code: public boolean checkHeartBeat() {
  
          String dataPath = executorMeta.getLocalDir();
          File localstate = new File(dataPath + "/data/" + startType + "/" + startType + ".heartbeat/");
          Long modefyTime = localstate.lastModified();
  
          if (System.currentTimeMillis() - modefyTime > JOYConstants.EXECUTOR_HEARTBEAT_TIMEOUT) {
  
              LOG.info("----------------------");
              modefyTime = localstate.lastModified();
              LOG.info(modefyTime.toString());
  
              LOG.info(Long.toString(new Date().getTime()));
              LOG.info(dataPath + "/data/" + startType + "/" + startType + ".heartbeat/");
  
              LOG.info("can't get heartbeat over " + String.valueOf(JOYConstants.EXECUTOR_HEARTBEAT_TIMEOUT) + " seconds");
              return false;
          } else
              return true;
      }
docs: check supervisor's heartBeat,
  
  @return