLocker.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,7 +28,7 @@
 
 extern "C" {
 
-static jfieldID objFieldId = NULL;
+static jfieldID objFieldId = nullptr;
 
 /*
  * Class:     nsk_share_gc_lock_jni_CharArrayCriticalLocker
@@ -45,31 +45,31 @@ JNIEXPORT jchar JNICALL Java_nsk_share_gc_lock_jni_CharArrayCriticalLocker_criti
   jchar hash = 0;
   time_t start_time, current_time;
 
-  if (objFieldId == NULL) {
+  if (objFieldId == nullptr) {
     jclass klass = ec_jni->GetObjectClass(o, TRACE_JNI_CALL);
     objFieldId = ec_jni->GetFieldID(klass, "obj", "Ljava/lang/Object;", TRACE_JNI_CALL);
   }
   arr = (jcharArray) ec_jni->GetObjectField(o, objFieldId, TRACE_JNI_CALL);
-  ec_jni->SetObjectField(o, objFieldId, NULL, TRACE_JNI_CALL);
+  ec_jni->SetObjectField(o, objFieldId, nullptr, TRACE_JNI_CALL);
 
   size = ec_jni->GetArrayLength(arr, TRACE_JNI_CALL);
-  start_time = time(NULL);
+  start_time = time(nullptr);
   current_time = 0;
   enterTime /= 1000;
   while (difftime(current_time, start_time) < enterTime) {
     hash = 0;
-    pa = (jchar*) ec_jni->GetPrimitiveArrayCritical(arr, NULL, TRACE_JNI_CALL);
-    if (pa != NULL) {
+    pa = (jchar*) ec_jni->GetPrimitiveArrayCritical(arr, nullptr, TRACE_JNI_CALL);
+    if (pa != nullptr) {
       for (i = 0; i < size; ++i) {
         hash ^= pa[i];
       }
     } else {
-      jni_env->FatalError("GetPrimitiveArrayCritical returned NULL");
+      jni_env->FatalError("GetPrimitiveArrayCritical returned null");
     }
     mssleep((long) sleepTime);
     ec_jni->ReleasePrimitiveArrayCritical(arr, pa, 0, TRACE_JNI_CALL);
     mssleep((long) sleepTime);
-    current_time = time(NULL);
+    current_time = time(nullptr);
   }
   ec_jni->SetObjectField(o, objFieldId, arr, TRACE_JNI_CALL);
   return hash;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/DoubleArrayCriticalLocker.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/DoubleArrayCriticalLocker.cpp
index fd6bba4822b..773ffc533a1 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/DoubleArrayCriticalLocker.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/DoubleArrayCriticalLocker.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,7 +28,7 @@
 
 extern "C" {
 
-static jfieldID objFieldId = NULL;
+static jfieldID objFieldId = nullptr;
 
 /*
  * Class:     nsk_share_gc_lock_jni_DoubleArrayCriticalLocker
@@ -45,31 +45,31 @@ JNIEXPORT jdouble JNICALL Java_nsk_share_gc_lock_jni_DoubleArrayCriticalLocker_c
   jdouble hash = 0;
   time_t start_time, current_time;
 
-  if (objFieldId == NULL) {
+  if (objFieldId == nullptr) {
     jclass klass = ec_jni->GetObjectClass(o, TRACE_JNI_CALL);
     objFieldId = ec_jni->GetFieldID(klass, "obj", "Ljava/lang/Object;", TRACE_JNI_CALL);
   }
   arr = (jdoubleArray) ec_jni->GetObjectField(o, objFieldId, TRACE_JNI_CALL);
-  ec_jni->SetObjectField(o, objFieldId, NULL, TRACE_JNI_CALL);
+  ec_jni->SetObjectField(o, objFieldId, nullptr, TRACE_JNI_CALL);
 
   size = ec_jni->GetArrayLength(arr, TRACE_JNI_CALL);
-  start_time = time(NULL);
+  start_time = time(nullptr);
   enterTime /= 1000;
   current_time = 0;
   while (difftime(current_time, start_time) < enterTime) {
     hash = 0;
-    pa = (jdouble*) ec_jni->GetPrimitiveArrayCritical(arr, NULL, TRACE_JNI_CALL);
-    if (pa != NULL) {
+    pa = (jdouble*) ec_jni->GetPrimitiveArrayCritical(arr, nullptr, TRACE_JNI_CALL);
+    if (pa != nullptr) {
       for (i = 0; i < size; ++i) {
         hash += pa[i];
       }
     } else {
-      jni_env->FatalError("GetPrimitiveArrayCritical returned NULL");
+      jni_env->FatalError("GetPrimitiveArrayCritical returned null");
     }
     mssleep((long) sleepTime);
     ec_jni->ReleasePrimitiveArrayCritical(arr, pa, 0, TRACE_JNI_CALL);
     mssleep((long) sleepTime);
-    current_time = time(NULL);
+    current_time = time(nullptr);
   }
   ec_jni->SetObjectField(o, objFieldId, arr, TRACE_JNI_CALL);
   return hash;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/FloatArrayCriticalLocker.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/FloatArrayCriticalLocker.cpp
index a82e9425338..e24138792fb 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/FloatArrayCriticalLocker.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/FloatArrayCriticalLocker.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,7 +28,7 @@
 
 extern "C" {
 
-static jfieldID objFieldId = NULL;
+static jfieldID objFieldId = nullptr;
 
 /*
  * Class:     nsk_share_gc_lock_jni_FloatArrayCriticalLocker
@@ -45,31 +45,31 @@ JNIEXPORT jfloat JNICALL Java_nsk_share_gc_lock_jni_FloatArrayCriticalLocker_cri
   jfloat hash = 0;
   time_t start_time, current_time;
 
-  if (objFieldId == NULL) {
+  if (objFieldId == nullptr) {
     jclass klass = ec_jni->GetObjectClass(o, TRACE_JNI_CALL);
     objFieldId = ec_jni->GetFieldID(klass, "obj", "Ljava/lang/Object;", TRACE_JNI_CALL);
   }
   arr = (jfloatArray) ec_jni->GetObjectField(o, objFieldId, TRACE_JNI_CALL);
-  ec_jni->SetObjectField(o, objFieldId, NULL, TRACE_JNI_CALL);
+  ec_jni->SetObjectField(o, objFieldId, nullptr, TRACE_JNI_CALL);
 
   size = ec_jni->GetArrayLength(arr, TRACE_JNI_CALL);
-  start_time = time(NULL);
+  start_time = time(nullptr);
   enterTime /= 1000;
   current_time = 0;
   while (difftime(current_time, start_time) < enterTime) {
     hash = 0;
-    pa = (jfloat*) ec_jni->GetPrimitiveArrayCritical(arr, NULL, TRACE_JNI_CALL);
-    if (pa != NULL) {
+    pa = (jfloat*) ec_jni->GetPrimitiveArrayCritical(arr, nullptr, TRACE_JNI_CALL);
+    if (pa != nullptr) {
       for (i = 0; i < size; ++i) {
         hash += pa[i];
       }
     } else {
-      jni_env->FatalError("GetPrimitiveArrayCritical returned NULL");
+      jni_env->FatalError("GetPrimitiveArrayCritical returned null");
     }
     mssleep((long) sleepTime);
     ec_jni->ReleasePrimitiveArrayCritical(arr, pa, 0, TRACE_JNI_CALL);
     mssleep((long) sleepTime);
-    current_time = time(NULL);
+    current_time = time(nullptr);
   }
   ec_jni->SetObjectField(o, objFieldId, arr, TRACE_JNI_CALL);
   return hash;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/IntArrayCriticalLocker.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/IntArrayCriticalLocker.cpp
index 465e4c56b32..b863984f9ac 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/IntArrayCriticalLocker.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/IntArrayCriticalLocker.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,7 +28,7 @@
 
 extern "C" {
 
-static jfieldID objFieldId = NULL;
+static jfieldID objFieldId = nullptr;
 
 /*
  * Class:     nsk_share_gc_lock_jni_IntArrayCriticalLocker
@@ -45,31 +45,31 @@ JNIEXPORT jint JNICALL Java_nsk_share_gc_lock_jni_IntArrayCriticalLocker_critica
   jint hash = 0;
   time_t start_time, current_time;
 
-  if (objFieldId == NULL) {
+  if (objFieldId == nullptr) {
     jclass klass = ec_jni->GetObjectClass(o, TRACE_JNI_CALL);
     objFieldId = ec_jni->GetFieldID(klass, "obj", "Ljava/lang/Object;", TRACE_JNI_CALL);
   }
   arr = (jintArray) ec_jni->GetObjectField(o, objFieldId, TRACE_JNI_CALL);
-  ec_jni->SetObjectField(o, objFieldId, NULL, TRACE_JNI_CALL);
+  ec_jni->SetObjectField(o, objFieldId, nullptr, TRACE_JNI_CALL);
 
   size = ec_jni->GetArrayLength(arr, TRACE_JNI_CALL);
-  start_time = time(NULL);
+  start_time = time(nullptr);
   enterTime /= 1000;
   current_time = 0;
   while (difftime(current_time, start_time) < enterTime) {
     hash = 0;
-    pa = (jint*) ec_jni->GetPrimitiveArrayCritical(arr, NULL, TRACE_JNI_CALL);
-    if (pa != NULL) {
+    pa = (jint*) ec_jni->GetPrimitiveArrayCritical(arr, nullptr, TRACE_JNI_CALL);
+    if (pa != nullptr) {
       for (i = 0; i < size; ++i) {
         hash ^= pa[i];
       }
     } else {
-      jni_env->FatalError("GetPrimitiveArrayCritical returned NULL");
+      jni_env->FatalError("GetPrimitiveArrayCritical returned null");
     }
     mssleep((long) sleepTime);
     ec_jni->ReleasePrimitiveArrayCritical(arr, pa, 0, TRACE_JNI_CALL);
     mssleep((long) sleepTime);
-    current_time = time(NULL);
+    current_time = time(nullptr);
   }
   ec_jni->SetObjectField(o, objFieldId, arr, TRACE_JNI_CALL);
   return hash;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/LongArrayCriticalLocker.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/LongArrayCriticalLocker.cpp
index 8073e9ed36e..dae07c708db 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/LongArrayCriticalLocker.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/LongArrayCriticalLocker.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,7 +28,7 @@
 
 extern "C" {
 
-static jfieldID objFieldId = NULL;
+static jfieldID objFieldId = nullptr;
 
 /*
  * Class:     nsk_share_gc_lock_jni_LongArrayCriticalLocker
@@ -45,31 +45,31 @@ JNIEXPORT jlong JNICALL Java_nsk_share_gc_lock_jni_LongArrayCriticalLocker_criti
   jlong hash = 0;
   time_t start_time, current_time;
 
-  if (objFieldId == NULL) {
+  if (objFieldId == nullptr) {
     jclass klass = ec_jni->GetObjectClass(o, TRACE_JNI_CALL);
     objFieldId = ec_jni->GetFieldID(klass, "obj", "Ljava/lang/Object;", TRACE_JNI_CALL);
   }
   arr = (jlongArray) ec_jni->GetObjectField(o, objFieldId, TRACE_JNI_CALL);
-  ec_jni->SetObjectField(o, objFieldId, NULL, TRACE_JNI_CALL);
+  ec_jni->SetObjectField(o, objFieldId, nullptr, TRACE_JNI_CALL);
 
   size = ec_jni->GetArrayLength(arr, TRACE_JNI_CALL);
-  start_time = time(NULL);
+  start_time = time(nullptr);
   enterTime /= 1000;
   current_time = 0;
   while (difftime(current_time, start_time) < enterTime) {
     hash = 0;
-    pa = (jlong*) ec_jni->GetPrimitiveArrayCritical(arr, NULL, TRACE_JNI_CALL);
-    if (pa != NULL) {
+    pa = (jlong*) ec_jni->GetPrimitiveArrayCritical(arr, nullptr, TRACE_JNI_CALL);
+    if (pa != nullptr) {
       for (i = 0; i < size; ++i) {
         hash ^= pa[i];
       }
     } else {
-      jni_env->FatalError("GetPrimitiveArrayCritical returned NULL");
+      jni_env->FatalError("GetPrimitiveArrayCritical returned null");
     }
     mssleep((long) sleepTime);
     ec_jni->ReleasePrimitiveArrayCritical(arr, pa, 0, TRACE_JNI_CALL);
     mssleep((long) sleepTime);
-    current_time = time(NULL);
+    current_time = time(nullptr);
   }
   ec_jni->SetObjectField(o, objFieldId, arr, TRACE_JNI_CALL);
   return hash;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/ShortArrayCriticalLocker.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/ShortArrayCriticalLocker.cpp
index a91a3cc37df..2b03591a709 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/ShortArrayCriticalLocker.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/ShortArrayCriticalLocker.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,7 +28,7 @@
 
 extern "C" {
 
-static jfieldID objFieldId = NULL;
+static jfieldID objFieldId = nullptr;
 
 /*
  * Class:     nsk_share_gc_lock_jni_ShortArrayCriticalLocker
@@ -45,31 +45,31 @@ JNIEXPORT jshort JNICALL Java_nsk_share_gc_lock_jni_ShortArrayCriticalLocker_cri
   jshort hash = 0;
   time_t start_time, current_time;
 
-  if (objFieldId == NULL) {
+  if (objFieldId == nullptr) {
   jclass klass = ec_jni->GetObjectClass(o, TRACE_JNI_CALL);
   objFieldId = ec_jni->GetFieldID(klass, "obj", "Ljava/lang/Object;", TRACE_JNI_CALL);
   }
   arr = (jshortArray) ec_jni->GetObjectField(o, objFieldId, TRACE_JNI_CALL);
-  ec_jni->SetObjectField(o, objFieldId, NULL, TRACE_JNI_CALL);
+  ec_jni->SetObjectField(o, objFieldId, nullptr, TRACE_JNI_CALL);
 
   size = ec_jni->GetArrayLength(arr, TRACE_JNI_CALL);
-  start_time = time(NULL);
+  start_time = time(nullptr);
   enterTime /= 1000;
   current_time = 0;
   while (current_time - start_time < enterTime) {
     hash = 0;
-    pa = (jshort*) ec_jni->GetPrimitiveArrayCritical(arr, NULL, TRACE_JNI_CALL);
-    if (pa != NULL) {
+    pa = (jshort*) ec_jni->GetPrimitiveArrayCritical(arr, nullptr, TRACE_JNI_CALL);
+    if (pa != nullptr) {
       for (i = 0; i < size; ++i) {
         hash ^= pa[i];
       }
     } else {
-      jni_env->FatalError("GetPrimitiveArrayCritical returned NULL");
+      jni_env->FatalError("GetPrimitiveArrayCritical returned null");
     }
     mssleep((long) sleepTime);
     ec_jni->ReleasePrimitiveArrayCritical(arr, pa, 0, TRACE_JNI_CALL);
     mssleep((long) sleepTime);
-    current_time = time(NULL);
+    current_time = time(nullptr);
   }
   ec_jni->SetObjectField(o, objFieldId, arr, TRACE_JNI_CALL);
   return hash;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/StringCriticalLocker.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/StringCriticalLocker.cpp
index bbb41cfef96..a8049b2bea9 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/StringCriticalLocker.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jni/StringCriticalLocker.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,7 +28,7 @@
 
 extern "C" {
 
-static jfieldID objFieldId = NULL;
+static jfieldID objFieldId = nullptr;
 
 /*
  * Class:     nsk_share_gc_lock_jni_StringCriticalLocker
@@ -45,31 +45,31 @@ JNIEXPORT jchar JNICALL Java_nsk_share_gc_lock_jni_StringCriticalLocker_critical
   jchar hash = 0;
   time_t start_time, current_time;
 
-  if (objFieldId == NULL) {
+  if (objFieldId == nullptr) {
     jclass klass = ec_jni->GetObjectClass(o, TRACE_JNI_CALL);
     objFieldId = ec_jni->GetFieldID(klass, "obj", "Ljava/lang/Object;", TRACE_JNI_CALL);
   }
   str = (jstring) ec_jni->GetObjectField(o, objFieldId, TRACE_JNI_CALL);
-  ec_jni->SetObjectField(o, objFieldId, NULL, TRACE_JNI_CALL);
+  ec_jni->SetObjectField(o, objFieldId, nullptr, TRACE_JNI_CALL);
 
   size = ec_jni->GetStringLength(str, TRACE_JNI_CALL);
-  start_time = time(NULL);
+  start_time = time(nullptr);
   enterTime /= 1000;
   current_time = 0;
   while (current_time - start_time < enterTime) {
     hash = 0;
-    pa = ec_jni->GetStringCritical(str, NULL, TRACE_JNI_CALL);
-    if (pa != NULL) {
+    pa = ec_jni->GetStringCritical(str, nullptr, TRACE_JNI_CALL);
+    if (pa != nullptr) {
       for (i = 0; i < size; ++i) {
         hash ^= pa[i];
       }
     } else {
-      jni_env->FatalError("GetStringCritical returned NULL");
+      jni_env->FatalError("GetStringCritical returned null");
     }
     mssleep((long) sleepTime);
     ec_jni->ReleaseStringCritical(str, pa, TRACE_JNI_CALL);
     mssleep((long) sleepTime);
-    current_time = time(NULL);
+    current_time = time(nullptr);
   }
   ec_jni->SetObjectField(o, objFieldId, str, TRACE_JNI_CALL);
   return hash;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp
index 7cde57969c7..4bbbef6e204 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIGlobalRefLocker.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,7 +29,7 @@
 
 extern "C" {
 
-static jfieldID objFieldId = NULL;
+static jfieldID objFieldId = nullptr;
 
