8353835: Implement JEP 500: Prepare to Make Final Mean Final

Reviewed-by: liach, vlivanov, dholmes, vyazici

make/test/JtregNativeJdk.gmk

@@ -80,6 +80,7 @@ else
 
   BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libExplicitAttach := -pthread
   BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libImplicitAttach := -pthread
+  BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libJNIAttachMutator := -pthread
   BUILD_JDK_JTREG_EXCLUDE += exerevokeall.c
   ifeq ($(call isTargetOs, linux), true)
     BUILD_JDK_JTREG_EXECUTABLES_LIBS_exelauncher := -ldl

src/hotspot/share/ci/ciField.cpp

@@ -258,17 +258,7 @@ void ciField::initialize_from(fieldDescriptor* fd) {
       // not be constant is when the field is a *special* static & final field
       // whose value may change.  The three examples are java.lang.System.in,
       // java.lang.System.out, and java.lang.System.err.
-      assert(vmClasses::System_klass() != nullptr, "Check once per vm");
-      if (k == vmClasses::System_klass()) {
-        // Check offsets for case 2: System.in, System.out, or System.err
-        if (_offset == java_lang_System::in_offset()  ||
-            _offset == java_lang_System::out_offset() ||
-            _offset == java_lang_System::err_offset()) {
-          _is_constant = false;
-          return;
-        }
-      }
-      _is_constant = true;
+      _is_constant = !fd->is_mutable_static_final();
     } else {
       // An instance field can be constant if it's a final static field or if
       // it's a final non-static field of a trusted class (classes in

src/hotspot/share/prims/jni.cpp

@@ -1867,6 +1867,32 @@ address jni_GetDoubleField_addr() {
   return (address)jni_GetDoubleField;
 }
 
+static void log_debug_if_final_static_field(JavaThread* current, const char* func_name, InstanceKlass* ik, int offset) {
+  if (log_is_enabled(Debug, jni)) {
+    fieldDescriptor fd;
+    bool found = ik->find_field_from_offset(offset, true, &fd);
+    assert(found, "bad field offset");
+    assert(fd.is_static(), "static/instance mismatch");
+    if (fd.is_final() && !fd.is_mutable_static_final()) {
+      ResourceMark rm(current);
+      log_debug(jni)("%s mutated final static field %s.%s", func_name, ik->external_name(), fd.name()->as_C_string());
+    }
+  }
+}
+
+static void log_debug_if_final_instance_field(JavaThread* current, const char* func_name, InstanceKlass* ik, int offset) {
+  if (log_is_enabled(Debug, jni)) {
+    fieldDescriptor fd;
+    bool found = ik->find_field_from_offset(offset, false, &fd);
+    assert(found, "bad field offset");
+    assert(!fd.is_static(), "static/instance mismatch");
+    if (fd.is_final()) {
+      ResourceMark rm(current);
+      log_debug(jni)("%s mutated final instance field %s.%s", func_name, ik->external_name(), fd.name()->as_C_string());
+    }
+  }
+}
+
 JNI_ENTRY_NO_PRESERVE(void, jni_SetObjectField(JNIEnv *env, jobject obj, jfieldID fieldID, jobject value))
   HOTSPOT_JNI_SETOBJECTFIELD_ENTRY(env, obj, (uintptr_t) fieldID, value);
   oop o = JNIHandles::resolve_non_null(obj);
@@ -1879,6 +1905,7 @@ JNI_ENTRY_NO_PRESERVE(void, jni_SetObjectField(JNIEnv *env, jobject obj, jfieldI
     o = JvmtiExport::jni_SetField_probe(thread, obj, o, k, fieldID, false, JVM_SIGNATURE_CLASS, (jvalue *)&field_value);
   }
   HeapAccess<ON_UNKNOWN_OOP_REF>::oop_store_at(o, offset, JNIHandles::resolve(value));
+  log_debug_if_final_instance_field(thread, "SetObjectField", InstanceKlass::cast(k), offset);
   HOTSPOT_JNI_SETOBJECTFIELD_RETURN();
 JNI_END
 
@@ -1901,6 +1928,7 @@ JNI_ENTRY_NO_PRESERVE(void, jni_Set##Result##Field(JNIEnv *env, jobject obj, jfi
     o = JvmtiExport::jni_SetField_probe(thread, obj, o, k, fieldID, false, SigType, (jvalue *)&field_value); \
   } \
   o->Fieldname##_field_put(offset, value); \
+  log_debug_if_final_instance_field(thread, "Set<Type>Field", InstanceKlass::cast(k), offset); \
   ReturnProbe; \
 JNI_END
 
@@ -2072,6 +2100,7 @@ JNI_ENTRY(void, jni_SetStaticObjectField(JNIEnv *env, jclass clazz, jfieldID fie
     JvmtiExport::jni_SetField_probe(thread, nullptr, nullptr, id->holder(), fieldID, true, JVM_SIGNATURE_CLASS, (jvalue *)&field_value);
   }
   id->holder()->java_mirror()->obj_field_put(id->offset(), JNIHandles::resolve(value));
+  log_debug_if_final_static_field(THREAD, "SetStaticObjectField", id->holder(), id->offset());
   HOTSPOT_JNI_SETSTATICOBJECTFIELD_RETURN();
 JNI_END
 
@@ -2093,6 +2122,7 @@ JNI_ENTRY(void, jni_SetStatic##Result##Field(JNIEnv *env, jclass clazz, jfieldID
     JvmtiExport::jni_SetField_probe(thread, nullptr, nullptr, id->holder(), fieldID, true, SigType, (jvalue *)&field_value); \
   } \
   id->holder()->java_mirror()-> Fieldname##_field_put (id->offset(), value); \
+  log_debug_if_final_static_field(THREAD, "SetStatic<Type>Field", id->holder(), id->offset()); \
   ReturnProbe;\
 JNI_END
 

src/hotspot/share/prims/jniCheck.cpp

@@ -233,7 +233,7 @@ functionExit(JavaThread* thr)
 }
 
 static inline void
-checkStaticFieldID(JavaThread* thr, jfieldID fid, jclass cls, int ftype)
+checkStaticFieldID(JavaThread* thr, jfieldID fid, jclass cls, int ftype, bool setter)
 {
   fieldDescriptor fd;
 
@@ -258,10 +258,18 @@ checkStaticFieldID(JavaThread* thr, jfieldID fid, jclass cls, int ftype)
       !(fd.field_type() == T_ARRAY && ftype == T_OBJECT)) {
     ReportJNIFatalError(thr, fatal_static_field_mismatch);
   }
+
+  /* check if setting a final field */
+  if (setter && fd.is_final() && !fd.is_mutable_static_final()) {
+    ResourceMark rm(thr);
+    stringStream ss;
+    ss.print("SetStatic<Type>Field called to mutate final static field %s.%s", k_oop->external_name(), fd.name()->as_C_string());
+    ReportJNIWarning(thr, ss.as_string());
+  }
 }
 
 static inline void
-checkInstanceFieldID(JavaThread* thr, jfieldID fid, jobject obj, int ftype)
+checkInstanceFieldID(JavaThread* thr, jfieldID fid, jobject obj, int ftype, bool setter)
 {
   fieldDescriptor fd;
 
@@ -287,14 +295,21 @@ checkInstanceFieldID(JavaThread* thr, jfieldID fid, jobject obj, int ftype)
     ReportJNIFatalError(thr, fatal_wrong_field);
 
   /* check for proper field type */
-  if (!InstanceKlass::cast(k_oop)->find_field_from_offset(offset,
-                                                              false, &fd))
+  if (!InstanceKlass::cast(k_oop)->find_field_from_offset(offset, false, &fd))
     ReportJNIFatalError(thr, fatal_instance_field_not_found);
 
   if ((fd.field_type() != ftype) &&
       !(fd.field_type() == T_ARRAY && ftype == T_OBJECT)) {
     ReportJNIFatalError(thr, fatal_instance_field_mismatch);
   }
+
+  /* check if setting a final field */
+  if (setter && fd.is_final()) {
+    ResourceMark rm(thr);
+    stringStream ss;
+    ss.print("Set<Type>Field called to mutate final instance field %s.%s", k_oop->external_name(), fd.name()->as_C_string());
+    ReportJNIWarning(thr, ss.as_string());
+  }
 }
 
 static inline void
@@ -1204,7 +1219,7 @@ JNI_ENTRY_CHECKED(ReturnType,  \
                                  jfieldID fieldID)) \
     functionEnter(thr); \
     IN_VM( \
-      checkInstanceFieldID(thr, fieldID, obj, FieldType); \
+      checkInstanceFieldID(thr, fieldID, obj, FieldType, false); \
     ) \
     ReturnType result = UNCHECKED()->Get##Result##Field(env,obj,fieldID); \
     functionExit(thr); \
@@ -1229,7 +1244,7 @@ JNI_ENTRY_CHECKED(void,  \
                                  ValueType val)) \
     functionEnter(thr); \
     IN_VM( \
-      checkInstanceFieldID(thr, fieldID, obj, FieldType); \
+      checkInstanceFieldID(thr, fieldID, obj, FieldType, true); \
     ) \
     UNCHECKED()->Set##Result##Field(env,obj,fieldID,val); \
     functionExit(thr); \
@@ -1395,7 +1410,7 @@ JNI_ENTRY_CHECKED(ReturnType,  \
     functionEnter(thr); \
     IN_VM( \
       jniCheck::validate_class(thr, clazz, false); \
-      checkStaticFieldID(thr, fieldID, clazz, FieldType); \
+      checkStaticFieldID(thr, fieldID, clazz, FieldType, false); \
     ) \
     ReturnType result = UNCHECKED()->GetStatic##Result##Field(env, \
                                                               clazz, \
@@ -1423,7 +1438,7 @@ JNI_ENTRY_CHECKED(void,  \
     functionEnter(thr); \
     IN_VM( \
       jniCheck::validate_class(thr, clazz, false); \
-      checkStaticFieldID(thr, fieldID, clazz, FieldType); \
+      checkStaticFieldID(thr, fieldID, clazz, FieldType, true); \
     ) \
     UNCHECKED()->SetStatic##Result##Field(env,clazz,fieldID,value); \
     functionExit(thr); \

src/hotspot/share/runtime/arguments.cpp

@@ -317,6 +317,10 @@ bool needs_module_property_warning = false;
 #define ENABLE_NATIVE_ACCESS_LEN 20
 #define ILLEGAL_NATIVE_ACCESS "illegal.native.access"
 #define ILLEGAL_NATIVE_ACCESS_LEN 21
+#define ENABLE_FINAL_FIELD_MUTATION "enable.final.field.mutation"
+#define ENABLE_FINAL_FIELD_MUTATION_LEN 27
+#define ILLEGAL_FINAL_FIELD_MUTATION "illegal.final.field.mutation"
+#define ILLEGAL_FINAL_FIELD_MUTATION_LEN 28
 
 // Return TRUE if option matches 'property', or 'property=', or 'property.'.
 static bool matches_property_suffix(const char* option, const char* property, size_t len) {
@@ -343,7 +347,9 @@ bool Arguments::internal_module_property_helper(const char* property, bool check
     if (matches_property_suffix(property_suffix, PATCH, PATCH_LEN) ||
         matches_property_suffix(property_suffix, LIMITMODS, LIMITMODS_LEN) ||
         matches_property_suffix(property_suffix, UPGRADE_PATH, UPGRADE_PATH_LEN) ||
-        matches_property_suffix(property_suffix, ILLEGAL_NATIVE_ACCESS, ILLEGAL_NATIVE_ACCESS_LEN)) {
+        matches_property_suffix(property_suffix, ILLEGAL_NATIVE_ACCESS, ILLEGAL_NATIVE_ACCESS_LEN) ||
+        matches_property_suffix(property_suffix, ENABLE_FINAL_FIELD_MUTATION, ENABLE_FINAL_FIELD_MUTATION_LEN) ||
+        matches_property_suffix(property_suffix, ILLEGAL_FINAL_FIELD_MUTATION, ILLEGAL_FINAL_FIELD_MUTATION_LEN)) {
       return true;
     }
 
@@ -1809,6 +1815,7 @@ static unsigned int addexports_count = 0;
 static unsigned int addopens_count = 0;
 static unsigned int patch_mod_count = 0;
 static unsigned int enable_native_access_count = 0;
+static unsigned int enable_final_field_mutation = 0;
 static bool patch_mod_javabase = false;
 
 // Check the consistency of vm_init_args
@@ -2273,6 +2280,19 @@ jint Arguments::parse_each_vm_init_arg(const JavaVMInitArgs* args, JVMFlagOrigin
       if (res != JNI_OK) {
         return res;
       }
+    } else if (match_option(option, "--enable-final-field-mutation=", &tail)) {
+      if (!create_numbered_module_property("jdk.module.enable.final.field.mutation", tail, enable_final_field_mutation++)) {
+        return JNI_ENOMEM;
+      }
+    } else if (match_option(option, "--illegal-final-field-mutation=", &tail)) {
+      if (strcmp(tail, "allow") == 0 || strcmp(tail, "warn") == 0 || strcmp(tail, "debug") == 0 || strcmp(tail, "deny") == 0) {
+        PropertyList_unique_add(&_system_properties, "jdk.module.illegal.final.field.mutation", tail,
+                                AddProperty, WriteableProperty, InternalProperty);
+      } else {
+        jio_fprintf(defaultStream::error_stream(),
+                    "Value specified to --illegal-final-field-mutation not recognized: '%s'\n", tail);
+        return JNI_ERR;
+      }
     } else if (match_option(option, "--sun-misc-unsafe-memory-access=", &tail)) {
       if (strcmp(tail, "allow") == 0 || strcmp(tail, "warn") == 0 || strcmp(tail, "debug") == 0 || strcmp(tail, "deny") == 0) {
         PropertyList_unique_add(&_system_properties, "sun.misc.unsafe.memory.access", tail,

src/hotspot/share/runtime/fieldDescriptor.cpp

@@ -46,6 +46,16 @@ bool fieldDescriptor::is_trusted_final() const {
   return is_final() && (is_static() || ik->is_hidden() || ik->is_record());
 }
 
+bool fieldDescriptor::is_mutable_static_final() const {
+  InstanceKlass* ik = field_holder();
+  // write protected fields (JLS 17.5.4)
+  if (is_final() && is_static() && ik == vmClasses::System_klass() &&
+      (offset() == java_lang_System::in_offset() || offset() == java_lang_System::out_offset() || offset() == java_lang_System::err_offset())) {
+   return true;
+  }
+  return false;
+}
+
 AnnotationArray* fieldDescriptor::annotations() const {
   InstanceKlass* ik = field_holder();
   Array<AnnotationArray*>* md = ik->fields_annotations();

src/hotspot/share/runtime/fieldDescriptor.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -98,6 +98,8 @@ class fieldDescriptor {
 
   bool is_trusted_final()         const;
 
+  bool is_mutable_static_final()  const;
+
   inline void set_is_field_access_watched(const bool value);
   inline void set_is_field_modification_watched(const bool value);
   inline void set_has_initialized_final_update(const bool value);

src/java.base/share/classes/java/lang/Module.java

@@ -37,6 +37,7 @@ import java.lang.module.ModuleDescriptor.Version;
 import java.lang.module.ResolvedModule;
 import java.lang.reflect.AccessFlag;
 import java.lang.reflect.AnnotatedElement;
+import java.lang.reflect.Field;
 import java.net.URI;
 import java.net.URL;
 import java.security.CodeSource;
@@ -115,6 +116,10 @@ public final class Module implements AnnotatedElement {
     @Stable
     private boolean enableNativeAccess;
 
+    // true if this module is allowed to mutate final instance fields
+    @Stable
+    private boolean enableFinalMutation;
+
     /**
      * Creates a new named Module. The resulting Module will be defined to the
      * VM but will not read any other modules, will not have any exports setup
@@ -262,7 +267,6 @@ public final class Module implements AnnotatedElement {
      * in the outer Module class as that would create a circular initializer dependency.
      */
     private static final class EnableNativeAccess {
-
         private EnableNativeAccess() {}
 
         private static final Unsafe UNSAFE = Unsafe.getUnsafe();
@@ -331,12 +335,52 @@ public final class Module implements AnnotatedElement {
     }
 
     /**
-     * Update all unnamed modules to allow access to restricted methods.
+     * Enable code in all unnamed modules to access restricted methods.
      */
-    static void implAddEnableNativeAccessToAllUnnamed() {
+    static void addEnableNativeAccessToAllUnnamed() {
         EnableNativeAccess.trySetEnableNativeAccess(ALL_UNNAMED_MODULE);
     }
 
+    /**
+     * This class exists to avoid using Unsafe during early initialization of Module.
+     */
+    private static final class EnableFinalMutation {
+        private static final Unsafe UNSAFE = Unsafe.getUnsafe();
+        private static final long ENABLE_FINAL_MUTATION_OFFSET =
+                UNSAFE.objectFieldOffset(Module.class, "enableFinalMutation");
+
+        private static boolean isEnableFinalMutation(Module module) {
+            return UNSAFE.getBooleanVolatile(module, ENABLE_FINAL_MUTATION_OFFSET);
+        }
+
+        private static boolean tryEnableFinalMutation(Module module) {
+            return UNSAFE.compareAndSetBoolean(module, ENABLE_FINAL_MUTATION_OFFSET, false, true);
+        }
+    }
+
+    /**
+     * Enable code in all unnamed modules to mutate final instance fields.
+     */
+    static void addEnableFinalMutationToAllUnnamed() {
+        EnableFinalMutation.tryEnableFinalMutation(ALL_UNNAMED_MODULE);
+    }
+
+    /**
+     * Enable code in this named module to mutate final instance fields.
+     */
+    boolean tryEnableFinalMutation() {
+        Module m = isNamed() ? this : ALL_UNNAMED_MODULE;
+        return EnableFinalMutation.tryEnableFinalMutation(m);
+    }
+
+    /**
+     * Return true if code in this module is allowed to mutate final instance fields.
+     */
+    boolean isFinalMutationEnabled() {
+        Module m = isNamed() ? this : ALL_UNNAMED_MODULE;
+        return EnableFinalMutation.isEnableFinalMutation(m);
+    }
+
     // --
 
     // special Module to mean "all unnamed modules"
@@ -718,8 +762,50 @@ public final class Module implements AnnotatedElement {
     }
 
     /**
-     * Returns {@code true} if this module exports or opens a package to
-     * the given module via its module declaration or CLI options.
+     * Returns {@code true} if this module statically exports a package to the given module.
+     * If the package is exported to the given module via {@code addExports} then this method
+     * returns {@code false}.
+     */
+    boolean isStaticallyExported(String pn, Module other) {
+        return isStaticallyExportedOrOpened(pn, other, false);
+    }
+
+    /**
+     * Returns {@code true} if this module statically opens a package to the given module.
+     * If the package is opened to the given module via {@code addOpens} then this method
+     * returns {@code false}.
+     */
+    boolean isStaticallyOpened(String pn, Module other) {
+        return isStaticallyExportedOrOpened(pn, other, true);
+    }
+
+    /**
+     * Returns {@code true} if this module exports or opens a package to the
+     * given module via its module declaration or CLI options.
+     */
+    private boolean isStaticallyExportedOrOpened(String pn, Module other, boolean open) {
+        // all packages in unnamed modules are exported and open
+        if (!isNamed())
+            return true;
+
+        // all packages are exported/open to self
+        if (other == this && descriptor.packages().contains(pn))
+            return true;
+
+        // all packages in open and automatic modules are exported/open
+        if (descriptor.isOpen() || descriptor.isAutomatic())
+            return descriptor.packages().contains(pn);
+
+        // exported/opened via module descriptor
+        if (isExplicitlyExportedOrOpened(pn, other, open))
+            return true;
+
+        return false;
+    }
+
+    /**
+     * Returns {@code true} if this module exports or opens a package to the
+     * given module via its module declaration or CLI options.
      */
     private boolean isExplicitlyExportedOrOpened(String pn, Module other, boolean open) {
         // test if package is open to everyone or <other>
@@ -818,11 +904,16 @@ public final class Module implements AnnotatedElement {
         return isReflectivelyExportedOrOpened(pn, other, true);
     }
 
-
     /**
      * If the caller's module is this module then update this module to export
      * the given package to the given module.
      *
+     * <p> Exporting a package with this method does not allow the given module to
+     * {@linkplain Field#set(Object, Object) reflectively set} or {@linkplain
+     * java.lang.invoke.MethodHandles.Lookup#unreflectSetter(Field) obtain a method
+     * handle with write access} to a public final field declared in a public class
+     * in the package.
+     *
      * <p> This method has no effect if the package is already exported (or
      * <em>open</em>) to the given module. </p>
      *
@@ -860,21 +951,27 @@ public final class Module implements AnnotatedElement {
             if (caller != this) {
                 throw new IllegalCallerException(caller + " != " + this);
             }
-            implAddExportsOrOpens(pn, other, /*open*/false, /*syncVM*/true);
+            implAddExports(pn, other);
         }
 
         return this;
     }
 
     /**
-     * If this module has <em>opened</em> a package to at least the caller
-     * module then update this module to open the package to the given module.
-     * Opening a package with this method allows all types in the package,
+     * If this module has <em>opened</em> the given package to at least the caller
+     * module, then update this module to also open the package to the given module.
+     *
+     * <p> Opening a package with this method allows all types in the package,
      * and all their members, not just public types and their public members,
-     * to be reflected on by the given module when using APIs that support
-     * private access or a way to bypass or suppress default Java language
+     * to be reflected on by the given module when using APIs that either support
+     * private access or provide a way to bypass or suppress Java language
      * access control checks.
      *
+     * <p> Opening a package with this method does not allow the given module to
+     * {@linkplain Field#set(Object, Object) reflectively set} or {@linkplain
+     * java.lang.invoke.MethodHandles.Lookup#unreflectSetter(Field) obtain a method
+     * handle with write access} to a final field declared in a class in the package.
+     *
      * <p> This method has no effect if the package is already <em>open</em>
      * to the given module. </p>
      *
@@ -913,7 +1010,7 @@ public final class Module implements AnnotatedElement {
             Module caller = getCallerModule(Reflection.getCallerClass());
             if (caller != this && (caller == null || !isOpen(pn, caller)))
                 throw new IllegalCallerException(pn + " is not open to " + caller);
-            implAddExportsOrOpens(pn, other, /*open*/true, /*syncVM*/true);
+            implAddOpens(pn, other);
         }
 
         return this;
@@ -923,28 +1020,29 @@ public final class Module implements AnnotatedElement {
     /**
      * Updates this module to export a package unconditionally.
      *
-     * @apiNote This method is for JDK tests only.
+     * @apiNote Used by Proxy and other dynamic modules.
      */
     void implAddExports(String pn) {
-        implAddExportsOrOpens(pn, Module.EVERYONE_MODULE, false, true);
+        implAddExportsOrOpens(pn, Module.EVERYONE_MODULE, false, true, true);
     }
 
     /**
      * Updates this module to export a package to another module.
      *
-     * @apiNote Used by Instrumentation::redefineModule and --add-exports
+     * @apiNote Used by addExports, Instrumentation::redefineModule, and --add-exports
      */
     void implAddExports(String pn, Module other) {
-        implAddExportsOrOpens(pn, other, false, true);
+        implAddExportsOrOpens(pn, other, false, VM.isBooted(), true);
     }
 
     /**
      * Updates this module to export a package to all unnamed modules.
      *
-     * @apiNote Used by the --add-exports command line option.
+     * @apiNote Used by the --add-exports command line option and the launcher when
+     * an executable JAR file has the "Add-Exports" attribute in its main manifest.
      */
     void implAddExportsToAllUnnamed(String pn) {
-        implAddExportsOrOpens(pn, Module.ALL_UNNAMED_MODULE, false, true);
+        implAddExportsOrOpens(pn, Module.ALL_UNNAMED_MODULE, false, false, true);
     }
 
     /**
@@ -954,7 +1052,7 @@ public final class Module implements AnnotatedElement {
      * @apiNote This method is for VM white-box testing.
      */
     void implAddExportsNoSync(String pn) {
-        implAddExportsOrOpens(pn.replace('/', '.'), Module.EVERYONE_MODULE, false, false);
+        implAddExportsOrOpens(pn.replace('/', '.'), Module.EVERYONE_MODULE, false, true, false);
     }
 
     /**
@@ -964,7 +1062,7 @@ public final class Module implements AnnotatedElement {
      * @apiNote This method is for VM white-box testing.
      */
     void implAddExportsNoSync(String pn, Module other) {
-        implAddExportsOrOpens(pn.replace('/', '.'), other, false, false);
+        implAddExportsOrOpens(pn.replace('/', '.'), other, false, true, false);
     }
 
     /**
@@ -973,35 +1071,40 @@ public final class Module implements AnnotatedElement {
      * @apiNote This method is for JDK tests only.
      */
     void implAddOpens(String pn) {
-        implAddExportsOrOpens(pn, Module.EVERYONE_MODULE, true, true);
+        implAddExportsOrOpens(pn, Module.EVERYONE_MODULE, true, true, true);
     }
 
     /**
      * Updates this module to open a package to another module.
      *
-     * @apiNote Used by Instrumentation::redefineModule and --add-opens
+     * @apiNote Used by addOpens, Instrumentation::redefineModule, and --add-opens
      */
     void implAddOpens(String pn, Module other) {
-        implAddExportsOrOpens(pn, other, true, true);
+        implAddExportsOrOpens(pn, other, true, VM.isBooted(), true);
     }
 
     /**
      * Updates this module to open a package to all unnamed modules.
      *
-     * @apiNote Used by the --add-opens command line option.
+     * @apiNote Used by the --add-opens command line option and the launcher when
+     * an executable JAR file has the "Add-Opens" attribute in its main manifest.
      */
     void implAddOpensToAllUnnamed(String pn) {
-        implAddExportsOrOpens(pn, Module.ALL_UNNAMED_MODULE, true, true);
+        implAddExportsOrOpens(pn, Module.ALL_UNNAMED_MODULE, true, false, true);
     }
 
