Hello,
I've having a problem running my map/reduce job on my cluster. The map
phase, completes successfully, but the reduce phase fails with the
following error message:
Error: java.lang.NullPointerException
at
java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:768)
at
org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.getMapCompletionEvents(ReduceTask.java:2835)
at
org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.run(ReduceTask.java:2756)
I've done a lot of searching, and I've found some solutions as to not having
any underscores in my hosts names. I changed them all, but the problem still
hasn't resolved.
Does anyone have any idea what the problem can be?
Thanks,
Farrokh
