code: public void start() throws Throwable
     {
        if (!isExternal)
        {
           executorService = Executors.newSingleThreadExecutor(new ValidatorThreadFactory());
        }
  
        shutdown.set(false);
        interval = Long.MAX_VALUE;
        next = Long.MAX_VALUE;
  
        executorService.execute(new ConnectionValidatorRunner());
     }
docs: Start
  @exception Throwable Thrown if an error occurs