HADOOP-7854. UGI getCurrentUser is not synchronized. Contributed by Daryn Sharp.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1208926 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -150,6 +150,8 @@ Release 0.23.1 - Unreleased
    HADOOP-7864. Building mvn site with Maven < 3.0.2 causes OOM errors.
    (Andrew Bayer via eli)
 
+   HADOOP-7854. UGI getCurrentUser is not synchronized. (Daryn Sharp via jitendra)
+
 Release 0.23.0 - 2011-11-01 
 
   INCOMPATIBLE CHANGES

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/UserGroupInformation.java

@@ -449,7 +449,8 @@ public class UserGroupInformation {
    * @return the current user
    * @throws IOException if login fails
    */
-  public static UserGroupInformation getCurrentUser() throws IOException {
+  public synchronized
+  static UserGroupInformation getCurrentUser() throws IOException {
     AccessControlContext context = AccessController.getContext();
     Subject subject = Subject.getSubject(context);
     if (subject == null || subject.getPrincipals(User.class).isEmpty()) {