| /* |
| * Copyright (c) 2004, 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. |
| */ |
| |
| // 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); |
| } |
| } |
| |
| } |