 /*
  * Class:     nsk_share_gc_lock_jniref_JNIGlobalRefLocker
@@ -44,13 +44,13 @@ JNIEXPORT void JNICALL Java_nsk_share_gc_lock_jniref_JNIGlobalRefLocker_critical
         jobject gref;
         time_t start_time, current_time;
 
-        if (objFieldId == NULL) {
+        if (objFieldId == nullptr) {
                 jclass klass = ec_jni->GetObjectClass(o, TRACE_JNI_CALL);
                 objFieldId = ec_jni->GetFieldID(klass, "obj", "Ljava/lang/Object;", TRACE_JNI_CALL);
         }
         obj = ec_jni->GetObjectField(o, objFieldId, TRACE_JNI_CALL);
-        ec_jni->SetObjectField(o, objFieldId, NULL, TRACE_JNI_CALL);
-        start_time = time(NULL);
+        ec_jni->SetObjectField(o, objFieldId, nullptr, TRACE_JNI_CALL);
+        start_time = time(nullptr);
         enterTime /= 1000;
         current_time = 0;
         while (current_time - start_time < enterTime) {
@@ -58,7 +58,7 @@ JNIEXPORT void JNICALL Java_nsk_share_gc_lock_jniref_JNIGlobalRefLocker_critical
                 mssleep((long) sleepTime);
                 ec_jni->DeleteGlobalRef(gref, TRACE_JNI_CALL);
                 mssleep((long) sleepTime);
-                current_time = time(NULL);
+                current_time = time(nullptr);
         }
         ec_jni->SetObjectField(o, objFieldId, obj, TRACE_JNI_CALL);
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNILocalRefLocker.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNILocalRefLocker.cpp
index 20095130270..127322728a5 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNILocalRefLocker.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNILocalRefLocker.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,7 +28,7 @@
 
 extern "C" {
 
-static jfieldID objFieldId = NULL;
+static jfieldID objFieldId = nullptr;
 
 /*
  * Class:     nsk_share_gc_lock_jniref_JNILocalRefLocker
@@ -43,13 +43,13 @@ JNIEXPORT void JNICALL Java_nsk_share_gc_lock_jniref_JNILocalRefLocker_criticalN
         jobject gref;
         time_t start_time, current_time;
 
-        if (objFieldId == NULL) {
+        if (objFieldId == nullptr) {
                 jclass klass = ec_jni->GetObjectClass(o, TRACE_JNI_CALL);
                 objFieldId = ec_jni->GetFieldID(klass, "obj", "Ljava/lang/Object;", TRACE_JNI_CALL);
         }
         obj = ec_jni->GetObjectField(o, objFieldId, TRACE_JNI_CALL);
-        ec_jni->SetObjectField(o, objFieldId, NULL, TRACE_JNI_CALL);
-        start_time = time(NULL);
+        ec_jni->SetObjectField(o, objFieldId, nullptr, TRACE_JNI_CALL);
+        start_time = time(nullptr);
         enterTime /= 1000;
         current_time = 0;
         while (current_time - start_time < enterTime) {
@@ -57,7 +57,7 @@ JNIEXPORT void JNICALL Java_nsk_share_gc_lock_jniref_JNILocalRefLocker_criticalN
                 mssleep((long) sleepTime);
                 ec_jni->DeleteLocalRef(gref, TRACE_JNI_CALL);
                 mssleep((long) sleepTime);
-                current_time = time(NULL);
+                current_time = time(nullptr);
         }
         ec_jni->SetObjectField(o, objFieldId, obj, TRACE_JNI_CALL);
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIRefLocker.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIRefLocker.cpp
index a15c487cfd3..0fb552a8b03 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIRefLocker.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIRefLocker.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,7 +28,7 @@
 
 extern "C" {
 
-static jfieldID objFieldId = NULL;
+static jfieldID objFieldId = nullptr;
 
 /*
  * Class:     nsk_share_gc_lock_jniref_JNIRefLocker
@@ -43,15 +43,15 @@ JNIEXPORT void JNICALL Java_nsk_share_gc_lock_jniref_JNIRefLocker_criticalNative
         jobject gref, lref, gwref;
         time_t start_time, current_time;
 
-        if (objFieldId == NULL) {
+        if (objFieldId == nullptr) {
                 jclass klass = ec_jni->GetObjectClass(o, TRACE_JNI_CALL);
                 objFieldId = ec_jni->GetFieldID(klass, "obj", "Ljava/lang/Object;", TRACE_JNI_CALL);
         }
 
         obj = ec_jni->GetObjectField(o, objFieldId, TRACE_JNI_CALL);
-        ec_jni->SetObjectField(o, objFieldId, NULL, TRACE_JNI_CALL);
+        ec_jni->SetObjectField(o, objFieldId, nullptr, TRACE_JNI_CALL);
 
-        start_time = time(NULL);
+        start_time = time(nullptr);
         enterTime /= 1000;
         current_time = 0;
         while (current_time - start_time < enterTime) {
@@ -63,7 +63,7 @@ JNIEXPORT void JNICALL Java_nsk_share_gc_lock_jniref_JNIRefLocker_criticalNative
                 ec_jni->DeleteLocalRef(lref, TRACE_JNI_CALL);
                 ec_jni->DeleteWeakGlobalRef(gwref, TRACE_JNI_CALL);
                 mssleep((long) sleepTime);
-                current_time = time(NULL);
+                current_time = time(nullptr);
         }
         ec_jni->SetObjectField(o, objFieldId, obj, TRACE_JNI_CALL);
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIWeakGlobalRefLocker.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIWeakGlobalRefLocker.cpp
index d98379998ee..f4c35b20d90 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIWeakGlobalRefLocker.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/gc/lock/jniref/JNIWeakGlobalRefLocker.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,7 +28,7 @@
 
 extern "C" {
 
-static jfieldID objFieldId = NULL;
+static jfieldID objFieldId = nullptr;
 
 /*
  * Class:     nsk_share_gc_lock_jniref_JNIWeakGlobalRefLocker
@@ -43,14 +43,14 @@ JNIEXPORT void JNICALL Java_nsk_share_gc_lock_jniref_JNIWeakGlobalRefLocker_crit
         jobject gref;
         time_t start_time, current_time;
 
-        if (objFieldId == NULL) {
+        if (objFieldId == nullptr) {
                 jclass klass = ec_jni->GetObjectClass(o, TRACE_JNI_CALL);
                 objFieldId = ec_jni->GetFieldID(klass, "obj", "Ljava/lang/Object;", TRACE_JNI_CALL);
         }
         obj = ec_jni->GetObjectField(o, objFieldId, TRACE_JNI_CALL);
-        ec_jni->SetObjectField(o, objFieldId, NULL, TRACE_JNI_CALL);
+        ec_jni->SetObjectField(o, objFieldId, nullptr, TRACE_JNI_CALL);
 
-        start_time = time(NULL);
+        start_time = time(nullptr);
         enterTime /= 1000;
         current_time = 0;
         while (current_time - start_time < enterTime) {
@@ -58,7 +58,7 @@ JNIEXPORT void JNICALL Java_nsk_share_gc_lock_jniref_JNIWeakGlobalRefLocker_crit
                 mssleep((long) sleepTime);
                 ec_jni->DeleteWeakGlobalRef(gref, TRACE_JNI_CALL);
                 mssleep((long) sleepTime);
-                current_time = time(NULL);
+                current_time = time(nullptr);
         }
         ec_jni->SetObjectField(o, objFieldId, obj, TRACE_JNI_CALL);
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/jni/ExceptionCheckingJniEnv.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/jni/ExceptionCheckingJniEnv.cpp
index f9a232fd679..ca3e5dfff74 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/jni/ExceptionCheckingJniEnv.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/jni/ExceptionCheckingJniEnv.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2018, 2019, Google and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -35,8 +35,8 @@ static const char* get_dirname(const char* fullname) {
   const char* p;
   const char* base = fullname;;
 
-  if (fullname == NULL) {
-    return NULL;
+  if (fullname == nullptr) {
+    return nullptr;
   }
 
   for (p = fullname; *p != '\0'; p++) {
@@ -52,7 +52,7 @@ class JNIVerifier {
  public:
   JNIVerifier(ExceptionCheckingJniEnv *env, const char* base_message,
               int line, const char* file)
-      : _env(env), _base_message(base_message), _error_message(NULL),
+      : _env(env), _base_message(base_message), _error_message(nullptr),
         _line(line), _file(get_dirname(file)) {
   }
 
@@ -61,7 +61,7 @@ class JNIVerifier {
   JNIVerifier(ExceptionCheckingJniEnv *env, const char* base_message,
               U parameter,
               int line, const char* file)
-      : _env(env), _base_message(base_message), _error_message(NULL),
+      : _env(env), _base_message(base_message), _error_message(nullptr),
         _line(line), _file(get_dirname(file)) {
           PrintPreCall(parameter);
   }
@@ -71,7 +71,7 @@ class JNIVerifier {
               U parameter1,
               V parameter2,
               int line, const char* file)
-      : _env(env), _base_message(base_message), _error_message(NULL),
+      : _env(env), _base_message(base_message), _error_message(nullptr),
         _line(line), _file(get_dirname(file)) {
           PrintPreCall(parameter1, parameter2);
   }
@@ -80,7 +80,7 @@ class JNIVerifier {
   JNIVerifier(ExceptionCheckingJniEnv *env, const char* base_message,
               U parameter1, V parameter2, W parameter3,
               int line, const char* file)
-      : _env(env), _base_message(base_message), _error_message(NULL),
+      : _env(env), _base_message(base_message), _error_message(nullptr),
         _line(line), _file(get_dirname(file)) {
           PrintPreCall(parameter1, parameter2, parameter3);
   }
@@ -93,7 +93,7 @@ class JNIVerifier {
       _error_message = "internal error";
     }
 
-    if (_error_message != NULL) {
+    if (_error_message != nullptr) {
       GenerateErrorMessage();
     }
   }
@@ -173,7 +173,7 @@ class JNIVerifier {
     len += MAX_INTEGER_DIGITS + 1;
 
     char* full_message = (char*) malloc(len);
-    if (full_message == NULL) {
+    if (full_message == nullptr) {
       _env->HandleError(_error_message);
       return;
     }
@@ -199,8 +199,8 @@ class JNIVerifier {
   }
 
   T ResultNotNull(T ptr) {
-    if (ptr == NULL) {
-      _error_message = "Return is NULL";
+    if (ptr == nullptr) {
+      _error_message = "Return is null";
     }
     return ptr;
   }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/jni/ExceptionCheckingJniEnv.hpp b/test/hotspot/jtreg/vmTestbase/nsk/share/jni/ExceptionCheckingJniEnv.hpp
index af6c0489991..2db7177c8f7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/jni/ExceptionCheckingJniEnv.hpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/jni/ExceptionCheckingJniEnv.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2018, 2019, Google and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -36,8 +36,8 @@
  *
  * ... JNIEnv* env ...
  *  jclass klass = env->GetObjectClass(o);
- *  if (klass == NULL) {
- *      printf("Error: GetObjectClass returned NULL\n");
+ *  if (klass == nullptr) {
+ *      printf("Error: GetObjectClass returned null\n");
  *      return;
  *  }
  *  if (env->ExceptionCheck()) {
@@ -48,7 +48,7 @@
  * ... ExceptionCheckingJniEnv* env ...
  *  jclass klass = env->GetObjectClass(o, TRACE_JNI_CALL);
  *
- *  Where now the JNI Exception checking and the NULL return checking are done
+ *  Where now the JNI Exception checking and the null return checking are done
  *  internally and will perform whatever action the ErrorHandler requires.
  *
  *  Note the TRACE_JNI_CALL parameter that allows to trace where the call is
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/jni/JNIreferences.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/jni/JNIreferences.cpp
index 7fa0f0d15ab..50b59a157e9 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/jni/JNIreferences.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/jni/JNIreferences.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2006, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,8 +27,8 @@
 extern "C" {
 
 
-static jobject* globalReferences = NULL;
-static jweak* weakReferences = NULL;
+static jobject* globalReferences = nullptr;
+static jweak* weakReferences = nullptr;
 
 JNIEXPORT jint JNICALL
 Java_nsk_share_ReferringObject_createJNIGlobalReferenceNative(JNIEnv *env,
@@ -37,19 +37,19 @@ Java_nsk_share_ReferringObject_createJNIGlobalReferenceNative(JNIEnv *env,
         jint i;
         jint result = -1;
 
-        if (globalReferences == NULL)
+        if (globalReferences == nullptr)
         {
                 globalReferences = (jobject*)malloc(sizeof(jobject) * maxJNIGlobalReferences);
 
-                if (globalReferences == NULL)
+                if (globalReferences == nullptr)
                 {
-                        NSK_COMPLAIN0("malloc return NULL\n");
+                        NSK_COMPLAIN0("malloc return null\n");
                         return -1;
                 }
 
                 for (i = 0; i < maxJNIGlobalReferences; i++)
                 {
-                        globalReferences[i] = NULL;
+                        globalReferences[i] = nullptr;
                 }
         }
 
@@ -57,17 +57,17 @@ Java_nsk_share_ReferringObject_createJNIGlobalReferenceNative(JNIEnv *env,
         {
                 jobject reference = globalReferences[i];
 
-                if (reference == NULL)
+                if (reference == nullptr)
                 {
                         reference = env->NewGlobalRef(object);
 
-                        if (reference == NULL)
+                        if (reference == nullptr)
                         {
-                                NSK_COMPLAIN0("NewGlobalRef return NULL\n");
+                                NSK_COMPLAIN0("NewGlobalRef return null\n");
 
                                 env->ThrowNew(
                                     env->FindClass("nsk/share/TestJNIError"),
-                                    "NewGlobalRef return NULL");
+                                    "NewGlobalRef return null");
                         }
 
                         globalReferences[i] = reference;
@@ -87,18 +87,18 @@ Java_nsk_share_ReferringObject_deleteJNIGlobalReferenceNative(JNIEnv *env,
 {
         jobject reference = globalReferences[index];
 
-        if (reference == NULL)
+        if (reference == nullptr)
         {
-                NSK_COMPLAIN1("globalReferences[%d] = NULL, possible wrong index is passed\n", index);
+                NSK_COMPLAIN1("globalReferences[%d] = null, possible wrong index is passed\n", index);
 
                 env->ThrowNew(
                     env->FindClass("nsk/share/TestBug"),
-                    "Requested globalReferences[] element is NULL, possible wrong index is passed");
+                    "Requested globalReferences[] element is null, possible wrong index is passed");
         }
 
         env->DeleteGlobalRef(reference);
 
-        globalReferences[index] = NULL;
+        globalReferences[index] = nullptr;
 }
 
 
@@ -109,13 +109,13 @@ Java_nsk_share_ReferringObject_createJNILocalReferenceNative(JNIEnv *env,
         jobject reference = env->NewLocalRef(object);
         jclass klass;
 
-        if (reference == NULL)
+        if (reference == nullptr)
         {
-                NSK_COMPLAIN0("NewLocalRef return NULL\n");
+                NSK_COMPLAIN0("NewLocalRef return null\n");
 
                 env->ThrowNew(
                     env->FindClass("nsk/share/TestJNIError"),
-                    "NewLocalRef return NULL");
+                    "NewLocalRef return null");
         }
 
         klass = env->GetObjectClass(createWicket);
@@ -136,20 +136,20 @@ Java_nsk_share_ReferringObject_createJNIWeakReferenceNative(JNIEnv *env,
         jint i;
         jint result = -1;
 
-        if (weakReferences == NULL)
+        if (weakReferences == nullptr)
         {
                 weakReferences = (jweak*)malloc(sizeof(jweak) * maxJNIWeakReferences);
 
-                if (weakReferences == NULL)
+                if (weakReferences == nullptr)
                 {
-                        NSK_COMPLAIN0("malloc return NULL\n");
+                        NSK_COMPLAIN0("malloc return null\n");
 
                         return -1;
                 }
 
                 for (i = 0; i < maxJNIWeakReferences; i++)
                 {
-                        weakReferences[i] = NULL;
+                        weakReferences[i] = nullptr;
                 }
         }
 
@@ -157,17 +157,17 @@ Java_nsk_share_ReferringObject_createJNIWeakReferenceNative(JNIEnv *env,
         {
                 jobject reference = weakReferences[i];
 
-                if (reference == NULL)
+                if (reference == nullptr)
                 {
                         reference = env->NewWeakGlobalRef(object);
 
-                        if (reference == NULL)
+                        if (reference == nullptr)
                         {
-                                NSK_COMPLAIN0("NewWeakGlobalRef return NULL\n");
+                                NSK_COMPLAIN0("NewWeakGlobalRef return null\n");
 
                                 env->ThrowNew(
                                     env->FindClass("nsk/share/TestJNIError"),
-                                    "NewWeakGlobalRef return NULL");
+                                    "NewWeakGlobalRef return null");
                         }
 
                         weakReferences[i] = reference;
@@ -187,16 +187,16 @@ Java_nsk_share_ReferringObject_deleteJNIWeakReferenceNative(JNIEnv *env,
 {
         jweak reference = weakReferences[index];
 
