Merge pull request #63 from singh264/openj9_issues_18089

Adjust ThreadListStackTracesTest for checkReentrantLock

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

@@ -20,6 +20,11 @@
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
+/*
+ * ===========================================================================
+ * (c) Copyright IBM Corp. 2023, 2023 All Rights Reserved
+ * ===========================================================================
+ */
 
 /**
  * @test
@@ -45,7 +50,15 @@ static void sleep(long millis) {
     }
 
     public void ensureReady(Thread vt, Thread.State expState) {
-        // wait while the thread is not ready or thread state is unexpected
+        /*
+         * Sleep for 1 second to allow the thread to reach the expected state.
+         * When the virtual thread is mounted, the virtual thread state,
+         * which is obtained from the carrier thread, can transition between
+         * WAITING and RUNNABLE before the virtual thread is parked on the
+         * lock.
+         */
+        sleep(1000);
+        // Wait while the thread is not ready or thread state is unexpected.
         while (!threadReady || (vt.getState() != expState)) {
             sleep(1);
         }
@@ -97,6 +110,10 @@ private static void checkReentrantLock() throws InterruptedException {
         String name = "ReentrantLockTestTask";
         TestTask task = new ReentrantLockTestTask();
         Thread vt = Thread.ofVirtual().name(name).start(task);
+        // Wait until vt is waiting to acquire the lock.
+        while (!reentrantLock.hasQueuedThread(vt)) {
+            TestTask.sleep(1);
+        }
         task.ensureReady(vt, expState);
         checkStates(vt, expState);
     }