test/java/lang/ThreadGroup/Stop.java

*** 1,7 ****
  /*
!  * Copyright (c) 1999, 2011, 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.
--- 1,7 ----
  /*
!  * 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
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
*** 26,87 ****
   * @bug 4176355
   * @summary Stopping a ThreadGroup that contains the current thread has
   *          unpredictable results.
   */
  
! public class Stop implements Runnable {
!     private static boolean groupStopped = false ;
!     private static final Object lock = new Object();
  
      private static final ThreadGroup group = new ThreadGroup("");
-     private static final Thread first = new Thread(group, new Stop());
-     private static final Thread second = new Thread(group, new Stop());
  
!     public void run() {
!         while (true) {
!             // Give the other thread a chance to start
!             try {
!                 Thread.sleep(1000);
!             } catch (InterruptedException e) {
              }
  
!             // When the first thread runs, it will stop the group.
!             if (Thread.currentThread() == first) {
!                 synchronized (lock) {
                      try {
                          group.stop();
!                     } finally {
!                         // Signal the main thread it is time to check
!                         // that the stopped thread group was successful
!                         groupStopped = true;
!                         lock.notifyAll();
!                     }
!                 }
!             }
!         }
!     }
  
      public static void main(String[] args) throws Exception {
          // Launch two threads as part of the same thread group
          first.start();
          second.start();
  
-         // Wait for the thread group stop to be issued
-         synchronized(lock){
-             while (!groupStopped) {
-                 lock.wait();
-                 // Give the other thread a chance to stop
-                 Thread.sleep(1000);
-             }
-         }
- 
          // Check that the second thread is terminated when the
          // first thread terminates the thread group.
!         boolean failed = second.isAlive();
! 
!         // Clean up any threads that may have not been terminated
!         first.stop();
!         second.stop();
!         if (failed)
!             throw new RuntimeException("Failure.");
      }
  }
--- 26,63 ----
   * @bug 4176355
   * @summary Stopping a ThreadGroup that contains the current thread has
   *          unpredictable results.
   */
  
! import java.util.concurrent.CountDownLatch;
  
+ public class Stop {
+ 
+     private static final CountDownLatch ready = new CountDownLatch(1);
      private static final ThreadGroup group = new ThreadGroup("");
  
!     private static final Thread second = new Thread(group, () -> {
!         ready.countDown();
!         while (true) { // keep it alive 
          }
+     });
  
!     private static final Thread first = new Thread(group, () -> {
!         // Wait until "second" is started
          try {
+             ready.await();
+         } catch (InterruptedException shouldNotHappen) {}
+         // Now stop the group
          group.stop();
!     });
  
      public static void main(String[] args) throws Exception {
          // Launch two threads as part of the same thread group
          first.start();
          second.start();
  
          // Check that the second thread is terminated when the
          // first thread terminates the thread group.
!         second.join();
!         // Test passed - if never get here the test times out and fails.
      }
  }