code: public static ScheduledFuture<?> asyncExecutePeriodically(Runnable task, long delay, long interval, TimeUnit t) {
  		if (task != null) {
  			try {
  				return Para.getScheduledExecutorService().scheduleAtFixedRate(task, delay, interval, t);
  			} catch (RejectedExecutionException ex) {
  				logger.warn(ex.getMessage());
  			}
  		}
  		return null;
  	}
docs: Executes a {@link java.lang.Runnable} at a fixed interval, asynchronously.
  @param task a task
  @param delay run after
  @param interval run at this interval of time
  @param t time unit
  @return a Future