https://hadoop.apache.org/docs/r3.2.0/api/org/apache/hadoop/mapred/lib/class-use/ChainMapper.html
Uses of Class org.apache.hadoop.mapred.lib.ChainMapper (Apache Hadoop Main 3.2.0 API)
https://hadoop.apache.org/docs/r2.7.1/api/org/apache/hadoop/mapred/lib/ChainMapper.html
ChainMapper (Apache Hadoop Main 2.7.1 API)
apache hadoopmainapi