Getting error in Hadoop Streaming Type mismatch in Key from Map

Question

While executing Hadoop streaming program, I am getting an error saying Type mismatch in key from Map.

java.lang.Exception: java.io.IOException: Type mismatch in key from map: expected org.apache.hadoop.io.Text, recieved org.apache.hadoop.io.LongWritable

Can anyone explain me what the is error is trying to say and how can I resolve it?

Answer 1

In Hadoop streaming you have to customize your output and split it into key value pairs. I would recommend you to go through this official document about how to split key value pairs in streaming:

http://hadoop.apache.org/common/docs/current/streaming.html#Customizing+How+Lines+are+Split+into+Key%2FValue+Pairs