[MAPREDUCE-5728] Check NPE for serializer/deserializer in MapTask

• Type: Improvement
• Status: Patch Available
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 2.2.0
• Component/s: client
• Labels: BB2015-05-TBR
• Assignee: Jerry He
• Reporter: Jerry He
• Created: 18/Jan/14 21:53
• Updated: 01/Sep/16 09:28

Description

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

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)

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

Issue Links

• duplicates: MAPREDUCE-2584 Check for serializers early, and give out more information regarding missing serializers