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
31public class Suspend implements Runnable {
32
33    private static volatile 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    }
77}
78