diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index b9aed27b852..1d4bddb4499 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -57,6 +57,9 @@ Release 2.4.1 - UNRELEASED
     HADOOP-10455. When there is an exception, ipc.Server should first check
     whether it is an terse exception.  (szetszwo)
 
+    HADOOP-10456. Bug in Configuration.java exposed by Spark
+    (ConcurrentModificationException).  (Nishkam Ravi via cnauroth)
+
 Release 2.4.0 - 2014-04-07 
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java
index 290c236aa25..18d4666ce06 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java
@@ -666,9 +666,9 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
      }
 
      this.updatingResource = new HashMap<String, String[]>(other.updatingResource);
+     this.finalParameters = new HashSet<String>(other.finalParameters);
    }
    
-    this.finalParameters = new HashSet<String>(other.finalParameters);
     synchronized(Configuration.class) {
       REGISTRY.put(this, null);
     }