-        if (reference == NULL)
+        if (reference == nullptr)
         {
-                NSK_COMPLAIN1("weakReferences[%d] = NULL, possible wrong index is passed\n", index);
+                NSK_COMPLAIN1("weakReferences[%d] = null, possible wrong index is passed\n", index);
 
                 env->ThrowNew(
                     env->FindClass("nsk/share/TestBug"),
-                    "Requested weakReferences[] element is NULL, possible wrong index is passed");
+                    "Requested weakReferences[] element is null, possible wrong index is passed");
         }
 
-        if (env->IsSameObject(reference, NULL) == JNI_TRUE)
+        if (env->IsSameObject(reference, nullptr) == JNI_TRUE)
         {
                 NSK_COMPLAIN0("TEST BUG: Weak reference was collected\n");
 
@@ -207,7 +207,7 @@ Java_nsk_share_ReferringObject_deleteJNIWeakReferenceNative(JNIEnv *env,
 
         env->DeleteWeakGlobalRef(reference);
 
-        weakReferences[index] = NULL;
+        weakReferences[index] = nullptr;
 }
 
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/jni/jni_tools.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/jni/jni_tools.cpp
index f8b9df264c9..2f5a5ff3bc0 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/jni/jni_tools.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/jni/jni_tools.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -51,7 +51,7 @@ int nsk_jni_check_exception(JNIEnv* jni, const char file[], int line)
     jthrowable throwable;
 
     NSK_TRACE(throwable = jni->ExceptionOccurred());
-    if (throwable != NULL) {
+    if (throwable != nullptr) {
         nsk_lcomplain(file, line, "Exception in JNI call (cleared):\n");
         NSK_TRACE(jni->ExceptionDescribe());
         NSK_TRACE(jni->ExceptionClear());
@@ -107,7 +107,7 @@ void mssleep(long millis) {
    struct timeval timeout;
    timeout.tv_sec = millis / 1000;
    timeout.tv_usec = (millis % 1000) * 1000;
-   select(0, NULL, NULL, NULL, &timeout);
+   select(0, nullptr, nullptr, nullptr, &timeout);
 #endif
 }
 
@@ -131,7 +131,7 @@ JavaVMOption*
 jni_create_vmoptions(int size, char *args[], int argsCnt)
 {
    int i;
-   JavaVMOption *options = NULL;
+   JavaVMOption *options = nullptr;
 
    if (size <= 0)
       return options;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/AddToBootstrapClassLoaderSearch/bootclssearch_agent.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/AddToBootstrapClassLoaderSearch/bootclssearch_agent.cpp
index 128b33bbf36..4340391d413 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/AddToBootstrapClassLoaderSearch/bootclssearch_agent.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/AddToBootstrapClassLoaderSearch/bootclssearch_agent.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -156,16 +156,16 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiEnv* jvmti;
     const char *p_segment1, *p_segment2, *phase_to_check;
 
-    jvmti = NULL;
-    p_segment1 = p_segment2 = phase_to_check = NULL;
+    jvmti = nullptr;
+    p_segment1 = p_segment2 = phase_to_check = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
 
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
-    p_segment1 = nsk_jvmti_findOptionStringValue("segment1", NULL);
-    if (!NSK_VERIFY(p_segment1 != NULL)) {
+    p_segment1 = nsk_jvmti_findOptionStringValue("segment1", nullptr);
+    if (!NSK_VERIFY(p_segment1 != nullptr)) {
         return JNI_ERR;
     } else {
         strncpy(segment1, p_segment1, (size_t) sizeof(segment1)/sizeof(char));
@@ -173,20 +173,20 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     // 'segment2' parameter is not mandatory
-    p_segment2 = nsk_jvmti_findOptionStringValue("segment2", NULL);
-    if (p_segment2 != NULL) {
+    p_segment2 = nsk_jvmti_findOptionStringValue("segment2", nullptr);
+    if (p_segment2 != nullptr) {
         strncpy(segment2, p_segment2, (size_t) sizeof(segment2)/sizeof(char));
         segment2[(size_t) sizeof(segment2)/sizeof(char) - 1] = 0;
         use_segment2 = JNI_TRUE;
     }
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     // Check what phase(s) we are going to test
-    phase_to_check = nsk_jvmti_findOptionStringValue("phasetocheck", NULL);
-    if (!NSK_VERIFY(phase_to_check != NULL)) {
+    phase_to_check = nsk_jvmti_findOptionStringValue("phasetocheck", nullptr);
+    if (!NSK_VERIFY(phase_to_check != nullptr)) {
         return JNI_ERR;
     } else if (strcmp(phase_to_check, "onload") == 0) {
         jvmti_phase_to_check = JVMTI_PHASE_ONLOAD;
@@ -227,7 +227,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
         jvmtiEvent eventsList[] = { JVMTI_EVENT_VM_INIT, JVMTI_EVENT_VM_DEATH };
         if (!NSK_VERIFY(nsk_jvmti_enableEvents(
-                     JVMTI_ENABLE, sizeof(eventsList)/sizeof(jvmtiEvent), eventsList, NULL))) {
+                     JVMTI_ENABLE, sizeof(eventsList)/sizeof(jvmtiEvent), eventsList, nullptr))) {
             return JNI_ERR;
         }
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/AddToSystemClassLoaderSearch/systemclssearch_agent.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/AddToSystemClassLoaderSearch/systemclssearch_agent.cpp
index 6be44a4f147..1d123242d49 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/AddToSystemClassLoaderSearch/systemclssearch_agent.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/AddToSystemClassLoaderSearch/systemclssearch_agent.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -156,16 +156,16 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     jvmtiEnv* jvmti;
     const char *p_segment1, *p_segment2, *phase_to_check;
 
-    jvmti = NULL;
-    p_segment1 = p_segment2 = phase_to_check = NULL;
+    jvmti = nullptr;
+    p_segment1 = p_segment2 = phase_to_check = nullptr;
 
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
 
     timeout = nsk_jvmti_getWaitTime() * 60 * 1000;
 
-    p_segment1 = nsk_jvmti_findOptionStringValue("segment1", NULL);
-    if (!NSK_VERIFY(p_segment1 != NULL)) {
+    p_segment1 = nsk_jvmti_findOptionStringValue("segment1", nullptr);
+    if (!NSK_VERIFY(p_segment1 != nullptr)) {
         return JNI_ERR;
     } else {
         strncpy(segment1, p_segment1, (size_t) sizeof(segment1)/sizeof(char));
@@ -173,20 +173,20 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     // 'segment2' parameter is not mandatory
-    p_segment2 = nsk_jvmti_findOptionStringValue("segment2", NULL);
-    if (p_segment2 != NULL) {
+    p_segment2 = nsk_jvmti_findOptionStringValue("segment2", nullptr);
+    if (p_segment2 != nullptr) {
         strncpy(segment2, p_segment2, (size_t) sizeof(segment2)/sizeof(char));
         segment2[(size_t) sizeof(segment2)/sizeof(char) - 1] = 0;
         use_segment2 = JNI_TRUE;
     }
 
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     // Check what phase(s) we are going to test
-    phase_to_check = nsk_jvmti_findOptionStringValue("phasetocheck", NULL);
-    if (!NSK_VERIFY(phase_to_check != NULL)) {
+    phase_to_check = nsk_jvmti_findOptionStringValue("phasetocheck", nullptr);
+    if (!NSK_VERIFY(phase_to_check != nullptr)) {
         return JNI_ERR;
     } else if (strcmp(phase_to_check, "onload") == 0) {
         jvmti_phase_to_check = JVMTI_PHASE_ONLOAD;
@@ -227,7 +227,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
         jvmtiEvent eventsList[] = { JVMTI_EVENT_VM_INIT, JVMTI_EVENT_VM_DEATH };
         if (!NSK_VERIFY(nsk_jvmti_enableEvents(
-                     JVMTI_ENABLE, sizeof(eventsList)/sizeof(jvmtiEvent), eventsList, NULL))) {
+                     JVMTI_ENABLE, sizeof(eventsList)/sizeof(jvmtiEvent), eventsList, nullptr))) {
             return JNI_ERR;
         }
     }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/Injector.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/Injector.cpp
index 6246c6c4884..b69faf76ffa 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/Injector.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/Injector.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -221,7 +221,7 @@ extern "C" {
 
         NSK_DISPLAY1("copying ConstantPool: %d\n", constantPoolSize);
         constantPool = (char**) malloc(constantPoolSize * sizeof(char*));
-        if (!NSK_VERIFY(constantPool != NULL)) {
+        if (!NSK_VERIFY(constantPool != nullptr)) {
             NSK_COMPLAIN0("out of memory\n");
             return NSK_FALSE;
         }
@@ -262,7 +262,7 @@ extern "C" {
             case CONSTANT_Utf8:
                 len = copy_u2();
                 utf8 = (char*) malloc(len + 1);
-                if (!NSK_VERIFY(utf8 != NULL)) {
+                if (!NSK_VERIFY(utf8 != nullptr)) {
                     NSK_COMPLAIN0("out of memory\n");
                     return NSK_FALSE;
                 }
@@ -295,7 +295,7 @@ extern "C" {
         u2 i;
 
         for (i = 1; i < constantPoolSize; i++) {
-            if (constantPool[i] != NULL) {
+            if (constantPool[i] != nullptr) {
                 free(constantPool[i]);
             }
         }
@@ -1138,7 +1138,7 @@ extern "C" {
         inputPos = (u1*) orig;
         endPos = orig + old_length;
         gen = (u1*) malloc(old_length * GROWTH_FACTOR);
-        if (!NSK_VERIFY(gen != NULL)) {
+        if (!NSK_VERIFY(gen != nullptr)) {
             NSK_COMPLAIN0("out of memory\n");
             return NSK_FALSE;
         }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/agent_tools.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/agent_tools.cpp
index b75f237c6a7..dc4da9bcf89 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/agent_tools.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/agent_tools.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -37,9 +37,9 @@ extern "C" {
  * Now the same source is used to build different agent libs, so these
  * variables are not shared between agents */
 
-static jthread agentThread = NULL;
-static jvmtiStartFunction agentThreadProc = NULL;
-static void* agentThreadArg = NULL;
+static jthread agentThread = nullptr;
+static jvmtiStartFunction agentThreadProc = nullptr;
+static void* agentThreadArg = nullptr;
 
 
 typedef enum { NEW, RUNNABLE, WAITING, SUSPENDED, TERMINATED } thread_state_t;
@@ -52,9 +52,9 @@ typedef struct agent_data_t {
 
 static agent_data_t agent_data;
 
-static jvmtiEnv* jvmti_env = NULL;
-static JavaVM* jvm = NULL;
-static JNIEnv* jni_env = NULL;
+static jvmtiEnv* jvmti_env = nullptr;
+static JavaVM* jvm = nullptr;
+static JNIEnv* jni_env = nullptr;
 
 static volatile int currentAgentStatus = NSK_STATUS_PASSED;
 
@@ -101,12 +101,12 @@ jvmtiEnv* nsk_jvmti_createJVMTIEnv(JavaVM* javaVM, void* reserved) {
     jvm = javaVM;
     if (!NSK_VERIFY(javaVM->GetEnv((void **)&jvmti_env, JVMTI_VERSION_1_1) == JNI_OK)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
     if (!NSK_JVMTI_VERIFY(init_agent_data(jvmti_env, &agent_data))) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
     return jvmti_env;
@@ -114,7 +114,7 @@ jvmtiEnv* nsk_jvmti_createJVMTIEnv(JavaVM* javaVM, void* reserved) {
 
 /** Dispose JVMTI environment */
 static int nsk_jvmti_disposeJVMTIEnv(jvmtiEnv* jvmti_env) {
-    if (jvmti_env != NULL) {
+    if (jvmti_env != nullptr) {
         if (!NSK_JVMTI_VERIFY(jvmti_env->DisposeEnvironment())) {
             nsk_jvmti_setFailStatus();
             return NSK_FALSE;
@@ -153,7 +153,7 @@ agentThreadWrapper(jvmtiEnv* jvmti_env, JNIEnv* agentJNI, void* arg) {
     rawMonitorEnter(jvmti_env, agent_data.monitor);
     agent_data.thread_state = TERMINATED;
     agentJNI->DeleteGlobalRef(agentThread);
-    agentThread = NULL;
+    agentThread = nullptr;
     rawMonitorNotify(jvmti_env, agent_data.monitor);
     rawMonitorExit(jvmti_env, agent_data.monitor);
 
@@ -167,31 +167,31 @@ static jthread startAgentThreadWrapper(JNIEnv *jni_env, jvmtiEnv* jvmti_env) {
     const char* THREAD_CTOR_NAME = "<init>";
     const char* THREAD_CTOR_SIGNATURE = "(Ljava/lang/String;)V";
 
-    jobject threadName = NULL;
-    jclass threadClass = NULL;
-    jmethodID threadCtor = NULL;
-    jobject threadObject = NULL;
-    jobject threadGlobalRef = NULL;
+    jobject threadName = nullptr;
+    jclass threadClass = nullptr;
+    jmethodID threadCtor = nullptr;
+    jobject threadObject = nullptr;
+    jobject threadGlobalRef = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni_env, (threadClass = jni_env->FindClass(THREAD_CLASS_NAME)) != NULL)) {
-        return NULL;
+    if (!NSK_JNI_VERIFY(jni_env, (threadClass = jni_env->FindClass(THREAD_CLASS_NAME)) != nullptr)) {
+        return nullptr;
     }
 
     if (!NSK_JNI_VERIFY(jni_env, (threadCtor =
-            jni_env->GetMethodID(threadClass, THREAD_CTOR_NAME, THREAD_CTOR_SIGNATURE)) != NULL))
-        return NULL;
+            jni_env->GetMethodID(threadClass, THREAD_CTOR_NAME, THREAD_CTOR_SIGNATURE)) != nullptr))
+        return nullptr;
 
-    if (!NSK_JNI_VERIFY(jni_env, (threadName = jni_env->NewStringUTF(THREAD_NAME)) != NULL))
-        return NULL;
+    if (!NSK_JNI_VERIFY(jni_env, (threadName = jni_env->NewStringUTF(THREAD_NAME)) != nullptr))
+        return nullptr;
 
     if (!NSK_JNI_VERIFY(jni_env, (threadObject =
-            jni_env->NewObject(threadClass, threadCtor, threadName)) != NULL))
-        return NULL;
+            jni_env->NewObject(threadClass, threadCtor, threadName)) != nullptr))
+        return nullptr;
 
     if (!NSK_JNI_VERIFY(jni_env, (threadGlobalRef =
-            jni_env->NewGlobalRef(threadObject)) != NULL)) {
+            jni_env->NewGlobalRef(threadObject)) != nullptr)) {
         jni_env->DeleteLocalRef(threadObject);
-        return NULL;
+        return nullptr;
     }
     agentThread = (jthread)threadGlobalRef;
 
@@ -199,7 +199,7 @@ static jthread startAgentThreadWrapper(JNIEnv *jni_env, jvmtiEnv* jvmti_env) {
             jvmti_env->RunAgentThread(agentThread, &agentThreadWrapper, agentThreadArg, THREAD_PRIORITY))) {
         jni_env->DeleteGlobalRef(threadGlobalRef);
         jni_env->DeleteLocalRef(threadObject);
-        return NULL;
+        return nullptr;
     }
     return agentThread;
 }
@@ -220,9 +220,9 @@ jthread nsk_jvmti_getAgentThread() {
 static jthread nsk_jvmti_runAgentThread(JNIEnv *jni_env, jvmtiEnv* jvmti_env) {
     /* start agent thread wrapper */
     jthread thread = startAgentThreadWrapper(jni_env, jvmti_env);
-    if (thread == NULL) {
+    if (thread == nullptr) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
     return thread;
@@ -247,7 +247,7 @@ static jint syncDebuggeeStatus(JNIEnv* jni_env, jvmtiEnv* jvmti_env, jint debugg
 
     /* we don't enter if-stmt in second call */
     if (agent_data.thread_state == NEW) {
-        if (nsk_jvmti_runAgentThread(jni_env, jvmti_env) == NULL)
+        if (nsk_jvmti_runAgentThread(jni_env, jvmti_env) == nullptr)
             goto monitor_exit_and_return;
 
         /* SP2.2-w - wait for agent thread */
@@ -371,31 +371,31 @@ Java_nsk_share_jvmti_DebugeeClass_resetAgentData(JNIEnv* jni_env, jclass cls) {
 
 /** Find loaded class by signature. */
 jclass nsk_jvmti_classBySignature(const char signature[]) {
-    jclass* classes = NULL;
+    jclass* classes = nullptr;
     jint count = 0;
-    jclass foundClass = NULL;
+    jclass foundClass = nullptr;
     int i;
 
-    if (!NSK_VERIFY(signature != NULL)) {
+    if (!NSK_VERIFY(signature != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
     if (!NSK_JVMTI_VERIFY(jvmti_env->GetLoadedClasses(&count, &classes))) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
     for (i = 0; i < count; i++) {
-        char* sig = NULL;
-        char* generic = NULL;
+        char* sig = nullptr;
+        char* generic = nullptr;
 
         if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(classes[i], &sig, &generic))) {
             nsk_jvmti_setFailStatus();
             break;
         }
 
-        if (sig != NULL && strcmp(signature, sig) == 0) {
+        if (sig != nullptr && strcmp(signature, sig) == 0) {
             foundClass = classes[i];
         }
 
