/*

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

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 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * 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

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 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 7196045

 * @bug 8014294

 * @summary Possible JVM deadlock in ThreadTimesClosure when using HotspotInternal non-public API.

 * @modules java.management/sun.management

 * @run main/othervm -XX:+UsePerfData -Xmx32m ThreadCpuTimesDeadlock

 */

import java.lang.management.ManagementFactory;

import javax.management.JMException;

import javax.management.MBeanServer;

import javax.management.MalformedObjectNameException;

import javax.management.ObjectName;

public class ThreadCpuTimesDeadlock {

    public static byte[] dummy;

    public static long duration = 10 * 1000;

    private static final String HOTSPOT_INTERNAL = "sun.management:type=HotspotInternal";

    public static void main(String[] args) {

        MBeanServer server = ManagementFactory.getPlatformMBeanServer();

        ObjectName objName= null;

        try {

            ObjectName hotspotInternal = new ObjectName(HOTSPOT_INTERNAL);

            try {

                server.registerMBean(new sun.management.HotspotInternal(), hotspotInternal);

            } catch (JMException e) {

                throw new RuntimeException("HotSpotWatcher: Failed to register the HotspotInternal MBean" + e);

            }

            objName= new ObjectName("sun.management:type=HotspotThreading");

        } catch (MalformedObjectNameException e1) {

            throw new RuntimeException("Bad object name" + e1);

        }

        // Thread that allocs memory to generate GC's

        Thread allocThread = new Thread() {

          public void run() {

            while (true) {

              dummy = new byte[4096];

            }

          }

        };

        allocThread.setDaemon(true);

        allocThread.start();

        long endTime = System.currentTimeMillis() + duration;

        long i = 0;

        while (true) {

            try {

                server.getAttribute(objName, "InternalThreadCpuTimes");

            } catch (Exception ex) {

                System.err.println("Exception while getting attribute: " + ex);

            }

            i++;

            if (i % 10000 == 0) {

                System.out.println("Successful iterations: " + i);

            }

            if (System.currentTimeMillis() > endTime) {

                break;

            }

        }

        System.out.println("PASSED.");

    }

}