David Holmes c93b24d852 8132785: java/lang/management/ThreadMXBean/ThreadLists.java fails intermittently
Reviewed-by: alanb, kevinw, dcubed, sspitsyn
2021-12-13 21:37:51 +00:00

95 lines
3.7 KiB
Java

/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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*
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
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*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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/*
* @test
* @bug 5047639 8132785
* @summary Check that the "java-level" APIs provide a consistent view of
* the thread list
* @comment Must run in othervm mode to avoid interference from other tests.
* @run main/othervm ThreadLists
*/
import java.lang.management.ManagementFactory;
import java.lang.management.ThreadMXBean;
import java.util.Map;
public class ThreadLists {
public static void main(String args[]) {
// Bug id : JDK-8151797
// Use a lambda expression so that call-site cleaner thread is started
Runnable printLambda = () -> {System.out.println("Starting Test");};
printLambda.run();
// get top-level thread group
ThreadGroup top = Thread.currentThread().getThreadGroup();
ThreadGroup parent;
do {
parent = top.getParent();
if (parent != null) top = parent;
} while (parent != null);
// get the thread count
int activeCount = top.activeCount();
// Now enumerate to see if we find any extras yet.
// Ensure the array is big enough for a few extras.
Thread[] threads = new Thread[activeCount * 2];
int newCount = top.enumerate(threads);
if (newCount != activeCount) {
System.out.println("Found different threads after enumeration:");
} else {
System.out.println("Initial set of enumerated threads:");
}
for (int i = 0; i < newCount; i++) {
System.out.println(" - Thread: " + threads[i].getName());
}
Map<Thread, StackTraceElement[]> stackTraces = Thread.getAllStackTraces();
ThreadMXBean threadBean = ManagementFactory.getThreadMXBean();
int threadCount = threadBean.getThreadCount();
long[] threadIds = threadBean.getAllThreadIds();
System.out.println("ThreadGroup: " + activeCount + " active thread(s)");
System.out.println("Thread: " + stackTraces.size() + " stack trace(s) returned");
System.out.println("ThreadMXBean: " + threadCount + " live threads(s)");
System.out.println("ThreadMXBean: " + threadIds.length + " thread Id(s)");
// check results are consistent
boolean failed = false;
if (activeCount != stackTraces.size()) failed = true;
if (activeCount != threadCount) failed = true;
if (activeCount != threadIds.length) failed = true;
if (failed) {
System.out.println("Set of stack-traced threads:");
for (Thread t : stackTraces.keySet()) {
System.out.println(" - Thread: " +
(t != null ? t.getName() : "null!"));
}
throw new RuntimeException("inconsistent results");
}
}
}