MAPREDUCE-6221. Stringifier is left unclosed in Chain#getChainElementConf(). Contributed by Ted Yu.

hadoop-mapreduce-project/CHANGES.txt

@@ -356,6 +356,9 @@ Release 2.7.0 - UNRELEASED
     MAPREDUCE-6233. org.apache.hadoop.mapreduce.TestLargeSort.testLargeSort
     failed in trunk (zxu via rkanter)
 
+    MAPREDUCE-6221. Stringifier is left unclosed in Chain#getChainElementConf().
+    (Ted Yu via ozawa)
+
 Release 2.6.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/chain/Chain.java

@@ -575,9 +575,8 @@ public class Chain {
   protected static Configuration getChainElementConf(Configuration jobConf,
       String confKey) {
     Configuration conf = null;
-    try {
-      Stringifier<Configuration> stringifier = 
-        new DefaultStringifier<Configuration>(jobConf, Configuration.class);
+    try (Stringifier<Configuration> stringifier =
+        new DefaultStringifier<Configuration>(jobConf, Configuration.class);) {
       String confString = jobConf.get(confKey, null);
       if (confString != null) {
         conf = stringifier.fromString(jobConf.get(confKey, null));