code: public ScheduledFuture<?> executePeriodically(Runnable command, long delay)
     {
        return executor.scheduleWithFixedDelay(command, 0, delay, TimeUnit.MILLISECONDS);
     }
docs: Execute specified <code>command</code> periodically with <code>delay</code>.
  
  @param command - command that must be executed
  @param delay - delay between each command execution
  @return