/*

 * Copyright (c) 2000, Oracle and/or its affiliates. All rights reserved.

 * 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

 * published by the Free Software Foundation.

 *

 * 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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

/*

 * @test

 * @bug     4363076

 * @summary Basic functional test of Thread.holdsLock(Object)

 * @author  Josh Bloch and Steffen Grarup

 */

public class HoldsLock {

    private static Object target = null;

    private static void checkLock(boolean value) {

        if (Thread.holdsLock(target) != value)

            throw new RuntimeException("Should be " + value);

    }

    static class LockThread extends Thread {

        public void run() {

            checkLock(false);

            synchronized(target) {

                checkLock(true);

            }

            checkLock(false);

        }

    }

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

        // Test null obj case

        try {

            checkLock(false);

            throw new RuntimeException("NullPointerException not thrown");

        } catch (NullPointerException e) {

        };

        // Test uncontested case

        target = new Object();

        checkLock(false);

        synchronized(target) {

            checkLock(true);

        }

        checkLock(false);

        // Test contested case

        synchronized(target) {

            checkLock(true);

            new LockThread().start();

            checkLock(true);

            Thread.sleep(100);

            checkLock(true);

        }

        checkLock(false);

    }

}