code: public Map<String, Accumulator<?, ?>> getJobAccumulators(JobID jobID) {
  		JobAccumulators jobAccumulators = this.jobAccumulators.get(jobID);
  		if (jobAccumulators == null) {
  			return new HashMap<String, Accumulator<?, ?>>();
  		}
  		return jobAccumulators.getAccumulators();
  	}
docs: Returns all collected accumulators for the job. For efficiency the
  internal accumulator is returned, so please use it read-only.