Got ArrayOutOfBound exception while analyzing the job history

HADOOP-3150 introduced 2 new type of tasks called the cleanup tasks. These are logged to history either as map tasks or reduce tasks. The number of maps/reducers is also logged to history. Since the number of maps will be less than the total number of map tasks logged to history (actual num maps + cleanup tasks), I think thats the reason for this exception. The important question is to investigate the effect of HADOOP-3150 on job history and code related to it.