     /**
      * Updates a module to export or open a module to another module.
-     *
-     * If {@code syncVM} is {@code true} then the VM is notified.
+     * @param pn package name
+     * @param other the module to export/open the package to
+     * @param open true to open, false to export
+     * @param reflectively true if exported/opened reflectively
+     * @param syncVM true to update the VM
      */
     private void implAddExportsOrOpens(String pn,
                                        Module other,
                                        boolean open,
+                                       boolean reflectively,
                                        boolean syncVM) {
         Objects.requireNonNull(other);
         Objects.requireNonNull(pn);
@@ -1031,7 +1134,7 @@ public final class Module implements AnnotatedElement {
             }
         }
 
-        if (VM.isBooted()) {
+        if (reflectively) {
             // add package name to ReflectionData.exports if absent
             Map<String, Boolean> map = ReflectionData.exports
                 .computeIfAbsent(this, other,

src/java.base/share/classes/java/lang/ModuleLayer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,6 +28,7 @@ package java.lang;
 import java.lang.module.Configuration;
 import java.lang.module.ModuleDescriptor;
 import java.lang.module.ResolvedModule;
+import java.lang.reflect.Field;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -252,6 +253,12 @@ public final class ModuleLayer {
          * module {@code target}. This method is a no-op if {@code source}
          * already exports the package to at least {@code target}.
          *
+         * <p> Exporting a package with this method does not allow the target module to
+         * {@linkplain Field#set(Object, Object) reflectively set} or {@linkplain
+         * java.lang.invoke.MethodHandles.Lookup#unreflectSetter(Field) obtain a method
+         * handle with write access} to a public final field declared in a public class
+         * in the package.
+         *
          * @param  source
          *         The source module
          * @param  pn
@@ -278,6 +285,11 @@ public final class ModuleLayer {
          * module {@code target}. This method is a no-op if {@code source}
          * already opens the package to at least {@code target}.
          *
+         * <p> Opening a package with this method does not allow the target module
+         * to {@linkplain Field#set(Object, Object) reflectively set} or {@linkplain
+         * java.lang.invoke.MethodHandles.Lookup#unreflectSetter(Field) obtain a method
+         * handle with write access} to a final field declared in a class in the package.
+         *
          * @param  source
          *         The source module
          * @param  pn

src/java.base/share/classes/java/lang/System.java

@@ -2096,18 +2096,33 @@ public final class System {
             public boolean isReflectivelyOpened(Module m, String pn, Module other) {
                 return m.isReflectivelyOpened(pn, other);
             }
-            public Module addEnableNativeAccess(Module m) {
-                return m.implAddEnableNativeAccess();
+            public void addEnableNativeAccess(Module m) {
+                m.implAddEnableNativeAccess();
             }
             public boolean addEnableNativeAccess(ModuleLayer layer, String name) {
                 return layer.addEnableNativeAccess(name);
             }
             public void addEnableNativeAccessToAllUnnamed() {
-                Module.implAddEnableNativeAccessToAllUnnamed();
+                Module.addEnableNativeAccessToAllUnnamed();
             }
             public void ensureNativeAccess(Module m, Class<?> owner, String methodName, Class<?> currentClass, boolean jni) {
                 m.ensureNativeAccess(owner, methodName, currentClass, jni);
             }
+            public boolean isStaticallyExported(Module m, String pn, Module other) {
+                return m.isStaticallyExported(pn, other);
+            }
+            public boolean isStaticallyOpened(Module m, String pn, Module other) {
+                return m.isStaticallyOpened(pn, other);
+            }
+            public boolean isFinalMutationEnabled(Module m) {
+                return m.isFinalMutationEnabled();
+            }
+            public boolean tryEnableFinalMutation(Module m) {
+                return m.tryEnableFinalMutation();
+            }
+            public void addEnableFinalMutationToAllUnnamed() {
+                Module.addEnableFinalMutationToAllUnnamed();
+            }
             public ServicesCatalog getServicesCatalog(ModuleLayer layer) {
                 return layer.getServicesCatalog();
             }

src/java.base/share/classes/java/lang/invoke/MethodHandles.java

@@ -3429,12 +3429,15 @@ return mh1;
          *         or if the field is {@code final} and write access
          *         is not enabled on the {@code Field} object
          * @throws NullPointerException if the argument is null
+         * @see <a href="{@docRoot}/java.base/java/lang/reflect/doc-files/MutationMethods.html">Mutation methods</a>
          */
         public MethodHandle unreflectSetter(Field f) throws IllegalAccessException {
             return unreflectField(f, true);
         }
 
         private MethodHandle unreflectField(Field f, boolean isSetter) throws IllegalAccessException {
+            @SuppressWarnings("deprecation")
+            boolean isAccessible = f.isAccessible();
             MemberName field = new MemberName(f, isSetter);
             if (isSetter && field.isFinal()) {
                 if (field.isTrustedFinalField()) {
@@ -3442,12 +3445,15 @@ return mh1;
                                                   : "final field has no write access";
                     throw field.makeAccessException(msg, this);
                 }
+                // check if write access to final field allowed
+                if (!field.isStatic() && isAccessible) {
+                    SharedSecrets.getJavaLangReflectAccess().checkAllowedToUnreflectFinalSetter(lookupClass, f);
+                }
             }
             assert(isSetter
                     ? MethodHandleNatives.refKindIsSetter(field.getReferenceKind())
                     : MethodHandleNatives.refKindIsGetter(field.getReferenceKind()));
-            @SuppressWarnings("deprecation")
-            Lookup lookup = f.isAccessible() ? IMPL_LOOKUP : this;
+            Lookup lookup = isAccessible ? IMPL_LOOKUP : this;
             return lookup.getDirectField(field.getReferenceKind(), f.getDeclaringClass(), field);
         }
 

src/java.base/share/classes/java/lang/reflect/AccessibleObject.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -160,18 +160,6 @@ public class AccessibleObject implements AnnotatedElement {
      * to the caller and the package containing the declaring class is not open
      * to the caller's module. </p>
      *
-     * <p> This method cannot be used to enable {@linkplain Field#set <em>write</em>}
-     * access to a <em>non-modifiable</em> final field.  The following fields
-     * are non-modifiable:
-     * <ul>
-     * <li>static final fields declared in any class or interface</li>
-     * <li>final fields declared in a {@linkplain Class#isHidden() hidden class}</li>
-     * <li>final fields declared in a {@linkplain Class#isRecord() record}</li>
-     * </ul>
-     * <p> The {@code accessible} flag when {@code true} suppresses Java language access
-     * control checks to only enable {@linkplain Field#get <em>read</em>} access to
-     * these non-modifiable final fields.
-     *
      * @param flag the new value for the {@code accessible} flag
      * @throws InaccessibleObjectException if access cannot be enabled
      *

src/java.base/share/classes/java/lang/reflect/Field.java

@@ -25,7 +25,18 @@
 
 package java.lang.reflect;
 
+import java.lang.annotation.Annotation;
+import java.net.URL;
+import java.security.CodeSource;
+import java.util.Map;
+import java.util.Set;
+import java.util.Objects;
 import jdk.internal.access.SharedSecrets;
+import jdk.internal.event.FinalFieldMutationEvent;
+import jdk.internal.loader.ClassLoaders;
+import jdk.internal.misc.VM;
+import jdk.internal.module.ModuleBootstrap;
+import jdk.internal.module.Modules;
 import jdk.internal.reflect.CallerSensitive;
 import jdk.internal.reflect.FieldAccessor;
 import jdk.internal.reflect.Reflection;
@@ -35,10 +46,6 @@ import sun.reflect.generics.repository.FieldRepository;
 import sun.reflect.generics.factory.CoreReflectionFactory;
 import sun.reflect.generics.factory.GenericsFactory;
 import sun.reflect.generics.scope.ClassScope;
-import java.lang.annotation.Annotation;
-import java.util.Map;
-import java.util.Set;
-import java.util.Objects;
 import sun.reflect.annotation.AnnotationParser;
 import sun.reflect.annotation.AnnotationSupport;
 import sun.reflect.annotation.TypeAnnotation;
@@ -165,6 +172,27 @@ class Field extends AccessibleObject implements Member {
     }
 
     /**
+     * {@inheritDoc}
+     *
+     * <p>If this reflected object represents a non-final field, and this method is
+     * used to enable access, then both <em>{@linkplain #get(Object) read}</em>
+     * and <em>{@linkplain #set(Object, Object) write}</em> access to the field
+     * are enabled.
+     *
+     * <p>If this reflected object represents a <em>non-modifiable</em> final field
+     * then enabling access only enables read access. Any attempt to {@linkplain
+     * #set(Object, Object) set} the field value throws an {@code
+     * IllegalAccessException}. The following fields are non-modifiable:
+     * <ul>
+     * <li>static final fields declared in any class or interface</li>
+     * <li>final fields declared in a {@linkplain Class#isRecord() record}</li>
+     * <li>final fields declared in a {@linkplain Class#isHidden() hidden class}</li>
+     * </ul>
+     * <p>If this reflected object represents a non-static final field in a class that
+     * is not a record class or hidden class, then enabling access will enable read
+     * access. Whether write access is allowed or not is checked when attempting to
+     * {@linkplain #set(Object, Object) set} the field value.
+     *
      * @throws InaccessibleObjectException {@inheritDoc}
      */
     @Override
@@ -762,18 +790,59 @@ class Field extends AccessibleObject implements Member {
      * the underlying field is inaccessible, the method throws an
      * {@code IllegalAccessException}.
      *
-     * <p>If the underlying field is final, this {@code Field} object has
-     * <em>write</em> access if and only if the following conditions are met:
+     * <p>If the underlying field is final, this {@code Field} object has <em>write</em>
+     * access if and only if all of the following conditions are true, where {@code D} is
+     * the field's {@linkplain #getDeclaringClass() declaring class}:
+     *
      * <ul>
-     * <li>{@link #setAccessible(boolean) setAccessible(true)} has succeeded for
-     *     this {@code Field} object;</li>
-     * <li>the field is non-static; and</li>
-     * <li>the field's declaring class is not a {@linkplain Class#isHidden()
-     *     hidden class}; and</li>
-     * <li>the field's declaring class is not a {@linkplain Class#isRecord()
-     *     record class}.</li>
+     * <li>{@link #setAccessible(boolean) setAccessible(true)} has succeeded for this
+     *     {@code Field} object.</li>
+     * <li><a href="doc-files/MutationMethods.html">final field mutation is enabled</a>
+     *     for the caller's module.</li>
+     * <li> At least one of the following conditions holds:
+     *     <ol type="a">
+     *     <li> {@code D} and the caller class are in the same module.</li>
+     *     <li> The field is {@code public} and {@code D} is {@code public} in a package
+     *     that the module containing {@code D} exports to at least the caller's module.</li>
+     *     <li> {@code D} is in a package that is {@linkplain Module#isOpen(String, Module)
+     *     open} to the caller's module.</li>
+     *     </ol>
+     * </li>
+     * <li>{@code D} is not a {@linkplain Class#isRecord() record class}.</li>
+     * <li>{@code D} is not a {@linkplain Class#isHidden() hidden class}.</li>
+     * <li>The field is non-static.</li>
      * </ul>
-     * If any of the above checks is not met, this method throws an
+     *
+     * <p>If any of the above conditions is not met, this method throws an
+     * {@code IllegalAccessException}.
+     *
+     * <p>These conditions are more restrictive than the conditions specified by {@link
+     * #setAccessible(boolean)} to suppress access checks. In particular, updating a
+     * module to export or open a package cannot be used to allow <em>write</em> access
+     * to final fields with the {@code set} methods defined by {@code Field}.
+     * Condition (b) is not met if the module containing {@code D} has been updated with
+     * {@linkplain Module#addExports(String, Module) addExports} to export the package to
+     * the caller's module. Condition (c) is not met if the module containing {@code D}
+     * has been updated with {@linkplain Module#addOpens(String, Module) addOpens} to open
+     * the package to the caller's module.
+     *
+     * <p>This method may be called by <a href="{@docRoot}/../specs/jni/index.html">
+     * JNI code</a> with no caller class on the stack. In that case, and when the
+     * underlying field is final, this {@code Field} object has <em>write</em> access
+     * if and only if all of the following conditions are true, where {@code D} is the
+     * field's {@linkplain #getDeclaringClass() declaring class}:
+     *
+     * <ul>
+     * <li>{@code setAccessible(true)} has succeeded for this {@code Field} object.</li>
+     * <li>final field mutation is enabled for the unnamed module.</li>
+     * <li>The field is {@code public} and {@code D} is {@code public} in a package that
+     *     is {@linkplain Module#isExported(String) exported} to all modules.</li>
+     * <li>{@code D} is not a {@linkplain Class#isRecord() record class}.</li>
+     * <li>{@code D} is not a {@linkplain Class#isHidden() hidden class}.</li>
+     * <li>The field is non-static.</li>
+     * </ul>
+     *
+     * <p>If any of the above conditions is not met, this method throws an
      * {@code IllegalAccessException}.
      *
      * <p> Setting a final field in this way
@@ -818,6 +887,8 @@ class Field extends AccessibleObject implements Member {
      *              and the field is an instance field.
      * @throws    ExceptionInInitializerError if the initialization provoked
      *              by this method fails.
+     *
+     * @see <a href="doc-files/MutationMethods.html">Mutation methods</a>
      */
     @CallerSensitive
     @ForceInline // to ensure Reflection.getCallerClass optimization
@@ -828,8 +899,14 @@ class Field extends AccessibleObject implements Member {
             Class<?> caller = Reflection.getCallerClass();
             checkAccess(caller, obj);
             getFieldAccessor().set(obj, value);
+            return;
+        }
+
+        FieldAccessor fa = getOverrideFieldAccessor();
+        if (!Modifier.isFinal(modifiers)) {
+            fa.set(obj, value);
         } else {
-            getOverrideFieldAccessor().set(obj, value);
+            setFinal(Reflection.getCallerClass(), obj, () -> fa.set(obj, value));
         }
     }
 
@@ -867,8 +944,14 @@ class Field extends AccessibleObject implements Member {
             Class<?> caller = Reflection.getCallerClass();
             checkAccess(caller, obj);
             getFieldAccessor().setBoolean(obj, z);
+            return;
+        }
+
+        FieldAccessor fa = getOverrideFieldAccessor();
+        if (!Modifier.isFinal(modifiers)) {
+            fa.setBoolean(obj, z);
         } else {
-            getOverrideFieldAccessor().setBoolean(obj, z);
+            setFinal(Reflection.getCallerClass(), obj, () -> fa.setBoolean(obj, z));
         }
     }
 
@@ -906,8 +989,14 @@ class Field extends AccessibleObject implements Member {
             Class<?> caller = Reflection.getCallerClass();
             checkAccess(caller, obj);
             getFieldAccessor().setByte(obj, b);
+            return;
+        }
+
+        FieldAccessor fa = getOverrideFieldAccessor();
+        if (!Modifier.isFinal(modifiers)) {
+            fa.setByte(obj, b);
         } else {
-            getOverrideFieldAccessor().setByte(obj, b);
+            setFinal(Reflection.getCallerClass(), obj, () -> fa.setByte(obj, b));
         }
     }
 
@@ -945,8 +1034,14 @@ class Field extends AccessibleObject implements Member {
             Class<?> caller = Reflection.getCallerClass();
             checkAccess(caller, obj);
             getFieldAccessor().setChar(obj, c);
+            return;
+        }
+
+        FieldAccessor fa = getOverrideFieldAccessor();
+        if (!Modifier.isFinal(modifiers)) {
+            fa.setChar(obj, c);
         } else {
-            getOverrideFieldAccessor().setChar(obj, c);
+            setFinal(Reflection.getCallerClass(), obj, () -> fa.setChar(obj, c));
         }
     }
 
@@ -984,8 +1079,14 @@ class Field extends AccessibleObject implements Member {
             Class<?> caller = Reflection.getCallerClass();
             checkAccess(caller, obj);
             getFieldAccessor().setShort(obj, s);
+            return;
+        }
+
+        FieldAccessor fa = getOverrideFieldAccessor();
+        if (!Modifier.isFinal(modifiers)) {
+            fa.setShort(obj, s);
         } else {
-            getOverrideFieldAccessor().setShort(obj, s);
+            setFinal(Reflection.getCallerClass(), obj, () -> fa.setShort(obj, s));
         }
     }
 
@@ -1023,8 +1124,14 @@ class Field extends AccessibleObject implements Member {
             Class<?> caller = Reflection.getCallerClass();
             checkAccess(caller, obj);
             getFieldAccessor().setInt(obj, i);
+            return;
+        }
+
+        FieldAccessor fa = getOverrideFieldAccessor();
+        if (!Modifier.isFinal(modifiers)) {
+            fa.setInt(obj, i);
         } else {
-            getOverrideFieldAccessor().setInt(obj, i);
+            setFinal(Reflection.getCallerClass(), obj, () -> fa.setInt(obj, i));
         }
     }
 
@@ -1062,8 +1169,14 @@ class Field extends AccessibleObject implements Member {
             Class<?> caller = Reflection.getCallerClass();
             checkAccess(caller, obj);
             getFieldAccessor().setLong(obj, l);
+            return;
+        }
+
+        FieldAccessor fa = getOverrideFieldAccessor();
+        if (!Modifier.isFinal(modifiers)) {
+            fa.setLong(obj, l);
         } else {
-            getOverrideFieldAccessor().setLong(obj, l);
+            setFinal(Reflection.getCallerClass(), obj, () -> fa.setLong(obj, l));
         }
     }
 
@@ -1101,8 +1214,14 @@ class Field extends AccessibleObject implements Member {
             Class<?> caller = Reflection.getCallerClass();
             checkAccess(caller, obj);
             getFieldAccessor().setFloat(obj, f);
+            return;
+        }
+
+        FieldAccessor fa = getOverrideFieldAccessor();
+        if (!Modifier.isFinal(modifiers)) {
+            fa.setFloat(obj, f);
         } else {
-            getOverrideFieldAccessor().setFloat(obj, f);
+            setFinal(Reflection.getCallerClass(), obj, () -> fa.setFloat(obj, f));
         }
     }
 
@@ -1140,8 +1259,14 @@ class Field extends AccessibleObject implements Member {
             Class<?> caller = Reflection.getCallerClass();
             checkAccess(caller, obj);
             getFieldAccessor().setDouble(obj, d);
+            return;
+        }
+
+        FieldAccessor fa = getOverrideFieldAccessor();
+        if (!Modifier.isFinal(modifiers)) {
+            fa.setDouble(obj, d);
         } else {
-            getOverrideFieldAccessor().setDouble(obj, d);
+            setFinal(Reflection.getCallerClass(), obj, () -> fa.setDouble(obj, d));
         }
     }
 
@@ -1304,5 +1429,244 @@ class Field extends AccessibleObject implements Member {
                                                        getDeclaringClass(),
                                                        getGenericType(),
                                                        TypeAnnotation.TypeAnnotationTarget.FIELD);
-}
+    }
+
+    /**
+     * A function that sets a field to a value.
+     */
+    @FunctionalInterface
+    private interface FieldSetter {
+        void setFieldValue() throws IllegalAccessException;
+    }
+
+    /**
+     * Attempts to set a final field.
+     */
+    private void setFinal(Class<?> caller, Object obj, FieldSetter setter) throws IllegalAccessException {
+        if (obj != null && isFinalInstanceInNormalClass()) {
+            preSetFinal(caller, false);
+            setter.setFieldValue();
+            postSetFinal(caller, false);
+        } else {
+            // throws IllegalAccessException if static, or field in record or hidden class
+            setter.setFieldValue();
+        }
+    }
+
+    /**
+     * Return true if this field is a final instance field in a normal class (not a
+     * record class or hidden class),
+     */
+    private boolean isFinalInstanceInNormalClass() {
+        return Modifier.isFinal(modifiers)
+                && !Modifier.isStatic(modifiers)
+                && !clazz.isRecord()
+                && !clazz.isHidden();
+    }
+
+    /**
+     * Check that the caller is allowed to unreflect for mutation a final instance field
+     * in a normal class.
+     * @throws IllegalAccessException if not allowed
+     */
+    void checkAllowedToUnreflectFinalSetter(Class<?> caller) throws IllegalAccessException {
+        Objects.requireNonNull(caller);
+        preSetFinal(caller, true);
+        postSetFinal(caller, true);
+    }
+
+    /**
+     * Invoke before attempting to mutate, or unreflect for mutation, a final instance
+     * field in a normal class.
+     * @throws IllegalAccessException if not allowed
+     */
+    private void preSetFinal(Class<?> caller, boolean unreflect) throws IllegalAccessException {
+        assert isFinalInstanceInNormalClass();
+
+        if (caller != null) {
+            // check if declaring class in package that is open to caller, or public field
+            // and declaring class is public in package exported to caller
+            if (!isFinalDeeplyAccessible(caller)) {
+                throw new IllegalAccessException(notAccessibleToCallerMessage(caller, unreflect));
+            }
+        } else {
+            // no java caller, only allowed if field is public in exported package
+            if (!Reflection.verifyPublicMemberAccess(clazz, modifiers)) {
+                throw new IllegalAccessException(notAccessibleToNoCallerMessage(unreflect));
+            }
+        }
+
+        // check if field mutation is enabled for caller module or illegal final field
+        // mutation is allowed
+        var mode = ModuleBootstrap.illegalFinalFieldMutation();
+        if (mode == ModuleBootstrap.IllegalFinalFieldMutation.DENY
+                && !Modules.isFinalMutationEnabled(moduleToCheck(caller))) {
+            throw new IllegalAccessException(callerNotAllowedToMutateMessage(caller, unreflect));
+        }
+    }
+
+    /**
+     * Invoke after mutating a final instance field, or when unreflecting a final instance
+     * field for mutation, to print a warning and record a JFR event.
+     */
+    private void postSetFinal(Class<?> caller, boolean unreflect) {
+        assert isFinalInstanceInNormalClass();
+
+        var mode = ModuleBootstrap.illegalFinalFieldMutation();
+        if (mode == ModuleBootstrap.IllegalFinalFieldMutation.WARN) {
+            // first mutation prints warning
+            Module moduleToCheck = moduleToCheck(caller);
+            if (Modules.tryEnableFinalMutation(moduleToCheck)) {
+                String warningMsg = finalFieldMutationWarning(caller, unreflect);
+                String targetModule = (caller != null && moduleToCheck.isNamed())
+                        ? moduleToCheck.getName()
+                        : "ALL-UNNAMED";
+                VM.initialErr().printf("""
+                        WARNING: %s
+                        WARNING: Use --enable-final-field-mutation=%s to avoid a warning
+                        WARNING: Mutating final fields will be blocked in a future release unless final field mutation is enabled
+                        """, warningMsg, targetModule);
+            }
+        } else if (mode == ModuleBootstrap.IllegalFinalFieldMutation.DEBUG) {
+            // print warning and stack trace
+            var sb = new StringBuilder(finalFieldMutationWarning(caller, unreflect));
+            StackWalker.getInstance(StackWalker.Option.RETAIN_CLASS_REFERENCE)
+                    .forEach(sf -> {
+                        sb.append(System.lineSeparator()).append("\tat " + sf);
+                    });
+            VM.initialErr().println(sb);
+        }
+
+        // record JFR event
+        FinalFieldMutationEvent.offer(getDeclaringClass(), getName());
+    }
+
+    /**
+     * Returns true if this final field is "deeply accessible" to the caller.
+     * The field is deeply accessible if declaring class is in a package that is open
+     * to the caller's module, or the field is public in a public class that is exported
+     * to the caller's module.
+     *
+     * Updates to the module of the declaring class at runtime with {@code Module.addExports}
+     * or {@code Module.addOpens} have no impact on the result of this method.
+     */
+    private boolean isFinalDeeplyAccessible(Class<?> caller) {
+        assert isFinalInstanceInNormalClass();
+
+        // all fields in unnamed modules are deeply accessible
+        Module declaringModule = clazz.getModule();
+        if (!declaringModule.isNamed()) return true;
+
+        // all fields in the caller's module are deeply accessible
+        Module callerModule = caller.getModule();
+        if (callerModule == declaringModule) return true;
+
+        // public field, public class, package exported to caller's module
+        String pn = clazz.getPackageName();
+        if (Modifier.isPublic(modifiers)
+                && Modifier.isPublic(clazz.getModifiers())
+                && Modules.isStaticallyExported(declaringModule, pn, callerModule)) {
+            return true;
+        }
+
+        // package open to caller's module
+        return Modules.isStaticallyOpened(declaringModule, pn, callerModule);
+    }
+
+    /**
+     * Returns the Module to use for access checks with the given caller.
+     */
+    private Module moduleToCheck(Class<?> caller) {
+        if (caller != null) {
+            return caller.getModule();
+        } else {
+            // no java caller, only allowed if field is public in exported package
+            return ClassLoaders.appClassLoader().getUnnamedModule();
+        }
+    }
+
+    /**
+     * Returns the warning message to print when this final field is mutated by
+     * the given possibly-null caller.
+     */
+    private String finalFieldMutationWarning(Class<?> caller, boolean unreflect) {
+        assert Modifier.isFinal(modifiers);
+        String source;
+        if (caller != null) {
+            source = caller + " in " + caller.getModule();
+            CodeSource cs = caller.getProtectionDomain().getCodeSource();
+            if (cs != null) {
+                URL url = cs.getLocation();
+                if (url != null) {
+                    source += " (" + url + ")";
+                }
+            }
+        } else {
+            source = "JNI attached thread with no caller frame";
+        }
+        return String.format("Final field %s in %s has been %s by %s",
+                name,
+                clazz,
+                (unreflect) ? "unreflected for mutation" : "mutated reflectively",
+                source);
+    }
+
+    /**
+     * Returns the message for an IllegalAccessException when a final field cannot be
+     * mutated because the declaring class is in a package that is not "deeply accessible"
+     * to the caller.
+     */
+    private String notAccessibleToCallerMessage(Class<?> caller, boolean unreflect) {
+        String exportsOrOpens = Modifier.isPublic(modifiers)
+                && Modifier.isPublic(clazz.getModifiers()) ? "exports" : "opens";
+        return String.format("%s, %s does not explicitly \"%s\" package %s to %s",
+                cannotSetFieldMessage(caller, unreflect),
+                clazz.getModule(),
+                exportsOrOpens,
+                clazz.getPackageName(),
+                caller.getModule());
+    }
+
+    /**
+     * Returns the exception message for the IllegalAccessException when this
+     * final field cannot be mutated because the caller module is not allowed
+     * to mutate final fields.
+     */
+    private String callerNotAllowedToMutateMessage(Class<?> caller, boolean unreflect) {
+        if (caller != null) {
+            return String.format("%s, %s is not allowed to mutate final fields",
+                    cannotSetFieldMessage(caller, unreflect),
+                    caller.getModule());
+        } else {
+            return notAccessibleToNoCallerMessage(unreflect);
+        }
+    }
+
+    /**
+     * Returns the message for an IllegalAccessException when a field is not
+     * accessible to a JNI attached thread.
+     */
+    private String notAccessibleToNoCallerMessage(boolean unreflect) {
+        return cannotSetFieldMessage("JNI attached thread with no caller frame cannot", unreflect);
+    }
+
+    /**
+     * Returns a message to indicate that the caller cannot set/unreflect this final field.
+     */
+    private String cannotSetFieldMessage(Class<?> caller, boolean unreflect) {
+        return cannotSetFieldMessage(caller + " (in " + caller.getModule() + ") cannot", unreflect);
+    }
+
+    /**
+     * Returns a message to indicate that a field cannot be set/unreflected.
+     */
+    private String cannotSetFieldMessage(String prefix, boolean unreflect) {
+        if (unreflect) {
+            return prefix + " unreflect final field " + clazz.getName() + "." + name
+                    + " (in " + clazz.getModule() + ") for mutation";
+        } else {
+            return prefix + " set final field " + clazz.getName() + "." + name
+                    + " (in " + clazz.getModule() + ")";
+        }
+    }
 }

