JDK 9 RFR of JDK-8132548: java/lang/ThreadGroup/Stop.java fails with "RuntimeException: Failure"

[Amy Lu]

Please review this trivial fix for test:java/lang/ThreadGroup/Stop.java

Though this is a test for a deprecated API, failed with very very low 
frequency and hard to reproduce (I got no luck to reproduce it), I’d 
like to patch it as suggested: extend the sleep in the main thread from 
one second to five seconds. Also added 'volatile' to the boolean 
variable 'groupStopped'.

bug: https://bugs.openjdk.java.net/browse/JDK-8132548
webrev: http://cr.openjdk.java.net/~amlu/8132548/webrev.00/

Thanks,
Amy


--- old/test/java/lang/ThreadGroup/Stop.java	2016-07-04 14:53:59.000000000 +0800
+++ new/test/java/lang/ThreadGroup/Stop.java	2016-07-04 14:53:58.000000000 +0800
@@ -1,5 +1,5 @@
  /*
- * Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
@@ -29,7 +29,7 @@
   */
  
  public class Stop implements Runnable {
-    private static boolean groupStopped = false ;
+    private static volatile boolean groupStopped = false ;
      private static final Object lock = new Object();
  
      private static final ThreadGroup group = new ThreadGroup("");
@@ -70,7 +70,7 @@
              while (!groupStopped) {
                  lock.wait();
                  // Give the other thread a chance to stop
-                Thread.sleep(1000);
+                Thread.sleep(5000);
              }
          }