HADOOP-8431. Running distcp wo args throws IllegalArgumentException. Contributed by Sandy Ryza

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1381841 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -263,6 +263,9 @@ Release 2.0.1-alpha - UNRELEASED
     HADOOP-8749. HADOOP-8031 changed the way in which relative xincludes are handled in 
     Configuration. (ahmed via tucu)
 
+    HADOOP-8431. Running distcp wo args throws IllegalArgumentException.
+    (Sandy Ryza via eli)
+
   BREAKDOWN OF HDFS-3042 SUBTASKS
 
     HADOOP-8220. ZKFailoverController doesn't handle failure to become active

hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/DistCp.java

@@ -98,6 +98,11 @@ public class DistCp extends Configured implements Tool {
    * @return On success, it returns 0. Else, -1.
    */
   public int run(String[] argv) {
+    if (argv.length < 1) {
+      OptionsParser.usage();
+      return DistCpConstants.INVALID_ARGUMENT;
+    }
+    
     try {
       inputOptions = (OptionsParser.parse(argv));