MAPREDUCE-6693. ArrayIndexOutOfBoundsException occurs when the length of the job name is equal to mapreduce.jobhistory.jobname.limit. Contributed by Ajith S.

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/main/java/org/apache/hadoop/mapreduce/v2/jobhistory/FileNameIndexUtils.java

@@ -311,7 +311,7 @@ public class FileNameIndexUtils {
       String encodedString, int limitLength) {
     assert(limitLength >= 0) : "limitLength should be positive integer";
 
-    if (encodedString.length() < limitLength) {
+    if (encodedString.length() <= limitLength) {
       return encodedString;
     }
 

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/test/java/org/apache/hadoop/mapreduce/v2/jobhistory/TestFileNameIndexUtils.java

@@ -481,4 +481,29 @@ public class TestFileNameIndexUtils {
     Assert.assertNull("Queue name incorrect after decoding old history file",
         info.getQueueName());
   }
+
+  @Test
+  public void testTrimJobNameEqualsLimitLength() throws IOException {
+    int jobNameTrimLength = 9;
+    JobIndexInfo info = new JobIndexInfo();
+    JobID oldJobId = JobID.forName(JOB_ID);
+    JobId jobId = TypeConverter.toYarn(oldJobId);
+    info.setJobId(jobId);
+    info.setSubmitTime(Long.parseLong(SUBMIT_TIME));
+    info.setUser(USER_NAME);
+    info.setJobName(JOB_NAME);
+    info.setFinishTime(Long.parseLong(FINISH_TIME));
+    info.setNumMaps(Integer.parseInt(NUM_MAPS));
+    info.setNumReduces(Integer.parseInt(NUM_REDUCES));
+    info.setJobStatus(JOB_STATUS);
+    info.setQueueName(QUEUE_NAME);
+    info.setJobStartTime(Long.parseLong(JOB_START_TIME));
+
+    String jobHistoryFile = FileNameIndexUtils.getDoneFileName(info,
+        jobNameTrimLength);
+    JobIndexInfo parsedInfo = FileNameIndexUtils.getIndexInfo(jobHistoryFile);
+
+    Assert.assertEquals("Job name did not get trimmed correctly", info
+        .getJobName().substring(0, jobNameTrimLength), parsedInfo.getJobName());
+  }
 }