Amazon EMR
Amazon EMR Release Guide

Process Data with a Custom JAR

A custom JAR runs a compiled Java program that you upload to Amazon S3. Compile the program against the version of Hadoop you want to launch and submit a CUSTOM_JAR step to your Amazon EMR cluster. For more information about compiling a JAR file, see Build Binaries Using Amazon EMR.

For more information about building a Hadoop MapReduce application, see