6799583: LogManager shutdown hook may cause a memory leak.
Reviewed-by: igor, swamyv
--- a/jdk/src/share/classes/java/util/logging/LogManager.java Fri Jan 30 22:30:32 2009 +0300
+++ b/jdk/src/share/classes/java/util/logging/LogManager.java Wed Feb 04 14:06:18 2009 +0300
@@ -215,6 +215,14 @@
// This private class is used as a shutdown hook.
// It does a "reset" to close all open handlers.
private class Cleaner extends Thread {
+
+ private Cleaner() {
+ /* Set context class loader to null in order to avoid
+ * keeping a strong reference to an application classloader.
+ */
+ this.setContextClassLoader(null);
+ }
+
public void run() {
// This is to ensure the LogManager.<clinit> is completed
// before synchronized block. Otherwise deadlocks are possible.
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/util/logging/ClassLoaderLeakTest.java Wed Feb 04 14:06:18 2009 +0300
@@ -0,0 +1,190 @@
+/*
+ * Copyright 2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/**
+ * @test
+ * @bug 6799583
+ *
+ * @summary Test verifes that LogManager shutdown hook does not cause
+ * an application classloader leaks.
+ *
+ * @run main/othervm ClassLoaderLeakTest
+ */
+
+import java.io.File;
+import java.lang.ref.WeakReference;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.concurrent.CountDownLatch;
+import java.util.logging.Logger;
+import java.util.logging.Logger;
+
+public class ClassLoaderLeakTest {
+
+ private static CountDownLatch doneSignal;
+ private static CountDownLatch launchSignal;
+ private static ThreadGroup appsThreadGroup;
+ private static Throwable launchFailure = null;
+
+ public static void main(String[] args) {
+ appsThreadGroup = new ThreadGroup("MyAppsThreadGroup");
+ doneSignal = new CountDownLatch(1);
+ launchSignal = new CountDownLatch(1);
+
+ Runnable launcher = new Runnable() {
+ public void run() {
+ try {
+ ClassLoader cl =
+ Thread.currentThread().getContextClassLoader();
+ Class appMain = cl.loadClass("AppTest");
+ Method launch =
+ appMain.getDeclaredMethod("launch", doneSignal.getClass());
+
+ Constructor c = appMain.getConstructor();
+
+ Object o = c.newInstance();
+
+ launch.invoke(o, doneSignal);
+
+ } catch (Throwable e) {
+ launchFailure = e;
+ } finally {
+ launchSignal.countDown();
+ }
+ }
+ };
+
+ /* prepare test class loader */
+ URL pwd = null;
+ try {
+
+ pwd = new File(System.getProperty("test.classes",".")).toURL();
+ } catch (MalformedURLException e) {
+ throw new RuntimeException("Test failed.", e);
+ }
+ URL[] urls = new URL[] { pwd };
+
+ MyClassLoader appClassLoader = new MyClassLoader(urls, "test0");
+ WeakReference<MyClassLoader> ref =
+ new WeakReference<MyClassLoader>(appClassLoader);
+
+
+ Thread appThread = new Thread(appsThreadGroup, launcher, "AppThread-0");
+ appThread.setContextClassLoader(appClassLoader);
+
+ appThread.start();
+ appClassLoader = null;
+ launcher = null;
+ appThread = null;
+
+ /* wait for laucnh completion */
+ try {
+ launchSignal.await();
+ } catch (InterruptedException e) {
+ }
+
+ /* check if launch failed */
+ if (launchFailure != null) {
+ throw new RuntimeException("Test failed.", launchFailure);
+ }
+
+ /* wait for test app excution completion */
+ try {
+ doneSignal.await();
+ } catch (InterruptedException e) {
+ }
+
+ /* give a chence to GC */
+ waitAndGC(5);
+
+ if (ref.get() != null) {
+ throw new RuntimeException("Test failed: classloader is still alive");
+ }
+
+ System.out.println("Test passed.");
+ }
+
+ private static class MyClassLoader extends URLClassLoader {
+
+ private static boolean verbose =
+ Boolean.getBoolean("verboseClassLoading");
+ private String uniqClassName;
+
+ public MyClassLoader(URL[] urls, String uniq) {
+ super(urls);
+
+ uniqClassName = uniq;
+ }
+
+ public Class loadClass(String name) throws ClassNotFoundException {
+ if (verbose) {
+ System.out.printf("%s: load class %s\n", uniqClassName, name);
+ }
+ if (uniqClassName.equals(name)) {
+ return Object.class;
+ }
+ return super.loadClass(name);
+ }
+
+ public String toString() {
+ return "MyClassLoader(" + uniqClassName + ")";
+ }
+ }
+
+ private static void waitAndGC(int sec) {
+ int cnt = sec;
+ System.out.print("Wait ");
+ while (cnt-- > 0) {
+ try {
+ Thread.sleep(1000);
+ } catch (InterruptedException e) {
+ }
+ // do GC every 3 seconds
+ if (cnt % 3 == 2) {
+ System.gc();
+ System.out.print("+");
+ } else {
+ System.out.print(".");
+ }
+ //checkErrors();
+ }
+ System.out.println("");
+ }
+}
+
+
+class AppTest {
+ public AppTest() {
+
+ }
+
+ public void launch(CountDownLatch done) {
+ Logger log = Logger.getLogger("app_test_logger");
+ log.fine("Test app is launched");
+
+ done.countDown();
+ }
+}