code: public TaskCompletionEvent[] getTaskCompletionEvents(
      JobID jobid, int fromEventId, int maxEvents) throws IOException{
  
      JobInProgress job = this.jobs.get(jobid);
      if (null != job) {
        return job.inited() ? job.getTaskCompletionEvents(fromEventId, maxEvents)
           : TaskCompletionEvent.EMPTY_ARRAY;
      }
  
      return completedJobStatusStore.readJobTaskCompletionEvents(jobid, fromEventId, maxEvents);
    }
docs: /*
  Returns a list of TaskCompletionEvent for the given job,
  starting from fromEventId.
  @see org.apache.hadoop.mapred.JobSubmissionProtocol#getTaskCompletionEvents(java.lang.String, int, int)