Backport 12894a8

Author: duke

test/hotspot/jtreg/serviceability/jvmti/vthread/ThreadListStackTracesTest/ThreadListStackTracesTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 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
@@ -45,8 +45,9 @@ static void sleep(long millis) {
     }
 
     public void ensureReadyAndWaiting(Thread vt, Thread.State expState, ReentrantLock rlock) {
+        sleep(50); // reliability: wait for a potential class loading to complete
         // wait while the thread is not ready or thread state is unexpected
-        while (!threadReady || (vt.getState() != expState) || !rlock.hasQueuedThreads()) {
+        while (!threadReady || (vt.getState() != expState) || !rlock.hasQueuedThread(vt)) {
             sleep(1);
         }
     }
@@ -125,11 +126,12 @@ private static void checkStates(Thread vt, Thread.State expState) {
         int jvmtiExpState = (expState == Thread.State.WAITING) ?
                             JVMTI_THREAD_STATE_WAITING :
                             JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER;
+        Thread.State state = vt.getState();
 
-        System.out.printf("State: expected: %s single: %x multi: %x\n",
-                          vt.getState(), singleState, multiState);
+        System.out.printf("State: expected: %s, vt.getState(): %s, jvmtiExpState: %x single: %x multi: %x\n",
+                          expState, state, jvmtiExpState, singleState, multiState);
 
-        if (vt.getState() != expState) {
+        if (state != expState) {
             failed("Java thread state is wrong");
         }
         if ((singleState & jvmtiExpState) == 0) {