OutPutCommitter describes the commit of MapReduce task. FileOutputCommitter is the default available class available for OutputCommitter in MapReduce. It performs the following operations:
Create temporary output directory for the job during initialization.
Then, it cleans the job as in removes temporary output directory post job completion.
Sets up the task temporary output.
Identifies whether a task needs commit. The commit is applied if required.
JobSetup, JobCleanup and TaskCleanup are important tasks during output commit.