@@ -405,19 +405,19 @@ jclass nsk_jvmti_classBySignature(const char signature[]) {
             break;
         }
 
-        if (foundClass != NULL)
+        if (foundClass != nullptr)
             break;
     }
 
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)classes))) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
     if (!NSK_JNI_VERIFY(jni_env, (foundClass = (jclass)
-                jni_env->NewGlobalRef(foundClass)) != NULL)) {
+                jni_env->NewGlobalRef(foundClass)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
     return foundClass;
@@ -425,19 +425,19 @@ jclass nsk_jvmti_classBySignature(const char signature[]) {
 
 /** Find alive thread by name. */
 jthread nsk_jvmti_threadByName(const char name[]) {
-    jthread* threads = NULL;
+    jthread* threads = nullptr;
     jint count = 0;
-    jthread foundThread = NULL;
+    jthread foundThread = nullptr;
     int i;
 
-    if (!NSK_VERIFY(name != NULL)) {
+    if (!NSK_VERIFY(name != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
     if (!NSK_JVMTI_VERIFY(jvmti_env->GetAllThreads(&count, &threads))) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
     for (i = 0; i < count; i++) {
@@ -448,27 +448,27 @@ jthread nsk_jvmti_threadByName(const char name[]) {
             break;
         }
 
-        if (info.name != NULL && strcmp(name, info.name) == 0) {
+        if (info.name != nullptr && strcmp(name, info.name) == 0) {
             foundThread = threads[i];
         }
         if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)info.name))) {
             nsk_jvmti_setFailStatus();
-            return NULL;
+            return nullptr;
         }
-        if (foundThread != NULL) {
+        if (foundThread != nullptr) {
             break;
         }
     }
 
     if (!NSK_JVMTI_VERIFY(jvmti_env->Deallocate((unsigned char*)threads))) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
     if (!NSK_JNI_VERIFY(jni_env, (foundThread = (jthread)
-                jni_env->NewGlobalRef(foundThread)) != NULL)) {
+                jni_env->NewGlobalRef(foundThread)) != nullptr)) {
         nsk_jvmti_setFailStatus();
-        return NULL;
+        return nullptr;
     }
 
     return foundThread;
@@ -507,7 +507,7 @@ int nsk_jvmti_addBreakpointCapabilities() {
 /** Find line location. */
 jlocation nsk_jvmti_getLineLocation(jclass cls, jmethodID method, int line) {
     jint count = 0;
-    jvmtiLineNumberEntry* table = NULL;
+    jvmtiLineNumberEntry* table = nullptr;
     jlocation location = NSK_JVMTI_INVALID_JLOCATION;
     int i;
 
@@ -574,7 +574,7 @@ int nsk_jvmti_enableEvents(jvmtiEventMode enable, int size, jvmtiEvent list[], j
 
 typedef jint (JNICALL *checkStatus_type)(JNIEnv* jni_env, jclass cls, jint debuggeeStatus);
 
-static checkStatus_type checkStatus_func = NULL;
+static checkStatus_type checkStatus_func = nullptr;
 
 /**
  * Proxy function to gain sequential access to checkStatus of each agent
@@ -600,9 +600,9 @@ static void JNICALL nativeMethodBind(jvmtiEnv* jvmti_env, JNIEnv *jni_env,
 
     jvmtiPhase phase;
     jclass cls;
-    char *class_sig = NULL;
-    char *name = NULL;
-    char *sig = NULL;
+    char *class_sig = nullptr;
+    char *name = nullptr;
+    char *sig = nullptr;
 
     if (!NSK_JVMTI_VERIFY(jvmti_env->GetPhase(&phase))) {
         nsk_jvmti_setFailStatus();
@@ -612,12 +612,12 @@ static void JNICALL nativeMethodBind(jvmtiEnv* jvmti_env, JNIEnv *jni_env,
     if (phase != JVMTI_PHASE_START && phase != JVMTI_PHASE_LIVE)
         return;
 
-    if (NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(mid, &name, &sig, NULL))) {
+    if (NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(mid, &name, &sig, nullptr))) {
         if (strcmp(name, BIND_METHOD_NAME) == 0 &&
                 strcmp(sig, BIND_METHOD_SIGNATURE) == 0) {
 
             if (NSK_JVMTI_VERIFY(jvmti_env->GetMethodDeclaringClass(mid, &cls))
-             && NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(cls, &class_sig, NULL))
+             && NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(cls, &class_sig, nullptr))
              && strcmp(class_sig, BIND_CLASS_NAME) == 0
              && address != (void*)Java_nsk_share_jvmti_DebugeeClass_checkStatus) {
                 checkStatus_func = (checkStatus_type)address;
@@ -626,13 +626,13 @@ static void JNICALL nativeMethodBind(jvmtiEnv* jvmti_env, JNIEnv *jni_env,
         }
     }
 
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
 
-    if (sig != NULL)
+    if (sig != nullptr)
         jvmti_env->Deallocate((unsigned char*)sig);
 
-    if (class_sig != NULL)
+    if (class_sig != nullptr)
         jvmti_env->Deallocate((unsigned char*)class_sig);
 }
 
@@ -642,14 +642,14 @@ static void JNICALL nativeMethodBind(jvmtiEnv* jvmti_env, JNIEnv *jni_env,
  */
 int nsk_jvmti_init_MA(jvmtiEventCallbacks* callbacks) {
 
-    if (callbacks == NULL) {
-        NSK_COMPLAIN0("callbacks should not be NULL\n");
+    if (callbacks == nullptr) {
+        NSK_COMPLAIN0("callbacks should not be null\n");
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
 
-    if (callbacks->NativeMethodBind != NULL) {
-        NSK_COMPLAIN0("callbacks.NativeMethodBind should be NULL\n");
+    if (callbacks->NativeMethodBind != nullptr) {
+        NSK_COMPLAIN0("callbacks.NativeMethodBind should be null\n");
         nsk_jvmti_setFailStatus();
         return NSK_FALSE;
     }
@@ -667,7 +667,7 @@ int nsk_jvmti_init_MA(jvmtiEventCallbacks* callbacks) {
         return NSK_FALSE;
 
     if (!NSK_JVMTI_VERIFY(
-            jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, NULL)))
+            jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_NATIVE_METHOD_BIND, nullptr)))
         return NSK_FALSE;
 
     return NSK_TRUE;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/aod/jvmti_aod.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/aod/jvmti_aod.cpp
index 6269379d8c7..98d82172679 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/aod/jvmti_aod.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/aod/jvmti_aod.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -79,7 +79,7 @@ Options* nsk_jvmti_aod_getMultiagentsOptions(jvmtiEnv *jvmti) {
 
     NSK_COMPLAIN1("Options for jvmtiEnv %p weren't found\n", jvmti);
 
-    return NULL;
+    return nullptr;
 }
 
 /*
@@ -101,7 +101,7 @@ void nsk_jvmti_aod_deallocate(jvmtiEnv *jvmti, unsigned char* mem) {
 int nsk_jvmti_aod_getClassName(jvmtiEnv *jvmti, jclass klass, char classNameBuffer[]) {
     char* className;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(klass, &className, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti->GetClassSignature(klass, &className, nullptr))) {
         NSK_COMPLAIN0("Failed to get class name\n");
         classNameBuffer[0] = '\0';
         return NSK_FALSE;
@@ -161,25 +161,25 @@ jthread nsk_jvmti_aod_createThread(JNIEnv *jni) {
     jmethodID threadConstructor;
     jthread thread;
 
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->FindClass("java/lang/Thread")) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->FindClass("java/lang/Thread")) != nullptr)) {
         NSK_COMPLAIN0("Failed to get the java.lang.Thread class\n");
-        return NULL;
+        return nullptr;
     }
     if (!NSK_JNI_VERIFY(jni,
-            (threadConstructor = jni->GetMethodID(klass, "<init>", "()V")) != NULL)) {
+            (threadConstructor = jni->GetMethodID(klass, "<init>", "()V")) != nullptr)) {
         NSK_COMPLAIN0("Failed to get java.lang.Thread constructor\n");
-        return NULL;
+        return nullptr;
     }
 
     if (!NSK_JNI_VERIFY (jni,
-            (thread = jni->NewObject(klass, threadConstructor, NULL)) != NULL)) {
+            (thread = jni->NewObject(klass, threadConstructor, nullptr)) != nullptr)) {
         NSK_COMPLAIN0("Failed to create Thread object\n");
-        return NULL;
+        return nullptr;
     }
 
-    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != nullptr)) {
         NSK_COMPLAIN0("Failed to create global reference\n");
-        return NULL;
+        return nullptr;
     }
 
     return thread;
@@ -191,28 +191,28 @@ jthread nsk_jvmti_aod_createThreadWithName(JNIEnv *jni, const char* threadName)
     jthread thread;
     jstring threadNameString;
 
-    if (!NSK_JNI_VERIFY(jni, (threadNameString = jni->NewStringUTF(threadName)) != NULL))
-        return NULL;
+    if (!NSK_JNI_VERIFY(jni, (threadNameString = jni->NewStringUTF(threadName)) != nullptr))
+        return nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (klass = jni->FindClass("java/lang/Thread")) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (klass = jni->FindClass("java/lang/Thread")) != nullptr)) {
         NSK_COMPLAIN0("Failed to get the java.lang.Thread class\n");
-        return NULL;
+        return nullptr;
     }
     if (!NSK_JNI_VERIFY(jni,
-            (threadConstructor = jni->GetMethodID(klass, "<init>", "(Ljava/lang/String;)V")) != NULL)) {
+            (threadConstructor = jni->GetMethodID(klass, "<init>", "(Ljava/lang/String;)V")) != nullptr)) {
         NSK_COMPLAIN0("Failed to get java.lang.Thread constructor\n");
-        return NULL;
+        return nullptr;
     }
 
     if (!NSK_JNI_VERIFY(jni,
-            (thread = jni->NewObject(klass, threadConstructor, threadNameString)) != NULL)) {
+            (thread = jni->NewObject(klass, threadConstructor, threadNameString)) != nullptr)) {
         NSK_COMPLAIN0("Failed to create Thread object\n");
-        return NULL;
+        return nullptr;
     }
 
-    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != NULL)) {
+    if (!NSK_JNI_VERIFY(jni, (thread = jni->NewGlobalRef(thread)) != nullptr)) {
         NSK_COMPLAIN0("Failed to create global reference\n");
-        return NULL;
+        return nullptr;
     }
 
     return thread;
@@ -230,8 +230,8 @@ int nsk_jvmti_aod_redefineClass(
         NSK_COMPLAIN1("Option '%s' isn't specified\n", PATH_TO_NEW_BYTE_CODE_OPTION);
         return NSK_FALSE;
     }
-    if (fileName == NULL) {
-        NSK_COMPLAIN0("File name is NULL\n");
+    if (fileName == nullptr) {
+        NSK_COMPLAIN0("File name is null\n");
         return NSK_FALSE;
     }
     {
@@ -250,7 +250,7 @@ int nsk_jvmti_aod_redefineClass(
 
             bytecode = fopen(file, "rb");
             error= JVMTI_ERROR_NONE;
-            if (bytecode == NULL) {
+            if (bytecode == nullptr) {
                 NSK_COMPLAIN1("Error opening file '%s'\n", file);
                 return NSK_FALSE;
             }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/hotswap/HotSwap.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/hotswap/HotSwap.cpp
index 97f30c106c0..5976eb39ec7 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/hotswap/HotSwap.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/hotswap/HotSwap.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -59,17 +59,17 @@ static int vm_mode = VM_MODE_COMPILED;
 static int bci_mode = BCI_MODE_EMCP;
 static int sync_freq = 0;
 
-static jclass profile_klass = NULL;
-static jfieldID count_field = NULL;
+static jclass profile_klass = nullptr;
+static jfieldID count_field = nullptr;
 
 /* test objects */
 static int max_classes;
-static char** names = NULL;
-static jvmtiClassDefinition* old_class_def = NULL;
-static jvmtiClassDefinition* new_class_def = NULL;
+static char** names = nullptr;
+static jvmtiClassDefinition* old_class_def = nullptr;
+static jvmtiClassDefinition* new_class_def = nullptr;
 static int classCount = 0;
 /* lock to access classCount */
-static jrawMonitorID classLoadLock = NULL;
+static jrawMonitorID classLoadLock = nullptr;
 static int newFlag = NSK_FALSE;
 
 /* ========================================================================== */
@@ -99,8 +99,8 @@ ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *jni_env,
         jint *new_class_data_len, unsigned char** new_class_data) {
     jint name_len;
 
-    if (name != NULL &&
-            class_being_redefined == NULL &&
+    if (name != nullptr &&
+            class_being_redefined == nullptr &&
             (strcmp(name, PROFILE_CLASS_NAME) != 0) &&
             (strncmp(name, package_name, package_name_length) == 0)) {
         if (!NSK_JVMTI_VERIFY(jvmti_env->RawMonitorEnter(classLoadLock))) {
@@ -139,20 +139,20 @@ static void JNICALL
 CompiledMethodLoad(jvmtiEnv *jvmti_env, jmethodID method,
         jint code_size, const void* code_addr, jint map_length,
         const jvmtiAddrLocationMap* map, const void* compile_info) {
-    char *name = NULL;
-    char *signature = NULL;
+    char *name = nullptr;
+    char *signature = nullptr;
 
     CompiledMethodLoadEventsCount++;
 
-    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, NULL))) {
+    if (!NSK_JVMTI_VERIFY(jvmti_env->GetMethodName(method, &name, &signature, nullptr))) {
         nsk_jvmti_setFailStatus();
         return;
     }
     NSK_DISPLAY3("CompiledMethodLoad event: %s%s (0x%p)\n",
         name, signature, code_addr);
-    if (name != NULL)
+    if (name != nullptr)
         jvmti_env->Deallocate((unsigned char*)name);
-    if (signature != NULL)
+    if (signature != nullptr)
         jvmti_env->Deallocate((unsigned char*)signature);
 }
 
@@ -175,20 +175,20 @@ Exception(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jthread thread,
     if (sync_freq && ((ExceptionEventsCount % sync_freq) == 0)) {
 
         if (nsk_getVerboseMode()) {
-            jclass klass = NULL;
-            char *signature = NULL;
+            jclass klass = nullptr;
+            char *signature = nullptr;
 
-            if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != NULL)) {
+            if (!NSK_JNI_VERIFY(jni_env, (klass = jni_env->GetObjectClass(exception)) != nullptr)) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
-            if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, NULL))) {
+            if (!NSK_JVMTI_VERIFY(jvmti_env->GetClassSignature(klass, &signature, nullptr))) {
                 nsk_jvmti_setFailStatus();
                 return;
             }
             NSK_DISPLAY2("Exception event %d: %s\n",
                 ExceptionEventsCount.load(), signature);
-            if (signature != NULL)
+            if (signature != nullptr)
                 jvmti_env->Deallocate((unsigned char*)signature);
         }
 
@@ -200,7 +200,7 @@ Exception(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jthread thread,
         if (vm_mode == VM_MODE_MIXED) {
             if (!NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(
                     ((newFlag) ? JVMTI_DISABLE : JVMTI_ENABLE),
-                    JVMTI_EVENT_SINGLE_STEP, NULL)))
+                    JVMTI_EVENT_SINGLE_STEP, nullptr)))
                 nsk_jvmti_setFailStatus();
         }
 
@@ -217,16 +217,16 @@ Exception(jvmtiEnv *jvmti_env, JNIEnv *jni_env, jthread thread,
 
 /* ========================================================================== */
 
-static jrawMonitorID waitLock = NULL;
+static jrawMonitorID waitLock = nullptr;
 
 static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     int i;
 
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return NSK_FALSE;
 
     if (vm_mode != VM_MODE_COMPILED) {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, NULL)))
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, nullptr)))
             return NSK_FALSE;
     }
 
@@ -235,27 +235,27 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
 
     for (i = 0; i < classCount; i++) {
         NSK_DISPLAY1("Find class: %s\n", names[i]);
-        if (!NSK_JNI_VERIFY(jni, (old_class_def[i].klass = jni->FindClass(names[i])) != NULL))
+        if (!NSK_JNI_VERIFY(jni, (old_class_def[i].klass = jni->FindClass(names[i])) != nullptr))
             return NSK_FALSE;
 
         if (!NSK_JNI_VERIFY(jni, (old_class_def[i].klass = (jclass)
-                jni->NewGlobalRef(old_class_def[i].klass)) != NULL))
+                jni->NewGlobalRef(old_class_def[i].klass)) != nullptr))
             return NSK_FALSE;
     }
 
     if (bci_mode != BCI_MODE_EMCP) {
         NSK_DISPLAY1("Find class: %s\n", PROFILE_CLASS_NAME);
-        if (!NSK_JNI_VERIFY(jni, (profile_klass = jni->FindClass(PROFILE_CLASS_NAME)) != NULL))
+        if (!NSK_JNI_VERIFY(jni, (profile_klass = jni->FindClass(PROFILE_CLASS_NAME)) != nullptr))
             return NSK_FALSE;
 
         if (!NSK_JNI_VERIFY(jni, (profile_klass = (jclass)
-                jni->NewGlobalRef(profile_klass)) != NULL))
+                jni->NewGlobalRef(profile_klass)) != nullptr))
             return NSK_FALSE;
 
         if (!NSK_JNI_VERIFY(jni, (count_field =
                 jni->GetStaticFieldID(profile_klass,
                                       (bci_mode == BCI_MODE_CALL) ? "callCount" : "allocCount",
-                                      "I")) != NULL))
+                                      "I")) != nullptr))
             return NSK_FALSE;
 
         if (!NSK_JVMTI_VERIFY(jvmti->Allocate(classCount * sizeof(jvmtiClassDefinition),
@@ -273,7 +273,7 @@ static int prepare(jvmtiEnv* jvmti, JNIEnv* jni) {
     }
 
     if (sync_freq) {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION, NULL)))
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION, nullptr)))
             return NSK_FALSE;
     }
 
