svn merge -c 1199571 from branch-0.20-security for HADOOP-7664.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.20-security-205@1199572 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -27,6 +27,10 @@ Release 0.20.205.1 - unreleased
     HADOOP-5124. A few optimizations to FsNamesystem#RecentInvalidateSets.
     (Hairong Kuang via jitendra)
 
+    HADOOP-7664. Remove warmings when overriding final parameter configuration
+    if the override value is same as the final parameter value.
+    (Ravi Prakash via szetszwo)
+
   BUG FIXES
 
     HADOOP-7784. Fixed jsvc packaging. (Eric Yang)

src/core/org/apache/hadoop/conf/Configuration.java

@@ -1215,7 +1215,7 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
               if (storeResource) {
                 updatingResource.put(attr, name.toString());
               }
-            } else {
+            } else if (!value.equals(properties.getProperty(attr))) {
               LOG.warn(name+":a attempt to override final parameter: "+attr
                      +";  Ignoring.");
             }