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 * 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.

 *

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 */

/**

 * @test

 * @bug 8022595

 * @summary JSR292: deadlock during class loading of MethodHandles, MethodHandleImpl & MethodHandleNatives

 * @library /testlibrary

 * @modules java.base/jdk.internal.misc

 *          java.management

 * @run main/othervm ConcurrentClassLoadingTest

 */

import jdk.test.lib.Utils;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

import java.util.Random;

import java.util.concurrent.BrokenBarrierException;

import java.util.concurrent.CyclicBarrier;

public class ConcurrentClassLoadingTest {

    int numThreads = 0;

    CyclicBarrier l;

    private static final Random rand = Utils.getRandomInstance();

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

        ConcurrentClassLoadingTest test = new ConcurrentClassLoadingTest();

        test.parseArgs(args);

        test.run();

    }

    void parseArgs(String[] args) {

        int i = 0;

        while (i < args.length) {

            String flag = args[i];

            switch(flag) {

                case "-numThreads":

                    numThreads = Integer.parseInt(args[++i]);

                    break;

                default:

                    throw new Error("Unknown flag: " + flag);

            }

            ++i;

        }

    }

    void init() {

        if (numThreads == 0) {

            numThreads = Runtime.getRuntime().availableProcessors();

        }

        l = new CyclicBarrier(numThreads + 1);

        System.out.printf("Threads: %d\n", numThreads);

    }

    final List<Loader> loaders = new ArrayList<>();

    void prepare() {

        List<String> c = new ArrayList<>(Arrays.asList(classNames));

        // Split classes between loading threads

        int count = (classNames.length / numThreads) + 1;

        for (int t = 0; t < numThreads; t++) {

            List<String> sel = new ArrayList<>();

            System.out.printf("Thread #%d:\n", t);

            for (int i = 0; i < count; i++) {

                if (c.isEmpty()) {

                    break;

                }

                int k = rand.nextInt(c.size());

                String elem = c.remove(k);

                sel.add(elem);

                System.out.printf("\t%s\n", elem);

            }

            loaders.add(new Loader(sel));

        }

        // Print diagnostic info when the test hangs

        Runtime.getRuntime().addShutdownHook(new Thread() {

            public void run() {

                boolean alive = false;

                for (Loader l : loaders) {

                    if (!l.isAlive())  continue;

                    if (!alive) {

                        System.out.println("Some threads are still alive:");

                        alive = true;

                    }

                    System.out.println(l.getName());

                    for (StackTraceElement elem : l.getStackTrace()) {

                        System.out.println("\t"+elem.toString());

                    }

                }

            }

        });

    }

    public void run() throws Throwable {

        init();

        prepare();

        for (Loader loader : loaders) {

            loader.start();

        }

        l.await();

        for (Loader loader : loaders) {

            loader.join();

        }

    }

    class Loader extends Thread {

        List<String> classes;

        public Loader(List<String> classes) {

            this.classes = classes;

            setDaemon(true);

        }

        @Override

        public void run() {

            try {

                l.await();

                for (String name : classes) {

                    Class.forName(name).getName();

                }

            } catch (ClassNotFoundException | BrokenBarrierException | InterruptedException e) {

                throw new Error(e);

            }

        }

    }

    final static String[] classNames = {

            "java.lang.invoke.CallSite",

            "java.lang.invoke.ConstantCallSite",

            "java.lang.invoke.LambdaConversionException",

            "java.lang.invoke.LambdaMetafactory",

            "java.lang.invoke.MethodHandle",

            "java.lang.invoke.MethodHandleInfo",

            "java.lang.invoke.MethodHandleProxies",

            "java.lang.invoke.MethodHandles",

            "java.lang.invoke.MethodType",

            "java.lang.invoke.MutableCallSite",

            "java.lang.invoke.SerializedLambda",

            "java.lang.invoke.SwitchPoint",

            "java.lang.invoke.VolatileCallSite",

            "java.lang.invoke.WrongMethodTypeException"

    };

}