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 *

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 * published by the Free Software Foundation.

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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 6331746

 * @summary Test a deadlock and will be blocked forever if the deadlock is present.

 * @author Shanliang JIANG

 * @run main DeadlockTest

 */

import javax.management.*;

import javax.management.timer.*;

public class DeadlockTest extends StandardMBean {

    public <T> DeadlockTest(T implementation, Class<T> mbeanInterface)

    throws NotCompliantMBeanException {

        super(implementation, mbeanInterface);

    }

    public MBeanInfo getCachedMBeanInfo() {

        return super.getCachedMBeanInfo();

    }

    public void cacheMBeanInfo(MBeanInfo mi) {

        super.cacheMBeanInfo(mi);

    }

    public static void main(String[] args) throws Exception {

        System.out.println("main: No deadlock please.");

        System.out.println("main: Create a BadBay to hold the lock forever.");

        DeadlockTest dt = new DeadlockTest(new Timer(), TimerMBean.class);

        BadBoy bb = new BadBoy(dt);

        bb.start();

        synchronized(bb) {

            while(!bb.gotLock) {

                bb.wait(); // if blocked here, means failing to get lock, impossible.

            }

        }

        System.out.println("main: The BadBay is holding the lock forever.");

        System.out.println("main: Create a WorkingBoy to see blocking ...");

        WorkingBoy wb = new WorkingBoy(dt);

        synchronized(wb) {

            wb.start();

            while(!wb.done) {

                wb.wait(); // if blocked here, the deadlock happends

            }

        }

        System.out.println("main: OK, bye bye.");

    }

    private static class BadBoy extends Thread {

        public BadBoy(Object o) {

            setDaemon(true);

            this.o = o;

        }

        public void run() {

            System.out.println("BadBoy-run: keep synchronization lock forever!");

            synchronized(o) {

                synchronized(this) {

                    gotLock = true;

                    this.notify();

                }

                try {

                    Thread.sleep(10000000);

                } catch (Exception e) {

                    // OK

                }

            }

        }

        final Object o;

        public boolean gotLock;

    }

    private static class WorkingBoy extends Thread {

        public WorkingBoy(DeadlockTest sm) {

            setDaemon(true);

            this.sm = sm;

        }

        public void run() {

            try {

                System.out.println("WorkingBoy-run: calling StandardMBean methods ...");

                System.out.println("WorkingBoy-run: calling setImplementation ...");

                sm.setImplementation(new Timer());

                System.out.println("WorkingBoy-run: calling getImplementation ...");

                sm.getImplementation();

                System.out.println("WorkingBoy-run: calling getMBeanInterface ...");

                sm.getMBeanInterface();

                System.out.println("WorkingBoy-run: calling getImplementationClass ...");

                sm.getImplementationClass();

                System.out.println("WorkingBoy-run: calling cacheMBeanInfo ...");

                sm.cacheMBeanInfo(null);

                System.out.println("WorkingBoy-run: calling getCachedMBeanInfo ...");

                sm.getCachedMBeanInfo();

                System.out.println("WorkingBoy-run: All done!");

                synchronized(this) {

                    done = true;

                    this.notifyAll();

                }

            } catch (NotCompliantMBeanException ne) {

                // Impossible?

                throw new RuntimeException(ne);

            }

        }

        final DeadlockTest sm;

        public boolean done;

    }

}