identityreducer in the new Hadoop API

hadoop, mapreduce

Solution

Mainly because in the new API `Mapper` and `Reducer` are classes instead of interfaces, they are the new replacement of IdentityMapper/Reducer.

So you just have to use `Mapper.class` and `Reducer.class` to get the identity.

Problem

I spent almost a day but couldn't figure out how to use IdentityReducer in the new Hadoop API. All references or classes I can find are with the old API. And obviously mixing up old API idetntitreducer class in the new API codebase doesn't go well. Any help will be appreciated.

Original source