Why are there two separate packages map-reduce package in Apache\'s hadoop package tree:
org.apache.hadoop.mapred
http://javasourcecode.or
They are separated out because both of these packages represent 2 different APIs. org.apache.hadoop.mapred
is the older API and org.apache.hadoop.mapreduce
is the new one. And it was done to allow programmers write MapReduce jobs in a more convenient, easier and sophisticated fashion. You might find this presentation useful, which talks about the differences in detail.
Hope this answers your question.