src/java.base/share/classes/java/lang/reflect/ReflectAccess.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -78,4 +78,9 @@ final class ReflectAccess implements JavaLangReflectAccess {
     {
         return ctor.newInstanceWithCaller(args, true, caller);
     }
+
+    @Override
+    public void checkAllowedToUnreflectFinalSetter(Class<?> caller, Field f) throws IllegalAccessException {
+        f.checkAllowedToUnreflectFinalSetter(caller);
+    }
 }

src/java.base/share/classes/java/lang/reflect/doc-files/MutationMethods.html

@@ -0,0 +1,69 @@
+<!doctype html>
+<!--
+ Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+
+ This code is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License version 2 only, as
+ published by the Free Software Foundation.  Oracle designates this
+ particular file as subject to the "Classpath" exception as provided
+ by Oracle in the LICENSE file that accompanied this code.
+
+ This code is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ version 2 for more details (a copy is included in the LICENSE file that
+ accompanied this code).
+
+ You should have received a copy of the GNU General Public License version
+ 2 along with this work; if not, write to the Free Software Foundation,
+ Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+
+ Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ or visit www.oracle.com if you need additional information or have any
+ questions.
+-->
+<html lang="en">
+<head>
+    <title>Mutation methods</title>
+</head>
+<body>
+
+<h1 id="mutation">Mutation methods</h1>
+
+<p>A number of methods in Java SE API provide <em>write</em> access to non-static
+final fields. This means that Java code can alter the value of a final field
+after the field has been initialized in a constructor.
+
+The methods that provide write access, known as <em>mutation methods</em> are:
+<ul>
+    <li>{@link java.lang.reflect.Field#set(Object, Object)}</li>
+    <li>{@link java.lang.reflect.Field#setBoolean(Object, boolean)}</li>
+    <li>{@link java.lang.reflect.Field#setByte(Object, byte)}</li>
+    <li>{@link java.lang.reflect.Field#setChar(Object, char)}</li>
+    <li>{@link java.lang.reflect.Field#setInt(Object, int)}</li>
+    <li>{@link java.lang.reflect.Field#setLong(Object, long)}</li>
+    <li>{@link java.lang.reflect.Field#setFloat(Object, float)}</li>
+    <li>{@link java.lang.reflect.Field#setDouble(Object, double)}</li>
+    <li>{@link java.lang.invoke.MethodHandles.Lookup#unreflectSetter(java.lang.reflect.Field)}</li>
+</ul>
+
+<p> The use of mutation methods to alter the values of final fields is
+strongly inadvisable because it undermines the correctness of programs written in
+expectation of final fields being immutable.
+
+<p> In the reference implementation, a module can be granted the capability to mutate
+final instance fields of classes in packages that are open to the module using
+the command line option <code>--enable-final-field-mutation=M1,M2, ... Mn}</code> where
+<code>M1</code>, <code>M2</code>, <code>...Mn</code> are module names (for the unnamed
+module, the special value <code>ALL-UNNAMED</code> can be used). Mutation of final
+instance fields of classes from modules not listed by that option is deemed
+<em>illegal</em>.
+The command line option <code>--illegal-final-field-mutation</code> controls how illegal
+final mutation is handled. Valid values for this command line option are "warn", "allow",
+"debug, and "deny".  If this option is not specified then the default is "warn" so that
+illegal final field mutation will result in a warning at runtime.
+
+</body>
+</html>
+

src/java.base/share/classes/jdk/internal/access/JavaLangAccess.java

@@ -205,7 +205,7 @@ public interface JavaLangAccess {
      * Updates the readability so that module m1 reads m2. The new read edge
      * does not result in a strong reference to m2 (m2 can be GC'ed).
      *
-     * This method is the same as m1.addReads(m2) but without a permission check.
+     * This method is the same as m1.addReads(m2) but without a caller check.
      */
     void addReads(Module m1, Module m2);
 
@@ -259,11 +259,11 @@ public interface JavaLangAccess {
     /**
      * Updates module m to allow access to restricted methods.
      */
-    Module addEnableNativeAccess(Module m);
+    void addEnableNativeAccess(Module m);
 
     /**
-     * Updates module named {@code name} in layer {@code layer} to allow access to restricted methods.
-     * Returns true iff the given module exists in the given layer.
+     * Updates module named {@code name} in layer {@code layer} to allow access to
+     * restricted methods. Returns true iff the given module exists in the given layer.
      */
     boolean addEnableNativeAccess(ModuleLayer layer, String name);
 
@@ -273,7 +273,8 @@ public interface JavaLangAccess {
     void addEnableNativeAccessToAllUnnamed();
 
     /**
-     * Ensure that the given module has native access. If not, warn or throw exception depending on the configuration.
+     * Ensure that the given module has native access. If not, warn or throw exception
+     * depending on the configuration.
      * @param m the module in which native access occurred
      * @param owner the owner of the restricted method being called (or the JNI method being bound)
      * @param methodName the name of the restricted method being called (or the JNI method being bound)
@@ -282,6 +283,31 @@ public interface JavaLangAccess {
      */
     void ensureNativeAccess(Module m, Class<?> owner, String methodName, Class<?> currentClass, boolean jni);
 
+    /**
+     * Enable code in all unnamed modules to mutate final instance fields.
+     */
+    void addEnableFinalMutationToAllUnnamed();
+
+    /**
+     * Enable code in a given module to mutate final instance fields.
+     */
+    boolean tryEnableFinalMutation(Module m);
+
+    /**
+     * Return true if code in a given module is allowed to mutate final instance fields.
+     */
+    boolean isFinalMutationEnabled(Module m);
+
+    /**
+     * Return true if a given module has statically exported the given package to a given other module.
+     */
+    boolean isStaticallyExported(Module module, String pn, Module other);
+
+    /**
+     * Return true if a given module has statically opened the given package to a given other module.
+     */
+    boolean isStaticallyOpened(Module module, String pn, Module other);
+
     /**
      * Returns the ServicesCatalog for the given Layer.
      */

src/java.base/share/classes/jdk/internal/access/JavaLangReflectAccess.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -67,4 +67,10 @@ public interface JavaLangReflectAccess {
     /** Returns a new instance created by the given constructor with access check */
     public <T> T newInstance(Constructor<T> ctor, Object[] args, Class<?> caller)
         throws IllegalAccessException, InstantiationException, InvocationTargetException;
+
+    /**
+     * Check that the caller is allowed to unreflect for mutation a final instance field
+     * in a class that is not a record or hidden class.
+     */
+    void checkAllowedToUnreflectFinalSetter(Class<?> caller, Field f) throws IllegalAccessException;
 }

src/java.base/share/classes/jdk/internal/event/FinalFieldMutationEvent.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package jdk.internal.event;
+
+public class FinalFieldMutationEvent extends Event {
+    public Class<?> declaringClass;
+    public String fieldName;
+
+    /**
+     * Commit a FinalFieldMutationEvent if enabled.
+     */
+    public static void offer(Class<?> declaringClass, String fieldName) {
+        if (enabled()) {
+            var event = new FinalFieldMutationEvent();
+            event.declaringClass = declaringClass;
+            event.fieldName = fieldName;
+            event.commit();
+        }
+    }
+
+    public static boolean enabled() {
+        // Generated by JFR
+        return false;
+    }
+}

src/java.base/share/classes/jdk/internal/module/ModuleBootstrap.java

@@ -452,9 +452,12 @@ public final class ModuleBootstrap {
         addExtraReads(bootLayer);
         addExtraExportsAndOpens(bootLayer);
 
-        // add enable native access
+        // enable native access to modules specified to --enable-native-access
         addEnableNativeAccess(bootLayer);
 
+        // allow final mutation by modules specified to --enable-final-field-mutation
+        addEnableFinalFieldMutation(bootLayer);
+
         Counters.add("jdk.module.boot.7.adjustModulesTime");
 
         // Step 8: CDS dump phase
@@ -721,7 +724,6 @@ public final class ModuleBootstrap {
      * additional packages specified on the command-line.
      */
     private static void addExtraExportsAndOpens(ModuleLayer bootLayer) {
-
         // --add-exports
         String prefix = "jdk.module.addexports.";
         Map<String, List<String>> extraExports = decode(prefix);
@@ -729,14 +731,12 @@ public final class ModuleBootstrap {
             addExtraExportsOrOpens(bootLayer, extraExports, false);
         }
 
-
         // --add-opens
         prefix = "jdk.module.addopens.";
         Map<String, List<String>> extraOpens = decode(prefix);
         if (!extraOpens.isEmpty()) {
             addExtraExportsOrOpens(bootLayer, extraOpens, true);
         }
-
     }
 
     private static void addExtraExportsOrOpens(ModuleLayer bootLayer,
@@ -807,6 +807,7 @@ public final class ModuleBootstrap {
     private static final Set<String> USER_NATIVE_ACCESS_MODULES;
     private static final Set<String> JDK_NATIVE_ACCESS_MODULES;
     private static final IllegalNativeAccess ILLEGAL_NATIVE_ACCESS;
+    private static final IllegalFinalFieldMutation ILLEGAL_FINAL_FIELD_MUTATION;
 
     public enum IllegalNativeAccess {
         ALLOW,
@@ -814,14 +815,26 @@ public final class ModuleBootstrap {
         DENY
     }
 
+    public enum IllegalFinalFieldMutation {
+        ALLOW,
+        WARN,
+        DEBUG,
+        DENY
+    }
+
+    static {
+        ILLEGAL_NATIVE_ACCESS = decodeIllegalNativeAccess();
+        USER_NATIVE_ACCESS_MODULES = decodeEnableNativeAccess();
+        JDK_NATIVE_ACCESS_MODULES = ModuleLoaderMap.nativeAccessModules();
+        ILLEGAL_FINAL_FIELD_MUTATION = decodeIllegalFinalFieldMutation();
+    }
+
     public static IllegalNativeAccess illegalNativeAccess() {
         return ILLEGAL_NATIVE_ACCESS;
     }
 
-    static {
-        ILLEGAL_NATIVE_ACCESS = addIllegalNativeAccess();
-        USER_NATIVE_ACCESS_MODULES = decodeEnableNativeAccess();
-        JDK_NATIVE_ACCESS_MODULES = ModuleLoaderMap.nativeAccessModules();
+    public static IllegalFinalFieldMutation illegalFinalFieldMutation() {
+        return ILLEGAL_FINAL_FIELD_MUTATION;
     }
 
     /**
@@ -881,7 +894,7 @@ public final class ModuleBootstrap {
     /**
      * Process the --illegal-native-access option (and its default).
      */
-    private static IllegalNativeAccess addIllegalNativeAccess() {
+    private static IllegalNativeAccess decodeIllegalNativeAccess() {
         String value = getAndRemoveProperty("jdk.module.illegal.native.access");
         // don't use a switch: bootstrapping issues!
         if (value == null) {
@@ -899,6 +912,71 @@ public final class ModuleBootstrap {
         }
     }
 
+    /**
+     * Process the --illegal-final-field-mutation option.
+     */
+    private static IllegalFinalFieldMutation decodeIllegalFinalFieldMutation() {
+        String value = getAndRemoveProperty("jdk.module.illegal.final.field.mutation");
+        if (value == null) {
+            return IllegalFinalFieldMutation.WARN; // default
+        } else if (value.equals("allow")) {
+            return IllegalFinalFieldMutation.ALLOW;
+        } else if (value.equals("warn")) {
+            return IllegalFinalFieldMutation.WARN;
+        } else if (value.equals("debug")) {
+            return IllegalFinalFieldMutation.DEBUG;
+        } else if (value.equals("deny")) {
+            return IllegalFinalFieldMutation.DENY;
+        } else {
+            fail("Value specified to --illegal-final-field-mutation not recognized:"
+                    + " '" + value + "'");
+            return null;
+        }
+    }
+
+    /**
+     * Process the modules specified to --enable-final-field-mutation and grant the
+     * capability to mutate finals to specified named modules or all unnamed modules.
+     */
+    private static void addEnableFinalFieldMutation(ModuleLayer bootLayer) {
+        for (String name : decodeEnableFinalFieldMutation()) {
+            if (name.equals("ALL-UNNAMED")) {
+                JLA.addEnableFinalMutationToAllUnnamed();
+            } else {
+                Module m = bootLayer.findModule(name).orElse(null);
+                if (m != null) {
+                    JLA.tryEnableFinalMutation(m);
+                } else {
+                    warnUnknownModule("--enable-final-field-mutation", name);
+                }
+            }
+        }
+    }
+
+    /**
+     * Returns the set of module names specified by --enable-final-field-mutation options.
+     */
+    private static Set<String> decodeEnableFinalFieldMutation() {
+        String prefix = "jdk.module.enable.final.field.mutation.";
+        int index = 0;
+        // the system property is removed after decoding
+        String value = getAndRemoveProperty(prefix + index);
+        Set<String> modules = new HashSet<>();
+        if (value == null) {
+            return modules;
+        }
+        while (value != null) {
+            for (String s : value.split(",")) {
+                if (!s.isEmpty()) {
+                    modules.add(s);
+                }
+            }
+            index++;
+            value = getAndRemoveProperty(prefix + index);
+        }
+        return modules;
+    }
+
     /**
      * Decodes the values of --add-reads, -add-exports, --add-opens or
      * --patch-modules options that are encoded in system properties.

src/java.base/share/classes/jdk/internal/module/Modules.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -139,6 +139,45 @@ public class Modules {
         JLA.addEnableNativeAccessToAllUnnamed();
     }
 
+    /**
+     * Enable code in all unnamed modules to mutate final instance fields.
+     */
+    public static void addEnableFinalMutationToAllUnnamed() {
+        JLA.addEnableFinalMutationToAllUnnamed();
+    }
+
+    /**
+     * Enable code in a given module to mutate final instance fields.
+     */
+    public static boolean tryEnableFinalMutation(Module m) {
+        return JLA.tryEnableFinalMutation(m);
+    }
+
+    /**
+     * Return true if code in a given module is allowed to mutate final instance fields.
+     */
+    public static boolean isFinalMutationEnabled(Module m) {
+        return JLA.isFinalMutationEnabled(m);
+    }
+
+    /**
+     * Return true if a given module has statically exported the given package to a given
+     * other module. "statically exported" means the module declaration, --add-exports on
+     * the command line, or Add-Exports in the main manifest of an executable JAR.
+     */
+    public static boolean isStaticallyExported(Module m, String pn, Module other) {
+        return JLA.isStaticallyExported(m, pn, other);
+    }
+
+    /**
+     * Return true if a given module has statically opened the given package to a given
+     * other module. "statically open" means the module declaration, --add-opens on the
+     * command line, or Add-Opens in the main manifest of an executable JAR.
+     */
+    public static boolean isStaticallyOpened(Module m, String pn, Module other) {
+        return JLA.isStaticallyOpened(m, pn, other);
+    }
+
     /**
      * Updates module m to use a service.
      * Same as m2.addUses(service) but without a caller check.

src/java.base/share/classes/sun/launcher/LauncherHelper.java

@@ -103,6 +103,7 @@ public final class LauncherHelper {
     private static final String ADD_EXPORTS = "Add-Exports";
     private static final String ADD_OPENS = "Add-Opens";
     private static final String ENABLE_NATIVE_ACCESS = "Enable-Native-Access";
+    private static final String ENABLE_FINAL_FIELD_MUTATION = "Enable-Final-Field-Mutation";
 
     private static StringBuilder outBuf = new StringBuilder();
 
@@ -647,6 +648,8 @@ public final class LauncherHelper {
         if (opens != null) {
             addExportsOrOpens(opens, true);
         }
+
+        // Enable-Native-Access
         String enableNativeAccess = mainAttrs.getValue(ENABLE_NATIVE_ACCESS);
         if (enableNativeAccess != null) {
             if (!enableNativeAccess.equals("ALL-UNNAMED")) {
@@ -655,6 +658,16 @@ public final class LauncherHelper {
             Modules.addEnableNativeAccessToAllUnnamed();
         }
 
+        // Enable-Final-Field-Mutation
+        String enableFinalFieldMutation = mainAttrs.getValue(ENABLE_FINAL_FIELD_MUTATION);
+        if (enableFinalFieldMutation != null) {
+            if (!enableFinalFieldMutation.equals("ALL-UNNAMED")) {
+                abort(null, "java.launcher.jar.error.illegal.effm.value",
+                        enableFinalFieldMutation);
+            }
+            Modules.addEnableFinalMutationToAllUnnamed();
+        }
+
         /*
          * Hand off to FXHelper if it detects a JavaFX application
          * This must be done after ensuring a Main-Class entry

src/java.base/share/classes/sun/launcher/resources/launcher.properties

@@ -70,6 +70,14 @@ java.launcher.opt.footer = \
 \                  by code in modules for which native access is not explicitly enabled.\n\
 \                  <value> is one of "deny", "warn" or "allow". The default value is "warn".\n\
 \                  This option will be removed in a future release.\n\
+\    --enable-final-field-mutation <module name>[,<module name>...]\n\
+\                  allow code in the specified modules to mutate final instance fields.\n\
+\                  <module name> can also be ALL-UNNAMED to indicate code on the class path.\n\
+\    --illegal-final-field-mutation=<value>\n\
+\                  allow or deny final field mutation by code in modules for which final\n\
+\                  field mutation is not explicitly enabled.\n\
+\                  <value> is one of "deny", "warn", "debug", or "allow". The default value is "warn".\n\
+\                  This option will be removed in a future release.\n\
 \    --list-modules\n\
 \                  list observable modules and exit\n\
 \    -d <module name>\n\
@@ -291,6 +299,8 @@ java.launcher.jar.error5=\
     Error: An unexpected error occurred while trying to close file {0}
 java.launcher.jar.error.illegal.ena.value=\
     Error: illegal value \"{0}\" for Enable-Native-Access manifest attribute. Only 'ALL-UNNAMED' is allowed
+java.launcher.jar.error.illegal.effm.value=\
+    Error: illegal value \"{0}\" for Enable-Final-Field-Mutation manifest attribute. Only 'ALL-UNNAMED' is allowed
 java.launcher.init.error=initialization error
 java.launcher.javafx.error1=\
     Error: The JavaFX launchApplication method has the wrong signature, it\n\

src/java.base/share/man/java.md

@@ -450,7 +450,7 @@ the JVM.
     > **Note:** This option will be removed in a future release.
 
     -   `allow`: This mode allows illegal native access in all modules,
-        without any warings.
+        without any warnings.
 
     -   `warn`: This mode is identical to `allow` except that a warning
         message is issued for the first illegal native access found in a module.
@@ -465,6 +465,39 @@ the JVM.
     run it with `--illegal-native-access=deny` along with any necessary `--enable-native-access`
     options.
 
+`--enable-final-field-mutation` *module*\[,*module*...\]
+:   Mutation of final fields is possible with the reflection API of the Java Platform.
+    However, it compromises safety and performance in all programs.
+    This option allows code in the specified modules to mutate final fields by reflection.
+    Attempts by code in any other module to mutate final fields by reflection are deemed _illegal_.
+
+    *module* can be the name of a module on the module path, or `ALL-UNNAMED` to indicate
+    code on the class path.
+
+-`--illegal-final-field-mutation=`*parameter*
+:   This option specifies a mode for how _illegal_ final field mutation is handled:
+
+    > **Note:** This option will be removed in a future release.
+
+    -   `allow`: This mode allows illegal final field mutation in all modules,
+        without any warnings.
+
+    -   `warn`: This mode is identical to `allow` except that a warning message is
+        issued for the first illegal final field mutation performaed in a module.
+        This mode is the default for the current JDK but will change in a future
+        release.
+
+    -   `debug`: This mode is identical to `allow` except that a warning message
+        and stack trace are printed for every illegal final field mutation.
+
+    -   `deny`: This mode disables final field mutation. That is, any illegal final
+        field mutation access causes an `IllegalAccessException`. This mode will
+        become the default in a future release.
+
+    To verify that your application is ready for a future version of the JDK,
+    run it with `--illegal-final-field-mutation=deny` along with any necessary
+    `--enable-final-field-mutation` options.
+
 `--finalization=`*value*
 :   Controls whether the JVM performs finalization of objects. Valid values
     are "enabled" and "disabled". Finalization is enabled by default, so the
@@ -701,7 +734,8 @@ the Java HotSpot Virtual Machine.
     - A class descriptor is in decorated format (`Lname;`) when it should not be.
     - A `NULL` parameter is allowed, but its use is questionable.
     - Calling other JNI functions in the scope of `Get/ReleasePrimitiveArrayCritical`
-      or `Get/ReleaseStringCritical`
+      or `Get/ReleaseStringCritical`.
+    - A JNI call was made to mutate a final field.
 
