# HG changeset patch
# User dcubed
# Date 1305575789 25200
# Node ID 5dfc211872f41e5071ca2e285ee72f90e30584bb
# Parent  8b66cd6c5ebc119616d8e994f2a06ba9e47eacf6
6977677: 3/2 Deadlock on logging subsystem initialization
Summary: Over synchronized Logger.getLogger() deadlocks with LogManager.<clinit>via PlatformLogger
Reviewed-by: dsamersoff, never, acorn, mchung

diff -r 8b66cd6c5ebc -r 5dfc211872f4 jdk/src/share/classes/java/util/logging/Logger.java
--- a/jdk/src/share/classes/java/util/logging/Logger.java	Mon May 16 17:28:18 2011 +0200
+++ b/jdk/src/share/classes/java/util/logging/Logger.java	Mon May 16 12:56:29 2011 -0700
@@ -310,7 +310,20 @@
      * @return a suitable Logger
      * @throws NullPointerException if the name is null.
      */
-    public static synchronized Logger getLogger(String name) {
+
+    // Synchronization is not required here. All synchronization for
+    // adding a new Logger object is handled by LogManager.addLogger().
+    public static Logger getLogger(String name) {
+        // This method is intentionally not a wrapper around a call
+        // to getLogger(name, resourceBundleName). If it were then
+        // this sequence:
+        //
+        //     getLogger("Foo", "resourceBundleForFoo");
+        //     getLogger("Foo");
+        //
+        // would throw an IllegalArgumentException in the second call
+        // because the wrapper would result in an attempt to replace
+        // the existing "resourceBundleForFoo" with null.
         LogManager manager = LogManager.getLogManager();
         return manager.demandLogger(name);
     }
@@ -355,7 +368,10 @@
      *             a different resource bundle name.
      * @throws NullPointerException if the name is null.
      */
-    public static synchronized Logger getLogger(String name, String resourceBundleName) {
+
+    // Synchronization is not required here. All synchronization for
+    // adding a new Logger object is handled by LogManager.addLogger().
+    public static Logger getLogger(String name, String resourceBundleName) {
         LogManager manager = LogManager.getLogManager();
         Logger result = manager.demandLogger(name);
         if (result.resourceBundleName == null) {
@@ -417,7 +433,10 @@
      * @throws MissingResourceException if the resourceBundleName is non-null and
      *             no corresponding resource can be found.
      */
-    public static synchronized Logger getAnonymousLogger(String resourceBundleName) {
+
+    // Synchronization is not required here. All synchronization for
+    // adding a new anonymous Logger object is handled by doSetParent().
+    public static Logger getAnonymousLogger(String resourceBundleName) {
         LogManager manager = LogManager.getLogManager();
         // cleanup some Loggers that have been GC'ed
         manager.drainLoggerRefQueueBounded();
diff -r 8b66cd6c5ebc -r 5dfc211872f4 jdk/test/java/util/logging/LoggingDeadlock4.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/util/logging/LoggingDeadlock4.java	Mon May 16 12:56:29 2011 -0700
@@ -0,0 +1,111 @@
+/*
+ * Copyright (c) 2011, 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     6977677
+ * @summary Deadlock between LogManager.<clinit> and Logger.getLogger()
+ * @author  Daniel D. Daugherty
+ * @build LoggingDeadlock4
+ * @run main/timeout=15 LoggingDeadlock4
+ */
+
+import java.awt.Container;
+import java.util.concurrent.CountDownLatch;
+import java.util.logging.LogManager;
+import java.util.logging.Logger;
+
+public class LoggingDeadlock4 {
+    private static CountDownLatch barrier      = new CountDownLatch(1);
+    private static CountDownLatch lmIsRunning  = new CountDownLatch(1);
+    private static CountDownLatch logIsRunning = new CountDownLatch(1);
+
+    public static void main(String[] args) {
+        System.out.println("main: LoggingDeadlock4 is starting.");
+
+        // Loading the java.awt.Container class will create a
+        // sun.util.logging.PlatformLogger$JavaLogger object
+        // that has to be redirected when the LogManager class
+        // is initialized. This can cause a deadlock between
+        // LogManager.<clinit> and Logger.getLogger().
+        try {
+            Class.forName("java.awt.Container");
+        } catch (ClassNotFoundException cnfe) {
+            throw new RuntimeException("Test failed: could not load"
+                + " java.awt.Container." + cnfe);
+        }
+
+        Thread lmThread = new Thread("LogManagerThread") {
+            public void run() {
+                // let main know LogManagerThread is running
+                lmIsRunning.countDown();
+
+                System.out.println(Thread.currentThread().getName()
+                    + ": is running.");
+
+                try {
+                    barrier.await();  // wait for race to start
+                } catch (InterruptedException e) {
+                }
+
+                LogManager manager = LogManager.getLogManager();
+            }
+        };
+        lmThread.start();
+
+        Thread logThread = new Thread("LoggerThread") {
+            public void run() {
+                // let main know LoggerThread is running
+                logIsRunning.countDown();
+
+                System.out.println(Thread.currentThread().getName()
+                    + ": is running.");
+
+                try {
+                    barrier.await();  // wait for race to start
+                } catch (InterruptedException e) {
+                }
+
+                Logger foo = Logger.getLogger("foo logger");
+            }
+        };
+        logThread.start();
+
+        try {
+            // wait for LogManagerThread and LoggerThread to get going
+            lmIsRunning.await();
+            logIsRunning.await();
+        } catch (InterruptedException e) {
+        }
+
+        barrier.countDown();  // start the race
+
+        try {
+            lmThread.join();
+            logThread.join();
+        } catch (InterruptedException ie) {
+        }
+
+        System.out.println("main: LoggingDeadlock4 is done.");
+    }
+}