[jira] [Created] (MAPREDUCE-5728) Guide NPE for serializer/deserializer in MapTask

["Jerry He (JIRA)" <ji...@apache.org>]

Jerry He created MAPREDUCE-5728:
-----------------------------------

             Summary: Guide NPE for serializer/deserializer in MapTask
                 Key: MAPREDUCE-5728
                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-5728
             Project: Hadoop Map/Reduce
          Issue Type: Improvement
          Components: client
    Affects Versions: 2.2.0
            Reporter: Jerry He
            Assignee: Jerry He
            Priority: Minor
             Fix For: 2.3.0, 2.2.1


Currently we will get NPE if the serializer/deserializer is not configured correctly.

{code}
14/01/14 11:52:35 INFO mapred.JobClient: Task Id : attempt_201401072154_0027_m_000002_2, Status : FAILED
java.lang.NullPointerException
        at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.<init>(MapTask.java:944)
        at org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:672)
        at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:740)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:368)
        at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
        at java.security.AccessController.doPrivileged(AccessController.java:362)
        at javax.security.auth.Subject.doAs(Subject.java:573)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1502)
        at org.apache.hadoop.mapred.Child.main(Child.java:249)
{code}

serializationFactory.getSerializer and serializationFactory.getDeserializer returns NULL in this case.
Let's guide NPE for serializer/deserializer in MapTask so that we don't get meaningless NPE.



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