@@ -318,7 +318,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
         return;
 
     if (sync_freq) {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_EXCEPTION, NULL)))
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_EXCEPTION, nullptr)))
             nsk_jvmti_setFailStatus();
     } else {
 
@@ -333,7 +333,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
             if (vm_mode == VM_MODE_MIXED) {
                 if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(
                         (((i % 2) == 0) ? JVMTI_DISABLE : JVMTI_ENABLE),
-                        JVMTI_EVENT_SINGLE_STEP, NULL)))
+                        JVMTI_EVENT_SINGLE_STEP, nullptr)))
                     nsk_jvmti_setFailStatus();
             }
 
@@ -348,7 +348,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
     }
 
     if (vm_mode != VM_MODE_COMPILED) {
-        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, NULL)))
+        if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, nullptr)))
             nsk_jvmti_setFailStatus();
     }
 
@@ -360,7 +360,7 @@ agentProc(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
 
 /** Agent library initialization. */
 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-    jvmtiEnv* jvmti = NULL;
+    jvmtiEnv* jvmti = nullptr;
     jvmtiCapabilities caps;
     jvmtiEventCallbacks callbacks;
     const char* optValue;
@@ -388,7 +388,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     package_name = nsk_jvmti_findOptionStringValue("package",
         DEFAULT_PACKAGE_NAME);
-    if (!NSK_VERIFY(package_name != NULL))
+    if (!NSK_VERIFY(package_name != nullptr))
         return JNI_ERR;
     NSK_DISPLAY1("package: %s\n", package_name);
 
@@ -403,7 +403,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     NSK_DISPLAY1("classes: %d\n", max_classes);
 
     optValue = nsk_jvmti_findOptionValue("mode");
-    if (optValue != NULL) {
+    if (optValue != nullptr) {
         if (strcmp(optValue, "compiled") == 0)
             vm_mode = VM_MODE_COMPILED;
         else if (strcmp(optValue, "interpreted") == 0)
@@ -417,7 +417,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     }
 
     optValue = nsk_jvmti_findOptionValue("bci");
-    if (optValue != NULL) {
+    if (optValue != nullptr) {
         if (strcmp(optValue, "emcp") == 0)
             bci_mode = BCI_MODE_EMCP;
         else if (strcmp(optValue, "call") == 0)
@@ -437,7 +437,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     /* allocate tables for classes */
@@ -464,7 +464,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
     if (!NSK_JVMTI_VERIFY(jvmti->AddCapabilities(&caps)))
         return JNI_ERR;
 
-    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, NULL)))
+    if (!NSK_VERIFY(nsk_jvmti_setAgentProc(agentProc, nullptr)))
         return JNI_ERR;
 
     /* set event callbacks */
@@ -481,9 +481,9 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
         return JNI_ERR;
 
     /* enable events */
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, nullptr)))
         return JNI_ERR;
-    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL)))
+    if (!NSK_JVMTI_VERIFY(jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_FollowRefObjects.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_FollowRefObjects.cpp
index 2a9931971b5..bf48fd1da73 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_FollowRefObjects.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_FollowRefObjects.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2006, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -131,13 +131,13 @@ JNIEXPORT jboolean JNICALL Java_nsk_jvmti_unit_FollowReferences_FollowRefObjects
         jboolean fCopy;
         const char * s;
 
-        if (!NSK_VERIFY((s = jni->GetStringUTFChars(sInfo, &fCopy)) != NULL)) {
+        if (!NSK_VERIFY((s = jni->GetStringUTFChars(sInfo, &fCopy)) != nullptr)) {
             NSK_COMPLAIN1("Can't get string at %#p\n", sInfo);
             return JNI_FALSE;
         }
 
         if (!s) {
-            NSK_COMPLAIN1("Can't get string at %#p: NULL\n", sInfo);
+            NSK_COMPLAIN1("Can't get string at %#p: null\n", sInfo);
             return JNI_FALSE;
         }
 
@@ -193,7 +193,7 @@ static RefToVerify * findRefToVerify(jlong tagFrom, jlong tagTo, jint refKind)
         }
     }
 
-    return NULL;
+    return nullptr;
 }
 
 static jboolean addRefToVerify(jlong tagFrom, jlong tagTo, jint refKind, int expectedCount, int actualCount)
@@ -238,7 +238,7 @@ JNIEXPORT jboolean JNICALL Java_nsk_jvmti_unit_FollowReferences_FollowRefObjects
     }
 
     pRefRec = findRefToVerify(tagFrom, tagTo, refKind);
-    if (pRefRec != NULL) {
+    if (pRefRec != nullptr) {
         pRefRec->_expectedCount += count;
         return JNI_TRUE;
     }
@@ -251,7 +251,7 @@ jboolean markRefToVerify(jlong tagFrom, jlong tagTo, int refKind)
     RefToVerify * pRefRec;
 
     pRefRec = findRefToVerify(tagFrom, tagTo, refKind);
-    if (pRefRec != NULL) {
+    if (pRefRec != nullptr) {
         pRefRec->_actualCount++;
         return JNI_TRUE;
     }
@@ -380,14 +380,14 @@ jint JNICALL wrongStringPrimitiveValueCallback(
 
 void jvmti_FollowRefObject_init()
 {
-    g_wrongHeapCallbacks.heap_iteration_callback         = NULL;
+    g_wrongHeapCallbacks.heap_iteration_callback         = nullptr;
     g_wrongHeapCallbacks.heap_reference_callback         = wrongHeapReferenceCallback;
     g_wrongHeapCallbacks.primitive_field_callback        = wrongPrimitiveFieldCallback;
     g_wrongHeapCallbacks.array_primitive_value_callback  = wrongArrayPrimitiveValueCallback;
     g_wrongHeapCallbacks.string_primitive_value_callback = wrongStringPrimitiveValueCallback;
 
-    Java_nsk_jvmti_unit_FollowReferences_FollowRefObjects_resetTags(NULL, NULL);
-    Java_nsk_jvmti_unit_FollowReferences_FollowRefObjects_resetRefsToVerify(NULL, NULL);
+    Java_nsk_jvmti_unit_FollowReferences_FollowRefObjects_resetTags(nullptr, nullptr);
+    Java_nsk_jvmti_unit_FollowReferences_FollowRefObjects_resetRefsToVerify(nullptr, nullptr);
 }
 
 /* ============================================================================= */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_tools.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_tools.cpp
index 444e5c55d1f..e07c453fd0e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_tools.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_tools.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -100,9 +100,9 @@ static int check_option(int dashed, const char name[], const char value[]) {
             return NSK_FALSE;
         }
         {
-            char* end = NULL;
+            char* end = nullptr;
             long n = strtol(value, &end, 10);
-            if (end == NULL || end == value || *end != '\0') {
+            if (end == nullptr || end == value || *end != '\0') {
                 nsk_complain("nsk_jvmti_parseOptions(): not integer value in option: %s=%s\n", name, value);
                 return NSK_FALSE;
             }
@@ -140,7 +140,7 @@ static int add_option(const char opt[], int opt_len, const char val[], int val_l
     name = (char*)malloc(opt_len + 1);
     value = (char*)malloc(val_len + 1);
 
-    if (name == NULL || value == NULL) {
+    if (name == nullptr || value == nullptr) {
         nsk_complain("nsk_jvmti_parseOptions(): out of memory\n");
         success = NSK_FALSE;
     } else {
@@ -166,9 +166,9 @@ static int add_option(const char opt[], int opt_len, const char val[], int val_l
     }
 
     if (!success) {
-        if (name != NULL)
+        if (name != nullptr)
             free(name);
-        if (value != NULL)
+        if (value != nullptr)
             free(value);
     }
 
@@ -184,9 +184,9 @@ static void nsk_jvmti_free() {
         }
         context.options.count = 0;
     }
-    if (context.options.string != NULL) {
+    if (context.options.string != nullptr) {
         free(context.options.string);
-        context.options.string = NULL;
+        context.options.string = nullptr;
     }
 }
 
@@ -198,18 +198,18 @@ static char* token(char **s, const char *delim) {
   char *p;
   char *start = *s;
 
-  if (s == NULL || *s == NULL) {
-    return NULL;
+  if (s == nullptr || *s == nullptr) {
+    return nullptr;
   }
 
   p = strpbrk(*s, delim);
-  if (p != NULL) {
+  if (p != nullptr) {
     /* Advance to next token. */
     *p = '\0';
     *s = p + 1;
   } else {
     /* End of tokens. */
-    *s = NULL;
+    *s = nullptr;
   }
 
   return start;
@@ -218,11 +218,11 @@ static char* token(char **s, const char *delim) {
 int nsk_jvmti_parseOptions(const char options[]) {
     int success = NSK_TRUE;
 
-    char *str = NULL;
-    char *name = NULL;
-    char *value = NULL;
+    char *str = nullptr;
+    char *name = nullptr;
+    char *value = nullptr;
     const char *delimiters = " ,~";
-    if (options == NULL)
+    if (options == nullptr)
         return success;
 
     /*
@@ -233,10 +233,10 @@ int nsk_jvmti_parseOptions(const char options[]) {
 
     /* Create a temporary copy of the options string to be tokenized. */
     str = strdup(options);
-    while ((name = token(&str, delimiters)) != NULL) {
+    while ((name = token(&str, delimiters)) != nullptr) {
         value = strchr(name, '=');
 
-        if (value != NULL) {
+        if (value != nullptr) {
             *value++ = '\0';
         }
         if (!add_option(name, (int)strlen(name), value,
@@ -248,7 +248,7 @@ int nsk_jvmti_parseOptions(const char options[]) {
     if (!success) {
         nsk_jvmti_free();
     }
-    if (str != NULL) {
+    if (str != nullptr) {
       free(str);
     }
     return success;
@@ -257,45 +257,45 @@ int nsk_jvmti_parseOptions(const char options[]) {
 /*************************************************************/
 
 /**
- * Returns value of given option name; or NULL if no such option found.
- * If search name is NULL then complains an error and returns NULL.
+ * Returns value of given option name; or nullptr if no such option found.
+ * If search name is nullptr then complains an error and returns nullptr.
  */
 const char* nsk_jvmti_findOptionValue(const char name[]) {
     int i;
 
-    if (name == NULL) {
-        nsk_complain("nsk_jvmti_findOptionValue(): option name is NULL\n");
-        return NULL;
+    if (name == nullptr) {
+        nsk_complain("nsk_jvmti_findOptionValue(): option name is null\n");
+        return nullptr;
     }
 
     for (i = 0; i < context.options.count; i++) {
         if (strcmp(name, context.options.names[i]) == 0)
             return context.options.values[i];
     }
-    return NULL;
+    return nullptr;
 }
 
 /**
  * Returns string value of given option; or defaultValue if no such option found.
- * If options is specified but has empty value then complains an error and returns NULL.
+ * If options is specified but has empty value then complains an error and returns nullptr.
  */
 const char* nsk_jvmti_findOptionStringValue(const char name[], const char* defaultValue) {
     const char* value;
 
-    if (name == NULL) {
-        nsk_complain("nsk_jvmti_findOptionStringValue(): option name is NULL\n");
-        return NULL;
+    if (name == nullptr) {
+        nsk_complain("nsk_jvmti_findOptionStringValue(): option name is null\n");
+        return nullptr;
     }
 
     value = nsk_jvmti_findOptionValue(name);
-    if (value == NULL) {
+    if (value == nullptr) {
         return defaultValue;
     }
 
     if (strlen(value) <= 0) {
         nsk_complain("nsk_jvmti_findOptionStringValue(): empty value of option: %s=%s\n",
                                                                             name, value);
-        return NULL;
+        return nullptr;
     }
     return value;
 }
@@ -307,13 +307,13 @@ const char* nsk_jvmti_findOptionStringValue(const char name[], const char* defau
 int nsk_jvmti_findOptionIntValue(const char name[], int defaultValue) {
     const char* value;
 
-    if (name == NULL) {
-        nsk_complain("nsk_jvmti_findOptionIntValue(): option name is NULL\n");
+    if (name == nullptr) {
+        nsk_complain("nsk_jvmti_findOptionIntValue(): option name is null\n");
         return -1;
     }
 
     value = nsk_jvmti_findOptionValue(name);
-    if (value == NULL) {
+    if (value == nullptr) {
         return defaultValue;
     }
 
@@ -324,10 +324,10 @@ int nsk_jvmti_findOptionIntValue(const char name[], int defaultValue) {
     }
 
     {
-        char* endptr = NULL;
+        char* endptr = nullptr;
         int n = strtol(value, &endptr, 10);
 
-        if (endptr == NULL || *endptr != '\0') {
+        if (endptr == nullptr || *endptr != '\0') {
             nsk_complain("nsk_jvmti_findOptionIntValue(): not integer value of option: %s=%s\n",
                                                                             name, value);
             return -1;
@@ -345,24 +345,24 @@ int nsk_jvmti_getOptionsCount() {
 
 /**
  * Returns name of i-th parsed option.
- * If no such option then complains an error and returns NULL.
+ * If no such option then complains an error and returns nullptr.
  */
 const char* nsk_jvmti_getOptionName(int i) {
     if (i < 0 || i >= context.options.count) {
         nsk_complain("nsk_jvmti_getOptionName(): option index out of bounds: %d\n", i);
-        return NULL;
+        return nullptr;
     }
     return context.options.names[i];
 }
 
 /**
  * Returns value of i-th parsed option.
- * If no such option then complains an error and returns NULL.
+ * If no such option then complains an error and returns nullptr.
  */
 const char* nsk_jvmti_getOptionValue(int i) {
     if (i < 0 || i >= context.options.count) {
         nsk_complain("nsk_jvmti_getOptionValue(): option index out of bounds: %d\n", i);
-        return NULL;
+        return nullptr;
     }
     return context.options.values[i];
 }
@@ -414,10 +414,10 @@ int nsk_jvmti_lverify(int positive, jvmtiError error, jvmtiError expected,
 
 JNIEXPORT jstring JNICALL
 Java_nsk_share_jvmti_ArgumentHandler_getAgentOptionsString(JNIEnv *jni, jobject obj) {
-    jstring str_obj = NULL;
+    jstring str_obj = nullptr;
 
-    if (!NSK_JNI_VERIFY(jni, (str_obj = jni->NewStringUTF(context.options.string)) != NULL)) {
-        return NULL;
+    if (!NSK_JNI_VERIFY(jni, (str_obj = jni->NewStringUTF(context.options.string)) != nullptr)) {
+        return nullptr;
     }
     return str_obj;
 }
@@ -453,13 +453,13 @@ int nsk_jvmti_redefineClass(jvmtiEnv * jvmti,
         jclass classToRedefine,
         const char * fileName) {
     redefineAttempted = NSK_TRUE;
-    if (nsk_jvmti_findOptionValue(NSK_JVMTI_OPT_PATH_TO_NEW_BYTE_CODE) == NULL) {
+    if (nsk_jvmti_findOptionValue(NSK_JVMTI_OPT_PATH_TO_NEW_BYTE_CODE) == nullptr) {
         nsk_printf("#   error expected: %s \n", NSK_JVMTI_OPT_PATH_TO_NEW_BYTE_CODE);
         nsk_printf("Hint :: missing java -agentlib:agentlib=%s=DirName, ($TESTBASE/bin) \n",
                    NSK_JVMTI_OPT_PATH_TO_NEW_BYTE_CODE);
         return NSK_FALSE;
     }
-    if (fileName == NULL) {
+    if (fileName == nullptr) {
         nsk_printf("# error file name expected did not found \n");
         return NSK_FALSE;
     }
@@ -479,7 +479,7 @@ int nsk_jvmti_redefineClass(jvmtiEnv * jvmti,
 
             bytecode = fopen(file, "rb");
             error= JVMTI_ERROR_NONE;
-            if (bytecode == NULL) {
+            if (bytecode == nullptr) {
                 nsk_printf("# error **Agent::error opening file %s \n",file);
                 return NSK_FALSE;
             }
@@ -594,7 +594,7 @@ int suspendThreadAtMethod(jvmtiEnv *jvmti, jclass cls, jobject thread, jmethodID
     }
 
     int result = NSK_TRUE;
-    jmethodID method = NULL;
+    jmethodID method = nullptr;
     jlocation loc;
 
