// Return thread IDs of deadlocked threads or null if any.
// It finds deadlocks involving only monitors if it's a Tiger VM.
// Otherwise, it finds deadlocks involving both monitors and
// the concurrent locks.
public long[] findDeadlockedThreads() throws IOException {
ThreadMXBean tm = getThreadMXBean();
if (supportsLockUsage && tm.isSynchronizerUsageSupported()) {
return tm.findDeadlockedThreads();
} else {
return tm.findMonitorDeadlockedThreads();
}
}
public static void main(String[] argv) throws Exception {
mbean = newPlatformMXBeanProxy(server, THREAD_MXBEAN_NAME, ThreadMXBean.class);
if (!mbean.isSynchronizerUsageSupported()) {
System.out.println("Monitoring of synchronizer usage not supported");
return;
}
thread.setDaemon(true);
thread.start();
// wait until myThread acquires mutex and lock owner is set.
while (!(mutex.isLocked() && mutex.getLockOwner() == thread)) {
try {
Thread.sleep(100);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
long[] ids = new long[] {thread.getId()};
// validate the local access
ThreadInfo[] infos = getThreadMXBean().getThreadInfo(ids, true, true);
if (infos.length != 1) {
throw new RuntimeException(
"Returned ThreadInfo[] of length=" + infos.length + ". Expected to be 1.");
}
thread.checkThreadInfo(infos[0]);
// validate the remote access
infos = mbean.getThreadInfo(ids, true, true);
if (infos.length != 1) {
throw new RuntimeException(
"Returned ThreadInfo[] of length=" + infos.length + ". Expected to be 1.");
}
thread.checkThreadInfo(infos[0]);
boolean found = false;
infos = mbean.dumpAllThreads(true, true);
for (ThreadInfo ti : infos) {
if (ti.getThreadId() == thread.getId()) {
thread.checkThreadInfo(ti);
found = true;
}
}
if (!found) {
throw new RuntimeException("No ThreadInfo found for MyThread");
}
System.out.println("Test passed");
}