code: public synchronized void enableAlarm() {
      if (!this.isAlarmEnabled) {
        LOG.log(Level.FINE, "Enabling the alarm and scheduling it to fire in {0} ms.", this.taskStatusCheckPeriod);
        this.isAlarmEnabled = true;
        this.scheduleAlarm();
      } else {
        LOG.log(Level.FINE, "Alarm is already enabled.");
      }
    }
docs: Enable the period alarm to send status updates.