     Expect a performance degradation when this option is used.
 

src/jdk.jfr/share/classes/jdk/jfr/events/FinalFieldMutationEvent.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jfr.events;
+
+import jdk.jfr.Category;
+import jdk.jfr.Description;
+import jdk.jfr.Label;
+import jdk.jfr.Name;
+import jdk.jfr.internal.Type;
+import jdk.jfr.internal.MirrorEvent;
+import jdk.jfr.internal.RemoveFields;
+
+@Category("Java Application")
+@Label("Final Field Mutation")
+@Name(Type.EVENT_NAME_PREFIX + "FinalFieldMutation")
+@RemoveFields("duration")
+@StackFilter({
+        "java.lang.reflect.Field",
+        "java.lang.reflect.ReflectAccess",
+        "java.lang.invoke.MethodHandles$Lookup"
+})
+public final class FinalFieldMutationEvent extends MirrorEvent {
+
+    @Label("Declaring Class")
+    @Description("Declaring class with final field")
+    public Class<?> declaringClass;
+
+    @Label("Field Name")
+    @Description("Field name of final field")
+    public String fieldName;
+
+}

src/jdk.jfr/share/classes/jdk/jfr/internal/JDKEvents.java

@@ -76,6 +76,7 @@ public final class JDKEvents {
         jdk.internal.event.VirtualThreadSubmitFailedEvent.class,
         jdk.internal.event.X509CertificateEvent.class,
         jdk.internal.event.X509ValidationEvent.class,
+        jdk.internal.event.FinalFieldMutationEvent.class,
         DirectBufferStatisticsEvent.class,
         InitialSecurityPropertyEvent.class,
         MethodTraceEvent.class,

src/jdk.jfr/share/classes/jdk/jfr/internal/MirrorEvents.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,6 +34,7 @@ import jdk.jfr.events.ExceptionThrownEvent;
 import jdk.jfr.events.FileForceEvent;
 import jdk.jfr.events.FileReadEvent;
 import jdk.jfr.events.FileWriteEvent;
+import jdk.jfr.events.FinalFieldMutationEvent;
 import jdk.jfr.events.ProcessStartEvent;
 import jdk.jfr.events.SecurityPropertyModificationEvent;
 import jdk.jfr.events.SecurityProviderServiceEvent;
@@ -77,6 +78,7 @@ final class MirrorEvents {
         register("jdk.internal.event.ErrorThrownEvent", ErrorThrownEvent.class);
         register("jdk.internal.event.ExceptionStatisticsEvent", ExceptionStatisticsEvent.class);
         register("jdk.internal.event.ExceptionThrownEvent", ExceptionThrownEvent.class);
+        register("jdk.internal.event.FinalFieldMutationEvent", FinalFieldMutationEvent.class);
     };
 
     private static void register(String eventClassName, Class<? extends MirrorEvent> mirrorClass) {

src/jdk.jfr/share/classes/jdk/jfr/internal/PlatformEventType.java

@@ -125,6 +125,7 @@ public final class PlatformEventType extends Type {
                      Type.EVENT_NAME_PREFIX + "FileWrite" -> 6;
                 case Type.EVENT_NAME_PREFIX + "FileRead",
                      Type.EVENT_NAME_PREFIX + "FileForce" -> 5;
+                case Type.EVENT_NAME_PREFIX + "FinalFieldMutation" -> 4;
                 default -> 3;
             };
         }

src/jdk.jfr/share/conf/jfr/default.jfc

@@ -117,6 +117,11 @@
       <setting name="period">everyChunk</setting>
     </event>
 
+    <event name="jdk.FinalFieldMutation">
+      <setting name="enabled">true</setting>
+      <setting name="stackTrace">true</setting>
+    </event>
+
     <event name="jdk.SyncOnValueBasedClass">
       <setting name="enabled">true</setting>
       <setting name="stackTrace">true</setting>

src/jdk.jfr/share/conf/jfr/profile.jfc

@@ -117,6 +117,11 @@
       <setting name="period">everyChunk</setting>
     </event>
 
+    <event name="jdk.FinalFieldMutation">
+      <setting name="enabled">true</setting>
+      <setting name="stackTrace">true</setting>
+    </event>
+
     <event name="jdk.SyncOnValueBasedClass">
       <setting name="enabled">true</setting>
       <setting name="stackTrace">true</setting>

test/hotspot/jtreg/runtime/jni/mutateFinals/MutateFinals.java

@@ -0,0 +1,356 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.lang.reflect.Method;
+import java.util.Objects;
+
+/**
+ * Invoked by MutateFinalsTest, either directly or in a child VM, with the name of the
+ * test method in this class to execute.
+ */
+
+public class MutateFinals {
+
+    /**
+     *  Usage: java MutateFinals <method-name>
+     */
+    public static void main(String[] args) throws Exception {
+        invoke(args[0]);
+    }
+
+    /**
+     * Invokes the given method.
+     */
+    static void invoke(String methodName) throws Exception {
+        Method m = MutateFinals.class.getDeclaredMethod(methodName);
+        m.invoke(null);
+    }
+
+    /**
+     * JNI SetObjectField.
+     */
+    private static void testJniSetObjectField() throws Exception {
+        class C {
+            final Object value;
+            C(Object value) {
+                this.value = value;
+            }
+        }
+        Object oldValue = new Object();
+        Object newValue = new Object();
+        var obj = new C(oldValue);
+        jniSetObjectField(obj, newValue);
+        assertTrue(obj.value == newValue);
+    }
+
+    /**
+     * JNI SetBooleanField.
+     */
+    private static void testJniSetBooleanField() throws Exception {
+        class C {
+            final boolean value;
+            C(boolean value) {
+                this.value = value;
+            }
+        }
+        var obj = new C(false);
+        jniSetBooleanField(obj, true);
+        assertTrue(obj.value);
+    }
+
+    /**
+     * JNI SetByteField.
+     */
+    private static void testJniSetByteField() throws Exception {
+        class C {
+            final byte value;
+            C(byte value) {
+                this.value = value;
+            }
+        }
+        byte oldValue = (byte) 1;
+        byte newValue = (byte) 2;
+        var obj = new C(oldValue);
+        jniSetByteField(obj, newValue);
+        assertEquals(newValue, obj.value);
+    }
+
+    /**
+     * JNI SetCharField.
+     */
+    private static void testJniSetCharField() throws Exception {
+        class C {
+            final char value;
+            C(char value) {
+                this.value = value;
+            }
+        }
+        char oldValue = 'A';
+        char newValue = 'B';
+        var obj = new C(oldValue);
+        jniSetCharField(obj, newValue);
+        assertEquals(newValue, obj.value);
+    }
+
+    /**
+     * JNI SetShortField.
+     */
+    private static void testJniSetShortField() throws Exception {
+        class C {
+            final short value;
+            C(short value) {
+                this.value = value;
+            }
+        }
+        short oldValue = (short) 1;
+        short newValue = (short) 2;
+        var obj = new C(oldValue);
+        jniSetShortField(obj, newValue);
+        assertEquals(newValue, obj.value);
+    }
+
+    /**
+     * JNI SetIntField.
+     */
+    private static void testJniSetIntField() throws Exception {
+        class C {
+            final int value;
+            C(int value) {
+                this.value = value;
+            }
+        }
+        int oldValue = 1;
+        int newValue = 2;
+        var obj = new C(oldValue);
+        jniSetIntField(obj, newValue);
+        assertEquals(newValue, obj.value);
+    }
+
+    /**
+     * JNI SetLongField.
+     */
+    private static void testJniSetLongField() throws Exception {
+        class C {
+            final long value;
+            C(long value) {
+                this.value = value;
+            }
+        }
+        long oldValue = 1L;
+        long newValue = 2L;
+        var obj = new C(oldValue);
+        jniSetLongField(obj, newValue);
+        assertEquals(newValue, obj.value);
+    }
+
+    /**
+     * JNI SetFloatField.
+     */
+    private static void testJniSetFloatField() throws Exception {
+        class C {
+            final float value;
+            C(float value) {
+                this.value = value;
+            }
+        }
+        float oldValue = 1.0f;
+        float newValue = 2.0f;
+        var obj = new C(oldValue);
+        jniSetFloatField(obj, newValue);
+        assertEquals(newValue, obj.value);
+    }
+
+    /**
+     * JNI SetDoubleField.
+     */
+    private static void testJniSetDoubleField() throws Exception {
+        class C {
+            final double value;
+            C(double value) {
+                this.value = value;
+            }
+        }
+        double oldValue = 1.0d;
+        double newValue = 2.0d;
+        var obj = new C(oldValue);
+        jniSetDoubleField(obj, newValue);
+        assertEquals(newValue, obj.value);
+    }
+
+    /**
+     * JNI SetStaticObjectField.
+     */
+    private static void testJniSetStaticObjectField() throws Exception {
+        class C {
+            static final Object value = new Object();
+        }
+        Object newValue = new Object();
+        jniSetStaticObjectField(C.class, newValue);
+        assertTrue(C.value == newValue);
+    }
+
+    /**
+     * JNI SetStaticBooleanField.
+     */
+    private static void testJniSetStaticBooleanField() throws Exception {
+        class C {
+            static final boolean value = false;
+        }
+        jniSetStaticBooleanField(C.class, true);
+        // use reflection as field treated as constant by compiler
+        boolean value = (boolean) C.class.getDeclaredField("value").get(null);
+        assertTrue(value);
+    }
+
+    /**
+     * JNI SetStaticByteField.
+     */
+    private static void testJniSetStaticByteField() throws Exception {
+        class C {
+            static final byte value = (byte) 1;
+        }
+        byte newValue = (byte) 2;
+        jniSetStaticByteField(C.class, newValue);
+        // use reflection as field treated as constant by compiler
+        byte value = (byte) C.class.getDeclaredField("value").get(null);
+        assertEquals(newValue, value);
+    }
+
+    /**
+     * JNI SetStaticCharField.
+     */
+    private static void testJniSetStaticCharField() throws Exception {
+        class C {
+            static final char value = 'A';
+        }
+        char newValue = 'B';
+        jniSetStaticCharField(C.class, newValue);
+        // use reflection as field treated as constant by compiler
+        char value = (char) C.class.getDeclaredField("value").get(null);
+        assertEquals(newValue, value);
+    }
+
+    /**
+     * JNI SetStaticShortField.
+     */
+    private static void testJniSetStaticShortField() throws Exception {
+        class C {
+            static final short value = (short) 1;
+        }
+        short newValue = (short) 2;
+        jniSetStaticShortField(C.class, newValue);
+        // use reflection as field treated as constant by compiler
+        short value = (short) C.class.getDeclaredField("value").get(null);
+        assertEquals(newValue, value);
+    }
+
+    /**
+     * JNI SetStaticIntField.
+     */
+    private static void testJniSetStaticIntField() throws Exception {
+        class C {
+            static final int value = 1;
+        }
+        int newValue = 2;
+        jniSetStaticIntField(C.class, newValue);
+        // use reflection as field treated as constant by compiler
+        int value = (int) C.class.getDeclaredField("value").get(null);
+        assertEquals(newValue, value);
+    }
+
+    /**
+     * JNI SetStaticLongField.
+     */
+    private static void testJniSetStaticLongField() throws Exception {
+        class C {
+            static final long value = 1L;
+        }
+        long newValue = 2L;
+        jniSetStaticLongField(C.class, newValue);
+        // use reflection as field treated as constant by compiler
+        long value = (long) C.class.getDeclaredField("value").get(null);
+        assertEquals(newValue, value);
+    }
+
+    /**
+     * JNI SetStaticFloatField.
+     */
+    private static void testJniSetStaticFloatField() throws Exception {
+        class C {
+            static final float value = 1.0f;
+        }
+        float newValue = 2.0f;
+        jniSetStaticFloatField(C.class, newValue);
+        // use reflection as field treated as constant by compiler
+        float value = (float) C.class.getDeclaredField("value").get(null);
+        assertEquals(newValue, value);
+    }
+
+    /**
+     * JNI SetStaticDoubleField.
+     */
+    private static void testJniSetStaticDoubleField() throws Exception {
+        class C {
+            static final double value = 1.0d;
+        }
+        double newValue = 2.0f;
+        jniSetStaticDoubleField(C.class, newValue);
+        // use reflection as field treated as constant by compiler
+        double value = (double) C.class.getDeclaredField("value").get(null);
+        assertEquals(newValue, value);
+    }
+
+    private static native void jniSetObjectField(Object obj, Object value);
+    private static native void jniSetBooleanField(Object obj, boolean value);
+    private static native void jniSetByteField(Object obj, byte value);
+    private static native void jniSetCharField(Object obj, char value);
+    private static native void jniSetShortField(Object obj, short value);
+    private static native void jniSetIntField(Object obj, int value);
+    private static native void jniSetLongField(Object obj, long value);
+    private static native void jniSetFloatField(Object obj, float value);
+    private static native void jniSetDoubleField(Object obj, double value);
+
+    private static native void jniSetStaticObjectField(Class<?> clazz, Object value);
+    private static native void jniSetStaticBooleanField(Class<?> clazz, boolean value);
+    private static native void jniSetStaticByteField(Class<?> clazz, byte value);
+    private static native void jniSetStaticCharField(Class<?> clazz, char value);
+    private static native void jniSetStaticShortField(Class<?> clazz, short value);
+    private static native void jniSetStaticIntField(Class<?> clazz, int value);
+    private static native void jniSetStaticLongField(Class<?> clazz, long value);
+    private static native void jniSetStaticFloatField(Class<?> clazz, float value);
+    private static native void jniSetStaticDoubleField(Class<?> clazz, double value);
+
+    static {
+        System.loadLibrary("MutateFinals");
+    }
+
+    private static void assertTrue(boolean e) {
+        if (!e) throw new RuntimeException("Not true as expected");
+    }
+
+    private static void assertEquals(Object expected, Object actual) {
+        if (!Objects.equals(expected, actual)) {
+            throw new RuntimeException("Actual: " + actual + ", expected: " + expected);
+        }
+    }
+}

test/hotspot/jtreg/runtime/jni/mutateFinals/MutateFinalsTest.java

@@ -0,0 +1,170 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8353835
+ * @summary Test JNI SetXXXField methods to set final instance and final static fields
+ * @key randomness
+ * @modules java.management
+ * @library /test/lib
+ * @compile MutateFinals.java
+ * @run junit/native/timeout=300 MutateFinalsTest
+ */
+
+import java.util.List;
+import java.util.stream.Stream;
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import jdk.test.lib.process.ProcessTools;
+import jdk.test.lib.process.OutputAnalyzer;
+
+class MutateFinalsTest {
+
+    static String javaLibraryPath;
+
+    @BeforeAll
+    static void init() {
+        javaLibraryPath = System.getProperty("java.library.path");
+    }
+
+    /**
+     * The names of the test methods that use JNI to set final instance fields.
+     */
+    static Stream<String> mutateInstanceFieldMethods() {
+        return Stream.of(
+                "testJniSetObjectField",
+                "testJniSetBooleanField",
+                "testJniSetByteField",
+                "testJniSetCharField",
+                "testJniSetShortField",
+                "testJniSetIntField",
+                "testJniSetLongField",
+                "testJniSetFloatField",
+                "testJniSetDoubleField"
+        );
+    }
+
+    /**
+     * The names of the test methods that use JNI to set final static fields.
+     */
+    static Stream<String> mutateStaticFieldMethods() {
+        return Stream.of(
+                "testJniSetStaticObjectField",
+                "testJniSetStaticBooleanField",
+                "testJniSetStaticByteField",
+                "testJniSetStaticCharField",
+                "testJniSetStaticShortField",
+                "testJniSetStaticIntField",
+                "testJniSetStaticLongField",
+                "testJniSetStaticFloatField",
+                "testJniSetStaticDoubleField"
+        );
+    }
+
+    /**
+     * The names of all test methods that use JNI to set final fields.
+     */
+    static Stream<String> allMutationMethods() {
+        return Stream.concat(mutateInstanceFieldMethods(), mutateStaticFieldMethods());
+    }
+
+    /**
+     * Mutate a final field with JNI.
+     */
+    @ParameterizedTest
+    @MethodSource("allMutationMethods")
+    void testMutateFinal(String methodName) throws Exception {
+        MutateFinals.invoke(methodName);
+    }
+
+    /**
+     * Mutate a final instance field with JNI. The test launches a child VM with -Xcheck:jni
+     * and expects a warning in the output.
+     */
+    @ParameterizedTest
+    @MethodSource("mutateInstanceFieldMethods")
+    void testMutateInstanceFinalWithXCheckJni(String methodName) throws Exception {
+        test(methodName, "-Xcheck:jni")
+            .shouldContain("WARNING in native method: Set<Type>Field called to mutate final instance field")
+            .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Mutate final static fields with JNI. The test launches a child VM with -Xcheck:jni
+     * and expects a warning in the output.
+     */
+    @ParameterizedTest
+    @MethodSource("mutateStaticFieldMethods")
+    void testMutateStaticFinalWithXCheckJni(String methodName) throws Exception {
+        test(methodName, "-Xcheck:jni")
+            .shouldContain("WARNING in native method: SetStatic<Type>Field called to mutate final static field")
+            .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Mutate a final instance field with JNI. The test launches a child VM with -Xlog
+     * and expects a log message in the output.
+     */
+    @ParameterizedTest
+    @MethodSource("mutateInstanceFieldMethods")
+    void testMutateInstanceFinalWithLogging(String methodName) throws Exception {
+        String type = methodName.contains("Object") ? "Object" : "<Type>";
+        test(methodName, "-Xlog:jni=debug")
+            .shouldContain("[debug][jni] Set" + type + "Field mutated final instance field")
+            .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Mutate a final static field with JNI. The test launches a child VM with -Xlog
+     * and expects a log message in the output.
+     */
+    @ParameterizedTest
+    @MethodSource("mutateStaticFieldMethods")
+    void testMutateStaticFinalWithLogging(String methodName) throws Exception {
+        String type = methodName.contains("Object") ? "Object" : "<Type>";
+        test(methodName, "-Xlog:jni=debug")
+            .shouldContain("[debug][jni] SetStatic" + type + "Field mutated final static field")
+            .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Launches MutateFinals with the given method name as parameter, and the given VM options.
+     */
+    private OutputAnalyzer test(String methodName, String... vmopts) throws Exception {
+        Stream<String> s1 = Stream.of(
+                "-Djava.library.path=" + javaLibraryPath,
+                "--enable-native-access=ALL-UNNAMED");
+        Stream<String> s2 = Stream.of(vmopts);
+        Stream<String> s3 = Stream.of("MutateFinals", methodName);
+        String[] opts = Stream.concat(Stream.concat(s1, s2), s3).toArray(String[]::new);
+        var outputAnalyzer = ProcessTools
+                .executeTestJava(opts)
+                .outputTo(System.err)
+                .errorTo(System.err);
+        return outputAnalyzer;
+    }
+}

test/hotspot/jtreg/runtime/jni/mutateFinals/libMutateFinals.c

@@ -0,0 +1,160 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#include <stdio.h>
+#include "jni.h"
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetObjectField(JNIEnv *env, jclass ignore, jobject obj, jobject value) {
+    jclass clazz = (*env)->GetObjectClass(env, obj);
+    jfieldID fid = (*env)->GetFieldID(env, clazz, "value", "Ljava/lang/Object;");
+    if (fid != NULL) {
+        (*env)->SetObjectField(env, obj, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetBooleanField(JNIEnv *env, jclass ignore, jobject obj, jboolean value) {
+    jclass clazz = (*env)->GetObjectClass(env, obj);
+    jfieldID fid = (*env)->GetFieldID(env, clazz, "value", "Z");
+    if (fid != NULL) {
+        (*env)->SetBooleanField(env, obj, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetByteField(JNIEnv *env, jclass ignore, jobject obj, jbyte value) {
+    jclass clazz = (*env)->GetObjectClass(env, obj);
+    jfieldID fid = (*env)->GetFieldID(env, clazz, "value", "B");
+    if (fid != NULL) {
+        (*env)->SetByteField(env, obj, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetCharField(JNIEnv *env, jclass ignore, jobject obj, jchar value) {
+    jclass clazz = (*env)->GetObjectClass(env, obj);
+    jfieldID fid = (*env)->GetFieldID(env, clazz, "value", "C");
+    if (fid != NULL) {
+        (*env)->SetCharField(env, obj, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetShortField(JNIEnv *env, jclass ignore, jobject obj, jshort value) {
+    jclass clazz = (*env)->GetObjectClass(env, obj);
+    jfieldID fid = (*env)->GetFieldID(env, clazz, "value", "S");
+    if (fid != NULL) {
+        (*env)->SetShortField(env, obj, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetIntField(JNIEnv *env, jclass ignore, jobject obj, jint value) {
+    jclass clazz = (*env)->GetObjectClass(env, obj);
+    jfieldID fid = (*env)->GetFieldID(env, clazz, "value", "I");
+    if (fid != NULL) {
+        (*env)->SetIntField(env, obj, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetLongField(JNIEnv *env, jclass ignore, jobject obj, jlong value) {
+    jclass clazz = (*env)->GetObjectClass(env, obj);
+    jfieldID fid = (*env)->GetFieldID(env, clazz, "value", "J");
+    if (fid != NULL) {
+        (*env)->SetLongField(env, obj, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetFloatField(JNIEnv *env, jclass ignore, jobject obj, jfloat value) {
+    jclass clazz = (*env)->GetObjectClass(env, obj);
+    jfieldID fid = (*env)->GetFieldID(env, clazz, "value", "F");
+    if (fid != NULL) {
+        (*env)->SetFloatField(env, obj, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetDoubleField(JNIEnv *env, jclass ignore, jobject obj, jdouble value) {
+    jclass clazz = (*env)->GetObjectClass(env, obj);
+    jfieldID fid = (*env)->GetFieldID(env, clazz, "value", "D");
+    if (fid != NULL) {
+        (*env)->SetDoubleField(env, obj, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetStaticObjectField(JNIEnv *env, jclass ignore, jclass clazz, jobject value) {
+    jfieldID fid = (*env)->GetStaticFieldID(env, clazz, "value", "Ljava/lang/Object;");
+    if (fid != NULL) {
+        (*env)->SetStaticObjectField(env, clazz, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetStaticBooleanField(JNIEnv *env, jclass ignore, jclass clazz, jboolean value) {
+    jfieldID fid = (*env)->GetStaticFieldID(env, clazz, "value", "Z");
+    if (fid != NULL) {
+        (*env)->SetStaticBooleanField(env, clazz, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetStaticByteField(JNIEnv *env, jclass ignore, jclass clazz, jbyte value) {
+    jfieldID fid = (*env)->GetStaticFieldID(env, clazz, "value", "B");
+    if (fid != NULL) {
+        (*env)->SetStaticByteField(env, clazz, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetStaticCharField(JNIEnv *env, jclass ignore, jclass clazz, jchar value) {
+    jfieldID fid = (*env)->GetStaticFieldID(env, clazz, "value", "C");
+    if (fid != NULL) {
+        (*env)->SetStaticCharField(env, clazz, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetStaticShortField(JNIEnv *env, jclass ignore, jclass clazz, jshort value) {
+    jfieldID fid = (*env)->GetStaticFieldID(env, clazz, "value", "S");
+    if (fid != NULL) {
+        (*env)->SetStaticShortField(env, clazz, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetStaticIntField(JNIEnv *env, jclass ignore, jclass clazz, jint value) {
+    jfieldID fid = (*env)->GetStaticFieldID(env, clazz, "value", "I");
+    if (fid != NULL) {
+        (*env)->SetStaticIntField(env, clazz, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetStaticLongField(JNIEnv *env, jclass ignore, jclass clazz, jlong value) {
+    jfieldID fid = (*env)->GetStaticFieldID(env, clazz, "value", "J");
+    if (fid != NULL) {
+        (*env)->SetStaticLongField(env, clazz, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetStaticFloatField(JNIEnv *env, jclass ignore, jclass clazz, jfloat value) {
+    jfieldID fid = (*env)->GetStaticFieldID(env, clazz, "value", "F");
+    if (fid != NULL) {
+        (*env)->SetStaticFloatField(env, clazz, fid, value);
+    }
+}
+
+JNIEXPORT void JNICALL Java_MutateFinals_jniSetStaticDoubleField(JNIEnv *env, jclass ignore, jclass clazz, jdouble value) {
+    jfieldID fid = (*env)->GetStaticFieldID(env, clazz, "value", "D");
+    if (fid != NULL) {
+        (*env)->SetStaticDoubleField(env, clazz, fid, value);
+    }
+}

test/jdk/java/lang/invoke/MethodHandlesGeneralTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,6 +29,7 @@
  * @run junit/othervm/timeout=2500 -XX:+IgnoreUnrecognizedVMOptions
  *                                 -XX:-VerifyDependencies
  *                                 -esa
+ *                                 --enable-final-field-mutation=ALL-UNNAMED
  *                                 test.java.lang.invoke.MethodHandlesGeneralTest
  */
 

test/jdk/java/lang/invoke/VarHandles/accessibility/TestFieldLookupAccessibility.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,10 +27,12 @@
  * @compile TestFieldLookupAccessibility.java
  *          pkg/A.java pkg/B_extends_A.java pkg/C.java
  *          pkg/subpkg/B_extends_A.java pkg/subpkg/C.java
- * @run testng/othervm TestFieldLookupAccessibility
+ * @run testng/othervm --enable-final-field-mutation=ALL-UNNAMED -DwriteAccess=true TestFieldLookupAccessibility
+ * @run testng/othervm --illegal-final-field-mutation=deny -DwriteAccess=false TestFieldLookupAccessibility
  */
 
-import org.testng.Assert;
+import static org.testng.Assert.*;
+import org.testng.annotations.BeforeClass;
 import org.testng.annotations.DataProvider;
 import org.testng.annotations.Test;
 import pkg.B_extends_A;
@@ -48,6 +50,14 @@ import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 public class TestFieldLookupAccessibility {
+    static boolean writeAccess;
+
+    @BeforeClass
+    static void setup() {
+        String s = System.getProperty("writeAccess");
+        assertNotNull(s);
+        writeAccess = Boolean.valueOf(s);
+    }
 
     // The set of possible field lookup mechanisms
     enum FieldLookup {
@@ -118,7 +128,11 @@ public class TestFieldLookupAccessibility {
             }
 
             boolean isAccessible(Field f) {
-                return !(Modifier.isStatic(f.getModifiers()) && Modifier.isFinal(f.getModifiers()));
+                if (Modifier.isFinal(f.getModifiers())) {
+                    return !Modifier.isStatic(f.getModifiers()) && writeAccess;
+                } else {
+                    return true;
+                }
             }
 
             // Setting the accessibility bit of a Field grants access to non-static
@@ -226,15 +240,15 @@ public class TestFieldLookupAccessibility {
                 collect(Collectors.toSet());
         if (!actualFieldNames.equals(expected)) {
             if (actualFieldNames.isEmpty()) {
-                Assert.assertEquals(actualFieldNames, expected, "No accessibility failures:");
+                assertEquals(actualFieldNames, expected, "No accessibility failures:");
             }
             else {
-                Assert.assertEquals(actualFieldNames, expected, "Accessibility failures differ:");
+                assertEquals(actualFieldNames, expected, "Accessibility failures differ:");
             }
         }
         else {
             if (!actual.values().stream().allMatch(IllegalAccessException.class::isInstance)) {
-                Assert.fail("Expecting an IllegalArgumentException for all failures " + actual);
+                fail("Expecting an IllegalArgumentException for all failures " + actual);
             }
         }
     }

test/jdk/java/lang/invoke/unreflect/UnreflectTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -24,9 +24,10 @@
 /*
  * @test
  * @bug 8238358 8247444
- * @run testng/othervm UnreflectTest
  * @summary Test Lookup::unreflectSetter and Lookup::unreflectVarHandle on
  *          trusted final fields (declared in hidden classes and records)
+ * @run junit/othervm --enable-final-field-mutation=ALL-UNNAMED -DwriteAccess=true UnreflectTest
+ * @run junit/othervm --illegal-final-field-mutation=deny -DwriteAccess=false UnreflectTest
  */
 
 import java.io.IOException;
@@ -38,25 +39,25 @@ import java.lang.reflect.Field;
 import java.lang.reflect.Modifier;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.nio.file.Paths;
 
-import org.testng.annotations.Test;
-import static org.testng.Assert.*;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.BeforeAll;
+import static org.junit.jupiter.api.Assertions.*;
 
