https://hadoop.apache.org/docs/r1.2.1/api/org/apache/hadoop/mapred/lib/aggregate/ValueAggregatorReducer.html
ValueAggregatorReducer (Hadoop 1.2.1 API)
hadoopapi
https://hadoop.apache.org/docs/current/api/org/apache/hadoop/mapreduce/lib/aggregate/ValueAggregatorReducer.html
ValueAggregatorReducer (Apache Hadoop Main 3.5.0 API)
declaration: package: org.apache.hadoop.mapreduce.lib.aggregate, class: ValueAggregatorReducer
apache hadoopmainapi