[MAPREDUCE-796] Encountered "ClassCastException" on tasktracker while running wordcount with MultithreadedMapRunner

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.20.1
• Fix Version/s: 0.20.1
• Component/s: examples
• Hadoop Flags: Reviewed
• Release Note: Multithreaded mapper was modified to create a new Runtime exception (object) from a throwable instead of casting a throwable into a RuntimeException, once the Multithreaded map encounters a fault.
• Tags: ygridqa
• Assignee: Amar Kamat
• Reporter: Suman Sehgal
• Created: 23/Jul/09 11:29
• Updated: 31/Aug/09 05:25
• Resolved: 07/Aug/09 11:20

Description

ClassCastException for OutOfMemoryError is encountered on tasktracker while running wordcount example with MultithreadedMapRunner.

Stack trace :
=========
java.lang.ClassCastException: java.lang.OutOfMemoryError cannot be cast to java.lang.RuntimeException
at org.apache.hadoop.mapreduce.lib.map.MultithreadedMapper.run(MultithreadedMapper.java:149)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:581)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:303)
at org.apache.hadoop.mapred.Child.main(Child.java:170)