ID #1060

Hadoop 2.6 errors: Unable to initialize MapOutputCollector org.apache.hadoop.mapred.MapTask$MapOutputBuffer java.lang.NullPointerException

This error message is very general and could be related to multiple issues. After taking a look at the source code and my error message, I found it is related to the value type of my mapper. Because hadoop requires the map value out type implement Writable, and this type does not this sort of problem occurs. To fix the error, first check if your Map value out (which will be used for output collectors) is a type that implements Writable. For primitive Java types, make sure you use the Writable counterparts that come with hadoop, e.g., use IntWritable instead of Integer.

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