     // We need to ensure that the thread is suspended at the right place when the top
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/unit/Heap.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/unit/Heap.cpp
index fe7f3f16f16..8306fd07c5e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/unit/Heap.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/unit/Heap.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@ static jboolean user_data_error_flag = JNI_FALSE;
 static jvmtiEventObjectFree object_free_callback;
 
 static void JNICALL default_object_free(jvmtiEnv *env, jlong tag) {
-    if (object_free_callback != NULL) {
+    if (object_free_callback != nullptr) {
         (*object_free_callback)(env, tag);
     }
 }
@@ -58,9 +58,9 @@ static jvmtiIterationControl JNICALL default_heap_object_callback
 }
 
 static jvmtiHeapObjectCallback heap_object_callback = default_heap_object_callback;
-static jvmtiHeapRootCallback heap_root_callback = NULL;
-static jvmtiStackReferenceCallback stack_ref_callback = NULL;
-static jvmtiObjectReferenceCallback object_ref_callback = NULL;
+static jvmtiHeapRootCallback heap_root_callback = nullptr;
+static jvmtiStackReferenceCallback stack_ref_callback = nullptr;
+static jvmtiObjectReferenceCallback object_ref_callback = nullptr;
 
 /*
  * Basic tagging functions
@@ -182,13 +182,13 @@ JNIEXPORT jint JNICALL Java_nsk_share_jvmti_unit_Heap_getObjectsWithTags
 
     /* get rid of any arrays that we are holding from a previous call */
 
-    if (object_results_ref != NULL) {
+    if (object_results_ref != nullptr) {
         env->DeleteGlobalRef(object_results_ref);
-        object_results_ref = NULL;
+        object_results_ref = nullptr;
     }
-    if (tag_results_ref != NULL) {
+    if (tag_results_ref != nullptr) {
         env->DeleteGlobalRef(tag_results_ref);
-        tag_results_ref = NULL;
+        tag_results_ref = nullptr;
     }
 
     /* copy input list-of-tags from java into C */
@@ -210,7 +210,7 @@ JNIEXPORT jint JNICALL Java_nsk_share_jvmti_unit_Heap_getObjectsWithTags
 
     cls = env->FindClass("java/lang/Object");
 
-    object_array = env->NewObjectArray(count, cls, NULL);
+    object_array = env->NewObjectArray(count, cls, nullptr);
     tag_array = env->NewLongArray(count);
 
     for (i=0; i<count; i++) {
@@ -333,7 +333,7 @@ static jvmtiIterationControl JNICALL simple_stack_ref_callback
      jlong thread_tag, jint depth, jmethodID method, jint slot, void* user_data)
 {
     if (root_kind == JVMTI_HEAP_ROOT_STACK_LOCAL) {
-        if (method == NULL) {
+        if (method == nullptr) {
             fprintf(stderr, "WARNING: jmethodID missing for STACK_LOCAL\n");
         }
     }
@@ -362,23 +362,23 @@ JNIEXPORT void JNICALL Java_nsk_share_jvmti_unit_Heap_setHeapRootCallback
     (JNIEnv *env, jclass cls)
 {
     heap_root_callback = simple_heap_root_callback;
-    stack_ref_callback = NULL;
-    object_ref_callback = NULL;
+    stack_ref_callback = nullptr;
+    object_ref_callback = nullptr;
 }
 
 JNIEXPORT void JNICALL Java_nsk_share_jvmti_unit_Heap_setStackRefCallback
     (JNIEnv *env, jclass cls)
 {
-    heap_root_callback = NULL;
+    heap_root_callback = nullptr;
     stack_ref_callback = simple_stack_ref_callback;
-    object_ref_callback = NULL;
+    object_ref_callback = nullptr;
 }
 
 JNIEXPORT void JNICALL Java_nsk_share_jvmti_unit_Heap_setObjectRefCallback
     (JNIEnv *env, jclass cls)
 {
-    heap_root_callback = NULL;
-    stack_ref_callback = NULL;
+    heap_root_callback = nullptr;
+    stack_ref_callback = nullptr;
     object_ref_callback = simple_object_ref_callback;
 }
 
@@ -450,7 +450,7 @@ jint Agent_Initialize(JavaVM *vm, char *options, void *reserved)
 
 
     /* enable OBJECT_FREE events */
-    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, NULL);
+    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, nullptr);
     if (err != JVMTI_ERROR_NONE) {
         fprintf(stderr, "SetEventNotificationMode failed, error=%d\n", err);
         return -1;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/native/native_thread.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/native/native_thread.cpp
index c6e95b11f78..d17856ee22a 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/native/native_thread.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/native/native_thread.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -73,12 +73,12 @@ typedef
 /***************************************************************/
 
 /**
- * Return a new thread mirror, or NULL if failed.
+ * Return a new thread mirror, or nullptr if failed.
  */
 void* THREAD_new(PROCEDURE procedure, void* context) {
     THREAD* thread = (THREAD*)malloc(sizeof(THREAD));
-    if (thread == NULL)
-        return NULL;
+    if (thread == nullptr)
+        return nullptr;
     thread->procedure = procedure;
     thread->context   = context;
     thread->started   = 0; /* No */
@@ -102,30 +102,30 @@ void* procedure(void* t) {
 }
 
 /**
- * Return the thread if started OK, or NULL if failed.
+ * Return the thread if started OK, or nullptr if failed.
  */
 void* THREAD_start(void* t) {
     THREAD* thread = (THREAD*)t;
-    if (thread == NULL)
-        return NULL;
+    if (thread == nullptr)
+        return nullptr;
     if (thread->started != 0)
-        return NULL;
+        return nullptr;
 /*  thread->started  = 0;      -- not yet */
     thread->finished = 0;
     thread->status   = 0;
     {
 
 #ifdef windows
-    uintptr_t result = _beginthreadex(NULL,0,procedure,thread,0,&(thread->id));
+    uintptr_t result = _beginthreadex(nullptr,0,procedure,thread,0,&(thread->id));
     if (result == 0) {
         perror("failed to create a native thread");
-        return NULL;
+        return nullptr;
     }
 #elif sun
-    int result = thr_create(NULL,0,procedure,thread,0,&(thread->id));
+    int result = thr_create(nullptr,0,procedure,thread,0,&(thread->id));
     if (result != 0) {
         perror("failed to create a native thread");
-        return NULL;
+        return nullptr;
     }
 #else // !windows & !sun
     pthread_attr_t attr;
@@ -135,7 +135,7 @@ void* THREAD_start(void* t) {
     int result = pthread_create(&(thread->id), &attr, procedure, thread);
     if (result != 0) {
         perror("failed to create a native thread");
-        return NULL;
+        return nullptr;
     }
     pthread_attr_destroy(&attr);
 #endif // !windows & !sun
@@ -147,11 +147,11 @@ void* THREAD_start(void* t) {
 
 /**
  * Return 1 if the thread has been started, or 0 if not,
- * or -1 if thread == NULL.
+ * or -1 if thread == nullptr.
  */
 int THREAD_isStarted(void* t) {
     THREAD* thread = (THREAD*)t;
-    if (thread == NULL)
+    if (thread == nullptr)
         return -1;
     return (thread->started == 1);
 }
@@ -159,11 +159,11 @@ int THREAD_isStarted(void* t) {
 /**
  * Return 1 if the thread has been started and already has finished,
  * or 0 if the thread hasn't finish (or even hasn't been started),
- * or -1 if thread == NULL.
+ * or -1 if thread == nullptr.
  */
 int THREAD_hasFinished(void* t) {
     THREAD* thread = (THREAD*)t;
-    if (thread == NULL)
+    if (thread == nullptr)
         return -1;
     return (thread->finished == 1);
 }
@@ -171,11 +171,11 @@ int THREAD_hasFinished(void* t) {
 /**
  * Return thread->status if thread has finished,
  * or return 0 if thread hasn't finished,
- * or retuen -1 if thread == NULL.
+ * or retuen -1 if thread == nullptr.
  */
 int THREAD_status(void* t) {
     THREAD* thread = (THREAD*)t;
-    if (thread == NULL)
+    if (thread == nullptr)
         return -1;
     return thread->status;
 }
@@ -184,11 +184,11 @@ int THREAD_status(void* t) {
 
 /**
  * Cycle with 1 second sleeps until the thread has finished;
- * or return immediately, if thread == NULL.
+ * or return immediately, if thread == nullptr.
  */
 void THREAD_waitFor(void* t) {
     THREAD* thread = (THREAD*)t;
-    if (thread == NULL)
+    if (thread == nullptr)
         return;
     while (thread->finished == 0)
         THREAD_sleep(1); /* yield for a second */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/native/nsk_list.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/native/nsk_list.cpp
index 74f2416dfce..63708bd84f4 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/native/nsk_list.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/native/nsk_list.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,16 +48,16 @@ const void* nsk_list_create() {
 
     /* create nsk_list_info */
     list_info = (nsk_list_info *)malloc(sizeof(nsk_list_info));
-    if (list_info == NULL) {
-        return NULL;
+    if (list_info == nullptr) {
+        return nullptr;
     }
 
     list_info->allocated_count = NSK_LIST_INIT_COUNT;
     list_info->elements_count = 0;
     list_info->arr = (const void **)malloc(list_info->allocated_count * nsk_list_size_void);
-    if (list_info->arr == NULL) {
+    if (list_info->arr == nullptr) {
         free(list_info);
-        return NULL;
+        return nullptr;
     }
 
     return list_info;
@@ -84,7 +84,7 @@ int nsk_list_add(const void *plist, const void *p) {
     if (list_info->elements_count >= list_info->allocated_count) {
         list_info->allocated_count += NSK_LIST_INIT_COUNT;
         list_info->arr = (const void **)realloc((void *)list_info->arr, list_info->allocated_count * nsk_list_size_void);
-        if (list_info->arr == NULL) {
+        if (list_info->arr == nullptr) {
             return NSK_FALSE;
         }
     }
@@ -131,7 +131,7 @@ const void* nsk_list_get(const void *plist, int i) {
         return list_info->arr[i];
     }
 
-    return NULL;
+    return nullptr;
 }
 
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/native/nsk_mutex.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/native/nsk_mutex.cpp
index d057e364dea..305317ffffa 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/native/nsk_mutex.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/native/nsk_mutex.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,7 +35,7 @@ MUTEX* MUTEX_create()
         MUTEX* mutex = (MUTEX*)malloc(sizeof(pthread_mutex_t));
         if (mutex)
         {
-                pthread_mutex_init((pthread_mutex_t*)mutex, NULL);
+                pthread_mutex_init((pthread_mutex_t*)mutex, nullptr);
         }
         return mutex;
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/native/nsk_tools.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/native/nsk_tools.cpp
index 91992159a96..3ba69427fd6 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/native/nsk_tools.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/native/nsk_tools.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -67,8 +67,8 @@ static const char* file_basename(const char* fullname) {
     const char* p;
     const char* base = fullname;;
 
-    if (fullname == NULL)
-        return NULL;
+    if (fullname == nullptr)
+        return nullptr;
 
     for (p = fullname; *p != '\0'; p++) {
         if (*p == '/' || *p == '\\')
@@ -82,7 +82,7 @@ static const char* file_basename(const char* fullname) {
 void nsk_display(const char format[], ...) {
     va_list ap;
     va_start(ap,format);
-    nsk_lvdisplay(NULL,0,format,ap);
+    nsk_lvdisplay(nullptr,0,format,ap);
     va_end(ap);
 }
 
@@ -94,14 +94,14 @@ void nsk_ldisplay(const char file[], int line, const char format[], ...) {
 }
 
 void nsk_vdisplay(const char format[], va_list ap) {
-    nsk_lvdisplay(NULL,0,format,ap);
+    nsk_lvdisplay(nullptr,0,format,ap);
 }
 
 void nsk_lvdisplay(const char file[], int line, const char format[], va_list ap)
 {
     if (!nsk_context.verbose)
         return;
-    if (file != NULL)
+    if (file != nullptr)
         (void) nsk_printf("- %s, %d: ",file_basename(file),line);
     (void) nsk_vprintf(format,ap);
 }
@@ -111,7 +111,7 @@ void nsk_lvdisplay(const char file[], int line, const char format[], va_list ap)
 void nsk_complain(const char format[], ...) {
     va_list ap;
     va_start(ap,format);
-    nsk_lvcomplain(NULL,0,format,ap);
+    nsk_lvcomplain(nullptr,0,format,ap);
     va_end(ap);
 }
 
@@ -124,7 +124,7 @@ void nsk_lcomplain(const char file[], int line, const char format[], ...)
 }
 
 void nsk_vcomplain(const char format[], va_list ap) {
-    nsk_lvcomplain(NULL,0,format,ap);
+    nsk_lvcomplain(nullptr,0,format,ap);
 }
 
 void nsk_lvcomplain(const char file[], int line,
@@ -157,7 +157,7 @@ void nsk_lvcomplain(const char file[], int line,
       strncpy(msg_buf2, msg_buf, sizeof(msg_buf2));
       // Only include up to the 1st newline in the exception's error message.
       nl_ptr = strchr(msg_buf2, '\n');
-      if (nl_ptr != NULL) {
+      if (nl_ptr != nullptr) {
         nl_ptr++;       // Skip past the newline char.
         *nl_ptr = '\0'; // Terminate the string after the newline char.
       } else if (strlen(msg_buf2) != 0) {
@@ -165,14 +165,14 @@ void nsk_lvcomplain(const char file[], int line,
       }
       (void) nsk_printf("The following fake exception stacktrace is for failure analysis. \n");
       (void) nsk_printf("nsk.share.Fake_Exception_for_RULE_Creation: ");
-      if (file != NULL) {
+      if (file != nullptr) {
         (void) nsk_printf("(%s:%d) ", file_basename(file), line);
       }
       (void) nsk_printf(msg_buf2);
       (void) nsk_printf("\tat nsk_lvcomplain(%s:%d)\n", file_basename(__FILE__), __LINE__);
     }
 
-    if (file != NULL) {
+    if (file != nullptr) {
         (void) nsk_printf("# ERROR: %s, %d: ", file_basename(file), line);
     } else {
         (void) nsk_printf("# ERROR: ");
@@ -265,7 +265,7 @@ void nsk_printHexBytes(const char indent[], int columns,
 
     size_t i;
 
-    if (size <= 0 || bytes == NULL)
+    if (size <= 0 || bytes == nullptr)
         return;
 
     for (i = 0; i < size; i += columns) {
@@ -298,7 +298,7 @@ void nsk_printHexBytes(const char indent[], int columns,
 /*************************************************************/
 
 const char* nsk_null_string(const char* str) {
-    return (str == NULL)? "<NULL>" : str;
+    return (str == nullptr)? "<null>" : str;
 }
 
 /*************************************************************/
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/stress/jni/gclocker/libgcl001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/stress/jni/gclocker/libgcl001.cpp
index 54b9e9df6e4..773b2aae28b 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/stress/jni/gclocker/libgcl001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/stress/jni/gclocker/libgcl001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -37,22 +37,22 @@
 #define BODY(type)                                                          \
   int hash = 0;                                                             \
   jsize i, arraySize, stringSize;                                           \
-  jchar *nativeStr = NULL;                                                  \
-  type *nativeArray = NULL;                                                 \
+  jchar *nativeStr = nullptr;                                                  \
+  type *nativeArray = nullptr;                                                 \
                                                                             \
   arraySize = env->GetArrayLength(array); CE                                \
   stringSize = env->GetStringLength(str); CE                                \
                                                                             \
-  nativeArray = (type *)env->GetPrimitiveArrayCritical(array, NULL); CE     \
+  nativeArray = (type *)env->GetPrimitiveArrayCritical(array, nullptr); CE     \
   qsort(nativeArray, arraySize, sizeof(type), *type##comp);                 \
                                                                             \
-  nativeStr = (jchar *)env->GetStringCritical(str, NULL); CE                \
+  nativeStr = (jchar *)env->GetStringCritical(str, nullptr); CE                \
                                                                             \
   for (i = 0; i < stringSize; ++i)                                          \
     hash += (int)nativeStr[i];                                              \
   env->ReleaseStringCritical(str, nativeStr); CE                            \
                                                                             \
-  nativeStr = (jchar *)env->GetStringCritical(str, NULL); CE                \
+  nativeStr = (jchar *)env->GetStringCritical(str, nullptr); CE                \
                                                                             \
   env->ReleasePrimitiveArrayCritical(array, nativeArray, 0); CE             \
                                                                             \
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/stress/jni/libjnistress001.cpp b/test/hotspot/jtreg/vmTestbase/nsk/stress/jni/libjnistress001.cpp
index 2e056006824..2eaba727ff4 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/stress/jni/libjnistress001.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/stress/jni/libjnistress001.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -108,8 +108,8 @@ Java_nsk_stress_jni_JNIter001_jnistress (JNIEnv *env, jobject jobj, jstring jstr
       }
       if (memcmp(digest, element->checkstr[j], DIGESTLENGTH) == 0) {
         env->ReleaseStringUTFChars(jstr, element->str[j]); CE
-        element->str[j] = NULL;
-        element->checkstr[j] = NULL;
+        element->str[j] = nullptr;
+        element->checkstr[j] = nullptr;
       } else {
         compared = 0;
         printf("The element No. %d has been corrupted %s vs %s\n", j,
@@ -217,8 +217,8 @@ Java_nsk_stress_jni_JNIter001_jnistress1(JNIEnv *env, jobject jobj, jstring jstr
       free(elem);
       if (memcmp(digest, javachars->checkstr[j], javachars->size[j]) == 0) {
         env->ReleaseStringChars(jstr, javachars->str[j]); CE
-        javachars->str[j] = NULL;
-        javachars->checkstr[j] = NULL;
+        javachars->str[j] = nullptr;
+        javachars->checkstr[j] = nullptr;
         javachars->size[j] = 0;
       } else {
         equal = 0;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/stress/jni/libjnistress003.cpp b/test/hotspot/jtreg/vmTestbase/nsk/stress/jni/libjnistress003.cpp
index 7bccbc95900..7fa25b831c2 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/stress/jni/libjnistress003.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/stress/jni/libjnistress003.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -141,8 +141,8 @@ Java_nsk_stress_jni_JNIter003_jniBodyChangeArray (JNIEnv *env, jobject jobj,
   jdouble *doubleOrig, *doubleClone;
   int i;
 
