1 /*
   2  * Copyright (c) 1999, 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
  21  * questions.
  22  */
  23 
  24 /**
  25  * @test
  26  * @bug 4176355
  27  * @summary Suspending a ThreadGroup that contains the current thread has
  28  *          unpredictable results.
  29  */
  30 
  31 public class Suspend implements Runnable {
  32     private static Thread first=null;
  33     private static Thread second=null;
  34     private static ThreadGroup group = new ThreadGroup("");
  35     private static int count = 0;
  36 
  37     Suspend() {
  38         Thread thread = new Thread(group, this);
  39         if (first == null)
  40             first = thread;
  41         else
  42             second = thread;
  43 
  44         thread.start();
  45     }
  46 
  47     public void run() {
  48         while (true) {
  49             try {
  50                 Thread.sleep(1000); // Give other thread a chance to start
  51                 if (Thread.currentThread() == first)
  52                     group.suspend();
  53                 else
  54                     count++;
  55             } catch(InterruptedException e){
  56             }
  57         }
  58     }
  59 
  60     public static void main(String[] args) throws Exception {
  61         for (int i=0; i<2; i++)
  62             new Suspend();
  63         Thread.sleep(3000);
  64         boolean failed = (count > 1);
  65         first.stop(); second.stop();
  66         if (failed)
  67             throw new RuntimeException("Failure.");
  68     }
  69 }