From 4ff49a75165cd362b30f586629d3935c964f49dd Mon Sep 17 00:00:00 2001
From: Luke Lu <llu@apache.org>
Date: Mon, 30 Sep 2013 17:01:51 +0000
Subject: [PATCH] HADOOP-9964. Fix deadlocks in TestHttpServer by synchronize
 ReflectionUtils.printThreadInfo. (Junping Du via llu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1527651 13f79535-47bb-0310-9956-ffa450edef68
---
 hadoop-common-project/hadoop-common/CHANGES.txt                | 3 +++
 .../src/main/java/org/apache/hadoop/util/ReflectionUtils.java  | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index ec2b47efd1f..b3a94f72f0f 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -61,6 +61,9 @@ Release 2.3.0 - UNRELEASED
 
   BUG FIXES
 
+    HADOOP-9964. Fix deadlocks in TestHttpServer by synchronize
+    ReflectionUtils.printThreadInfo. (Junping Du via llu)
+
     HADOOP-9582. Non-existent file to "hadoop fs -conf" doesn't throw error
     (Ashwin Shankar via jlowe)
 
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/ReflectionUtils.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/ReflectionUtils.java
index 4fee5f4f952..be63c816201 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/ReflectionUtils.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/ReflectionUtils.java
@@ -154,7 +154,7 @@ public class ReflectionUtils {
    * @param stream the stream to
    * @param title a string title for the stack trace
    */
-  public static void printThreadInfo(PrintWriter stream,
+  public synchronized static void printThreadInfo(PrintWriter stream,
                                      String title) {
     final int STACK_DEPTH = 20;
     boolean contention = threadBean.isThreadContentionMonitoringEnabled();