/*

 * Copyright 2004 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

// See bug 5094825 / ClassLoadDeadlock.sh

import java.net.*;

import java.security.*;

public class ClassLoaderDeadlock {

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

        // create a new classloader

        URL url = new URL("file:provider/");

        final DelayClassLoader cl = new DelayClassLoader(url);

        // install a provider on the custom class loader as the most prefered provider

        Class clazz = cl.loadClass("HashProvider");

        Provider p = (Provider)clazz.newInstance();

        Security.insertProviderAt(p, 1);

        // add a delay in class loading for reproducability

        cl.delay = 1000;

        new Thread() {

            public void run() {

                try {

                    // load a random system class

                    // this locks the DelayClassLoader and after the delay the system class loader

                    Class c1 = cl.loadClass("java.lang.String");

                    System.out.println(c1);

                } catch (Exception e) {

                    e.printStackTrace();

                }

            }

        }.start();

        // make sure the other thread got a chance to run and grab the lock

        Thread.sleep(200);

        // load a random class from a signed JAR file to trigger JAR signature verification

        // locks system class loader first and then tries to lock DelayClassLoader to load the hashes

        // DEADLOCK HAPPENS HERE

        Class c2 = Class.forName("com.abc.Tst1");

        // NOT REACHED

        System.out.println(c2);

        System.out.println("OK");

    }

    static class DelayClassLoader extends URLClassLoader {

        volatile int delay;

        DelayClassLoader(URL url) {

            super(new URL[] {url});

        }

        protected synchronized Class loadClass(String name, boolean resolve) throws ClassNotFoundException {

            System.out.println("-loadClass(" + name + "," + resolve + ")");

            try {

                // delay so that we hold the lock for a longer period

                // makes it much easier to reproduce

                Thread.sleep(delay);

            } catch (InterruptedException e) { e.printStackTrace(); }

            return super.loadClass(name, resolve);

        }

    }

}