0N/A/*
2362N/A * Copyright (c) 1999, Oracle and/or its affiliates. All rights reserved.
0N/A * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
0N/A *
0N/A * This code is free software; you can redistribute it and/or modify it
0N/A * under the terms of the GNU General Public License version 2 only, as
0N/A * published by the Free Software Foundation.
0N/A *
0N/A * This code is distributed in the hope that it will be useful, but WITHOUT
0N/A * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
0N/A * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
0N/A * version 2 for more details (a copy is included in the LICENSE file that
0N/A * accompanied this code).
0N/A *
0N/A * You should have received a copy of the GNU General Public License version
0N/A * 2 along with this work; if not, write to the Free Software Foundation,
0N/A * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
0N/A *
2362N/A * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
2362N/A * or visit www.oracle.com if you need additional information or have any
2362N/A * questions.
0N/A */
0N/A
0N/A/* @test
0N/A * @bug 4178693
0N/A * @summary Ensure that null queue arguments don't crash the Reference handler
0N/A * @author Mark Reinhold
0N/A */
0N/A
0N/Aimport java.lang.ref.Reference;
0N/Aimport java.lang.ref.WeakReference;
0N/A
0N/A
0N/Apublic class NullQueue {
0N/A
0N/A private static Reference r = null;
0N/A
0N/A private static Thread findThread(String name) {
0N/A /* Find reference-handler thread */
0N/A ThreadGroup tg = Thread.currentThread().getThreadGroup();
0N/A for (ThreadGroup tgn = tg;
0N/A tgn != null;
0N/A tg = tgn, tgn = tg.getParent());
0N/A int nt = tg.activeCount();
0N/A Thread[] ts = new Thread[nt];
0N/A tg.enumerate(ts);
0N/A Thread refHandler = null;
0N/A for (int i = 0; i < ts.length; i++) {
0N/A if (ts[i].getName().equals(name)) return ts[i];
0N/A }
0N/A return null;
0N/A }
0N/A
0N/A private static void fork(Runnable proc) throws InterruptedException {
0N/A Thread t = new Thread(proc);
0N/A t.start();
0N/A t.join();
0N/A }
0N/A
0N/A public static void main(String[] args) throws Exception {
0N/A
0N/A Thread refHandler = findThread("Reference Handler");
0N/A if (refHandler == null)
0N/A throw new Exception("Couldn't find Reference-handler thread");
0N/A if (!refHandler.isAlive())
0N/A throw new Exception("Reference-handler thread is not alive");
0N/A
0N/A /* Invoke a Reference constructor, passing null for the queue */
0N/A fork(new Runnable() {
0N/A public void run() {
0N/A r = new WeakReference(new Object(), null);
0N/A }});
0N/A
0N/A /* Force the reference to be cleared and enqueued by the GC */
0N/A for (int i = 0;; i++) {
0N/A Thread.sleep(10);
0N/A System.gc();
0N/A if (r.get() == null) break;
0N/A if (i >= 10)
0N/A throw new Exception("Couldn't cause weak ref to be cleared");
0N/A }
0N/A
0N/A /* Check that the handler is still alive */
0N/A if (!refHandler.isAlive())
0N/A throw new Exception("Reference-handler thread died");
0N/A
0N/A }
0N/A
0N/A}