92 lines
3.2 KiB
Java
92 lines
3.2 KiB
Java
/*
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* Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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// See bug 5094825 / ClassLoadDeadlock.sh
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import java.net.*;
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import java.security.*;
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public class ClassLoaderDeadlock {
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public static void main(String[] args) throws Exception {
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// create a new classloader
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URL url = new URL("file:provider/");
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final DelayClassLoader cl = new DelayClassLoader(url);
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// install a provider on the custom class loader as the most prefered provider
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Class clazz = cl.loadClass("HashProvider");
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Provider p = (Provider)clazz.newInstance();
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Security.insertProviderAt(p, 1);
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// add a delay in class loading for reproducability
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cl.delay = 1000;
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new Thread() {
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public void run() {
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try {
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// load a random system class
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// this locks the DelayClassLoader and after the delay the system class loader
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Class c1 = cl.loadClass("java.lang.String");
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System.out.println(c1);
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} catch (Exception e) {
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e.printStackTrace();
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}
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}
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}.start();
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// make sure the other thread got a chance to run and grab the lock
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Thread.sleep(200);
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// load a random class from a signed JAR file to trigger JAR signature verification
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// locks system class loader first and then tries to lock DelayClassLoader to load the hashes
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// DEADLOCK HAPPENS HERE
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Class c2 = Class.forName("com.abc.Tst1");
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// NOT REACHED
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System.out.println(c2);
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System.out.println("OK");
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}
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static class DelayClassLoader extends URLClassLoader {
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volatile int delay;
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DelayClassLoader(URL url) {
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super(new URL[] {url});
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}
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protected synchronized Class loadClass(String name, boolean resolve) throws ClassNotFoundException {
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System.out.println("-loadClass(" + name + "," + resolve + ")");
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try {
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// delay so that we hold the lock for a longer period
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// makes it much easier to reproduce
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Thread.sleep(delay);
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} catch (InterruptedException e) { e.printStackTrace(); }
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return super.loadClass(name, resolve);
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}
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}
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}
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