Java example source code file (TimedAcquireLeak.java)

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Java - Java tags/keywords

callable, cyclicbarrier, error, file, future, integer, ioexception, nanoseconds, process, quiesce, regex, resume, semaphore, string, threading, threads, throwable, util

The TimedAcquireLeak.java Java example source code

/*
 * 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.
 */

/*
 * @test
 * @bug 6460501 6236036 6500694 6490770
 * @summary Repeated failed timed waits shouldn't leak memory
 * @author Martin Buchholz
 */

// Note: this file is now out of sync with the jsr166 CVS repository due to the fix for 7092140

import java.util.*;
import java.util.regex.*;
import java.util.concurrent.*;
import java.util.concurrent.locks.*;
import static java.util.concurrent.TimeUnit.*;
import java.io.*;

public class TimedAcquireLeak {
    static String javahome() {
        String jh = System.getProperty("java.home");
        return (jh.endsWith("jre")) ? jh.substring(0, jh.length() - 4) : jh;
    }

    static final File bin = new File(javahome(), "bin");

    static String javaProgramPath(String programName) {
        return new File(bin, programName).getPath();
    }

    static final String java = javaProgramPath("java");
    static final String jmap = javaProgramPath("jmap");
    static final String jps  = javaProgramPath("jps");

    static String outputOf(Reader r) throws IOException {
        final StringBuilder sb = new StringBuilder();
        final char[] buf = new char[1024];
        int n;
        while ((n = r.read(buf)) > 0)
            sb.append(buf, 0, n);
        return sb.toString();
    }

    static String outputOf(InputStream is) throws IOException {
        return outputOf(new InputStreamReader(is, "UTF-8"));
    }

    static final ExecutorService drainers = Executors.newFixedThreadPool(12);
    static Future<String> futureOutputOf(final InputStream is) {
        return drainers.submit(
            new Callable<String>() { public String call() throws IOException {
                    return outputOf(is); }});}

    static String outputOf(final Process p) {
        try {
            Future<String> outputFuture = futureOutputOf(p.getInputStream());
            Future<String> errorFuture = futureOutputOf(p.getErrorStream());
            final String output = outputFuture.get();
            final String error = errorFuture.get();
            // Check for successful process completion
            equal(error, "");
            equal(p.waitFor(), 0);
            equal(p.exitValue(), 0);
            return output;
        } catch (Throwable t) { unexpected(t); throw new Error(t); }
    }

    static String commandOutputOf(String... cmd) {
        try { return outputOf(new ProcessBuilder(cmd).start()); }
        catch (Throwable t) { unexpected(t); throw new Error(t); }
    }

    // To be called exactly twice by the parent process
    static <T> T rendezvousParent(Process p,
                                  Callable<T> callable) throws Throwable {
        p.getInputStream().read();
        T result = callable.call();
        OutputStream os = p.getOutputStream();
        os.write((byte)'\n'); os.flush();
        return result;
    }

    // To be called exactly twice by the child process
    public static void rendezvousChild() {
        try {
            for (int i = 0; i < 100; i++) {
                System.gc(); System.runFinalization(); Thread.sleep(50);
            }
            System.out.write((byte)'\n'); System.out.flush();
            System.in.read();
        } catch (Throwable t) { throw new Error(t); }
    }

    static String match(String s, String regex, int group) {
        Matcher matcher = Pattern.compile(regex).matcher(s);
        matcher.find();
        return matcher.group(group);
    }

    static int objectsInUse(final Process child,
                            final String childPid,
                            final String className) {
        final String regex =
            "(?m)^ *[0-9]+: +([0-9]+) +[0-9]+ +\\Q"+className+"\\E$";
        final Callable<Integer> objectsInUse =
            new Callable<Integer>() { public Integer call() {
                Integer i = Integer.parseInt(
                    match(commandOutputOf(jmap, "-histo:live", childPid),
                          regex, 1));
                if (i > 100)
                    System.out.print(
                        commandOutputOf(jmap,
                                        "-dump:file=dump,format=b",
                                        childPid));
                return i;
            }};
        try { return rendezvousParent(child, objectsInUse); }
        catch (Throwable t) { unexpected(t); return -1; }
    }

    static void realMain(String[] args) throws Throwable {
        // jmap doesn't work on Windows
        if (System.getProperty("os.name").startsWith("Windows"))
            return;

        final String childClassName = Job.class.getName();
        final String classToCheckForLeaks = Job.classToCheckForLeaks();
        final String uniqueID =
            String.valueOf(new Random().nextInt(Integer.MAX_VALUE));

        final String[] jobCmd = {
            java, "-Xmx8m", "-XX:+UsePerfData",
            "-classpath", System.getProperty("test.classes", "."),
            childClassName, uniqueID
        };
        final Process p = new ProcessBuilder(jobCmd).start();

        final String childPid =
            match(commandOutputOf(jps, "-m"),
                  "(?m)^ *([0-9]+) +\\Q"+childClassName+"\\E *"+uniqueID+"$", 1);

        final int n0 = objectsInUse(p, childPid, classToCheckForLeaks);
        final int n1 = objectsInUse(p, childPid, classToCheckForLeaks);
        equal(p.waitFor(), 0);
        equal(p.exitValue(), 0);
        failed += p.exitValue();

        // Check that no objects were leaked.
        System.out.printf("%d -> %d%n", n0, n1);
        check(Math.abs(n1 - n0) < 2); // Almost always n0 == n1
        check(n1 < 20);
        drainers.shutdown();
    }

    //----------------------------------------------------------------
    // The main class of the child process.
    // Job's job is to:
    // - provide the name of a class to check for leaks.
    // - call rendezvousChild exactly twice, while quiescent.
    // - in between calls to rendezvousChild, run code that may leak.
    //----------------------------------------------------------------
    public static class Job {
        static String classToCheckForLeaks() {
            return
                "java.util.concurrent.locks.AbstractQueuedSynchronizer$Node";
        }

        public static void main(String[] args) throws Throwable {
            final ReentrantLock lock = new ReentrantLock();
            lock.lock();

            final ReentrantReadWriteLock rwlock
                = new ReentrantReadWriteLock();
            final ReentrantReadWriteLock.ReadLock readLock
                = rwlock.readLock();
            final ReentrantReadWriteLock.WriteLock writeLock
                = rwlock.writeLock();
            rwlock.writeLock().lock();

            final BlockingQueue<Object> q = new LinkedBlockingQueue