code: protected synchronized void submit() {
      try {
        if (theJobConf.getBoolean("create.empty.dir.if.nonexist", false)) {
          FileSystem fs = FileSystem.get(theJobConf);
          Path inputPaths[] = FileInputFormat.getInputPaths(theJobConf);
          for (int i = 0; i < inputPaths.length; i++) {
            if (!fs.exists(inputPaths[i])) {
              try {
                fs.mkdirs(inputPaths[i]);
              } catch (IOException e) {
  
              }
            }
          }
        }
        RunningJob running = jc.submitJob(theJobConf);
        this.mapredJobID = running.getID();
        this.state = Job.RUNNING;
      } catch (IOException ioe) {
        this.state = Job.FAILED;
        this.message = StringUtils.stringifyException(ioe);
      }
    }
docs: Submit this job to mapred. The state becomes RUNNING if submission
  is successful, FAILED otherwise.