1 /*
2 * Copyright (c) 2005, 2015, 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 /*
26 * @test
27 * @bug 5086470
28 * @key intermittent
29 * @summary Basic Test for the following methods:
30 * - ThreadMXBean.findDeadlockedThreads()
31 * - ThreadMXBean.findMonitorDeadlockedThreads()
32 * @author Mandy Chung
33 *
34 * @build MonitorDeadlock
35 * @build SynchronizerDeadlock
36 * @build ThreadDump
37 * @run main/othervm FindDeadlocks
38 */
39
40 import java.lang.management.*;
41 import java.util.*;
42
43 public class FindDeadlocks {
44 static ThreadMXBean mbean = ManagementFactory.getThreadMXBean();
45 public static void main(String[] argv) {
46 ThreadMXBean mbean = ManagementFactory.getThreadMXBean();
47 // create deadlocked threads
48 MonitorDeadlock md = new MonitorDeadlock();
49
50 // no deadlock
51 if (findDeadlocks() != null) {
52 throw new RuntimeException("TEST FAILED: Should return null.");
53 }
54
55 // Let the threads to proceed
56 md.goDeadlock();
57 // wait until the deadlock is ready
58 md.waitUntilDeadlock();
59
60 long[] mthreads = findDeadlocks();
61 if (mthreads == null) {
62 ThreadDump.dumpStacks();
63 throw new RuntimeException("TEST FAILED: Deadlock not detected.");
64 }
65 md.checkResult(mthreads);
66
67 // create deadlocked threads on synchronizers
68 SynchronizerDeadlock sd = new SynchronizerDeadlock();
69
70 // Let the threads to proceed
71 sd.goDeadlock();
72 // wait until the deadlock is ready
73 sd.waitUntilDeadlock();
74
75 // Find Deadlock
76 long[] threads = findDeadlocks();
77 if (threads == null) {
78 ThreadDump.dumpStacks();
79 throw new RuntimeException("TEST FAILED: Deadlock not detected.");
80 }
81
82 // form a list of newly deadlocked threads
83 long[] newList = new long[threads.length - mthreads.length];
84 int count = 0;
85 for (int i = 0; i < threads.length; i++) {
86 long id = threads[i];
87 boolean isNew = true;
88 for (int j = 0; j < mthreads.length; j++) {
89 if (mthreads[j] == id) {
90 isNew = false;
91 break;
92 }
93 }
94 if (isNew) {
95 newList[count++] = id;
96 }
97 }
98
99 if (mbean.isSynchronizerUsageSupported()) {
100 sd.checkResult(newList);
101 } else {
102 // monitoring of synchronizer usage not supported
103 if (count != 0) {
104 throw new RuntimeException("TEST FAILED: NewList should be empty.");
105 }
106 }
107
108 // Print Deadlock stack trace
109 System.out.println("Found threads that are in deadlock:-");
110 ThreadInfo[] infos = mbean.getThreadInfo(threads, Integer.MAX_VALUE);
111 for (int i = 0; i < infos.length; i++) {
112 ThreadDump.printThreadInfo(infos[i]);
113 }
114
115 System.out.println("Test passed");
116 }
117 static long[] findDeadlocks() {
118 long[] threads;
119 if (mbean.isSynchronizerUsageSupported()) {
120 threads = mbean.findDeadlockedThreads();
121 } else {
122 threads = mbean.findMonitorDeadlockedThreads();
123 }
124 return threads;
125 }
126
127 }