-public class UnreflectTest {
-    static final MethodHandles.Lookup LOOKUP = MethodHandles.lookup();
-    static final Class<?> hiddenClass = defineHiddenClass();
-    private static Class<?> defineHiddenClass() {
+class UnreflectTest {
+    static Class<?> hiddenClass;
+    static boolean writeAccess;
+
+    @BeforeAll
+    static void setup() throws Exception {
         String classes = System.getProperty("test.classes");
-        Path cf = Paths.get(classes, "Fields.class");
-        try {
+        Path cf = Path.of(classes, "Fields.class");
         byte[] bytes = Files.readAllBytes(cf);
-            return MethodHandles.lookup().defineHiddenClass(bytes, true).lookupClass();
-        } catch (IOException e) {
-            throw new UncheckedIOException(e);
-        } catch (IllegalAccessException e) {
-            throw new RuntimeException(e);
-        }
+        hiddenClass = MethodHandles.lookup().defineHiddenClass(bytes, true).lookupClass();
+
+        String s = System.getProperty("writeAccess");
+        assertNotNull(s);
+        writeAccess = Boolean.valueOf(s);
     }
 
     /*
@@ -64,7 +65,7 @@ public class UnreflectTest {
      * can write the value of a non-static final field in a normal class
      */
     @Test
-    public void testFieldsInNormalClass() throws Throwable {
+    void testFieldsInNormalClass() throws Throwable {
         // despite the name "HiddenClass", this class is loaded by the
         // class loader as non-hidden class
         Class<?> c = Fields.class;
@@ -72,7 +73,11 @@ public class UnreflectTest {
         assertFalse(c.isHidden());
         readOnlyAccessibleObject(c, "STATIC_FINAL", null, true);
         readWriteAccessibleObject(c, "STATIC_NON_FINAL", null, false);
+        if (writeAccess) {
             readWriteAccessibleObject(c, "FINAL", o, true);
+        } else {
+            readOnlyAccessibleObject(c, "FINAL", o, true);
+        }
         readWriteAccessibleObject(c, "NON_FINAL", o, false);
     }
 
@@ -81,7 +86,7 @@ public class UnreflectTest {
      * has NO write the value of a non-static final field in a hidden class
      */
     @Test
-    public void testFieldsInHiddenClass() throws Throwable {
+    void testFieldsInHiddenClass() throws Throwable {
         assertTrue(hiddenClass.isHidden());
         Object o = hiddenClass.newInstance();
         readOnlyAccessibleObject(hiddenClass, "STATIC_FINAL", null, true);
@@ -99,7 +104,8 @@ public class UnreflectTest {
      * Test Lookup::unreflectSetter and Lookup::unreflectVarHandle that
      * cannot write the value of a non-static final field in a record class
      */
-    public void testFieldsInRecordClass() throws Throwable {
+    @Test
+    void testFieldsInRecordClass() throws Throwable {
         assertTrue(TestRecord.class.isRecord());
         Object o = new TestRecord(1);
         readOnlyAccessibleObject(TestRecord.class, "STATIC_FINAL", null, true);
@@ -121,16 +127,12 @@ public class UnreflectTest {
         assertTrue(f.trySetAccessible());
 
         // Field object with read-only access
-        MethodHandle mh = LOOKUP.unreflectGetter(f);
+        MethodHandles.Lookup lookup = MethodHandles.lookup();
+        MethodHandle mh = lookup.unreflectGetter(f);
         Object value = Modifier.isStatic(modifier) ? mh.invoke() : mh.invoke(o);
         assertTrue(value == f.get(o));
-        try {
-            LOOKUP.unreflectSetter(f);
-            assertTrue(false, "should fail to unreflect a setter for " + name);
-        } catch (IllegalAccessException e) {
-        }
-
-        VarHandle vh = LOOKUP.unreflectVarHandle(f);
+        assertThrows(IllegalAccessException.class, () -> lookup.unreflectSetter(f));
+        VarHandle vh = lookup.unreflectVarHandle(f);
         if (isFinal) {
             assertFalse(vh.isAccessModeSupported(VarHandle.AccessMode.SET));
         } else {
@@ -163,7 +165,7 @@ public class UnreflectTest {
             throw e;
         }
 
-        VarHandle vh = LOOKUP.unreflectVarHandle(f);
+        VarHandle vh = MethodHandles.lookup().unreflectVarHandle(f);
         if (isFinal) {
             assertFalse(vh.isAccessModeSupported(VarHandle.AccessMode.SET));
         } else {

test/jdk/java/lang/reflect/AccessibleObject/HiddenClassTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -23,9 +23,9 @@
 
 /**
  * @test
- * @build Fields HiddenClassTest
- * @run testng/othervm HiddenClassTest
  * @summary Test java.lang.reflect.AccessibleObject with modules
+ * @run junit/othervm --enable-final-field-mutation=ALL-UNNAMED -DwriteAccess=true HiddenClassTest
+ * @run junit/othervm --illegal-final-field-mutation=deny -DwriteAccess=false HiddenClassTest
  */
 
 import java.io.IOException;
@@ -37,22 +37,24 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 
-import org.testng.annotations.Test;
-import static org.testng.Assert.*;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.BeforeAll;
+import static org.junit.jupiter.api.Assertions.*;
 
-public class HiddenClassTest {
-    static final Class<?> hiddenClass = defineHiddenClass();
-    private static Class<?> defineHiddenClass() {
+class HiddenClassTest {
+    static Class<?> hiddenClass;
+    static boolean writeAccess;
+
+    @BeforeAll
+    static void setup() throws Exception {
         String classes = System.getProperty("test.classes");
-        Path cf = Paths.get(classes, "Fields.class");
-        try {
+        Path cf = Path.of(classes, "Fields.class");
         byte[] bytes = Files.readAllBytes(cf);
-            return MethodHandles.lookup().defineHiddenClass(bytes, true).lookupClass();
-        } catch (IOException e) {
-            throw new UncheckedIOException(e);
-        } catch (IllegalAccessException e) {
-            throw new RuntimeException(e);
-        }
+        hiddenClass = MethodHandles.lookup().defineHiddenClass(bytes, true).lookupClass();
+
+        String s = System.getProperty("writeAccess");
+        assertNotNull(s);
+        writeAccess = Boolean.valueOf(s);
     }
 
     /*
@@ -60,7 +62,7 @@ public class HiddenClassTest {
      * in a normal class
      */
     @Test
-    public void testFieldsInNormalClass() throws Throwable {
+    void testFieldsInNormalClass() throws Throwable {
         // despite the name "HiddenClass", this class is loaded by the
         // class loader as non-hidden class
         Class<?> c = Fields.class;
@@ -68,7 +70,11 @@ public class HiddenClassTest {
         assertFalse(c.isHidden());
         readOnlyAccessibleObject(c, "STATIC_FINAL", null, true);
         readWriteAccessibleObject(c, "STATIC_NON_FINAL", null, false);
+        if (writeAccess) {
             readWriteAccessibleObject(c, "FINAL", o, true);
+        } else {
+            readOnlyAccessibleObject(c, "FINAL", o, true);
+        }
         readWriteAccessibleObject(c, "NON_FINAL", o, false);
     }
 
@@ -77,7 +83,7 @@ public class HiddenClassTest {
      * in a hidden class
      */
     @Test
-    public void testFieldsInHiddenClass() throws Throwable {
+    void testFieldsInHiddenClass() throws Throwable {
         assertTrue(hiddenClass.isHidden());
         Object o = hiddenClass.newInstance();
         readOnlyAccessibleObject(hiddenClass, "STATIC_FINAL", null, true);
@@ -96,11 +102,7 @@ public class HiddenClassTest {
         }
         assertTrue(f.trySetAccessible());
         assertTrue(f.get(o) != null);
-        try {
-            f.set(o, null);
-            assertTrue(false, "should fail to set " + name);
-        } catch (IllegalAccessException e) {
-        }
+        assertThrows(IllegalAccessException.class, () -> f.set(o, null));
     }
 
     private static void readWriteAccessibleObject(Class<?> c, String name, Object o, boolean isFinal) throws Exception {
@@ -113,10 +115,6 @@ public class HiddenClassTest {
         }
         assertTrue(f.trySetAccessible());
         assertTrue(f.get(o) != null);
-        try {
         f.set(o, null);
-        } catch (IllegalAccessException e) {
-            throw e;
-        }
     }
 }

test/jdk/java/lang/reflect/Field/NegativeTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -24,9 +24,9 @@
 /**
  * @test
  * @bug 8277451
- * @run testng NegativeTest
  * @summary Test exception thrown due to bad receiver and bad value on
  *          Field with and without setAccessible(true)
+ * @run testng/othervm --enable-final-field-mutation=ALL-UNNAMED NegativeTest
  */
 
 import java.lang.reflect.Field;

test/jdk/java/lang/reflect/Field/Set.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2004, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,6 +26,7 @@
  * @bug 4250960 5044412
  * @summary Should not be able to set final fields through reflection unless setAccessible(true) passes and is not static
  * @author David Bowen (modified by Doug Lea)
+ * @run main/othervm --enable-final-field-mutation=ALL-UNNAMED Set
 */
 
 import java.lang.reflect.*;

test/jdk/java/lang/reflect/Field/mutateFinals/FinalFieldMutationEventTest.java

@@ -0,0 +1,203 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8353835
+ * @summary Basic test for JFR FinalFieldMutation event
+ * @requires vm.hasJFR
+ * @modules jdk.jfr/jdk.jfr.events
+ * @run junit FinalFieldMutationEventTest
+ * @run junit/othervm --illegal-final-field-mutation=allow FinalFieldMutationEventTest
+ * @run junit/othervm --illegal-final-field-mutation=warn FinalFieldMutationEventTest
+ * @run junit/othervm --illegal-final-field-mutation=debug FinalFieldMutationEventTest
+ * @run junit/othervm --illegal-final-field-mutation=deny FinalFieldMutationEventTest
+ */
+
+import java.lang.annotation.Annotation;
+import java.lang.invoke.MethodHandles;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.stream.Stream;
+import jdk.jfr.Recording;
+import jdk.jfr.consumer.RecordedClass;
+import jdk.jfr.consumer.RecordedEvent;
+import jdk.jfr.consumer.RecordedMethod;
+import jdk.jfr.consumer.RecordingFile;
+import jdk.jfr.events.FinalFieldMutationEvent;
+import jdk.jfr.events.StackFilter;
+
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
+class FinalFieldMutationEventTest {
+    private static final String EVENT_NAME = "jdk.FinalFieldMutation";
+
+    /**
+     * Test class with final field.
+     */
+    private static class C {
+        final int value;
+        C(int value) {
+            this.value = value;
+        }
+    }
+
+    /**
+     * Test jdk.FinalFieldMutation is recorded when mutating a final field.
+     */
+    @Test
+    void testFieldSet() throws Exception {
+        Field field = C.class.getDeclaredField("value");
+        field.setAccessible(true);
+
+        try (Recording recording = new Recording()) {
+            recording.enable(EVENT_NAME).withStackTrace();
+
+            boolean mutated = false;
+            recording.start();
+            try {
+                var obj = new C(100);
+                try {
+                    field.setInt(obj, 200);
+                    mutated = true;
+                } catch (IllegalAccessException e) {
+                    // denied
+                }
+            } finally {
+                recording.stop();
+            }
+
+            // FinalFieldMutation event should be recorded if field mutated
+            List<RecordedEvent> events = find(recording, EVENT_NAME);
+            System.err.println(events);
+            if (mutated) {
+                assertEquals(1, events.size(), "1 event expected");
+                checkEvent(events.get(0), field, "FinalFieldMutationEventTest::testFieldSet");
+            } else {
+                assertEquals(0, events.size(), "No events expected");
+            }
+        }
+    }
+
+    /**
+     * Test jdk.FinalFieldMutation is recorded when unreflecting a field field for mutation.
+     */
+    @Test
+    void testUnreflectSetter() throws Exception {
+        Field field = C.class.getDeclaredField("value");
+        field.setAccessible(true);
+
+        try (Recording recording = new Recording()) {
+            recording.enable(EVENT_NAME).withStackTrace();
+
+            boolean unreflected = false;
+            recording.start();
+            try {
+                MethodHandles.lookup().unreflectSetter(field);
+                unreflected = true;
+            } catch (IllegalAccessException e) {
+                // denied
+            } finally {
+                recording.stop();
+            }
+
+            // FinalFieldMutation event should be recorded if field unreflected for set
+            List<RecordedEvent> events = find(recording, EVENT_NAME);
+            System.err.println(events);
+            if (unreflected) {
+                assertEquals(1, events.size(), "1 event expected");
+                checkEvent(events.get(0), field, "FinalFieldMutationEventTest::testUnreflectSetter");
+            } else {
+                assertEquals(0, events.size(), "No events expected");
+            }
+        }
+    }
+
+    /**
+     * Test that a FinalFieldMutationEvent event has the declaringClass and fieldName of
+     * the given Field, and the expected top frame.
+     */
+    private void checkEvent(RecordedEvent e, Field f, String expectedTopFrame) {
+        RecordedClass clazz = e.getClass("declaringClass");
+        assertNotNull(clazz);
+        assertEquals(f.getDeclaringClass().getName(), clazz.getName());
+        assertEquals(f.getName(), e.getString("fieldName"));
+
+        // check the top-frame of the stack trace
+        RecordedMethod m = e.getStackTrace().getFrames().getFirst().getMethod();
+        assertEquals(expectedTopFrame, m.getType().getName() + "::" + m.getName());
+    }
+
+    /**
+     * Tests that FinalFieldMutationEvent's stack filter value names classes/methods that
+     * exist. This will help detect stale values when the implementation is refactored.
+     */
+    @Test
+    void testFinalFieldMutationEventStackFilter() throws Exception {
+        String[] filters = FinalFieldMutationEvent.class.getAnnotation(StackFilter.class).value();
+        for (String filter : filters) {
+            String[] classAndMethod = filter.split("::");
+            String cn = classAndMethod[0];
+
+            // throws if class not found
+            Class<?> clazz = Class.forName(cn);
+
+            // if the filter has a method name then check a method of that name exists
+            if (classAndMethod.length > 1) {
+                String mn = classAndMethod[1];
+                Method method = Stream.of(clazz.getDeclaredMethods())
+                        .filter(m -> m.getName().equals(mn))
+                        .findFirst()
+                        .orElse(null);
+                assertNotNull(method, cn + "::" + mn + " not found");
+            }
+        }
+    }
+
+    /**
+     * Returns the list of events in the given recording with the given name.
+     */
+    private List<RecordedEvent> find(Recording recording, String name) throws Exception {
+        Path recordingFile = recordingFile(recording);
+        return RecordingFile.readAllEvents(recordingFile)
+                .stream()
+                .filter(e -> e.getEventType().getName().equals(name))
+                .toList();
+    }
+
+    /**
+     * Return the file path to the recording file.
+     */
+    private Path recordingFile(Recording recording) throws Exception {
+        Path recordingFile = recording.getDestination();
+        if (recordingFile == null) {
+            ProcessHandle h = ProcessHandle.current();
+            recordingFile = Path.of("recording-" + recording.getId() + "-pid" + h.pid() + ".jfr");
+            recording.dump(recordingFile);
+        }
+        return recordingFile;
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/MutateFinalsTest.java

@@ -0,0 +1,358 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8353835
+ * @summary Test Field.set and Lookup.unreflectSetter on final instance fields
+ * @run junit/othervm -DwriteAccess=true MutateFinalsTest
+ * @run junit/othervm --enable-final-field-mutation=ALL-UNNAMED -DwriteAccess=true MutateFinalsTest
+ * @run junit/othervm --illegal-final-field-mutation=allow -DwriteAccess=true MutateFinalsTest
+ * @run junit/othervm --illegal-final-field-mutation=warn -DwriteAccess=true MutateFinalsTest
+ * @run junit/othervm --illegal-final-field-mutation=debug -DwriteAccess=true MutateFinalsTest
+ * @run junit/othervm --illegal-final-field-mutation=deny -DwriteAccess=false MutateFinalsTest
+ */
+
+import java.lang.invoke.MethodHandles;
+import java.lang.reflect.Field;
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
+class MutateFinalsTest {
+    static boolean writeAccess;
+
+    @BeforeAll
+    static void setup() throws Exception {
+        String s = System.getProperty("writeAccess");
+        assertNotNull(s);
+        writeAccess = Boolean.valueOf(s);
+    }
+
+    @Test
+    void testFieldSet() throws Exception {
+        class C {
+            final String value;
+            C(String value) {
+                this.value = value;
+            }
+        }
+        Field f = C.class.getDeclaredField("value");
+
+        String oldValue = "oldValue";
+        String newValue = "newValue";
+        var obj = new C(oldValue);
+
+        f.setAccessible(false);
+        assertThrows(NullPointerException.class, () -> f.set(null, newValue));
+        assertThrows(IllegalAccessException.class, () -> f.set(obj, newValue));
+        assertTrue(obj.value == oldValue);
+
+        f.setAccessible(true);
+        assertThrows(NullPointerException.class, () -> f.set(null, newValue));
+        if (writeAccess) {
+            assertThrows(IllegalArgumentException.class, () -> f.set("not a C", newValue));
+            assertThrows(IllegalArgumentException.class, () -> f.set(obj, 100)); // not a string
+            f.set(obj, newValue);
+            assertTrue(obj.value == newValue);
+        } else {
+            assertThrows(IllegalAccessException.class, () -> f.set(obj, newValue));
+            assertTrue(obj.value == oldValue);
+        }
+    }
+
+    @Test
+    void testFieldSetBoolean() throws Throwable {
+        class C {
+            final boolean value;
+            C(boolean value) {
+                this.value = value;
+            }
+        }
+        Field f = C.class.getDeclaredField("value");
+
+        boolean oldValue = false;
+        boolean newValue = true;
+        var obj = new C(oldValue);
+
+        f.setAccessible(false);
+        assertThrows(NullPointerException.class, () -> f.setBoolean(null, newValue));
+        assertThrows(IllegalAccessException.class, () -> f.setBoolean(obj, newValue));
+        assertTrue(obj.value == oldValue);
+
+        f.setAccessible(true);
+        assertThrows(NullPointerException.class, () -> f.setBoolean(null, newValue));
+        if (writeAccess) {
+            assertThrows(IllegalArgumentException.class, () -> f.setBoolean("not a C", newValue));
+            f.setBoolean(obj, newValue);
+            assertTrue(obj.value == newValue);
+        } else {
+            assertThrows(IllegalAccessException.class, () -> f.setBoolean(obj, newValue));
+            assertTrue(obj.value == oldValue);
+        }
+    }
+
+    @Test
+    void testFieldSetByte() throws Exception {
+        class C {
+            final byte value;
+            C(byte value) {
+                this.value = value;
+            }
+        }
+        Field f = C.class.getDeclaredField("value");
+
+        byte oldValue = (byte) 1;
+        byte newValue = (byte) 2;
+        var obj = new C(oldValue);
+
+        f.setAccessible(false);
+        assertThrows(NullPointerException.class, () -> f.setByte(null, newValue));
+        assertThrows(IllegalAccessException.class, () -> f.setByte(obj, newValue));
+        assertTrue(obj.value == oldValue);
+
+        f.setAccessible(true);
+        assertThrows(NullPointerException.class, () -> f.setByte(null, newValue));
+        if (writeAccess) {
+            assertThrows(IllegalArgumentException.class, () -> f.setByte("not a C", newValue));
+            f.setByte(obj, newValue);
+            assertTrue(obj.value == newValue);
+        } else {
+            assertThrows(IllegalAccessException.class, () -> f.setByte(obj, newValue));
+            assertTrue(obj.value == oldValue);
+        }
+    }
+
+    @Test
+    void testFieldSetChar() throws Exception {
+        class C {
+            final char value;
+            C(char value) {
+                this.value = value;
+            }
+        }
+        Field f = C.class.getDeclaredField("value");
+
+        char oldValue = 'A';
+        char newValue = 'B';
+        var obj = new C(oldValue);
+
+        f.setAccessible(false);
+        assertThrows(NullPointerException.class, () -> f.setChar(null, newValue));
+        assertThrows(IllegalAccessException.class, () -> f.setChar(obj, newValue));
+        assertTrue(obj.value == oldValue);
+
+        f.setAccessible(true);
+        assertThrows(NullPointerException.class, () -> f.setChar(null, newValue));
+        if (writeAccess) {
+            assertThrows(IllegalArgumentException.class, () -> f.setChar("not a C", newValue));
+            f.setChar(obj, newValue);
+            assertTrue(obj.value == newValue);
+        } else {
+            assertThrows(IllegalAccessException.class, () -> f.setChar(obj, newValue));
+            assertTrue(obj.value == oldValue);
+        }
+    }
+
+    @Test
+    void testFieldSetShort() throws Exception {
+        class C {
+            final short value;
+            C(short value) {
+                this.value = value;
+            }
+        }
+        Field f = C.class.getDeclaredField("value");
+
+        short oldValue = (short) 1;
+        short newValue = (short) 2;
+        var obj = new C(oldValue);
+
+        f.setAccessible(false);
+        assertThrows(NullPointerException.class, () -> f.setShort(null, newValue));
+        assertThrows(IllegalAccessException.class, () -> f.setShort(obj, newValue));
+        assertTrue(obj.value == oldValue);
+
+        f.setAccessible(true);
+        assertThrows(NullPointerException.class, () -> f.setShort(null, newValue));
+        if (writeAccess) {
+            assertThrows(IllegalArgumentException.class, () -> f.setShort("not a C", newValue));
+            f.setShort(obj, newValue);
+            assertTrue(obj.value == newValue);
+        } else {
+            assertThrows(IllegalAccessException.class, () -> f.setShort(obj, newValue));
+            assertTrue(obj.value == oldValue);
+        }
+    }
+
+    @Test
+    void testFieldSetInt() throws Exception {
+        class C {
+            final int value;
+            C(int value) {
+                this.value = value;
+            }
+        }
+        Field f = C.class.getDeclaredField("value");
+
+        int oldValue = 1;
+        int newValue = 2;
+        var obj = new C(oldValue);
+
+        f.setAccessible(false);
+        assertThrows(NullPointerException.class, () -> f.setInt(null, newValue));
+        assertThrows(IllegalAccessException.class, () -> f.setInt(obj, newValue));
+        assertTrue(obj.value == oldValue);
+
+        f.setAccessible(true);
+        assertThrows(NullPointerException.class, () -> f.setInt(null, newValue));
+        if (writeAccess) {
+            assertThrows(IllegalArgumentException.class, () -> f.setInt("not a C", newValue));
+            f.setInt(obj, newValue);
+            assertTrue(obj.value == newValue);
+        } else {
+            assertThrows(IllegalAccessException.class, () -> f.setInt(obj, newValue));
+            assertTrue(obj.value == oldValue);
+        }
+    }
+
+    @Test
+    void testFieldSetLong() throws Exception {
+        class C {
+            final long value;
+            C(long value) {
+                this.value = value;
+            }
+        }
+        Field f = C.class.getDeclaredField("value");
+
+        long oldValue = 1L;
+        long newValue = 2L;
+        var obj = new C(oldValue);
+
+        f.setAccessible(false);
+        assertThrows(NullPointerException.class, () -> f.setLong(null, newValue));
+        assertThrows(IllegalAccessException.class, () -> f.setLong(obj, newValue));
+        assertTrue(obj.value == oldValue);
+
+        f.setAccessible(true);
+        assertThrows(NullPointerException.class, () -> f.setLong(null, newValue));
+        if (writeAccess) {
+            assertThrows(IllegalArgumentException.class, () -> f.setLong("not a C", newValue));
+            f.setLong(obj, newValue);
+            assertTrue(obj.value == newValue);
+        } else {
+            assertThrows(IllegalAccessException.class, () -> f.setLong(obj, newValue));
+            assertTrue(obj.value == oldValue);
+        }
+    }
+
+    @Test
+    void testFieldSetFloat() throws Exception {
+        class C {
+            final float value;
+            C(float value) {
+                this.value = value;
+            }
+        }
+        Field f = C.class.getDeclaredField("value");
+
+        float oldValue = 1.0f;
+        float newValue = 2.0f;
+        var obj = new C(oldValue);
+
+        f.setAccessible(false);
+        assertThrows(NullPointerException.class, () -> f.setFloat(null, newValue));
+        assertThrows(IllegalAccessException.class, () -> f.setFloat(obj, newValue));
+        assertTrue(obj.value == oldValue);
+
+        f.setAccessible(true);
+        assertThrows(NullPointerException.class, () -> f.setFloat(null, newValue));
+        if (writeAccess) {
+            assertThrows(IllegalArgumentException.class, () -> f.setFloat("not a C", newValue));
+            f.setFloat(obj, newValue);
+            assertTrue(obj.value == newValue);
+        } else {
+            assertThrows(IllegalAccessException.class, () -> f.setFloat(obj, newValue));
+            assertTrue(obj.value == oldValue);
+        }
+    }
+
+    @Test
+    void testFieldSetDouble() throws Exception {
+        class C {
+            final double value;
+            C(double value) {
+                this.value = value;
+            }
+        }
+        Field f = C.class.getDeclaredField("value");
+
+        double oldValue = 1.0d;
+        double newValue = 2.0d;
+        var obj = new C(oldValue);
+
+        f.setAccessible(false);
+        assertThrows(NullPointerException.class, () -> f.setDouble(null, newValue));
+        assertThrows(IllegalAccessException.class, () -> f.setDouble(obj, newValue));
+        assertTrue(obj.value == oldValue);
+
+        f.setAccessible(true);
+        assertThrows(NullPointerException.class, () -> f.setDouble(null, newValue));
+        if (writeAccess) {
+            assertThrows(IllegalArgumentException.class, () -> f.setDouble("not a C", newValue));
+            f.setDouble(obj, newValue);
+            assertTrue(obj.value == newValue);
+        } else {
+            assertThrows(IllegalAccessException.class, () -> f.setDouble(obj, newValue));
+            assertTrue(obj.value == oldValue);
+        }
+    }
+
+    @Test
+    void testUnreflectSetter() throws Throwable {
+        class C {
+            final Object value;
+            C(Object value) {
+                this.value = value;
+            }
+        }
+        Field f = C.class.getDeclaredField("value");
+
+        Object oldValue = new Object();
+        var obj = new C(oldValue);
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> MethodHandles.lookup().unreflectSetter(f));
+
+        f.setAccessible(true);
+        if (writeAccess) {
+            Object newValue = new Object();
+            MethodHandles.lookup().unreflectSetter(f).invoke(obj, newValue);
+            assertTrue(obj.value == newValue);
+        } else {
+            assertThrows(IllegalAccessException.class, () -> MethodHandles.lookup().unreflectSetter(f));
+        }
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/cli/CommandLineTest.java

