Hadoop Word Count MapReduce Tutorial Deprecated

Question

I have done some work using Python Hadoop Streaming and I think it will be more helpful if I learn Java and begin to learn writing Mapreduce in Java and also have a better understanding of the hadoop code base.

I wanted to run the wordcount example and step through every line to learn it. However, I set up Eclipse and Maven, and finally I let all the red errors go away however, after all of that, in front of me is just paragraphs of deprecated code.

(1). Am I just wasting my time to learn something that will not be valid soon?

(2). Is it possible to use Eclipse to step through a complete Map Reduce so you can have a good idea of what is going on after every step? I am not a Java programmer but I am 100% in and want to learn it well. Can anyone point me to the right direction to learn it? DEBUG? JUNIT?

Answer 1

firstly, learn Java and MapReduce will lead to a deeper understanding of how MapReduce work. The version of Hadoop you used maybe a high version, old MapReduce APIs are deprecated, new APIs are encouraged.

if you want to discover how MR works, you can use remote debug, open the DEBUG level log, use related JUnit test classes, dive into the source code.

Have fine to learn how MR works.