-  if ((orig == NULL) || (clone == NULL)) {
-    fprintf(stderr, "JNI received a NULL array from Java\n");
+  if ((orig == nullptr) || (clone == nullptr)) {
+    fprintf(stderr, "JNI received a null array from Java\n");
     return JNI_FALSE;
   }
   if (count == limit) {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/stress/strace/strace005.cpp b/test/hotspot/jtreg/vmTestbase/nsk/stress/strace/strace005.cpp
index 4cc89978fd1..77f83b374c0 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/stress/strace/strace005.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/stress/strace/strace005.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@ JNI_OnLoad(JavaVM *vm, void *reserved)
 
     FIND_CLASS(stackOverflowErrorClass, "java/lang/StackOverflowError");
     stackOverflowErrorClass = (jclass) env->NewGlobalRef(stackOverflowErrorClass);
-    if (stackOverflowErrorClass == NULL) {
+    if (stackOverflowErrorClass == nullptr) {
         printf("Can't create global ref for stack overflow class\n");
         return 0;
     }
@@ -56,7 +56,7 @@ JNI_OnUnload(JavaVM *vm, void *reserved)
     JNIEnv *env;
 
     if (vm->GetEnv((void **) &env, JNI_VERSION) != JNI_OK) {
-        if (stackOverflowErrorClass != NULL) {
+        if (stackOverflowErrorClass != nullptr) {
             env->DeleteGlobalRef(stackOverflowErrorClass);
         }
     } else {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/stress/strace/strace006.cpp b/test/hotspot/jtreg/vmTestbase/nsk/stress/strace/strace006.cpp
index 9b5329f2cb9..a70030fb095 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/stress/strace/strace006.cpp
+++ b/test/hotspot/jtreg/vmTestbase/nsk/stress/strace/strace006.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -44,7 +44,7 @@ JNI_OnLoad(JavaVM *vm, void *reserved)
 
     FIND_CLASS(stackOverflowErrorClass, "java/lang/StackOverflowError");
     stackOverflowErrorClass = (jclass) env->NewGlobalRef(stackOverflowErrorClass);
-    if (stackOverflowErrorClass == NULL) {
+    if (stackOverflowErrorClass == nullptr) {
         printf("Can't create global ref for stack overflow class\n");
         return 0;
     }
@@ -58,7 +58,7 @@ JNI_OnUnload(JavaVM *vm, void *reserved)
     JNIEnv *env;
 
     if (vm->GetEnv((void **) &env, JNI_VERSION) != JNI_OK) {
-        if (stackOverflowErrorClass != NULL) {
+        if (stackOverflowErrorClass != nullptr) {
             env->DeleteGlobalRef(stackOverflowErrorClass);
         }
     } else {
diff --git a/test/hotspot/jtreg/vmTestbase/vm/mlvm/indy/func/jvmti/share/IndyRedefineClass.cpp b/test/hotspot/jtreg/vmTestbase/vm/mlvm/indy/func/jvmti/share/IndyRedefineClass.cpp
index 2f4cefd19b5..04d4c6094cc 100644
--- a/test/hotspot/jtreg/vmTestbase/vm/mlvm/indy/func/jvmti/share/IndyRedefineClass.cpp
+++ b/test/hotspot/jtreg/vmTestbase/vm/mlvm/indy/func/jvmti/share/IndyRedefineClass.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@
 
 extern "C" {
 
-static jvmtiEnv* gJvmtiEnv = NULL;
+static jvmtiEnv* gJvmtiEnv = nullptr;
 
 static jboolean gIsMethodEntryWorking = JNI_FALSE;
 static jboolean gIsSingleStepWorking = JNI_FALSE;
@@ -88,13 +88,13 @@ static void popFrameLogic(jvmtiEnv * jvmti_env, jthread thread) {
     if (tls->countOfFramesToPop <= 0) {
 
         NSK_DISPLAY0("Disabling single step\n");
-        if (!NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, NULL)))
+        if (!NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, nullptr)))
             gIsErrorOccured = JNI_TRUE;
 
     } else {
 
         NSK_DISPLAY0("Enabling single step\n");
-        if (!NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, NULL)))
+        if (!NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, nullptr)))
             gIsErrorOccured = JNI_TRUE;
 
         if (tls->countOfFramesToPop == 1) {
@@ -132,7 +132,7 @@ MethodEntry(jvmtiEnv *jvmti_env,
     }
 
     NSK_DISPLAY2("Entering redefine tigger method: %s.%s\n", mn->classSig, mn->methodName);
-    free(mn); mn = NULL;
+    free(mn); mn = nullptr;
 
     if (gIsClassRedefined) {
         NSK_DISPLAY0("Class is already redefined.\n");
@@ -168,7 +168,7 @@ SingleStep(jvmtiEnv *jvmti_env,
     gIsSingleStepWorking = JNI_TRUE;
     locStr = locationToString(jvmti_env, method, location);
 
-    if (locStr == NULL) {
+    if (locStr == nullptr) {
         NSK_DISPLAY0("Error in Single step event: locationToString failed\n");
         gIsErrorOccured = JNI_TRUE;
     } else {
@@ -186,7 +186,7 @@ jint Agent_Initialize(JavaVM * vm, char * options, void * reserved) {
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
 
-    if (!NSK_VERIFY((gJvmtiEnv = nsk_jvmti_createJVMTIEnv(vm, reserved)) != NULL))
+    if (!NSK_VERIFY((gJvmtiEnv = nsk_jvmti_createJVMTIEnv(vm, reserved)) != nullptr))
         return JNI_ERR;
 
     if (nsk_jvmti_findOptionValue("debuggerCompatible")) {
@@ -210,10 +210,10 @@ jint Agent_Initialize(JavaVM * vm, char * options, void * reserved) {
     if (!NSK_JVMTI_VERIFY(gJvmtiEnv->SetEventCallbacks(&callbacks, sizeof(callbacks))))
             return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(gJvmtiEnv->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, NULL)))
+    if (!NSK_JVMTI_VERIFY(gJvmtiEnv->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, nullptr)))
             return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(gJvmtiEnv->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, NULL)))
+    if (!NSK_JVMTI_VERIFY(gJvmtiEnv->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, nullptr)))
             return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/vm/mlvm/indy/func/jvmti/stepBreakPopReturn/stepBreakPopReturn.cpp b/test/hotspot/jtreg/vmTestbase/vm/mlvm/indy/func/jvmti/stepBreakPopReturn/stepBreakPopReturn.cpp
index bcae1379e45..3221037484b 100644
--- a/test/hotspot/jtreg/vmTestbase/vm/mlvm/indy/func/jvmti/stepBreakPopReturn/stepBreakPopReturn.cpp
+++ b/test/hotspot/jtreg/vmTestbase/vm/mlvm/indy/func/jvmti/stepBreakPopReturn/stepBreakPopReturn.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@
 
 extern "C" {
 
-static jvmtiEnv* gJvmtiEnv = NULL;
+static jvmtiEnv* gJvmtiEnv = nullptr;
 
 static char * gszDebuggeeMethodName = (char*) "NONE";
 static char * gszDebuggeeClassName = (char*) "NONE";
@@ -89,7 +89,7 @@ MethodEntry(jvmtiEnv *jvmti_env,
             gIsMethodEntryWorking = JNI_TRUE;
 
             if (!gIsBreakpointSet)
-                NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, NULL));
+                NSK_JVMTI_VERIFY(jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_SINGLE_STEP, nullptr));
         }
     }
 
@@ -108,7 +108,7 @@ SingleStep(jvmtiEnv *jvmti_env,
 
     locStr = locationToString(jvmti_env, method, location);
 
-    if (locStr == NULL) {
+    if (locStr == nullptr) {
         NSK_DISPLAY0("Error: Single step event has no location\n");
         gErrorHappened = JNI_TRUE;
     } else {
@@ -116,13 +116,13 @@ SingleStep(jvmtiEnv *jvmti_env,
         free(locStr);
     }
 
-    NSK_JVMTI_VERIFY(gJvmtiEnv->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, NULL));
+    NSK_JVMTI_VERIFY(gJvmtiEnv->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_SINGLE_STEP, nullptr));
 
     if (!gIsDebuggerCompatible) {
         if (!NSK_JVMTI_VERIFY(jvmti_env->SetBreakpoint(method, location)))
             return;
 
-        NSK_JVMTI_VERIFY(gJvmtiEnv->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, NULL));
+        NSK_JVMTI_VERIFY(gJvmtiEnv->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_BREAKPOINT, nullptr));
         gIsBreakpointSet = JNI_TRUE;
 
         NSK_DISPLAY0("Pop a frame\n");
@@ -150,7 +150,7 @@ Breakpoint(jvmtiEnv *jvmti_env,
     gIsBreakpointWorking = JNI_TRUE;
 
     locStr = locationToString(jvmti_env, method, location);
-    if (locStr == NULL) {
+    if (locStr == nullptr) {
         NSK_DISPLAY0("Error: Breakpoint event has no location\n");
         gErrorHappened = JNI_TRUE;
     } else {
@@ -159,7 +159,7 @@ Breakpoint(jvmtiEnv *jvmti_env,
     }
 
     NSK_JVMTI_VERIFY(jvmti_env->ClearBreakpoint(method, location));
-    NSK_JVMTI_VERIFY(gJvmtiEnv->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_BREAKPOINT, NULL));
+    NSK_JVMTI_VERIFY(gJvmtiEnv->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_BREAKPOINT, nullptr));
     gIsBreakpointSet = JNI_FALSE;
 
     NSK_DISPLAY0("Forcing early return.\n");
@@ -173,7 +173,7 @@ jint Agent_Initialize(JavaVM * vm, char * options, void * reserved) {
     if (!NSK_VERIFY(nsk_jvmti_parseOptions(options)))
         return JNI_ERR;
 
-    if (!NSK_VERIFY((gJvmtiEnv = nsk_jvmti_createJVMTIEnv(vm, reserved)) != NULL))
+    if (!NSK_VERIFY((gJvmtiEnv = nsk_jvmti_createJVMTIEnv(vm, reserved)) != nullptr))
         return JNI_ERR;
 
     if (nsk_jvmti_findOptionValue("debuggerCompatible")) {
@@ -198,7 +198,7 @@ jint Agent_Initialize(JavaVM * vm, char * options, void * reserved) {
     if (!NSK_JVMTI_VERIFY(gJvmtiEnv->SetEventCallbacks(&callbacks, sizeof(callbacks))))
         return JNI_ERR;
 
-    if (!NSK_JVMTI_VERIFY(gJvmtiEnv->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, NULL)))
+    if (!NSK_JVMTI_VERIFY(gJvmtiEnv->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_METHOD_ENTRY, nullptr)))
         return JNI_ERR;
 
     return JNI_OK;
diff --git a/test/hotspot/jtreg/vmTestbase/vm/mlvm/meth/stress/jni/nativeAndMH/nativeAndMH.cpp b/test/hotspot/jtreg/vmTestbase/vm/mlvm/meth/stress/jni/nativeAndMH/nativeAndMH.cpp
index 4124b7fb8e7..27dfa84dead 100644
--- a/test/hotspot/jtreg/vmTestbase/vm/mlvm/meth/stress/jni/nativeAndMH/nativeAndMH.cpp
+++ b/test/hotspot/jtreg/vmTestbase/vm/mlvm/meth/stress/jni/nativeAndMH/nativeAndMH.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,16 +48,16 @@ Java_vm_mlvm_meth_stress_jni_nativeAndMH_Test_native01(
     jobjectArray arguments;
     jobject result;
 
-    if (!NSK_JNI_VERIFY(pEnv, (mhClass = pEnv->GetObjectClass(mhToCall)) != NULL))
-        return NULL;
+    if (!NSK_JNI_VERIFY(pEnv, (mhClass = pEnv->GetObjectClass(mhToCall)) != nullptr))
+        return nullptr;
 
-    if (!NSK_JNI_VERIFY(pEnv, NULL != (mid = pEnv->GetMethodID(mhClass, "invokeWithArguments", "([Ljava/lang/Object;)Ljava/lang/Object;"))))
-        return NULL;
+    if (!NSK_JNI_VERIFY(pEnv, nullptr != (mid = pEnv->GetMethodID(mhClass, "invokeWithArguments", "([Ljava/lang/Object;)Ljava/lang/Object;"))))
+        return nullptr;
 
-    NSK_JNI_VERIFY(pEnv, NULL != (objectClass = pEnv->FindClass("java/lang/Object")));
+    NSK_JNI_VERIFY(pEnv, nullptr != (objectClass = pEnv->FindClass("java/lang/Object")));
 
-    if (!NSK_JNI_VERIFY(pEnv, NULL != (arguments = pEnv->NewObjectArray(ARGS_COUNT, objectClass, NULL))))
-        return NULL;
+    if (!NSK_JNI_VERIFY(pEnv, nullptr != (arguments = pEnv->NewObjectArray(ARGS_COUNT, objectClass, nullptr))))
+        return nullptr;
 
     NSK_JNI_VERIFY_VOID(pEnv, pEnv->SetObjectArrayElement(arguments, 0, a1));
     NSK_JNI_VERIFY_VOID(pEnv, pEnv->SetObjectArrayElement(arguments, 1, a2));
@@ -67,7 +67,7 @@ Java_vm_mlvm_meth_stress_jni_nativeAndMH_Test_native01(
     NSK_JNI_VERIFY_VOID(pEnv, pEnv->SetObjectArrayElement(arguments, 5, a6));
 
     // Swap arguments
-    NSK_JNI_VERIFY(pEnv, NULL != (result = pEnv->CallObjectMethod(mhToCall, mid, arguments)));
+    NSK_JNI_VERIFY(pEnv, nullptr != (result = pEnv->CallObjectMethod(mhToCall, mid, arguments)));
     return result;
 }
 
diff --git a/test/hotspot/jtreg/vmTestbase/vm/mlvm/share/mlvmJvmtiUtils.cpp b/test/hotspot/jtreg/vmTestbase/vm/mlvm/share/mlvmJvmtiUtils.cpp
index 1c0f79dd667..d44a5cedd73 100644
--- a/test/hotspot/jtreg/vmTestbase/vm/mlvm/share/mlvmJvmtiUtils.cpp
+++ b/test/hotspot/jtreg/vmTestbase/vm/mlvm/share/mlvmJvmtiUtils.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -36,7 +36,7 @@ void copyFromJString(JNIEnv * pEnv, jstring src, char ** dst) {
     const char * pStr;
         jsize len;
 
-    if (!NSK_VERIFY((pStr = pEnv->GetStringUTFChars(src, NULL)) != NULL)) {
+    if (!NSK_VERIFY((pStr = pEnv->GetStringUTFChars(src, nullptr)) != nullptr)) {
         return;
     }
 
@@ -70,30 +70,30 @@ struct MethodName * getMethodName(jvmtiEnv * pJvmtiEnv, jmethodID method) {
     jclass clazz;
     struct MethodName * mn;
 
-    if (!NSK_JVMTI_VERIFY(pJvmtiEnv->GetMethodName(method, &szName, NULL, NULL))) {
-        return NULL;
+    if (!NSK_JVMTI_VERIFY(pJvmtiEnv->GetMethodName(method, &szName, nullptr, nullptr))) {
+        return nullptr;
     }
 
     JvmtiResource szNameResource(pJvmtiEnv, szName);
 
     if (!NSK_JVMTI_VERIFY(pJvmtiEnv->GetMethodDeclaringClass(method, &clazz))) {
-        return NULL;
+        return nullptr;
     }
 
-    if (!NSK_JVMTI_VERIFY(pJvmtiEnv->GetClassSignature(clazz, &szSignature, NULL))) {
-        return NULL;
+    if (!NSK_JVMTI_VERIFY(pJvmtiEnv->GetClassSignature(clazz, &szSignature, nullptr))) {
+        return nullptr;
     }
 
     JvmtiResource szSignatureResource(pJvmtiEnv, szSignature);
 
     if (strlen(szName) + 1 > sizeof(mn->methodName) ||
         strlen(szSignature) + 1 > sizeof(mn->classSig)) {
-      return NULL;
+      return nullptr;
     }
 
     mn = (MethodName*) malloc(sizeof(MethodNameStruct));
-    if (mn == NULL) {
-      return NULL;
+    if (mn == nullptr) {
+      return nullptr;
     }
 
     strncpy(mn->methodName, szName, sizeof(mn->methodName) - 1);
@@ -115,17 +115,17 @@ char * locationToString(jvmtiEnv * pJvmtiEnv, jmethodID method, jlocation locati
     if (!pMN)
         return strdup("NONE");
 
