1 /* 2 * Copyright (c) 1999, 2013 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 7181748 27 * @summary Suspending a ThreadGroup that contains the current thread has 28 * unpredictable results. 29 */ 30 31 public class Suspend implements Runnable { 32 33 private static int count = 0; 34 private static final ThreadGroup group = new ThreadGroup(""); 35 private static final Thread first = new Thread(group, new Suspend()); 36 private static final Thread second = new Thread(group, new Suspend()); 37 38 public void run() { 39 while (true) { 40 try { 41 Thread.sleep(100); 42 if (Thread.currentThread() == first) { 43 if (second.isAlive()) { 44 group.suspend(); 45 } 46 } else { 47 count++; 48 } 49 } catch (InterruptedException e) { 50 } 51 } 52 } 53 54 public static void main(String[] args) throws Exception { 55 // Launch two threads as part of the same thread group 56 first.start(); 57 second.start(); 58 59 // Wait for the thread group suspend to be issued 60 while (!first.isAlive() || !second.isAlive()) { 61 Thread.sleep(100); 62 } 63 Thread.sleep(1000); 64 // Suppose, the thread group is now suspended 65 66 count = 0; 67 Thread.sleep(1000); 68 69 // Increment of the count indicates that the second thread is still running 70 boolean failed = (count > 1); 71 first.stop(); 72 second.stop(); 73 if (failed) 74 throw new RuntimeException("Failure."); 75 } 76 }