code: private void cleanupJob(JobInProgress job) {
     
      cleanupQueue.add(job.getJobID());
      
      while(cleanupQueue.size()> JOBS_IN_MUMAK_MEMORY) {
        JobID removedJob = cleanupQueue.poll();
  //      retireJob(removedJob, "");
      } 
    }
docs: The cleanupJob method maintains the queue cleanQueue. When a job is finalized,
  it is added to the cleanupQueue. Jobs are removed from the cleanupQueue
  so that its size is maintained to be less than that specified by
  JOBS_IN_MUMAK_MEMORY.
  @param job : The JobInProgress object that was just finalized and is
  going to be added to the cleanupQueue.