diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/RegionStates.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/RegionStates.java
index 36bc8e28ba1..a29d675e287 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/RegionStates.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/RegionStates.java
@@ -20,6 +20,7 @@ package org.apache.hadoop.hbase.master;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -144,9 +145,8 @@ public class RegionStates {
   /**
    * @return an unmodifiable the region assignment map
    */
-  @SuppressWarnings("unchecked")
   public synchronized Map<HRegionInfo, ServerName> getRegionAssignments() {
-    return (Map<HRegionInfo, ServerName>)regionAssignments.clone();
+    return Collections.unmodifiableMap(regionAssignments);
   }
 
   /**