/*

 * 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.

 */

/* @test

 * @bug 4404702

 * @summary When the RMI runtime (lazily) spawns system threads that could

 * outlive the application context in which they were (happened to be)

 * created, such threads should not inherit (thread local) data specific to

 * such an application context for various isolation reasons (see 4219095).

 * While there is not yet a practical means for a general solution to this

 * problem, the particular problem documented in 4404702-- the inheritance

 * of the parent thread's context class loader, preventing that loader from

 * being garbage collected in the future-- can be easily fixed.  This test

 * verifies that the context class loader in effect when the first remote

 * object is exported (and thus when some long-lived RMI daemon threads are

 * created) can be garbage collected after the remote object has been

 * unexported.  [Note that this test is somewhat at the mercy of other J2SE

 * subsystems also not holding on to the loader in their daemon threads.]

 * @author Peter Jones

 *

 * @build RuntimeThreadInheritanceLeak

 * @build RuntimeThreadInheritanceLeak_Stub

 * @run main/othervm RuntimeThreadInheritanceLeak

 */

import java.lang.ref.Reference;

import java.lang.ref.ReferenceQueue;

import java.lang.ref.WeakReference;

import java.net.URL;

import java.net.URLClassLoader;

import java.rmi.Remote;

import java.rmi.RemoteException;

import java.rmi.server.UnicastRemoteObject;

import java.util.Iterator;

import java.util.Map;

public class RuntimeThreadInheritanceLeak implements Remote {

    private static final int TIMEOUT = 20000;

    public static void main(String[] args) {

        System.err.println("\nRegression test for bug 4404702\n");

        /*

         * HACK: Work around the fact that java.util.logging.LogManager's

         * (singleton) construction also has this bug-- it will register a

         * "shutdown hook", i.e. a thread, which will inherit and pin the

         * current thread's context class loader for the lifetime of the VM--

         * by causing the LogManager to be initialized now, instead of by

         * RMI when our special context class loader is set.

         */

        java.util.logging.LogManager.getLogManager();

        /*

         * HACK: Work around the fact that the non-native, thread-based

         * SecureRandom seed generator (ThreadedSeedGenerator) seems to

         * have this bug too (which had been causing this test to fail

         * when run with jtreg on Windows XP-- see 4910382).

         */

        (new java.security.SecureRandom()).nextInt();

        RuntimeThreadInheritanceLeak obj = new RuntimeThreadInheritanceLeak();

        try {

            ClassLoader loader = URLClassLoader.newInstance(new URL[0]);

            ReferenceQueue refQueue = new ReferenceQueue();

            Reference loaderRef = new WeakReference(loader, refQueue);

            System.err.println("created loader: " + loader);

            Thread.currentThread().setContextClassLoader(loader);

            UnicastRemoteObject.exportObject(obj);

            Thread.currentThread().setContextClassLoader(

                ClassLoader.getSystemClassLoader());

            System.err.println(

                "exported remote object with loader as context class loader");

            loader = null;

            System.err.println("nulled strong reference to loader");

            UnicastRemoteObject.unexportObject(obj, true);

            System.err.println("unexported remote object");

            /*

             * HACK: Work around the fact that the sun.misc.GC daemon thread

             * also has this bug-- it will have inherited our loader as its

             * context class loader-- by giving it a chance to pass away.

             */

            Thread.sleep(2000);

            System.gc();

            System.err.println(

                "waiting to be notified of loader being weakly reachable...");

            Reference dequeued = refQueue.remove(TIMEOUT);

            if (dequeued == null) {

                System.err.println(

                    "TEST FAILED: loader not deteced weakly reachable");

                dumpThreads();

                throw new RuntimeException(

                    "TEST FAILED: loader not detected weakly reachable");

            }

            System.err.println(

                "TEST PASSED: loader detected weakly reachable");

            dumpThreads();

        } catch (RuntimeException e) {

            throw e;

        } catch (Exception e) {

            throw new RuntimeException("TEST FAILED: unexpected exception", e);

        } finally {

            try {

                UnicastRemoteObject.unexportObject(obj, true);

            } catch (RemoteException e) {

            }

        }

    }

    /**

     * Dumps information about all live threads to System.err,

     * including their context class loaders.

     **/

    private static void dumpThreads() {

        System.err.println(

            "current live threads and their context class loaders:");

        Map threads = Thread.getAllStackTraces();

        for (Iterator iter = threads.entrySet().iterator(); iter.hasNext();) {

            Map.Entry e = (Map.Entry) iter.next();

            Thread t = (Thread) e.getKey();

            System.err.println("  thread: " + t);

            System.err.println("  context class loader: " +

                               t.getContextClassLoader());

            StackTraceElement[] trace = (StackTraceElement[]) e.getValue();

            for (int i = 0; i < trace.length; i++) {

                System.err.println("    " + trace[i]);

            }

        }

    }

}