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/*
* Copyright (c) 2022, 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.
*/
/*
* @test
* @bug 4699981 8295278
* @summary This is a testcase for JDK-4699981. When 2 threads are loading the same class with
* the same classloader, and somehow one of the 2 threads releases the
* synchronization lock on the classloader, the JVM code
* throws ClassCircularityError, mistakenly.
* @library /test/lib
* @compile test-classes/Base.java test-classes/Derived.java test-classes/Support.java
* @run main/othervm ParallelCircularityTest
*/
import java.net.URL;
import java.net.URLClassLoader;
public class ParallelCircularityTest {
private Object lock = new Object();
private void test() throws Exception {
URL location = getClass().getProtectionDomain().getCodeSource().getLocation();
URLLoader loader = new URLLoader(new URL[] {location}, getClass().getClassLoader().getParent());
Class cls = loader.loadClass("Support");
Thread t1 = new Thread(new Run1(cls));
t1.start();
Thread.sleep(1000);
// Load Derived, will trigger a loadClassInternal for Base
loader.loadClass("Derived");
}
public static void main(String[] args) throws Exception {
ParallelCircularityTest pct = new ParallelCircularityTest();
pct.test();
}
public class URLLoader extends URLClassLoader {
private boolean m_firstTime = true;
public URLLoader(URL[] urls, ClassLoader parent) {
super(urls, parent);
}
public Class loadClass(String name) throws ClassNotFoundException {
if (name.equals("Base")) {
if (m_firstTime) {
m_firstTime = false;
// Notify the other thread
synchronized (lock) {
lock.notifyAll();
}
// Wait on the classloader to have the JVM throw ClassCircularityError
try {
synchronized (this) {
wait(5000);
}
}
catch (InterruptedException ignored) { }
}
}
return super.loadClass(name);
}
}
public class Run1 implements Runnable {
private Class cls;
public Run1(Class cls) {
this.cls = cls;
}
public void run() {
synchronized (lock) {
try {
lock.wait();
}
catch (InterruptedException ignored) {}
}
// Trigger loadClassInternal for Base
try {
cls.newInstance();
} catch (Throwable x) {
x.printStackTrace();
}
}
}
}
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