From 599ed0bb5fd62e26c71651bc02f198cd27636cfb Mon Sep 17 00:00:00 2001
From: SendaoYan <syan@openjdk.org>
Date: Wed, 21 Jan 2026 03:39:02 +0000
Subject: [PATCH] 8375485: Tests in vmTestbase/nsk are failing due to missing
 class unloading after 8373945

Reviewed-by: lmesnik, cjplummer
---
 .../jvmti/scenarios/events/EM02/em02t003.java   | 17 ++++++++++++++++-
 .../vmTestbase/nsk/share/ClassUnloader.java     | 17 ++++++++++++++++-
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t003.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t003.java
index d4cb4a8569a..a23732dc554 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t003.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t003.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -105,6 +105,21 @@ public class em02t003 extends DebugeeClass {
                 return Consts.TEST_FAILED;
             }
 
+            while (thrd.isAlive()) {
+                logger.display("Thread state: " + thrd.getState()
+                    + " - waiting for completion.");
+                try {
+                    // small delay to avoid produce huge amount of output
+                    Thread.sleep(100);
+                } catch (InterruptedException e) {
+                }
+            }
+            try {
+                // give some time wait thread to exit completely
+                Thread.sleep(2000);
+            } catch (InterruptedException e) {
+            }
+
             logger.display("MethodCompiling:: Provoke unloading compiled method - "
                                 + "\n\ttrying to unload class...");
             thrd = null;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/ClassUnloader.java b/test/hotspot/jtreg/vmTestbase/nsk/share/ClassUnloader.java
index 94b086f5757..5c7d2b8d640 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/share/ClassUnloader.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/share/ClassUnloader.java
@@ -239,6 +239,9 @@ public class ClassUnloader {
      *
      * @see WhiteBox.getWhiteBox().fullGC()
      */
+
+    public static final int MAX_UNLOAD_ATTEMPS = 10;
+
     public boolean unloadClass() {
 
         // free references to class and class loader to be able for collecting by GC
@@ -247,14 +250,26 @@ public class ClassUnloader {
 
         // force class unloading by triggering full GC
         WhiteBox.getWhiteBox().fullGC();
+        int count = 0;
+        while (count++ < MAX_UNLOAD_ATTEMPS && !isClassLoaderReclaimed()) {
+            System.out.println("ClassUnloader: waiting for class loader reclaiming... " + count);
+            WhiteBox.getWhiteBox().fullGC();
+            try {
+                // small delay to give more changes to process objects
+                // inside VM like jvmti deferred queue
+                Thread.sleep(100);
+            } catch (InterruptedException e) {
+            }
+        }
 
         // force GC to unload marked class loader and its classes
         if (isClassLoaderReclaimed()) {
-            Runtime.getRuntime().gc();
+            System.out.println("ClassUnloader: class loader has been reclaimed.");
             return true;
         }
 
         // class loader has not been reclaimed
+        System.out.println("ClassUnloader: class loader is still reachable.");
         return false;
     }
 }