@@ -0,0 +1,294 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8353835
+ * @summary Test the command line option --enable-final-field-mutation
+ * @library /test/lib
+ * @build CommandLineTestHelper
+ * @run junit CommandLineTest
+ */
+
+import java.util.regex.Pattern;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import static org.junit.jupiter.api.Assertions.*;
+
+import jdk.test.lib.process.ProcessTools;
+import jdk.test.lib.process.OutputAnalyzer;
+
+class CommandLineTest {
+
+    // helper class name
+    private static final String HELPER = "CommandLineTestHelper";
+
+    // warning output
+    private static final String WARNING_LINE1 =
+            "WARNING: Final field value in class " + HELPER;
+    private static final String WARNING_LINE3 =
+            "WARNING: Use --enable-final-field-mutation=ALL-UNNAMED to avoid a warning";
+    private static final String WARNING_LINE4 =
+            "WARNING: Mutating final fields will be blocked in a future release unless final field mutation is enabled";
+
+    // warning line 2 depends on the method
+    private static final String WARNING_MUTATED =
+            " has been mutated reflectively by class " + HELPER + " in unnamed module";
+    private static final String WARNING_UNREFLECTED =
+            " has been unreflected for mutation by class " + HELPER + " in unnamed module";
+
+    /**
+     * Test that a warning is printed by default.
+     */
+    @Test
+    void testDefault() throws Exception {
+        test("testFieldSetInt")
+            .shouldContain(WARNING_LINE1)
+            .shouldContain(WARNING_MUTATED)
+            .shouldContain(WARNING_LINE3)
+            .shouldContain(WARNING_LINE4)
+            .shouldHaveExitValue(0);
+
+        test("testUnreflectSetter")
+            .shouldContain(WARNING_LINE1)
+            .shouldContain(WARNING_UNREFLECTED)
+            .shouldContain(WARNING_LINE3)
+            .shouldContain(WARNING_LINE4)
+            .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Test allow mutation of finals.
+     */
+    @Test
+    void testAllow() throws Exception {
+        test("testFieldSetInt", "--illegal-final-field-mutation=allow")
+            .shouldNotContain(WARNING_LINE1)
+            .shouldNotContain(WARNING_MUTATED)
+            .shouldHaveExitValue(0);
+
+        test("testFieldSetInt", "--enable-final-field-mutation=ALL-UNNAMED")
+            .shouldNotContain(WARNING_LINE1)
+            .shouldNotContain(WARNING_MUTATED)
+            .shouldHaveExitValue(0);
+
+        // allow ALL-UNNAMED, deny by default
+        test("testFieldSetInt", "--enable-final-field-mutation=ALL-UNNAMED", "--illegal-final-field-mutation=deny")
+            .shouldNotContain(WARNING_LINE1)
+            .shouldNotContain(WARNING_MUTATED)
+            .shouldHaveExitValue(0);
+
+        test("testUnreflectSetter", "--illegal-final-field-mutation=allow")
+            .shouldNotContain(WARNING_LINE1)
+            .shouldNotContain(WARNING_UNREFLECTED)
+            .shouldHaveExitValue(0);
+
+        test("testUnreflectSetter", "--enable-final-field-mutation=ALL-UNNAMED")
+            .shouldNotContain(WARNING_LINE1)
+            .shouldNotContain(WARNING_UNREFLECTED)
+            .shouldHaveExitValue(0);
+
+        // allow ALL-UNNAMED, deny by default
+        test("testUnreflectSetter", "--enable-final-field-mutation=ALL-UNNAMED", "--illegal-final-field-mutation=deny")
+            .shouldNotContain(WARNING_LINE1)
+            .shouldNotContain(WARNING_UNREFLECTED)
+            .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Test warn on first mutation or unreflect of a final field.
+     */
+    @Test
+    void testWarn() throws Exception {
+        test("testFieldSetInt", "--illegal-final-field-mutation=warn")
+            .shouldContain(WARNING_LINE1)
+            .shouldContain(WARNING_MUTATED)
+            .shouldContain(WARNING_LINE3)
+            .shouldContain(WARNING_LINE4)
+            .shouldHaveExitValue(0);
+
+        test("testUnreflectSetter", "--illegal-final-field-mutation=warn")
+            .shouldContain(WARNING_LINE1)
+            .shouldContain(WARNING_UNREFLECTED)
+            .shouldContain(WARNING_LINE3)
+            .shouldContain(WARNING_LINE4)
+            .shouldHaveExitValue(0);
+
+        // should be one warning only, for Field.set
+        var output = test("testFieldSetInt+testUnreflectSetter", "--illegal-final-field-mutation=warn")
+            .shouldContain(WARNING_MUTATED)
+            .shouldNotContain(WARNING_UNREFLECTED)
+            .shouldHaveExitValue(0)
+            .getOutput();
+        assertEquals(1, countStrings(output, WARNING_LINE1));
+        assertEquals(1, countStrings(output, WARNING_LINE3));
+        assertEquals(1, countStrings(output, WARNING_LINE4));
+
+        // should be one warning only, for Lookup.unreflectSetter
+        output = test("testUnreflectSetter+testFieldSetInt", "--illegal-final-field-mutation=warn")
+            .shouldNotContain(WARNING_MUTATED)
+            .shouldContain(WARNING_UNREFLECTED)
+            .shouldHaveExitValue(0)
+            .getOutput();
+        assertEquals(1, countStrings(output, WARNING_LINE1));
+        assertEquals(1, countStrings(output, WARNING_LINE3));
+        assertEquals(1, countStrings(output, WARNING_LINE4));
+    }
+
+    /**
+     * Test debug mode.
+     */
+    @Test
+    void testDebug() throws Exception {
+        test("testFieldSetInt+testUnreflectSetter", "--illegal-final-field-mutation=debug")
+            .shouldContain("Final field value in class " + HELPER)
+            .shouldContain(WARNING_MUTATED)
+            .shouldContain("java.lang.reflect.Field.setInt")
+            .shouldContain(WARNING_UNREFLECTED)
+            .shouldContain("java.lang.invoke.MethodHandles$Lookup.unreflectSetter")
+            .shouldHaveExitValue(0);
+
+        test("testUnreflectSetter+testFieldSetInt", "--illegal-final-field-mutation=debug")
+            .shouldContain("Final field value in class " + HELPER)
+            .shouldContain(WARNING_UNREFLECTED)
+            .shouldContain("java.lang.invoke.MethodHandles$Lookup.unreflectSetter")
+            .shouldContain(WARNING_MUTATED)
+            .shouldContain("java.lang.reflect.Field.setInt")
+            .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Test deny mutation of finals.
+     */
+    @Test
+    void testDeny() throws Exception {
+        test("testFieldSetInt", "--illegal-final-field-mutation=deny")
+            .shouldNotContain(WARNING_LINE1)
+            .shouldNotContain(WARNING_MUTATED)
+            .shouldContain("java.lang.IllegalAccessException")
+            .shouldNotHaveExitValue(0);
+
+        test("testUnreflectSetter", "--illegal-final-field-mutation=deny")
+            .shouldNotContain(WARNING_LINE1)
+            .shouldNotContain(WARNING_UNREFLECTED)
+            .shouldContain("java.lang.IllegalAccessException")
+            .shouldNotHaveExitValue(0);
+    }
+
+    /**
+     * Test last usage of --illegal-final-field-mutation "wins".
+     */
+    @Test
+    void testLastOneWins() throws Exception {
+        test("testFieldSetInt", "--illegal-final-field-mutation=allow", "--illegal-final-field-mutation=deny")
+            .shouldNotContain(WARNING_LINE1)
+            .shouldNotContain(WARNING_MUTATED)
+            .shouldContain("java.lang.IllegalAccessException")
+            .shouldNotHaveExitValue(0);
+
+        test("testFieldSetInt", "--illegal-final-field-mutation=deny", "--illegal-final-field-mutation=warn")
+            .shouldContain(WARNING_LINE1)
+            .shouldContain(WARNING_MUTATED)
+            .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Test --illegal-final-field-mutation with bad values.
+     */
+    @ParameterizedTest
+    @ValueSource(strings = { "", "bad" })
+    void testInvalidValues(String value) throws Exception {
+        test("testFieldSetInt", "--illegal-final-field-mutation=" + value)
+            .shouldContain("Value specified to --illegal-final-field-mutation not recognized")
+            .shouldNotHaveExitValue(0);
+    }
+
+    /**
+     * Test setting the internal system properties (that correspond to the command line
+     * options) on the commannd line. They should be ignored.
+     */
+    @Test
+    void testSetPropertyOnCommandLine() throws Exception {
+        // --enable-final-field-mutation=ALL-UNNAMED
+        test("testFieldSetInt", "-Djdk.module.enable.final.field.mutation.0=ALL-UNNAMED")
+                .shouldContain(WARNING_LINE1)
+                .shouldContain(WARNING_MUTATED)
+                .shouldContain(WARNING_LINE3)
+                .shouldContain(WARNING_LINE4)
+                .shouldHaveExitValue(0);
+
+        // --illegal-final-field-mutation=allow
+        test("testFieldSetInt", "-Djdk.module.illegal.final.field.mutation=allow")
+                .shouldContain(WARNING_LINE1)
+                .shouldContain(WARNING_MUTATED)
+                .shouldContain(WARNING_LINE3)
+                .shouldContain(WARNING_LINE4)
+                .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Test setting the internal system properties (that correspond to the command line
+     * options) at runtime. They should be ignored.
+     */
+    @Test
+    void testSetPropertyAtRuntime() throws Exception {
+        // --enable-final-field-mutation=ALL-UNNAMED
+        test("setPropertyIllegalFinalFieldMutationAllow+testFieldSetInt")
+            .shouldContain(WARNING_LINE1)
+            .shouldContain(WARNING_MUTATED)
+            .shouldContain(WARNING_LINE3)
+            .shouldContain(WARNING_LINE4)
+            .shouldHaveExitValue(0);
+
+        // --illegal-final-field-mutation=allow
+        test("setPropertyEnableFinalFieldMutationAllUnnamed+testFieldSetInt")
+                .shouldContain(WARNING_LINE1)
+                .shouldContain(WARNING_MUTATED)
+                .shouldContain(WARNING_LINE3)
+                .shouldContain(WARNING_LINE4)
+                .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Launch helper with the given arguments and VM options.
+     */
+    private OutputAnalyzer test(String action, String... vmopts) throws Exception {
+        Stream<String> s1 = Stream.of(vmopts);
+        Stream<String> s2 = Stream.of(HELPER, action);
+        String[] opts = Stream.concat(s1, s2).toArray(String[]::new);
+        var outputAnalyzer = ProcessTools
+                .executeTestJava(opts)
+                .outputTo(System.err)
+                .errorTo(System.err);
+        return outputAnalyzer;
+    }
+
+    /**
+     * Counts the number of substrings in the given input string.
+     */
+    private int countStrings(String input, String substring) {
+        return input.split(Pattern.quote(substring)).length - 1;
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/cli/CommandLineTestHelper.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.lang.invoke.MethodHandles;
+
+public class CommandLineTestHelper {
+
+    /**
+     * The argument is a list of names of no-arg static methods in this class to invoke.
+     * The names are separated with a '+'.
+     */
+    public static void main(String[] args) throws Exception {
+        String[] methodNames = args.length > 0 ? args[0].split("\\+") : new String[0];
+        for (String methodName : methodNames) {
+            Method m = CommandLineTestHelper.class.getDeclaredMethod(methodName);
+            m.invoke(null);
+        }
+    }
+
+    static void testFieldSetInt() throws Exception {
+        class C {
+            final int value;
+            C(int value) {
+                this.value = value;
+            }
+        }
+        Field f = C.class.getDeclaredField("value");
+        f.setAccessible(true);
+        var obj = new C(100);
+        f.setInt(obj, 200);
+        if (obj.value != 200) {
+            throw new RuntimeException("Unexpected value: " + obj.value);
+        }
+    }
+
+    static void testUnreflectSetter() throws Throwable {
+        class C {
+            final int value;
+            C(int value) {
+                this.value = value;
+            }
+        }
+        Field f = C.class.getDeclaredField("value");
+        f.setAccessible(true);
+        var obj = new C(100);
+        MethodHandles.lookup().unreflectSetter(f).invoke(obj, 200);
+        if (obj.value != 200) {
+            throw new RuntimeException("Unexpected value: " + obj.value);
+        }
+    }
+
+    /**
+     * Set the internal system property that corresponds to the first usage of
+     * --enable-final-field-mutation.
+     */
+    static void setPropertyEnableFinalFieldMutationAllUnnamed() {
+        System.setProperty("jdk.module.enable.final.field.mutation.0", "ALL-UNNAMED");
+    }
+
+    /**
+     * Set the internal system property that corresponds to --illegal-final-field-mutation.
+     */
+    static void setPropertyIllegalFinalFieldMutationAllow() {
+        System.setProperty("jdk.module.illegal.final.field.mutation", "allow");
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/jar/ExecutableJarTest.java

@@ -0,0 +1,227 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8353835
+ * @summary Test the executable JAR file attribute Enable-Final-Field-Mutation
+ * @library /test/lib
+ * @build m/*
+ * @build ExecutableJarTestHelper jdk.test.lib.util.JarUtils
+ * @run junit ExecutableJarTest
+ */
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Map;
+import java.util.stream.Stream;
+import java.util.jar.Attributes;
+import java.util.jar.Manifest;
+
+import jdk.test.lib.process.ProcessTools;
+import jdk.test.lib.process.OutputAnalyzer;
+import jdk.test.lib.util.JarUtils;
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import static org.junit.jupiter.api.Assertions.*;
+
+class ExecutableJarTest {
+
+    // helper class name
+    private static final String HELPER = "ExecutableJarTestHelper";
+
+    // warning output
+    private static final String WARNING_LINE1 =
+            "WARNING: Final field value in class " + HELPER;
+
+    // warning line 2 depends on the method
+    private static final String WARNING_MUTATED =
+            " has been mutated reflectively by class " + HELPER + " in unnamed module";
+    private static final String WARNING_UNREFLECTED =
+            " has been unreflected for mutation by class " + HELPER + " in unnamed module";
+
+    /**
+     * Test executable JAR with code that uses Field.set to mutate a final field.
+     * A warning should be printed.
+     */
+    @Test
+    void testFieldSetExpectingWarning() throws Exception {
+        String jarFile = createExecutableJar(Map.of());
+        testExecutableJar(jarFile, "testFieldSetInt")
+                .shouldContain(WARNING_LINE1)
+                .shouldContain(WARNING_MUTATED)
+                .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Test executable JAR with code that uses Lookup.unreflectSetter to get MH to a
+     * final field. A warning should be printed.
+     */
+    @Test
+    void testUnreflectExpectingWarning() throws Exception {
+        String jarFile = createExecutableJar(Map.of());
+        testExecutableJar(jarFile, "testUnreflectSetter")
+                .shouldContain(WARNING_LINE1)
+                .shouldContain(WARNING_UNREFLECTED)
+                .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Test executable JAR with Enable-Final-Field-Mutation attribute and code that uses
+     * Field.set to mutate a final field. No warning should be printed.
+     */
+    @Test
+    void testFieldSetExpectingAllow() throws Exception {
+        String jarFile = createExecutableJar(Map.of("Enable-Final-Field-Mutation", "ALL-UNNAMED"));
+        testExecutableJar(jarFile, "testFieldSetInt")
+                .shouldNotContain(WARNING_LINE1)
+                .shouldNotContain(WARNING_MUTATED)
+                .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Test executable JAR with Enable-Final-Field-Mutation attribute and code that uses
+     * Lookup.unreflectSetter to get MH to a final field. No warning should be printed.
+     */
+    @Test
+    void testUnreflectExpectingAllow() throws Exception {
+        String jarFile = createExecutableJar(Map.of("Enable-Final-Field-Mutation", "ALL-UNNAMED"));
+        testExecutableJar(jarFile, "testUnreflectSetter")
+                .shouldNotContain(WARNING_LINE1)
+                .shouldNotContain(WARNING_UNREFLECTED)
+                .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Test executable JAR with Enable-Final-Field-Mutation attribute and code that uses
+     * Field.set to mutate a final field of class in a named module. The package is opened
+     * with --add-open.
+     */
+    @Test
+    void testFieldSetWithAddOpens1() throws Exception {
+        String jarFile = createExecutableJar(Map.of(
+                "Enable-Final-Field-Mutation", "ALL-UNNAMED"));
+        testExecutableJar(jarFile, "testFieldInNamedModule",
+                "--illegal-final-field-mutation=deny",
+                "--module-path", modulePath(),
+                "--add-modules", "m",
+                "--add-opens", "m/p=ALL-UNNAMED")
+                .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Test executable JAR with Enable-Final-Field-Mutation attribute and code that uses
+     * Field.set to mutate a final field of class in a named module. The package is opened
+     * with with the Add-Opens attribute.
+     */
+    @Test
+    void testFieldSetWithAddOpens2() throws Exception {
+        String jarFile = createExecutableJar(Map.of(
+                "Enable-Final-Field-Mutation", "ALL-UNNAMED",
+                "Add-Opens", "m/p"));
+        testExecutableJar(jarFile, "testFieldInNamedModule",
+                "--illegal-final-field-mutation=deny",
+                "--module-path", modulePath(),
+                "--add-modules", "m")
+                .shouldHaveExitValue(0);
+    }
+
+    /**
+     * Test executable JAR with Enable-Final-Field-Mutation with that a value that is not
+     * "ALL-UNNAMED".
+     */
+    @ParameterizedTest
+    @ValueSource(strings = {"java.base", "BadValue", " ", ""})
+    void testFinalFieldMutationBadValue(String value) throws Exception {
+        String jarFile = createExecutableJar(Map.of("Enable-Final-Field-Mutation", value));
+        testExecutableJar(jarFile, "testFieldSetInt")
+                 .shouldContain("Error: illegal value \"" + value + "\" for Enable-Final-Field-Mutation" +
+                         " manifest attribute. Only ALL-UNNAMED is allowed")
+                 .shouldNotHaveExitValue(0);
+     }
+
+    /**
+     * Launch ExecutableJarTestHelper with the given arguments and VM options.
+     */
+    private OutputAnalyzer test(String action, String... vmopts) throws Exception {
+        Stream<String> s1 = Stream.of(vmopts);
+        Stream<String> s2 = Stream.of("ExecutableJarTestHelper", action);
+        String[] opts = Stream.concat(s1, s2).toArray(String[]::new);
+        var outputAnalyzer = ProcessTools
+                .executeTestJava(opts)
+                .outputTo(System.err)
+                .errorTo(System.err);
+        return outputAnalyzer;
+    }
+
+    /**
+     * Launch ExecutableJarTestHelper with the given arguments and VM options.
+     */
+    private OutputAnalyzer testExecutableJar(String jarFile,
+                                             String action,
+                                             String... vmopts) throws Exception {
+        Stream<String> s1 = Stream.of(vmopts);
+        Stream<String> s2 = Stream.of("-jar", jarFile, action);
+        String[] opts = Stream.concat(s1, s2).toArray(String[]::new);
+        var outputAnalyzer = ProcessTools
+                .executeTestJava(opts)
+                .outputTo(System.err)
+                .errorTo(System.err);
+        return outputAnalyzer;
+    }
+
+    /**
+     * Creates executable JAR named helper.jar with ExecutableJarTestHelper* classes.
+     */
+    private String createExecutableJar(Map<String, String> map) throws Exception {
+        Path jarFile = Path.of("helper.jar");
+        var man = new Manifest();
+        Attributes attrs = man.getMainAttributes();
+        attrs.put(Attributes.Name.MANIFEST_VERSION, "1.0");
+        attrs.put(Attributes.Name.MAIN_CLASS, "ExecutableJarTestHelper");
+        map.entrySet().forEach(e -> {
+            var name = new Attributes.Name(e.getKey());
+            attrs.put(name, e.getValue());
+        });
+        Path dir = Path.of(System.getProperty("test.classes"));
+        try (Stream<Path> stream = Files.list(dir)) {
+            Path[] files = Files.list(dir).filter(p -> {
+                        String fn = p.getFileName().toString();
+                        return fn.startsWith("ExecutableJarTestHelper") && fn.endsWith(".class");
+                    })
+                    .toArray(Path[]::new);
+            JarUtils.createJarFile(jarFile, man, dir, files);
+        }
+        return jarFile.toString();
+    }
+
+    /**
+     * Return the module path for the modules used by this test.
+     */
+    private String modulePath() {
+        return Path.of(System.getProperty("test.classes"), "modules").toString();
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/jar/ExecutableJarTestHelper.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.lang.invoke.MethodHandles;
+
+public class ExecutableJarTestHelper {
+
+    /**
+     * The argument is a list of names of no-arg static methods in this class to invoke.
+     * The names are separated with a '+'.
+     */
+    public static void main(String[] args) throws Exception {
+        String[] methodNames = args.length > 0 ? args[0].split("\\+") : new String[0];
+        for (String methodName : methodNames) {
+            Method m = ExecutableJarTestHelper.class.getDeclaredMethod(methodName);
+            m.invoke(null);
+        }
+    }
+
+    /**
+     * Uses Field.set to mutate a final field.
+     */
+    static void testFieldSetInt() throws Exception {
+        class C {
+            final int value;
+            C(int value) {
+                this.value = value;
+            }
+        }
+        Field f = C.class.getDeclaredField("value");
+        f.setAccessible(true);
+        var obj = new C(100);
+        f.setInt(obj, 200);
+        if (obj.value != 200) {
+            throw new RuntimeException("Unexpected value: " + obj.value);
+        }
+    }
+
+    /**
+     * Uses Lookup.unreflectSetter to get a method handle to set a final field.
+     */
+    static void testUnreflectSetter() throws Throwable {
+        class C {
+            final int value;
+            C(int value) {
+                this.value = value;
+            }
+        }
+        Field f = C.class.getDeclaredField("value");
+        f.setAccessible(true);
+        var obj = new C(100);
+        MethodHandles.lookup().unreflectSetter(f).invoke(obj, 200);
+        if (obj.value != 200) {
+            throw new RuntimeException("Unexpected value: " + obj.value);
+        }
+    }
+
+    /**
+     * Uses Field.set to mutate a final field of a class in a named module.
+     */
+    static void testFieldInNamedModule() throws Exception {
+        Class<?> c = Class.forName("p.C");
+        if (!c.getModule().isNamed()) {
+            throw new RuntimeException(c + " is not in a named module");
+        }
+        Object obj = c.getDeclaredConstructor(int.class).newInstance(100);
+        Field f = c.getDeclaredField("value");
+        f.setAccessible(true);
+        f.setInt(obj, 200);
+        int newValue = f.getInt(obj);
+        if (newValue != 200) {
+            throw new RuntimeException("Unexpected value: " + newValue);
+        }
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/jar/m/module-info.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * Module containing a class with a final field used by ExecutableJarTest.
+ */
+module m {
+    exports p;
+}

test/jdk/java/lang/reflect/Field/mutateFinals/jar/m/p/C.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package p;
+
+/**
+ * A class with a final field used by ExecutableJarTest.
+ */
+public class C {
+    private final int value;
+
+    public C(int value) {
+        this.value = value;
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/jni/JNIAttachMutator.java

@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
+import java.util.concurrent.CountDownLatch;
+
+/**
+ * Launched by JNIAttachMutatorTest to test a JNI attached thread attempting to mutate
+ * a final field.
+ */
+
+public class JNIAttachMutator {
+    private static final CountDownLatch finished = new CountDownLatch(1);
+    private static volatile Object obj;
+    private static volatile Throwable exc;
+
+    // public class, public final field
+    public static class C1 {
+        public final int value;
+        C1(int value) {
+            this.value = value;
+        }
+    }
+
+    // public class, non-public final field
+    public static class C2 {
+        final int value;
+        C2(int value) {
+            this.value = value;
+        }
+    }
+
+    // non-public class, public final field
+    static class C3 {
+        public final int value;
+        C3(int value) {
+            this.value = value;
+        }
+    }
+
+    /**
+     * Usage: java JNIAttachMutator <classname> <true|false>
+     */
+    public static void main(String[] args) throws Exception {
+        String cn = args[0];
+        boolean expectIAE = Boolean.parseBoolean(args[1]);
+
+        Class<?> clazz = Class.forName(args[0]);
+        Constructor<?> ctor = clazz.getDeclaredConstructor(int.class);
+        ctor.setAccessible(true);
+        obj = ctor.newInstance(100);
+
+        // start native thread
+        startThread();
+
+        // wait for native thread to finish
+        finished.await();
+
+        if (expectIAE) {
+            if (exc == null) {
+                // IAE expected
+                throw new RuntimeException("IllegalAccessException not thrown");
+            } else if (!(exc instanceof IllegalAccessException)) {
+                // unexpected exception
+                throw new RuntimeException(exc);
+            }
+        } else if (exc != null) {
+            // no exception expected
+            throw new RuntimeException(exc);
+        }
+    }
+
+    /**
+     * Invoked by JNI attached thread to get object.
+     */
+    static Object getObject() {
+        return obj;
+    }
+
+    /**
+     * Invoked by JNI attached thread to get Field object with accessible enabled.
+     */
+    static Field getField() throws NoSuchFieldException {
+        Field f = obj.getClass().getDeclaredField("value");
+        f.setAccessible(true);
+        return f;
+    }
+
+    /**
+     * Invoked by JNI attached thread when finished.
+     */
+    static void finish(Throwable ex) {
+        exc = ex;
+        finished.countDown();
+    }
+
+    private static native void startThread();
+
+    static {
+        System.loadLibrary("JNIAttachMutator");
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/jni/JNIAttachMutatorTest.java