-    len = snprintf(NULL, 0, format, pMN->classSig, pMN->methodName, location) + 1;
+    len = snprintf(nullptr, 0, format, pMN->classSig, pMN->methodName, location) + 1;
 
     if (len <= 0) {
         free(pMN);
-        return NULL;
+        return nullptr;
     }
 
     result = (char*) malloc(len);
-    if (result == NULL) {
+    if (result == nullptr) {
         free(pMN);
-        return NULL;
+        return nullptr;
     }
 
     snprintf(result, len, format, pMN->classSig, pMN->methodName, location);
@@ -137,16 +137,16 @@ char * locationToString(jvmtiEnv * pJvmtiEnv, jmethodID method, jlocation locati
 void * getTLS(jvmtiEnv * pJvmtiEnv, jthread thread, jsize sizeToAllocate) {
     void * tls;
     if (!NSK_JVMTI_VERIFY(pJvmtiEnv->GetThreadLocalStorage(thread, &tls)))
-        return NULL;
+        return nullptr;
 
     if (!tls) {
-        if (!NSK_VERIFY((tls = malloc(sizeToAllocate)) != NULL))
-            return NULL;
+        if (!NSK_VERIFY((tls = malloc(sizeToAllocate)) != nullptr))
+            return nullptr;
 
         memset(tls, 0, sizeToAllocate);
 
         if (!NSK_JVMTI_VERIFY(pJvmtiEnv->SetThreadLocalStorage(thread, tls)))
-            return NULL;
+            return nullptr;
     }
 
     return tls;
diff --git a/test/hotspot/jtreg/vmTestbase/vm/runtime/defmeth/shared/redefineClasses.cpp b/test/hotspot/jtreg/vmTestbase/vm/runtime/defmeth/shared/redefineClasses.cpp
index 4d5c8af7548..eac0d3fe601 100644
--- a/test/hotspot/jtreg/vmTestbase/vm/runtime/defmeth/shared/redefineClasses.cpp
+++ b/test/hotspot/jtreg/vmTestbase/vm/runtime/defmeth/shared/redefineClasses.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,7 +33,7 @@
 extern "C" {
 
 
-static jvmtiEnv *test_jvmti = NULL;
+static jvmtiEnv *test_jvmti = nullptr;
 static jvmtiCapabilities caps;
 
 /*
@@ -50,7 +50,7 @@ Java_vm_runtime_defmeth_shared_Util_redefineClassIntl(JNIEnv *env, jclass clazz,
     jvmtiClassDefinition classDef;
     jboolean result = JNI_TRUE;
 
-    if (!NSK_VERIFY(env != NULL) || !NSK_VERIFY(clazzToRedefine != NULL) || !NSK_VERIFY(bytecodeArray != NULL)) {
+    if (!NSK_VERIFY(env != nullptr) || !NSK_VERIFY(clazzToRedefine != nullptr) || !NSK_VERIFY(bytecodeArray != nullptr)) {
         return JNI_FALSE;
     }
 
@@ -61,7 +61,7 @@ Java_vm_runtime_defmeth_shared_Util_redefineClassIntl(JNIEnv *env, jclass clazz,
     }
 
     if (!NSK_JNI_VERIFY(env,
-            (classDef.class_bytes = (const unsigned char *) /* jbyte* */ env->GetByteArrayElements(bytecodeArray, NULL)) != NULL)) {
+            (classDef.class_bytes = (const unsigned char *) /* jbyte* */ env->GetByteArrayElements(bytecodeArray, nullptr)) != nullptr)) {
         return JNI_FALSE;
     }
 
@@ -86,7 +86,7 @@ jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 
     /* create JVMTI environment */
     if (!NSK_VERIFY((test_jvmti =
-            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != NULL))
+            nsk_jvmti_createJVMTIEnv(jvm, reserved)) != nullptr))
         return JNI_ERR;
 
     memset(&caps, 0, sizeof(jvmtiCapabilities));
diff --git a/test/hotspot/jtreg/vmTestbase/vm/share/ProcessUtils.cpp b/test/hotspot/jtreg/vmTestbase/vm/share/ProcessUtils.cpp
index 0388af34e74..c624db6ee98 100644
--- a/test/hotspot/jtreg/vmTestbase/vm/share/ProcessUtils.cpp
+++ b/test/hotspot/jtreg/vmTestbase/vm/share/ProcessUtils.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -49,12 +49,12 @@ JNIEXPORT jboolean JNICALL Java_vm_share_ProcessUtils_sendSignal
         if (!GenerateConsoleCtrlEvent(CTRL_BREAK_EVENT, 0)) {
                 dw = GetLastError();
                 FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
-                                NULL,
+                                nullptr,
                                 dw,
                                 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
                                 (LPTSTR) &lpMsgBuf,
                                 0,
-                                NULL
+                                nullptr
                              );
                 printf("%s\n", (LPTSTR)lpMsgBuf);
                 LocalFree(lpMsgBuf);
@@ -82,12 +82,12 @@ JNIEXPORT jboolean JNICALL Java_vm_share_ProcessUtils_sendCtrlBreak
         if (!GenerateConsoleCtrlEvent(CTRL_BREAK_EVENT, 0)) {
                 dw = GetLastError();
                 FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
-                                NULL,
+                                nullptr,
                                 dw,
                                 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
                                 (LPTSTR) &lpMsgBuf,
                                 0,
-                                NULL
+                                nullptr
                              );
                 printf("%s\n", (LPTSTR)lpMsgBuf);
                 LocalFree(lpMsgBuf);
@@ -111,12 +111,12 @@ void reportLastError(const char *msg) {
                 char *buf;
                 size_t n = (size_t)FormatMessage(
                                 FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS|FORMAT_MESSAGE_ALLOCATE_BUFFER,
-                                NULL,
+                                nullptr,
                                 errcode,
                                 0,
                                 (LPSTR) &buf,
                                 (DWORD)len,
-                                NULL);
+                                nullptr);
                 if (n > 3) {
                         /* Drop final '.', CR, LF */
                         if (buf[n - 1] == '\n') n--;
@@ -152,25 +152,25 @@ jboolean doDumpCore() {
                 strcat(path, "\\");
                 strcat(path, name);
                 dbghelp = LoadLibrary(path);
-                if (dbghelp == NULL)
+                if (dbghelp == nullptr)
                         reportLastError("Load DBGHELP.DLL from system directory");
         } else {
                 printf("GetSystemDirectory returned 0\n");
         }
 
         // try Windows directory
-        if (dbghelp == NULL) {
+        if (dbghelp == nullptr) {
                 size = GetWindowsDirectory(path, pathLen);
                 if (size > 6) {
                         strcat(path, "\\");
                         strcat(path, name);
                         dbghelp = LoadLibrary(path);
-                        if (dbghelp == NULL) {
+                        if (dbghelp == nullptr) {
                                 reportLastError("Load DBGHELP.DLL from Windows directory");
                         }
                 }
         }
-        if (dbghelp == NULL) {
+        if (dbghelp == nullptr) {
                 printf("Failed to load DBGHELP.DLL\n");
                 return JNI_FALSE;
         }
@@ -180,7 +180,7 @@ jboolean doDumpCore() {
                                         PMINIDUMP_USER_STREAM_INFORMATION, PMINIDUMP_CALLBACK_INFORMATION))
                                         GetProcAddress(dbghelp, "MiniDumpWriteDump");
 
-        if (_MiniDumpWriteDump == NULL) {
+        if (_MiniDumpWriteDump == nullptr) {
                 printf("Failed to find MiniDumpWriteDump() in module dbghelp.dll");
                 return JNI_FALSE;
         }
@@ -193,19 +193,19 @@ jboolean doDumpCore() {
                         MiniDumpWithUnloadedModules);
 #endif
 
-        dumpFile = CreateFile("core.mdmp", GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
+        dumpFile = CreateFile("core.mdmp", GENERIC_WRITE, 0, nullptr, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, nullptr);
 
         if (dumpFile == INVALID_HANDLE_VALUE) {
                 reportLastError("Failed to create file for dumping");
                 return JNI_FALSE;
         }
-        pmei = NULL;
+        pmei = nullptr;
 
 
         // Older versions of dbghelp.dll (the one shipped with Win2003 for example) may not support all
         // the dump types we really want. If first call fails, lets fall back to just use MiniDumpWithFullMemory then.
-        if (_MiniDumpWriteDump(hProcess, processId, dumpFile, dumpType, pmei, NULL, NULL) == FALSE &&
-                        _MiniDumpWriteDump(hProcess, processId, dumpFile, (MINIDUMP_TYPE)MiniDumpWithFullMemory, pmei, NULL, NULL) == FALSE) {
+        if (_MiniDumpWriteDump(hProcess, processId, dumpFile, dumpType, pmei, nullptr, nullptr) == FALSE &&
+                        _MiniDumpWriteDump(hProcess, processId, dumpFile, (MINIDUMP_TYPE)MiniDumpWithFullMemory, pmei, nullptr, nullptr) == FALSE) {
                 reportLastError("Call to MiniDumpWriteDump() failed");
                 return JNI_FALSE;
         }
diff --git a/test/jdk/java/awt/JAWT/myfile.cpp b/test/jdk/java/awt/JAWT/myfile.cpp
index 6157e2934eb..80f51f951a9 100644
--- a/test/jdk/java/awt/JAWT/myfile.cpp
+++ b/test/jdk/java/awt/JAWT/myfile.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,8 +52,8 @@ JNIEXPORT void JNICALL Java_MyCanvas_paint
 
     /* Get the drawing surface */
     JAWT_DrawingSurface* ds = awt.GetDrawingSurface(env, canvas);
-    if (ds == NULL) {
-        printf("NULL drawing surface\n");
+    if (ds == nullptr) {
+        printf("null drawing surface\n");
         return;
     }
 
@@ -67,7 +67,7 @@ JNIEXPORT void JNICALL Java_MyCanvas_paint
 
     /* Get the drawing surface info */
     JAWT_DrawingSurfaceInfo* dsi = ds->GetDrawingSurfaceInfo(ds);
-    if (dsi == NULL) {
+    if (dsi == nullptr) {
         printf("Error getting surface info\n");
         ds->Unlock(ds);
         return;
diff --git a/test/jdk/java/foreign/enablenativeaccess/org/openjdk/foreigntest/unnamed/libLinkerInvokerUnnamed.cpp b/test/jdk/java/foreign/enablenativeaccess/org/openjdk/foreigntest/unnamed/libLinkerInvokerUnnamed.cpp
index 271970817d7..cc8469cc68f 100644
--- a/test/jdk/java/foreign/enablenativeaccess/org/openjdk/foreigntest/unnamed/libLinkerInvokerUnnamed.cpp
+++ b/test/jdk/java/foreign/enablenativeaccess/org/openjdk/foreigntest/unnamed/libLinkerInvokerUnnamed.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,7 +27,7 @@
 void call(void* ctxt) {
     JavaVM* jvm = (JavaVM*) ctxt;
     JNIEnv* env;
-    jvm->AttachCurrentThread((void**)&env, NULL);
+    jvm->AttachCurrentThread((void**)&env, nullptr);
     jclass linkerClass = env->FindClass("java/lang/foreign/Linker");
     jmethodID nativeLinkerMethod = env->GetStaticMethodID(linkerClass, "nativeLinker", "()Ljava/lang/foreign/Linker;");
     env->CallStaticVoidMethod(linkerClass, nativeLinkerMethod);
diff --git a/test/jdk/java/foreign/enablenativeaccess/panama_module/org/openjdk/foreigntest/libLinkerInvokerModule.cpp b/test/jdk/java/foreign/enablenativeaccess/panama_module/org/openjdk/foreigntest/libLinkerInvokerModule.cpp
index 6c09f4900de..7056d702209 100644
--- a/test/jdk/java/foreign/enablenativeaccess/panama_module/org/openjdk/foreigntest/libLinkerInvokerModule.cpp
+++ b/test/jdk/java/foreign/enablenativeaccess/panama_module/org/openjdk/foreigntest/libLinkerInvokerModule.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -35,7 +35,7 @@ typedef struct {
 void call(void* arg) {
     Context* context = (Context*)arg;
     JNIEnv* env;
-    context->jvm->AttachCurrentThread((void**)&env, NULL);
+    context->jvm->AttachCurrentThread((void**)&env, nullptr);
     jclass linkerClass = env->FindClass("java/lang/foreign/Linker");
     jmethodID nativeLinkerMethod = env->GetMethodID(linkerClass, "downcallHandle",
             "(Ljava/lang/foreign/FunctionDescriptor;[Ljava/lang/foreign/Linker$Option;)Ljava/lang/invoke/MethodHandle;");
diff --git a/test/jdk/java/foreign/loaderLookup/libLoaderLookupInvoker.cpp b/test/jdk/java/foreign/loaderLookup/libLoaderLookupInvoker.cpp
index b4305f2829e..607588cd56c 100644
--- a/test/jdk/java/foreign/loaderLookup/libLoaderLookupInvoker.cpp
+++ b/test/jdk/java/foreign/loaderLookup/libLoaderLookupInvoker.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@ struct Context {
 void call(void* ctxt) {
     Context* context = (Context*) ctxt;
     JNIEnv* env;
-    context->jvm->AttachCurrentThread((void**)&env, NULL);
+    context->jvm->AttachCurrentThread((void**)&env, nullptr);
     jclass symbolLookupClass = env->FindClass("java/lang/foreign/SymbolLookup");
     jmethodID loaderLookupMethod = env->GetStaticMethodID(symbolLookupClass, "loaderLookup", "()Ljava/lang/foreign/SymbolLookup;");
     context->res = env->NewGlobalRef(env->CallStaticObjectMethod(symbolLookupClass, loaderLookupMethod));
diff --git a/test/jdk/jni/nullCaller/CallHelper.hpp b/test/jdk/jni/nullCaller/CallHelper.hpp
index 1e8772bda09..40b3917966c 100644
--- a/test/jdk/jni/nullCaller/CallHelper.hpp
+++ b/test/jdk/jni/nullCaller/CallHelper.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -37,9 +37,9 @@
 class CallHelper {
 public:
     CallHelper(JNIEnv* e, const std::string& cname, const std::string& mname, const std::string& sig) :
-        classname(cname), method(mname), signature(sig), m(NULL), env(e) {
+        classname(cname), method(mname), signature(sig), m(nullptr), env(e) {
         c = env->FindClass(classname.c_str());
-        assert (c != NULL);
+        assert (c != nullptr);
     }
 
 protected:
@@ -53,7 +53,7 @@ protected:
 
     // check the given object which is expected to be null
     void checkReturnNull(jobject obj) {
-        if (obj != NULL) {
+        if (obj != nullptr) {
             emitErrorMessage("Null return expected");
             ::exit(-1);
         }
@@ -61,7 +61,7 @@ protected:
 
     // check the given object which is expected to NOT be null
     void checkReturnNotNull(jobject obj) {
-        if (obj == NULL) {
+        if (obj == nullptr) {
             emitErrorMessage("Non-Null return expected");
             ::exit(-1);
         }
@@ -69,7 +69,7 @@ protected:
 
     // check if any unexpected exceptions were thrown
     void checkException() {
-        if (env->ExceptionOccurred() != NULL) {
+        if (env->ExceptionOccurred() != nullptr) {
             emitErrorMessage("Exception was thrown");
             env->ExceptionDescribe();
             ::exit(-1);
@@ -79,7 +79,7 @@ protected:
     // check if an expected exception was thrown
     void checkExpectedExceptionThrown(const std::string& exception) {
          jclass expected = env->FindClass(exception.c_str());
-         assert(expected != NULL);
+         assert(expected != nullptr);
          jthrowable t = env->ExceptionOccurred();
          if (env->IsInstanceOf(t, expected) == JNI_FALSE) {
             emitErrorMessage("Didn't get the expected " + exception);
@@ -106,7 +106,7 @@ public:
         : CallHelper(e, cname, mname, sig) {
 
         m = env->GetMethodID(c, method.c_str(), signature.c_str());
-        assert(m != NULL);
+        assert(m != nullptr);
     }
 
     // call on the given object, checking for exceptions and that the return is not null
@@ -168,7 +168,7 @@ public:
         : CallHelper(e, cname, mname, sig) {
 
         m = env->GetStaticMethodID(c, method.c_str(), signature.c_str());
-        assert(m != NULL);
+        assert(m != nullptr);
     }
 
     // call a method returning an object checking for exceptions and
diff --git a/test/jdk/jni/nullCaller/exeNullCallerTest.cpp b/test/jdk/jni/nullCaller/exeNullCallerTest.cpp
index 260a1edb9b4..db4e300eeb4 100644
--- a/test/jdk/jni/nullCaller/exeNullCallerTest.cpp
+++ b/test/jdk/jni/nullCaller/exeNullCallerTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -131,9 +131,9 @@ void getResourceAsStream(JNIEnv *env) {
 
     // fetch the open and closed classes
     jclass class_OpenResources = env->FindClass("open/OpenResources");
-    assert(class_OpenResources != NULL);
+    assert(class_OpenResources != nullptr);
     jclass class_ClosedResources = env->FindClass("closed/ClosedResources");
-    assert(class_ClosedResources != NULL);
+    assert(class_ClosedResources != nullptr);
 
     // Fetch the Module from one of the classes in the module
     jobject n = m_Class_getModule.callReturnNotNull(class_OpenResources);
@@ -202,7 +202,7 @@ int main(int argc, char *argv[]) {
       fprintf(stderr, "Error: pthread_create failed with error code %d \n", result);
       return -1;
     }
-    pthread_join(id, NULL);
+    pthread_join(id, nullptr);
 #else
     run(&argv);
 #endif //AIX