1 /*
   2  * Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
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  23 
  24 /**
  25  * @test
  26  * @bug 4176355
  27  * @summary Stopping a ThreadGroup that contains the current thread has
  28  *          unpredictable results.
  29  */
  30 
  31 public class Stop implements Runnable {
  32     private static boolean groupStopped = false ;

  33     private static final Object lock = new Object();
  34 
  35     private static final ThreadGroup group = new ThreadGroup("");
  36     private static final Thread first = new Thread(group, new Stop());
  37     private static final Thread second = new Thread(group, new Stop());
  38 
  39     public void run() {
  40         while (true) {
  41             // Give the other thread a chance to start
  42             try {
  43                 Thread.sleep(1000);
  44             } catch (InterruptedException e) {
  45             }
  46 
  47             // When the first thread runs, it will stop the group.
  48             if (Thread.currentThread() == first) {
  49                 synchronized (lock) {
  50                     try {
  51                         group.stop();
  52                     } finally {
  53                         // Signal the main thread it is time to check
  54                         // that the stopped thread group was successful
  55                         groupStopped = true;
  56                         lock.notifyAll();
  57                     }
  58                 }
  59             }
  60         }
  61     }
  62 
  63     public static void main(String[] args) throws Exception {
  64         // Launch two threads as part of the same thread group
  65         first.start();
  66         second.start();
  67 
  68         // Wait for the thread group stop to be issued

  69         synchronized(lock){
  70             while (!groupStopped) {
  71                 lock.wait();
  72                 // Give the other thread a chance to stop
  73                 Thread.sleep(1000);
  74             }
  75         }
  76 
  77         // Check that the second thread is terminated when the
  78         // first thread terminates the thread group.
  79         boolean failed = second.isAlive();
  80 
  81         // Clean up any threads that may have not been terminated
  82         first.stop();
  83         second.stop();
  84         if (failed)
  85             throw new RuntimeException("Failure.");
  86     }
  87 }
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