8151486: Class.forName causes memory leak
Summary: Remove ClassLoader.domains
Reviewed-by: coleenp, dholmes, mchung, naoto
--- a/jdk/src/java.base/share/classes/java/lang/ClassLoader.java Fri Oct 07 21:28:00 2016 +0530
+++ b/jdk/src/java.base/share/classes/java/lang/ClassLoader.java Fri Oct 07 12:01:24 2016 -0700
@@ -292,9 +292,6 @@
new ProtectionDomain(new CodeSource(null, (Certificate[]) null),
null, this, null);
- // The initiating protection domains for all classes loaded by this loader
- private final Set<ProtectionDomain> domains;
-
// Invoked by the VM to record every loaded class with this loader.
void addClass(Class<?> c) {
classes.addElement(c);
@@ -349,13 +346,11 @@
if (ParallelLoaders.isRegistered(this.getClass())) {
parallelLockMap = new ConcurrentHashMap<>();
package2certs = new ConcurrentHashMap<>();
- domains = Collections.synchronizedSet(new HashSet<>());
assertionLock = new Object();
} else {
// no finer-grained lock; lock on the classloader instance
parallelLockMap = null;
package2certs = new Hashtable<>();
- domains = new HashSet<>();
assertionLock = this;
}
}
@@ -640,7 +635,6 @@
}, new AccessControlContext(new ProtectionDomain[] {pd}));
}
}
- domains.add(pd);
}
/**
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/lang/ClassLoader/forNameLeak/ClassForName.java Fri Oct 07 12:01:24 2016 -0700
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2016, 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.
+ */
+
+import java.net.URLClassLoader;
+
+/*
+ * This class is loaded by the custom URLClassLoader, and then calls
+ * Class.forName();
+ */
+public class ClassForName implements Runnable {
+ static {
+ if (!(ClassForName.class.getClassLoader() instanceof URLClassLoader)) {
+ throw new RuntimeException("Supposed to be loaded by URLClassLoader");
+ }
+ }
+
+ public void run() {
+ try {
+ Class.forName(java.util.List.class.getName(), false,
+ ClassLoader.getSystemClassLoader());
+ } catch (Throwable e) {
+ e.printStackTrace();
+ }
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/lang/ClassLoader/forNameLeak/ClassForNameLeak.java Fri Oct 07 12:01:24 2016 -0700
@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 2016, 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 8151486
+ * @summary Call Class.forName() on the system classloader from a class loaded
+ * from a custom classloader.
+ * @library /lib/testlibrary
+ * @build jdk.testlibrary.Utils JarUtils
+ * @build ClassForName ClassForNameLeak
+ * @run main/othervm/policy=test.policy -Djava.security.manager ClassForNameLeak
+ */
+
+import java.lang.ref.PhantomReference;
+import java.lang.ref.Reference;
+import java.lang.ref.ReferenceQueue;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.nio.file.FileSystems;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.List;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import jdk.testlibrary.Utils;
+
+/*
+ * Create .jar, load ClassForName from .jar using a URLClassLoader
+ */
+public class ClassForNameLeak {
+ private static final long TIMEOUT = (long)(5000.0 * Utils.TIMEOUT_FACTOR);
+ private static final String TESTCLASSES = System.getProperty("test.classes", ".");
+ private static final String CLASSFILENAME = "ClassForName.class";
+ private static final int THREADS = 10;
+ private static final ReferenceQueue<ClassLoader> rq = new ReferenceQueue<>();
+
+ // Use a new classloader to load the ClassForName class, then run its
+ // Runnable.
+ public static PhantomReference<ClassLoader> loadAndRun(Path jarFilePath)
+ throws Exception {
+ ClassLoader classLoader = new URLClassLoader(
+ new URL[]{jarFilePath.toUri().toURL()}) {
+ @Override public String toString() { return "LeakedClassLoader"; }
+ };
+
+ Class<?> loadClass = Class.forName("ClassForName", true, classLoader);
+ ((Runnable) loadClass.newInstance()).run();
+
+ PhantomReference<ClassLoader> ref = new PhantomReference<>(classLoader, rq);
+ System.out.println("returning phantom ref: " + ref + " to " + classLoader);
+ return ref;
+ }
+
+ public static void main(final String[] args) throws Exception {
+ // Create a temporary .jar file containing ClassForName.class
+ Path testClassesDir = Paths.get(TESTCLASSES);
+ Path jarFilePath = Files.createTempFile("cfn", ".jar");
+ JarUtils.createJarFile(jarFilePath, testClassesDir, CLASSFILENAME);
+ jarFilePath.toFile().deleteOnExit();
+
+ // Remove the ClassForName.class file that jtreg built, to make sure
+ // we're loading from the tmp .jar
+ Path classFile = FileSystems.getDefault().getPath(TESTCLASSES,
+ CLASSFILENAME);
+ Files.delete(classFile);
+
+ // Make simultaneous calls to the test method, to stress things a bit
+ ExecutorService es = Executors.newFixedThreadPool(THREADS);
+
+ List<Callable<PhantomReference<ClassLoader>>> callables =
+ Stream.generate(() -> {
+ Callable<PhantomReference<ClassLoader>> cprcl = () -> {
+ return loadAndRun(jarFilePath);
+ };
+ return cprcl;
+ }).limit(THREADS).collect(Collectors.toList());
+
+ List<Future<PhantomReference<ClassLoader>>> refs = es.invokeAll(callables);
+
+ // Give the GC a chance to enqueue the PhantomReferences
+ for (int i = 0; i < 10; i++) {
+ System.gc();
+ }
+ // Make sure all PhantomReferences to the leaked classloader are enqueued
+ for (int j = 0; j < THREADS; j++) {
+ Reference rmRef = rq.remove(TIMEOUT);
+ if (rmRef == null) {
+ throw new RuntimeException("ClassLoader was never enqueued!");
+ } else {
+ System.out.println("Enqueued " + rmRef);
+ }
+ }
+ System.out.println("All Classloaders successfully enqued");
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/lang/ClassLoader/forNameLeak/test.policy Fri Oct 07 12:01:24 2016 -0700
@@ -0,0 +1,6 @@
+grant {
+ permission java.io.FilePermission "<<ALL FILES>>", "read, write, delete";
+ permission java.lang.RuntimePermission "createClassLoader";
+ permission java.lang.RuntimePermission "getClassLoader";
+ permission java.util.PropertyPermission "*", "read"; /* for Utils */
+};