code: public static SimulatorJobTracker startTracker(JobConf conf, long startTime)
    throws IOException, InterruptedException {
      return startTracker(conf, startTime, new SimulatorEngine());
    }
docs: Start the SimulatorJobTracker with given configuration after
  creating its own SimulatorEngine. Pretty much
  used for debugging only.
  @param conf :The starting configuration of the SimulatorJobTracker
  @param startTime :The starting time of simulation
  @return void
  @throws IOException
  @throws InterruptedException