title: How to schedule a Callable to run on a specific time?
body: <p>I need to run a callable at a specific time of day. One way to do it is to calculate the timediff between now and the desired time , and to use the executor.scheduleAtFixedRate . </p>
  
  <p>Have a better idea?</p>
  
  <p><code>executor.scheduleAtFixedRate(command, TIMEDIFF(now,run_time), period, TimeUnit.SECONDS))</code></p>