@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8353835
+ * @summary Test native thread attaching to the VM with JNI AttachCurrentThread and directly
+ *    invoking Field.set to set a final field
+ * @library /test/lib
+ * @build m/*
+ * @compile JNIAttachMutator.java
+ * @run junit JNIAttachMutatorTest
+ */
+
+import java.nio.file.Path;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+import org.junit.jupiter.params.provider.ValueSource;
+import jdk.test.lib.process.ProcessTools;
+import jdk.test.lib.process.OutputAnalyzer;
+
+class JNIAttachMutatorTest {
+    private static String testClasses;
+    private static String modulesDir;
+    private static String javaLibraryPath;
+
+    @BeforeAll
+    static void setup() {
+        testClasses = System.getProperty("test.classes");
+        modulesDir = Path.of(testClasses, "modules").toString();
+        javaLibraryPath = System.getProperty("java.library.path");
+    }
+
+    /**
+     * Final final mutation allowed. All final fields are public, in public classes,
+     * and in packages exported to all modules.
+     */
+    @ParameterizedTest
+    @ValueSource(strings = {
+            "JNIAttachMutator$C1",     // unnamed module
+            "p.C1",                    // named module
+    })
+    void testAllowed(String cn) throws Exception {
+        test(cn, false);
+    }
+
+    /**
+     * Final final mutation not allowed.
+     */
+    @ParameterizedTest
+    @ValueSource(strings = {
+            // unnamed module
+            "JNIAttachMutator$C2",      // public class, non-public final field
+            "JNIAttachMutator$C3",      // non-public class, public final field
+
+            // named module
+            "p.C2",                     // public class, non-public final field, exported package
+            "p.C3",                     // non-public class, public final field, exported package
+            "q.C"                       // public class, public final field, package not exported
+    })
+    void testDenied(String cn) throws Exception {
+        test(cn, true);
+    }
+
+    /**
+     * public final field, public class, package exported to some modules.
+     */
+    @Test
+    void testQualifiedExports() throws Exception {
+        test("q.C", true, "--add-exports", "m/q=ALL-UNNAMED");
+    }
+
+    /**
+     * Launches JNIAttachMutator to test a JNI attached thread mutating a final field.
+     * @param className the class with the field final
+     * @param expectIAE if IllegalAccessException is expected
+     * @param extraOps additional VM options
+     */
+    private void test(String className, boolean expectIAE, String... extraOps) throws Exception {
+        Stream<String> s1 = Stream.of(extraOps);
+        Stream<String> s2 = Stream.of(
+                "-cp", testClasses,
+                "-Djava.library.path=" + javaLibraryPath,
+                "--module-path", modulesDir,
+                "--add-modules", "m",
+                "--add-opens", "m/p=ALL-UNNAMED",    // allow setAccessible
+                "--add-opens", "m/q=ALL-UNNAMED",
+                "--enable-native-access=ALL-UNNAMED",
+                "--enable-final-field-mutation=ALL-UNNAMED",
+                "--illegal-final-field-mutation=deny",
+                "JNIAttachMutator",
+                className,
+                expectIAE ? "true" : "false");
+        String[] opts = Stream.concat(s1, s2).toArray(String[]::new);
+        OutputAnalyzer outputAnalyzer = ProcessTools
+                .executeTestJava(opts)
+                .outputTo(System.out)
+                .errorTo(System.out);
+        outputAnalyzer.shouldHaveExitValue(0);
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/jni/libJNIAttachMutator.c

@@ -0,0 +1,192 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+#include <stdio.h>
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <pthread.h>
+#endif
+#include "jni.h"
+
+#define STACK_SIZE 0x100000
+
+static JavaVM *vm;
+
+JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *jvm, void* reserved) {
+    vm = jvm;
+    return JNI_VERSION_1_8;
+}
+
+/**
+ * Invokes JNIAttachMutator.getObject()
+ */
+jobject getObject(JNIEnv* env) {
+    jclass clazz = (*env)->FindClass(env, "JNIAttachMutator");
+    if (clazz == NULL) {
+        fprintf(stderr, "FindClass failed\n");
+        return NULL;
+    }
+    jmethodID mid = (*env)->GetStaticMethodID(env, clazz, "getObject", "()Ljava/lang/Object;");
+    if (mid == NULL) {
+        fprintf(stderr, "GetMethodID for getObject failed\n");
+        return NULL;
+    }
+    jobject obj = (*env)->CallStaticObjectMethod(env, clazz, mid);
+    if (obj == NULL) {
+        fprintf(stderr, "CallObjectMethod to getObject failed\n");
+        return NULL;
+    }
+    return obj;
+}
+
+/**
+ * Invokes JNIAttachMutator.getField()
+ */
+jobject getField(JNIEnv* env) {
+    jclass clazz = (*env)->FindClass(env, "JNIAttachMutator");
+    if (clazz == NULL) {
+        fprintf(stderr, "FindClass failed\n");
+        return NULL;
+    }
+    jmethodID mid = (*env)->GetStaticMethodID(env, clazz, "getField", "()Ljava/lang/reflect/Field;");
+    if (mid == NULL) {
+        fprintf(stderr, "GetStaticMethodID for getField failed\n");
+        return NULL;
+    }
+    jobject obj = (*env)->CallStaticObjectMethod(env, clazz, mid);
+    if (obj == NULL) {
+        fprintf(stderr, "CallObjectMethod to getField failed\n");
+        return NULL;
+    }
+    return obj;
+}
+
+/**
+ * Invokes Field.setInt
+ */
+jboolean setInt(JNIEnv* env, jobject obj, jobject fieldObj, jint newValue) {
+    jclass fieldClass = (*env)->GetObjectClass(env, fieldObj);
+    jmethodID mid = (*env)->GetMethodID(env, fieldClass, "setInt", "(Ljava/lang/Object;I)V");
+    if (mid == NULL) {
+        fprintf(stderr, "GetMethodID for Field.setInt failed\n");
+        return JNI_FALSE;
+    }
+    (*env)->CallObjectMethod(env, fieldObj, mid, obj, newValue);
+    return JNI_TRUE;
+}
+
+/**
+ * Invokes JNIAttachMutator.finish
+ */
+void finish(JNIEnv* env, jthrowable ex) {
+    jclass clazz = (*env)->FindClass(env, "JNIAttachMutator");
+    if (clazz == NULL) {
+        fprintf(stderr, "FindClass failed\n");
+        return;
+    }
+
+    // invoke finish
+    jmethodID mid = (*env)->GetStaticMethodID(env, clazz, "finish", "(Ljava/lang/Throwable;)V");
+    if (mid == NULL) {
+        fprintf(stderr, "GetStaticMethodID failed\n");
+        return;
+    }
+    (*env)->CallStaticVoidMethod(env, clazz, mid, ex);
+    if ((*env)->ExceptionOccurred(env)) {
+        fprintf(stderr, "CallStaticVoidMethod failed\n");
+    }
+}
+
+/**
+ * Attach the current thread with JNI AttachCurrentThread.
+ */
+void* thread_main(void* arg) {
+    JNIEnv *env;
+    jint res;
+    jthrowable ex;
+
+    res = (*vm)->AttachCurrentThread(vm, (void **) &env, NULL);
+    if (res != JNI_OK) {
+        fprintf(stderr, "AttachCurrentThread failed: %d\n", res);
+        return NULL;
+    }
+
+    // invoke JNIAttachMutator.getObject to get the object to test
+    jobject obj = getObject(env);
+    if (obj == NULL) {
+        goto done;
+    }
+
+    // invoke JNIAttachMutator.getField to get the Field object with access enabled
+    jobject fieldObj = getField(env);
+    if (fieldObj == NULL) {
+        goto done;
+    }
+
+    // invoke Field.setInt to attempt to set the value to 200
+    if (!setInt(env, obj, fieldObj, 200)) {
+        goto done;
+    }
+
+  done:
+
+    ex = (*env)->ExceptionOccurred(env);
+    if (ex != NULL) {
+        (*env)->ExceptionDescribe(env);
+        (*env)->ExceptionClear(env);
+    }
+    finish(env, ex);
+
+    res = (*vm)->DetachCurrentThread(vm);
+    if (res != JNI_OK) {
+        fprintf(stderr, "DetachCurrentThread failed: %d\n", res);
+    }
+
+    return NULL;
+}
+
+#ifdef _WIN32
+static DWORD WINAPI win32_thread_main(void* p) {
+    thread_main(p);
+    return 0;
+}
+#endif
+
+JNIEXPORT void JNICALL Java_JNIAttachMutator_startThread(JNIEnv *env, jclass clazz) {
+#ifdef _WIN32
+    HANDLE handle = CreateThread(NULL, STACK_SIZE, win32_thread_main, NULL, 0, NULL);
+    if (handle == NULL) {
+        fprintf(stderr, "CreateThread failed: %d\n", GetLastError());
+    }
+#else
+    pthread_t tid;
+    pthread_attr_t attr;
+
+    pthread_attr_init(&attr);
+    pthread_attr_setstacksize(&attr, STACK_SIZE);
+    int res = pthread_create(&tid, &attr, thread_main, NULL);
+    if (res != 0) {
+        fprintf(stderr, "pthread_create failed: %d\n", res);
+    }
+#endif
+}

test/jdk/java/lang/reflect/Field/mutateFinals/jni/m/module-info.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * Module containing classes with final fields.
+ */
+module m {
+    exports p;
+}

test/jdk/java/lang/reflect/Field/mutateFinals/jni/m/p/C1.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package p;
+
+/**
+ * public class, public final field.
+ */
+public class C1 {
+    public final int value;
+
+    C1(int value) {
+        this.value = value;
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/jni/m/p/C2.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package p;
+
+/**
+ * public class, non-public final field.
+ */
+public class C2 {
+    final int value;
+
+    C2(int value) {
+        this.value = value;
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/jni/m/p/C3.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package p;
+
+/**
+ * non-public class, public final field.
+ */
+class C3 {
+    public final int value;
+
+    C3(int value) {
+        this.value = value;
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/jni/m/q/C.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package q;
+
+/**
+ * public class, public final field.
+ */
+public class C {
+    public final int value;
+
+    public C(int value) {
+        this.value = value;
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/modules/Driver.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8353835
+ * @summary Test mutating final fields in module test from code in modules test, m1, m2 and m3
+ * @build test/* m1/* m2/* m3/*
+ * @run junit/othervm --illegal-final-field-mutation=deny --enable-final-field-mutation=test,m1,m2,m3
+ *     test/test.TestMain
+ * @run junit/othervm --illegal-final-field-mutation=deny --enable-final-field-mutation=test,m1,m2,m3
+ *     --add-exports test/test.fieldholders=m3 test/test.TestMain
+ * @run junit/othervm --illegal-final-field-mutation=deny --enable-final-field-mutation=test,m1,m2,m3
+ *     --add-opens test/test.fieldholders=m2 test/test.TestMain
+ */

test/jdk/java/lang/reflect/Field/mutateFinals/modules/m1/module-info.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+@SuppressWarnings("module")
+module m1 {
+    requires test;
+    provides test.spi.Mutator with p1.M1Mutator;
+}

test/jdk/java/lang/reflect/Field/mutateFinals/modules/m1/p1/M1Mutator.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package p1;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.reflect.Field;
+
+public class M1Mutator implements test.spi.Mutator {
+
+    @Override
+    public void set(Field f, Object obj, Object value) throws IllegalAccessException {
+        f.set(obj, value);
+    }
+
+    @Override
+    public void setBoolean(Field f, Object obj, boolean value) throws IllegalAccessException {
+        f.setBoolean(obj, value);
+    }
+
+    @Override
+    public void setByte(Field f, Object obj, byte value) throws IllegalAccessException {
+        f.setByte(obj, value);
+    }
+
+    @Override
+    public void setChar(Field f, Object obj, char value) throws IllegalAccessException {
+        f.setChar(obj, value);
+    }
+
+    @Override
+    public void setShort(Field f, Object obj, short value) throws IllegalAccessException {
+        f.setShort(obj, value);
+    }
+
+    @Override
+    public void setInt(Field f, Object obj, int value) throws IllegalAccessException {
+        f.setInt(obj, value);
+    }
+
+    @Override
+    public void setLong(Field f, Object obj, long value) throws IllegalAccessException {
+        f.setLong(obj, value);
+    }
+
+    @Override
+    public void setFloat(Field f, Object obj, float value) throws IllegalAccessException {
+        f.setFloat(obj, value);
+    }
+
+    @Override
+    public void setDouble(Field f, Object obj, double value) throws IllegalAccessException {
+        f.setDouble(obj, value);
+    }
+
+    @Override
+    public MethodHandle unreflectSetter(Field f) throws IllegalAccessException {
+        return MethodHandles.lookup().unreflectSetter(f);
+    }
+
+}

test/jdk/java/lang/reflect/Field/mutateFinals/modules/m2/module-info.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+@SuppressWarnings("module")
+module m2 {
+    requires test;
+    provides test.spi.Mutator with p2.M2Mutator;
+}

test/jdk/java/lang/reflect/Field/mutateFinals/modules/m2/p2/M2Mutator.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package p2;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.reflect.Field;
+
+public class M2Mutator implements test.spi.Mutator {
+
+    @Override
+    public void set(Field f, Object obj, Object value) throws IllegalAccessException {
+        f.set(obj, value);
+    }
+
+    @Override
+    public void setBoolean(Field f, Object obj, boolean value) throws IllegalAccessException {
+        f.setBoolean(obj, value);
+    }
+
+    @Override
+    public void setByte(Field f, Object obj, byte value) throws IllegalAccessException {
+        f.setByte(obj, value);
+    }
+
+    @Override
+    public void setChar(Field f, Object obj, char value) throws IllegalAccessException {
+        f.setChar(obj, value);
+    }
+
+    @Override
+    public void setShort(Field f, Object obj, short value) throws IllegalAccessException {
+        f.setShort(obj, value);
+    }
+
+    @Override
+    public void setInt(Field f, Object obj, int value) throws IllegalAccessException {
+        f.setInt(obj, value);
+    }
+
+    @Override
+    public void setLong(Field f, Object obj, long value) throws IllegalAccessException {
+        f.setLong(obj, value);
+    }
+
+    @Override
+    public void setFloat(Field f, Object obj, float value) throws IllegalAccessException {
+        f.setFloat(obj, value);
+    }
+
+    @Override
+    public void setDouble(Field f, Object obj, double value) throws IllegalAccessException {
+        f.setDouble(obj, value);
+    }
+
+    @Override
+    public MethodHandle unreflectSetter(Field f) throws IllegalAccessException {
+        return MethodHandles.lookup().unreflectSetter(f);
+    }
+
+}

test/jdk/java/lang/reflect/Field/mutateFinals/modules/m3/module-info.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+@SuppressWarnings("module")
+module m3 {
+    requires test;
+    provides test.spi.Mutator with p3.M3Mutator;
+}

test/jdk/java/lang/reflect/Field/mutateFinals/modules/m3/p3/M3Mutator.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package p3;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.reflect.Field;
+
+public class M3Mutator implements test.spi.Mutator {
+
+    @Override
+    public void set(Field f, Object obj, Object value) throws IllegalAccessException {
+        f.set(obj, value);
+    }
+
+    @Override
+    public void setBoolean(Field f, Object obj, boolean value) throws IllegalAccessException {
+        f.setBoolean(obj, value);
+    }
+
+    @Override
+    public void setByte(Field f, Object obj, byte value) throws IllegalAccessException {
+        f.setByte(obj, value);
+    }
+
+    @Override
+    public void setChar(Field f, Object obj, char value) throws IllegalAccessException {
+        f.setChar(obj, value);
+    }
+
+    @Override
+    public void setShort(Field f, Object obj, short value) throws IllegalAccessException {
+        f.setShort(obj, value);
+    }
+
+    @Override
+    public void setInt(Field f, Object obj, int value) throws IllegalAccessException {
+        f.setInt(obj, value);
+    }
+
+    @Override
+    public void setLong(Field f, Object obj, long value) throws IllegalAccessException {
+        f.setLong(obj, value);
+    }
+
+    @Override
+    public void setFloat(Field f, Object obj, float value) throws IllegalAccessException {
+        f.setFloat(obj, value);
+    }
+
+    @Override
+    public void setDouble(Field f, Object obj, double value) throws IllegalAccessException {
+        f.setDouble(obj, value);
+    }
+
+    @Override
+    public MethodHandle unreflectSetter(Field f) throws IllegalAccessException {
+        return MethodHandles.lookup().unreflectSetter(f);
+    }
+
+}

test/jdk/java/lang/reflect/Field/mutateFinals/modules/test/module-info.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+module test {
+    requires org.junit.platform.console.standalone;
+    opens test to org.junit.platform.console.standalone;
+
+    opens test.fieldholders to m1;
+    exports test.fieldholders to m2;
+
+    exports test.spi;
+    uses test.spi.Mutator;
+    provides test.spi.Mutator with test.internal.TestMutator;
+}

test/jdk/java/lang/reflect/Field/mutateFinals/modules/test/test/TestMain.java

@@ -0,0 +1,556 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package test;
+
+import java.lang.reflect.Field;
+import java.util.ServiceLoader;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import test.spi.Mutator;
+import test.fieldholders.PublicFields;
+import test.fieldholders.PrivateFields;
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * Test mutating final fields from different modules.
+ */
+class TestMain {
+    static Map<Boolean, List<Mutator>> exportedToMutators;
+    static Map<Boolean, List<Mutator>> openToMutators;
+
+    // test module and the name of package with the fieldholder classes
+    static Module testModule;
+    static String fieldHoldersPackage;
+
+    @BeforeAll
+    static void setup() throws Exception {
+        testModule = TestMain.class.getModule();
+        fieldHoldersPackage = PublicFields.class.getPackageName();
+
+        List<Mutator> allMutators = ServiceLoader.load(Mutator.class)
+                .stream()
+                .map(ServiceLoader.Provider::get)
+                .toList();
+
+        // mutators that test.fieldholders is exported to
+        exportedToMutators = allMutators.stream()
+                .collect(Collectors.partitioningBy(m -> testModule.isExported(fieldHoldersPackage,
+                                                                              m.getClass().getModule()),
+                        Collectors.toList()));
+
+        // mutators that test.fieldholders is open to
+        openToMutators = allMutators.stream()
+                .collect(Collectors.partitioningBy(m -> testModule.isOpen(fieldHoldersPackage,
+                                                                          m.getClass().getModule()),
+                        Collectors.toList()));
+
+
+        // exported to at least test, m1 and m2
+        assertTrue(exportedToMutators.get(Boolean.TRUE).size() >= 3);
+
+        // open to at least test and m1
+        assertTrue(openToMutators.get(Boolean.TRUE).size() >= 2);
+    }
+
+    /**
+     * Returns a stream of mutators that test.fieldholders is exported to.
+     */
+    static Stream<Mutator> exportedToMutators() {
+        return exportedToMutators.get(Boolean.TRUE).stream();
+    }
+
+    /**
+     * Returns a stream of mutators that test.fieldholders is open to.
+     */
+    static Stream<Mutator> openToMutators() {
+        return openToMutators.get(Boolean.TRUE).stream();
+    }
+
+    /**
+     * Returns a stream of mutators that test.fieldholders is not exported to.
+     */
+    static Stream<Mutator> notExportedToMutators() {
+        List<Mutator> mutators = exportedToMutators.get(Boolean.FALSE);
+        if (mutators.isEmpty()) {
+            // can't return an empty stream at this time
+            return Stream.of(Mutator.throwing());
+        } else {
+            return mutators.stream();
+        }
+    }
+
+    /**
+     * Returns a stream of mutators that test.fieldholders is not open to.
+     */
+    static Stream<Mutator> notOpenToMutators() {
+        List<Mutator> mutators = openToMutators.get(Boolean.FALSE);
+        if (mutators.isEmpty()) {
+            // can't return an empty stream at this time
+            return Stream.of(Mutator.throwing());
+        } else {
+            return mutators.stream();
+        }
+    }
+
+    // public field, public class in package exported to mutator
+
+    @ParameterizedTest()
+    @MethodSource("exportedToMutators")
+    void testFieldSetExportedPackage(Mutator mutator) throws Exception {
+        Field f = PublicFields.objectField();
+        var obj = new PublicFields();
+        Object oldValue = obj.objectValue();
+        Object newValue = new Object();
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.set(f, obj, newValue));
+        assertTrue(obj.objectValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.set(f, obj, newValue);
+        assertTrue(obj.objectValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("exportedToMutators")
+    void testFieldSetBooleanExportedPackage(Mutator mutator) throws Exception {
+        Field f = PublicFields.booleanField();
+        var obj = new PublicFields();
+        boolean oldValue = obj.booleanValue();
+        boolean newValue = true;
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setBoolean(f, obj, newValue));
+        assertTrue(obj.booleanValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setBoolean(f, obj, newValue);
+        assertTrue(obj.booleanValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("exportedToMutators")
+    void testFieldSetByteExportedPackage(Mutator mutator) throws Exception {
+        Field f = PublicFields.byteField();
+        var obj = new PublicFields();
+        byte oldValue = obj.byteValue();
+        byte newValue = 10;
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setByte(f, obj, newValue));
+        assertTrue(obj.byteValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setByte(f, obj, newValue);
+        assertTrue(obj.byteValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("exportedToMutators")
+    void testFieldSetCharExportedPackage(Mutator mutator) throws Exception {
+        Field f = PublicFields.charField();
+        var obj = new PublicFields();
+        char oldValue = obj.charValue();
+        char newValue = 'Z';
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setChar(f, obj, newValue));
+        assertTrue(obj.charValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setChar(f, obj, newValue);
+        assertTrue(obj.charValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("exportedToMutators")
+    void testFieldSetShortExportedPackage(Mutator mutator) throws Exception {
+        Field f = PublicFields.shortField();
+        var obj = new PublicFields();
+        short oldValue = obj.shortValue();
+        short newValue = 99;
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setShort(f, obj, newValue));
+        assertTrue(obj.shortValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setShort(f, obj, newValue);
+        assertTrue(obj.shortValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("exportedToMutators")
+    void testFieldSetIntExportedPackage(Mutator mutator) throws Exception {
+        Field f = PublicFields.intField();
+        var obj = new PublicFields();
+        int oldValue = obj.intValue();
+        int newValue = 999;
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setInt(f, obj, newValue));
+        assertTrue(obj.intValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setInt(f, obj, newValue);
+        assertTrue(obj.intValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("exportedToMutators")
+    void testFieldSetLongExportedPackage(Mutator mutator) throws Exception {
+        Field f = PublicFields.longField();
+        var obj = new PublicFields();
+        long oldValue = obj.longValue();
+        long newValue = 9999;
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setLong(f, obj, newValue));
+        assertTrue(obj.longValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setLong(f, obj, newValue);
+        assertTrue(obj.longValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("exportedToMutators")
+    void testFieldSetFloatExportedPackage(Mutator mutator) throws Exception {
+        Field f = PublicFields.floatField();
+        var obj = new PublicFields();
+        float oldValue = obj.floatValue();
+        float newValue = 9.9f;
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setFloat(f, obj, newValue));
+        assertTrue(obj.floatValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setFloat(f, obj, newValue);
+        assertTrue(obj.floatValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("exportedToMutators")
+    void testFieldSetDoublExportedPackage(Mutator mutator) throws Exception {
+        Field f = PublicFields.doubleField();
+        var obj = new PublicFields();
+        double oldValue = obj.doubleValue();
+        double newValue = 99.9d;
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setDouble(f, obj, newValue));
+        assertTrue(obj.doubleValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setDouble(f, obj, newValue);
+        assertTrue(obj.doubleValue() == newValue);
+    }
+
+    @ParameterizedTest
+    @MethodSource("exportedToMutators")
+    void testUnreflectSetterExportedPackage(Mutator mutator) throws Throwable {
+        Field f = PublicFields.objectField();
+        var obj = new PublicFields();
+        Object oldValue = obj.objectValue();
+        Object newValue = new Object();
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.unreflectSetter(f));
+
+        f.setAccessible(true);
+        mutator.unreflectSetter(f).invokeExact(obj, newValue);
+        assertTrue(obj.objectValue() == newValue);
+    }
+
+    // private field, class in package opened to mutator
+
+    @ParameterizedTest()
+    @MethodSource("openToMutators")
+    void testFieldSetOpenPackage(Mutator mutator) throws Exception {
+        Field f = PrivateFields.objectField();
+        var obj = new PrivateFields();
+        Object oldValue = obj.objectValue();
+        Object newValue = new Object();
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.set(f, obj, newValue));
+        assertTrue(obj.objectValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.set(f, obj, newValue);
+        assertTrue(obj.objectValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("openToMutators")
+    void testFieldSetBooleanOpenPackage(Mutator mutator) throws Exception {
+        Field f = PrivateFields.booleanField();
+        var obj = new PrivateFields();
+        boolean oldValue = obj.booleanValue();
+        boolean newValue = true;
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setBoolean(f, obj, newValue));
+        assertTrue(obj.booleanValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setBoolean(f, obj, newValue);
+        assertTrue(obj.booleanValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("openToMutators")
+    void testFieldSetByteOpenPackage(Mutator mutator) throws Exception {
+        Field f = PrivateFields.byteField();
+        var obj = new PrivateFields();
+        byte oldValue = obj.byteValue();
+        byte newValue = 10;
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setByte(f, obj, newValue));
+        assertTrue(obj.byteValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setByte(f, obj, newValue);
+        assertTrue(obj.byteValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("openToMutators")
+    void testFieldSetCharOpenPackage(Mutator mutator) throws Exception {
+        Field f = PrivateFields.charField();
+        var obj = new PrivateFields();
+        char oldValue = obj.charValue();
+        char newValue = 'Z';
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setChar(f, obj, newValue));
+        assertTrue(obj.charValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setChar(f, obj, newValue);
+        assertTrue(obj.charValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("openToMutators")
+    void testFieldSetShortOpenPackage(Mutator mutator) throws Exception {
+        Field f = PrivateFields.shortField();
+        var obj = new PrivateFields();
+        short oldValue = obj.shortValue();
+        short newValue = 'Z';
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setShort(f, obj, newValue));
+        assertTrue(obj.shortValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setShort(f, obj, newValue);
+        assertTrue(obj.shortValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("openToMutators")
+    void testFieldSetIntOpenPackage(Mutator mutator) throws Exception {
+        Field f = PrivateFields.intField();
+        var obj = new PrivateFields();
+        int oldValue = obj.intValue();
+        int newValue = 99;
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setInt(f, obj, newValue));
+        assertTrue(obj.intValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setInt(f, obj, newValue);
+        assertTrue(obj.intValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("openToMutators")
+    void testFieldSetLongOpenPackage(Mutator mutator) throws Exception {
+        Field f = PrivateFields.longField();
+        var obj = new PrivateFields();
+        long oldValue = obj.longValue();
+        long newValue = 999;
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setLong(f, obj, newValue));
+        assertTrue(obj.longValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setLong(f, obj, newValue);
+        assertTrue(obj.longValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("openToMutators")
+    void testFieldSetFloatOpenPackage(Mutator mutator) throws Exception {
+        Field f = PrivateFields.floatField();
+        var obj = new PrivateFields();
+        float oldValue = obj.floatValue();
+        float newValue = 9.9f;
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setFloat(f, obj, newValue));
+        assertTrue(obj.floatValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setFloat(f, obj, newValue);
+        assertTrue(obj.floatValue() == newValue);
+    }
+
+    @ParameterizedTest()
+    @MethodSource("openToMutators")
+    void testFieldSetDoubleOpenPackage(Mutator mutator) throws Exception {
+        Field f = PrivateFields.doubleField();
+        var obj = new PrivateFields();
+        double oldValue = obj.doubleValue();
+        double newValue = 99.9d;
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.setDouble(f, obj, newValue));
+        assertTrue(obj.doubleValue() == oldValue);
+
+        f.setAccessible(true);
+        mutator.setDouble(f, obj, newValue);
+        assertTrue(obj.doubleValue() == newValue);
+    }
+
+    @ParameterizedTest
+    @MethodSource("openToMutators")
+    void testUnreflectSetterOpenPackage(Mutator mutator) throws Throwable {
+        Field f = PrivateFields.objectField();
+        var obj = new PrivateFields();
+        Object oldValue = obj.objectValue();
+        Object newValue = new Object();
+
+        f.setAccessible(false);
+        assertThrows(IllegalAccessException.class, () -> mutator.unreflectSetter(f));
+
+        f.setAccessible(true);
+        mutator.unreflectSetter(f).invokeExact(obj, newValue);
+        assertTrue(obj.objectValue() == newValue);
+    }
+
+    // public field, public class in package not exported to mutator
+
+    @ParameterizedTest
+    @MethodSource("notExportedToMutators")
+    void testFieldSetNotExportedPackage(Mutator mutator) throws Exception {
+        Field f = PublicFields.objectField();
+        var obj = new PublicFields();
+        Object oldValue = obj.objectValue();
+        Object newValue = new Object();
+
+        f.setAccessible(true);
+        var e1 = assertThrows(IllegalAccessException.class, () -> mutator.set(f, obj, newValue));
+        Module mutatorModule = mutator.getClass().getModule();
+        if (mutatorModule != testModule) {
+            assertTrue(e1.getMessage().contains("module " + testModule.getName()
+                    + " does not explicitly \"exports\" package "
+                    + f.getDeclaringClass().getPackageName()
+                    + " to module " + mutatorModule.getName()));
+        }
+        assertTrue(obj.objectValue() == oldValue);
+
+        // export package to mutator module, should have no effect on set method
+        testModule.addExports(fieldHoldersPackage, mutator.getClass().getModule());
+        var e2 = assertThrows(IllegalAccessException.class, () -> mutator.set(f, obj, newValue));
+        assertEquals(e1.getMessage(), e2.getMessage());
+        assertTrue(obj.objectValue() == oldValue);
+
+        // open package to mutator module, should have no effect on set method
+        testModule.addOpens(fieldHoldersPackage, mutator.getClass().getModule());
+        var e3 = assertThrows(IllegalAccessException.class, () -> mutator.set(f, obj, newValue));
+        assertEquals(e1.getMessage(), e3.getMessage());
+        assertTrue(obj.objectValue() == oldValue);
+    }
+
+    @ParameterizedTest
+    @MethodSource("notExportedToMutators")
+    void testUnreflectSetterNotExportedPackage(Mutator mutator) throws Exception {
+        Field f = PublicFields.objectField();
+
+        f.setAccessible(true);
+        assertThrows(IllegalAccessException.class, () -> mutator.unreflectSetter(f));
+
+        // export package to mutator module, should have no effect on unreflectSetter method
+        testModule.addExports(fieldHoldersPackage, mutator.getClass().getModule());
+        assertThrows(IllegalAccessException.class, () -> mutator.unreflectSetter(f));
+
+        // open package to mutator module, should have no effect on unreflectSetter method
+        testModule.addOpens(fieldHoldersPackage, mutator.getClass().getModule());
+        assertThrows(IllegalAccessException.class, () -> mutator.unreflectSetter(f));
+    }
+
+    // private field, class in package not opened to mutator
+
+    @ParameterizedTest
+    @MethodSource("notOpenToMutators")
+    void testFieldSetNotOpenPackage(Mutator mutator) throws Exception {
+        Field f = PrivateFields.objectField();
+        var obj = new PrivateFields();
+        Object oldValue = obj.objectValue();
+        Object newValue = new Object();
+
+        f.setAccessible(true);
+        var e1 = assertThrows(IllegalAccessException.class, () -> mutator.set(f, obj, newValue));
+        Module mutatorModule = mutator.getClass().getModule();
+        if (mutatorModule != testModule) {
+            assertTrue(e1.getMessage().contains("module " + testModule.getName()
+                    + " does not explicitly \"opens\" package "
+                    + f.getDeclaringClass().getPackageName()
+                    + " to module " + mutatorModule.getName()));
+        }
+        assertTrue(obj.objectValue() == oldValue);
+
+        // open package to mutator module, should have no effect on set method
+        testModule.addOpens(fieldHoldersPackage, mutator.getClass().getModule());
+        var e2 = assertThrows(IllegalAccessException.class, () -> mutator.set(f, obj, newValue));
+        assertEquals(e2.getMessage(), e2.getMessage());
+        assertTrue(obj.objectValue() == oldValue);
+    }
+
+    @ParameterizedTest
+    @MethodSource("notOpenToMutators")
+    void testUnreflectSetterNotOpenPackage(Mutator mutator) throws Exception {
+        Field f = PrivateFields.class.getDeclaredField("obj");
+
+        f.setAccessible(true);
+        assertThrows(IllegalAccessException.class, () -> mutator.unreflectSetter(f));
+
+        // open package to mutator module, should have no effect on unreflectSetter method
+        testModule.addOpens(fieldHoldersPackage, mutator.getClass().getModule());
+        assertThrows(IllegalAccessException.class, () -> mutator.unreflectSetter(f));
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/modules/test/test/fieldholders/PrivateFields.java

