# Package org.apache.hadoop.mapreduce.lib.chain

- Class Summary
  Class | Description
  --- | ---
  Chain | The Chain class provides all the common functionality for the `ChainMapper` and the `ChainReducer` classes.
  ChainMapper<KEYIN,VALUEIN,KEYOUT,VALUEOUT> | The ChainMapper class allows to use multiple Mapper classes within a single Map task.
  ChainReducer<KEYIN,VALUEIN,KEYOUT,VALUEOUT> | The ChainReducer class allows to chain multiple Mapper classes after a Reducer within the Reducer task.

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