svn merge -c 1176178 from trunk for HDFS-2366.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1189425 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -1076,6 +1076,9 @@ Release 0.23.0 - Unreleased
     HDFS-2333. Change DFSOutputStream back to package private, otherwise,
     there are two SC_START_IN_CTOR findbugs warnings.  (szetszwo)
 
+    HDFS-2366. Initialize WebHdfsFileSystem.ugi in object construction.
+    (szetszwo)
+
   BREAKDOWN OF HDFS-1073 SUBTASKS
 
     HDFS-1521. Persist transaction ID on disk between NN restarts.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/web/WebHdfsFileSystem.java

@@ -91,17 +91,24 @@ public class WebHdfsFileSystem extends HftpFileSystem {
 
   private static final KerberosUgiAuthenticator AUTH = new KerberosUgiAuthenticator();
 
-  private UserGroupInformation ugi;
+  private final UserGroupInformation ugi;
   private final AuthenticatedURL.Token authToken = new AuthenticatedURL.Token();
   protected Path workingDir;
 
+  {
+    try {
+      ugi = UserGroupInformation.getCurrentUser();
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
   @Override
   public synchronized void initialize(URI uri, Configuration conf
       ) throws IOException {
     super.initialize(uri, conf);
     setConf(conf);
 
-    ugi = UserGroupInformation.getCurrentUser();
     this.workingDir = getHomeDirectory();
   }