@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package test.fieldholders;
+
+import java.lang.reflect.Field;
+
+/**
+ * public class with private final fields.
+ */
+public class PrivateFields {
+    private final Object obj;
+    private final boolean z;
+    private final byte b;
+    private final char c;
+    private final short s;
+    private final int i;
+    private final long l;
+    private final float f;
+    private final double d;
+
+    public PrivateFields() {
+        obj = new Object();
+        z = false;
+        b = 0;
+        c = 0;
+        s = 0;
+        i = 0;
+        l = 0;
+        f = 0.0f;
+        d = 0.0d;
+    }
+
+    public static Field objectField() throws NoSuchFieldException {
+        return PrivateFields.class.getDeclaredField("obj");
+    }
+
+    public static Field booleanField() throws NoSuchFieldException {
+        return PrivateFields.class.getDeclaredField("z");
+    }
+
+    public static Field byteField() throws NoSuchFieldException {
+        return PrivateFields.class.getDeclaredField("b");
+    }
+
+    public static Field charField() throws NoSuchFieldException {
+        return PrivateFields.class.getDeclaredField("c");
+    }
+
+    public static Field shortField() throws NoSuchFieldException {
+        return PrivateFields.class.getDeclaredField("s");
+    }
+
+    public static Field intField() throws NoSuchFieldException {
+        return PrivateFields.class.getDeclaredField("i");
+    }
+
+    public static Field longField() throws NoSuchFieldException {
+        return PrivateFields.class.getDeclaredField("l");
+    }
+
+    public static Field floatField() throws NoSuchFieldException {
+        return PrivateFields.class.getDeclaredField("f");
+    }
+
+    public static Field doubleField() throws NoSuchFieldException {
+        return PrivateFields.class.getDeclaredField("d");
+    }
+
+    public Object objectValue() {
+        return obj;
+    }
+
+    public boolean booleanValue() {
+        return z;
+    }
+
+    public byte byteValue() {
+        return b;
+    }
+
+    public char charValue() {
+        return c;
+    }
+
+    public short shortValue() {
+        return s;
+    }
+
+    public int intValue() {
+        return i;
+    }
+
+    public long longValue() {
+        return l;
+    }
+
+    public float floatValue() {
+        return f;
+    }
+
+    public double doubleValue() {
+        return d;
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/modules/test/test/fieldholders/PublicFields.java

@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package test.fieldholders;
+
+import java.lang.reflect.Field;
+
+/**
+ * public class with public final fields.
+ */
+public class PublicFields {
+    public final Object obj;
+    public final boolean z;
+    public final byte b;
+    public final char c;
+    public final short s;
+    public final int i;
+    public final long l;
+    public final float f;
+    public final double d;
+
+    public PublicFields() {
+        obj = new Object();
+        z = false;
+        b = 0;
+        c = 0;
+        s = 0;
+        i = 0;
+        l = 0;
+        f = 0.0f;
+        d = 0.0d;
+    }
+
+    public static Field objectField() throws NoSuchFieldException {
+        return PublicFields.class.getDeclaredField("obj");
+    }
+
+    public static Field booleanField() throws NoSuchFieldException {
+        return PublicFields.class.getDeclaredField("z");
+    }
+
+    public static Field byteField() throws NoSuchFieldException {
+        return PublicFields.class.getDeclaredField("b");
+    }
+
+    public static Field charField() throws NoSuchFieldException {
+        return PublicFields.class.getDeclaredField("c");
+    }
+
+    public static Field shortField() throws NoSuchFieldException {
+        return PublicFields.class.getDeclaredField("s");
+    }
+
+    public static Field intField() throws NoSuchFieldException {
+        return PublicFields.class.getDeclaredField("i");
+    }
+
+    public static Field longField() throws NoSuchFieldException {
+        return PublicFields.class.getDeclaredField("l");
+    }
+
+    public static Field floatField() throws NoSuchFieldException {
+        return PublicFields.class.getDeclaredField("f");
+    }
+
+    public static Field doubleField() throws NoSuchFieldException {
+        return PublicFields.class.getDeclaredField("d");
+    }
+
+    public Object objectValue() {
+        return obj;
+    }
+
+    public boolean booleanValue() {
+        return z;
+    }
+
+    public byte byteValue() {
+        return b;
+    }
+
+    public char charValue() {
+        return c;
+    }
+
+    public short shortValue() {
+        return s;
+    }
+
+    public int intValue() {
+        return i;
+    }
+
+    public long longValue() {
+        return l;
+    }
+
+    public float floatValue() {
+        return f;
+    }
+
+    public double doubleValue() {
+        return d;
+    }
+}

test/jdk/java/lang/reflect/Field/mutateFinals/modules/test/test/internal/TestMutator.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package test.internal;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.reflect.Field;
+
+public class TestMutator implements test.spi.Mutator {
+
+    @Override
+    public void set(Field f, Object obj, Object value) throws IllegalAccessException {
+        f.set(obj, value);
+    }
+
+    @Override
+    public void setBoolean(Field f, Object obj, boolean value) throws IllegalAccessException {
+        f.setBoolean(obj, value);
+    }
+
+    @Override
+    public void setByte(Field f, Object obj, byte value) throws IllegalAccessException {
+        f.setByte(obj, value);
+    }
+
+    @Override
+    public void setChar(Field f, Object obj, char value) throws IllegalAccessException {
+        f.setChar(obj, value);
+    }
+
+    @Override
+    public void setShort(Field f, Object obj, short value) throws IllegalAccessException {
+        f.setShort(obj, value);
+    }
+
+    @Override
+    public void setInt(Field f, Object obj, int value) throws IllegalAccessException {
+        f.setInt(obj, value);
+    }
+
+    @Override
+    public void setLong(Field f, Object obj, long value) throws IllegalAccessException {
+        f.setLong(obj, value);
+    }
+
+    @Override
+    public void setFloat(Field f, Object obj, float value) throws IllegalAccessException {
+        f.setFloat(obj, value);
+    }
+
+    @Override
+    public void setDouble(Field f, Object obj, double value) throws IllegalAccessException {
+        f.setDouble(obj, value);
+    }
+
+    @Override
+    public MethodHandle unreflectSetter(Field f) throws IllegalAccessException {
+        return MethodHandles.lookup().unreflectSetter(f);
+    }
+
+}

test/jdk/java/lang/reflect/Field/mutateFinals/modules/test/test/spi/Mutator.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package test.spi;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.reflect.Field;
+
+public interface Mutator {
+    void set(Field f, Object obj, Object value) throws IllegalAccessException;
+    void setBoolean(Field f, Object obj, boolean value) throws IllegalAccessException;
+    void setByte(Field f, Object obj, byte value) throws IllegalAccessException;
+    void setChar(Field f, Object obj, char value) throws IllegalAccessException;
+    void setShort(Field f, Object obj, short value) throws IllegalAccessException;
+    void setInt(Field f, Object obj, int value) throws IllegalAccessException;
+    void setLong(Field f, Object obj, long value) throws IllegalAccessException;
+    void setFloat(Field f, Object obj, float value) throws IllegalAccessException;
+    void setDouble(Field f, Object obj, double value) throws IllegalAccessException;
+    MethodHandle unreflectSetter(Field f) throws IllegalAccessException;
+
+    static Mutator throwing() {
+        return new Mutator() {
+            @Override
+            public void set(Field f, Object obj, Object value) throws IllegalAccessException {
+                throw new IllegalAccessException();
+            }
+            @Override
+            public void setBoolean(Field f, Object obj, boolean value) throws IllegalAccessException {
+                throw new IllegalAccessException();
+            }
+            @Override
+            public void setByte(Field f, Object obj, byte value) throws IllegalAccessException {
+                throw new IllegalAccessException();
+            }
+            @Override
+            public void setChar(Field f, Object obj, char value) throws IllegalAccessException {
+                throw new IllegalAccessException();
+            }
+            @Override
+            public void setShort(Field f, Object obj, short value) throws IllegalAccessException {
+                throw new IllegalAccessException();
+            }
+            @Override
+            public void setInt(Field f, Object obj, int value) throws IllegalAccessException {
+                throw new IllegalAccessException();
+            }
+            @Override
+            public void setLong(Field f, Object obj, long value) throws IllegalAccessException {
+                throw new IllegalAccessException();
+            }
+            @Override
+            public void setFloat(Field f, Object obj, float value) throws IllegalAccessException {
+                throw new IllegalAccessException();
+            }
+            @Override
+            public void setDouble(Field f, Object obj, double value) throws IllegalAccessException {
+                throw new IllegalAccessException();
+            }
+            @Override
+            public MethodHandle unreflectSetter(Field f) throws IllegalAccessException {
+                throw new IllegalAccessException();
+            }
+            @Override
+            public String toString() {
+                return "<throwing>";
+            }
+        };
+    }
+}

test/jdk/java/util/jar/Attributes/NullAndEmptyKeysAndValues.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2025, Oracle and/or its affiliates. All rights reserved.
  * 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 @@ import static org.testng.Assert.*;
  * @test
  * @bug 8066619
  * @modules java.base/java.util.jar:+open
- * @run testng/othervm NullAndEmptyKeysAndValues
+ * @run testng/othervm --enable-final-field-mutation=ALL-UNNAMED NullAndEmptyKeysAndValues
  * @summary Tests manifests with {@code null} and empty string {@code ""}
  * values as section name, header name, or value in both main and named
  * attributes sections.

test/jdk/java/util/logging/FileHandlerLongLimit.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2025, Oracle and/or its affiliates. All rights reserved.
  * 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 @@ import java.util.logging.LogRecord;
  * @bug 8059767
  * @summary tests that FileHandler can accept a long limit.
  * @modules java.logging/java.util.logging:open
- * @run main/othervm FileHandlerLongLimit
+ * @run main/othervm --enable-final-field-mutation=ALL-UNNAMED FileHandlerLongLimit
  * @author danielfuchs
  * @key randomness
  */

test/jdk/jdk/jfr/event/metadata/TestLookForUntestedEvents.java

@@ -81,6 +81,10 @@ public class TestLookForUntestedEvents {
     private static final Set<String> coveredVirtualThreadEvents = Set.of(
         "VirtualThreadPinned", "VirtualThreadSubmitFailed");
 
+    // This event is tested in test/jdk/java/lang/reflect/Field/mutateFinals/FinalFieldMutationEventTest.java
+    private static final Set<String> coveredFinalFieldMutationEvents = Set.of(
+        "FinalFieldMutationEvent");
+
     // This is a "known failure list" for this test.
     // NOTE: if the event is not covered, a bug should be open, and bug number
     // noted in the comments for this set.
@@ -128,6 +132,7 @@ public class TestLookForUntestedEvents {
         eventsNotCoveredByTest.removeAll(hardToTestEvents);
         eventsNotCoveredByTest.removeAll(coveredGcEvents);
         eventsNotCoveredByTest.removeAll(coveredVirtualThreadEvents);
+        eventsNotCoveredByTest.removeAll(coveredFinalFieldMutationEvents);
         eventsNotCoveredByTest.removeAll(coveredContainerEvents);
         eventsNotCoveredByTest.removeAll(knownNotCoveredEvents);
 

test/jdk/sun/security/pkcs11/Cipher/CancelMultipart.java

@@ -26,7 +26,7 @@
  * @bug 8258833
  * @library /test/lib ..
  * @modules jdk.crypto.cryptoki/sun.security.pkcs11:open
- * @run main/othervm CancelMultipart
+ * @run main/othervm --enable-final-field-mutation=ALL-UNNAMED CancelMultipart
  */
 
 import java.lang.reflect.Field;

test/jdk/sun/security/provider/SecureRandom/DRBGS11n.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2025, Oracle and/or its affiliates. All rights reserved.
  * 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 @@ import java.lang.reflect.Field;
  * @bug 8157308
  * @modules java.base/sun.security.provider:+open
  * @summary Make AbstractDrbg non-Serializable
- * @run main DRBGS11n mech
- * @run main DRBGS11n capability
+ * @run main/othervm --enable-final-field-mutation=ALL-UNNAMED DRBGS11n mech
+ * @run main/othervm --enable-final-field-mutation=ALL-UNNAMED DRBGS11n capability
  */
 public class DRBGS11n {
 

test/jdk/sun/security/util/ManifestDigester/FindSection.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2025, Oracle and/or its affiliates. All rights reserved.
  * 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 @@ import static org.testng.Assert.*;
  * @bug 8217375
  * @modules java.base/sun.security.util:+open
  * @compile ../../tools/jarsigner/Utils.java
- * @run testng/othervm FindSection
+ * @run testng/othervm --enable-final-field-mutation=ALL-UNNAMED FindSection
  * @summary Check {@link ManifestDigester#findSection}.
  */
 public class FindSection {

test/langtools/jdk/jshell/CompletionSuggestionTest.java

@@ -32,7 +32,7 @@
  *          jdk.jshell/jdk.jshell:open
  * @build toolbox.ToolBox toolbox.JarTask toolbox.JavacTask
  * @build KullaTesting TestingInputStream Compiler
- * @run junit/timeout=480 CompletionSuggestionTest
+ * @run junit/othervm/timeout=480 --enable-final-field-mutation=ALL-UNNAMED CompletionSuggestionTest
  */
 
 import java.io.IOException;

test/lib/jdk/test/lib/jfr/EventNames.java

@@ -220,6 +220,7 @@ public class EventNames {
     public static final String VirtualThreadEnd = PREFIX + "VirtualThreadEnd";
     public static final String VirtualThreadPinned = PREFIX + "VirtualThreadPinned";
     public static final String VirtualThreadSubmitFailed = PREFIX + "VirtualThreadSubmitFailed";
+    public static final String FinalFieldMutation = PREFIX + "FinalFieldMutation";
 
     // Containers
     public static final String ContainerConfiguration = PREFIX + "ContainerConfiguration";

test/micro/org/openjdk/bench/java/lang/reflect/FieldSet.java

@@ -0,0 +1,151 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package org.openjdk.bench.java.lang.reflect;
+
+import java.lang.reflect.Field;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.ThreadLocalRandom;
+
+import org.openjdk.jmh.annotations.*;
+
+@BenchmarkMode(Mode.AverageTime)
+@State(Scope.Benchmark)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@Warmup(iterations = 10, time = 1, timeUnit = TimeUnit.SECONDS)
+@Measurement(iterations = 10, time = 2, timeUnit = TimeUnit.SECONDS)
+@Fork(3)
+public class FieldSet {
+
+    static class FieldHolder {
+        Object obj;
+        int intValue;
+        long longValue;
+        FieldHolder(Object obj, int i, long l) {
+            this.obj = obj;
+            this.intValue = i;
+            this.longValue = l;
+        }
+    }
+
+    static class FinalFieldHolder {
+        final Object obj;
+        final int intValue;
+        final long longValue;
+        FinalFieldHolder(Object obj, int i, long l) {
+            this.obj = obj;
+            this.intValue = i;
+            this.longValue = l;
+        }
+    }
+
+    private FieldHolder fieldHolder;
+    private FinalFieldHolder finalFieldHolder;
+
+    private Field objField1, objField2, objField3;
+    private Field intField1, intField2, intField3;
+    private Field longField1, longField2, longField3;
+
+    @Setup
+    public void setup() throws Exception {
+        fieldHolder = new FieldHolder(new Object(), 1, 1L);
+        finalFieldHolder = new FinalFieldHolder(new Object(), 1, 1L);
+
+        // non-final && !override
+        objField1 = FieldHolder.class.getDeclaredField("obj");
+        intField1 = FieldHolder.class.getDeclaredField("intValue");
+        longField1 = FieldHolder.class.getDeclaredField("longValue");
+
+        // non-final && override
+        objField2 = FieldHolder.class.getDeclaredField("obj");
+        objField2.setAccessible(true);
+        intField2 = FieldHolder.class.getDeclaredField("intValue");
+        intField2.setAccessible(true);
+        longField2 = FieldHolder.class.getDeclaredField("longValue");
+        longField2.setAccessible(true);
+
+        // final && override
+        objField3 = FinalFieldHolder.class.getDeclaredField("obj");
+        objField3.setAccessible(true);
+        intField3 = FinalFieldHolder.class.getDeclaredField("intValue");
+        intField3.setAccessible(true);
+        longField3 = FinalFieldHolder.class.getDeclaredField("longValue");
+        longField3.setAccessible(true);
+    }
+
+    // non-final && !override
+
+    @Benchmark
+    public void setNonFinalObjectField() throws Exception {
+        objField1.set(fieldHolder, new Object());
+    }
+
+    @Benchmark
+    public void setNonFinalIntField() throws Exception {
+        int newValue = ThreadLocalRandom.current().nextInt();
+        intField1.setInt(fieldHolder, newValue);
+    }
+
+    @Benchmark
+    public void setNonFinalLongField() throws Exception {
+        long newValue = ThreadLocalRandom.current().nextLong();
+        longField1.setLong(fieldHolder, newValue);
+    }
+
+    // non-final && override
+
+    @Benchmark
+    public void setNonFinalObjectFieldWithOverride() throws Exception {
+        objField2.set(fieldHolder, new Object());
+    }
+
+    @Benchmark
+    public void setNonFinalIntFieldWithOverride() throws Exception {
+        int newValue = ThreadLocalRandom.current().nextInt();
+        intField2.setInt(fieldHolder, newValue);
+    }
+
+    @Benchmark
+    public void setNonFinalLongFieldWithOverride() throws Exception {
+        long newValue = ThreadLocalRandom.current().nextLong();
+        longField2.setLong(fieldHolder, newValue);
+    }
+
+    // final && override
+
+    @Benchmark
+    public void setFinalObjectField()throws Exception {
+        objField3.set(finalFieldHolder, new Object());
+    }
+
+    @Benchmark
+    public void setFinalIntField() throws Exception {
+        int newValue = ThreadLocalRandom.current().nextInt();
+        intField3.setInt(finalFieldHolder, newValue);
+    }
+
+    @Benchmark
+    public void setFinalLongField() throws Exception {
+        long newValue = ThreadLocalRandom.current().nextLong();
+        longField3.setLong(finalFieldHolder, newValue);
+    }
+}