Monitor_contended01.java

/*
 * Copyright (c) 2007, 2012, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
/*
 * @Harness: java
 * @Runs: 0 = true
 */
package jtt.threads;

public final class Monitor_contended01 implements Runnable {

    private Monitor_contended01() {
    }

    static final Object cond = new Object();
    static final Object obj = new Object();

    boolean started = false;
    boolean acquired = false;

    public static boolean test(int i) throws InterruptedException {
        // test contention for monitor
        final Monitor_contended01 object = new Monitor_contended01();
        synchronized (obj) {
            new Thread(object).start();
            // wait for other thread to startup and contend
            synchronized (cond) {
                cond.wait(1000);
                if (!object.started) {
                    return false;
                }
            }
        }
        // wait for other thread to acquire monitor and then exit
        synchronized (cond) {
            cond.wait(1000);
        }
        return object.acquired;
    }

    public void run() {
        // signal that we have started up so first thread will release lock
        synchronized (cond) {
            started = true;
            cond.notifyAll();
        }
        synchronized (obj) {

        }
        // signal that we have successfully acquired and released the monitor
        synchronized (cond) {
            acquired = true;
            cond.notifyAll();
        }
    }

}