test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetObjectMonitorUsage/objmonusage006.java

/*
 * Copyright (c) 2003, 2018, 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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 * questions.
 */

package nsk.jvmti.GetObjectMonitorUsage;

import nsk.share.Wicket;
import java.io.PrintStream;

public class objmonusage006 {

    final static int JCK_STATUS_BASE = 95;
    final static int WAIT_TIME = 100;

    final static int N_LATE_CHECKS = 1000;
    final static int N_THREADS = 10;

    static {
        try {
            System.loadLibrary("objmonusage006");
        } catch (UnsatisfiedLinkError ule) {
            System.err.println("Could not load objmonusage006 library");
            System.err.println("java.library.path:"
                + System.getProperty("java.library.path"));
            throw ule;
        }
    }

    public static Wicket startingBarrier;
    static Object lockCheck = new Object();

    native static void check(Object obj);
    native static int getRes();

    public static void main(String args[]) {
        args = nsk.share.jvmti.JVMTITest.commonInit(args);

        // produce JCK-like exit status.
        System.exit(run(args, System.out) + JCK_STATUS_BASE);
    }

    public static int run(String args[], PrintStream out) {
        int res = -1;
        for (int i = 0; i < N_THREADS; i++) {
            System.out.println("Starting LockingThread #" + i + ".");

            // Original objmonusage005 test block starts here:
            //
            LockingThread thr = new LockingThread();
            startingBarrier = new Wicket();
            thr.start();
            startingBarrier.waitFor();
            check(lockCheck);
            thr.letItGo();
            //
            // Original objmonusage005 test block ends here.

            res = getRes();
            if (res != 0) {
                return res;
            }

            // The worker thread is free to exit after the letItGo()
            // call above. This loop stresses the use of JVM/TI
            // GetObjectMonitorUsage() at thread exit time.
            synchronized (lockCheck) {
                // lockCheck needs to be locked for JVM/TI
                // GetObjectMonitorUsage() to cover the right
                // code paths.
                System.out.println("LockingThread #" + i + " starting "
                                   + N_LATE_CHECKS + " late checks.");
                for (int j = 0; j < N_LATE_CHECKS; j++) {
                    check(lockCheck);
                    res = getRes();
                    if (res != 0) {
                        return res;
                    }
                }
                System.out.println("LockingThread #" + i + " ran "
                                   + N_LATE_CHECKS + " late checks.");
            }
        }

        return res;
    }

    static class LockingThread extends Thread {
        private volatile boolean flag = true;

        public synchronized void run() {
            synchronized (lockCheck) {
                startingBarrier.unlock();
                int i = 0;
                int n = 1000;
                while (flag) {
                    if (n <= 0) {
                        n = 1000;
                    }
                    if (i > n) {
                        i = 0;
                        n--;
                    }
                    i++;
                }
            }
        }

        public void letItGo() {
            flag = false;
        }
    }
}