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/*
* Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2021, BELLSOFT. 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.
*/
/*
* LoadLibraryUnload class calls ClassLoader.loadedLibrary from multiple threads
*/
/*
* The driver for this test is LoadLibraryUnloadTest.java.
*
* @bug 8266310
* @summary Loads a native library from multiple class loaders and multiple
* threads. This creates a race for loading the library. The winner
* loads the library in two threads. All threads except two would fail
* with UnsatisfiedLinkError when the class being loaded is already
* loaded in a different class loader that won the race. The test
* checks that the loaded class is GC'ed, that means the class loader
* is GC'ed and the native library is unloaded.
*/
import jdk.test.lib.Asserts;
import jdk.test.lib.Utils;
import java.lang.*;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.lang.reflect.*;
import java.lang.ref.WeakReference;
import java.net.URL;
import java.net.URLClassLoader;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import jdk.test.lib.util.ForceGC;
import p.Class1;
public class LoadLibraryUnload {
private static class TestLoader extends URLClassLoader {
public TestLoader() throws Exception {
super(new URL[] { Path.of(System.getProperty("test.classes")).toUri().toURL() });
}
@Override
public Class<?> loadClass(String name) throws ClassNotFoundException {
synchronized (getClassLoadingLock(name)) {
Class<?> clazz = findLoadedClass(name);
if (clazz == null) {
try {
clazz = findClass(name);
} catch (ClassNotFoundException ignore) {
}
if (clazz == null) {
clazz = super.loadClass(name);
}
}
return clazz;
}
}
}
private static class LoadLibraryFromClass implements Runnable {
Object object;
Method method;
Object canary;
public LoadLibraryFromClass(Class<?> fromClass, Object canary) {
try {
this.object = fromClass.newInstance();
this.method = fromClass.getDeclaredMethod("loadLibrary", Object.class);
this.canary = canary;
} catch (ReflectiveOperationException roe) {
throw new RuntimeException(roe);
}
}
@Override
public void run() {
try {
method.invoke(object, canary);
} catch (ReflectiveOperationException roe) {
throw new RuntimeException(roe);
}
}
}
public static void main(String[] args) throws Exception {
int LOADER_COUNT = 5;
List<Thread> threads = new ArrayList<>();
Object[] canary = new Object[LOADER_COUNT];
final WeakReference<Object> wCanary[] = new WeakReference[LOADER_COUNT];
for (int i = 0 ; i < LOADER_COUNT ; i++) {
// LOADER_COUNT loaders and 2X threads in total.
// winner loads the library in 2 threads
canary[i] = new Object();
wCanary[i] = new WeakReference<>(canary[i], null);
Class<?> clazz = new TestLoader().loadClass("p.Class1");
threads.add(new Thread(new LoadLibraryFromClass(clazz, canary[i])));
threads.add(new Thread(new LoadLibraryFromClass(clazz, canary[i])));
}
final Set<Throwable> exceptions = ConcurrentHashMap.newKeySet();
threads.forEach( t -> {
t.setUncaughtExceptionHandler((th, ex) -> {
// collect the root cause of each failure
Throwable rootCause = ex;
while((ex = ex.getCause()) != null) {
rootCause = ex;
}
exceptions.add(rootCause);
});
t.start();
});
// wait for all threads to finish
for (Thread t : threads) {
t.join();
}
// expect all errors to be UnsatisfiedLinkError
boolean allAreUnsatisfiedLinkError = exceptions
.stream()
.map(e -> e instanceof UnsatisfiedLinkError)
.reduce(true, (i, a) -> i && a);
// expect exactly 8 errors
int expectedErrorCount = (LOADER_COUNT - 1) * 2;
Asserts.assertTrue(exceptions.size() == expectedErrorCount,
"Expected to see " + expectedErrorCount + " failing threads");
Asserts.assertTrue(allAreUnsatisfiedLinkError,
"All errors have to be UnsatisfiedLinkError");
// release strong refs
threads = null;
canary = null;
exceptions.clear();
// Wait for the canary for each of the libraries to be GC'd (cleared)
boolean allClear = ForceGC.wait(() -> {
for (int i = 0; i < wCanary.length; i++) {
if (!wCanary[i].refersTo(null)) {
return false;
}
}
return true;
});
Asserts.assertTrue(allClear, "Not all WeakReferences cleared");
// Ensure the WeakReferences are strongly referenced until they can be dequeued
Reference.reachabilityFence(wCanary);
}
}
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