title: ScheduledExecutorService - Check if scheduled task has already been completed
body: <p>I have a server side application where clients can request to reload the configuration. If a client request to reload the configuration, this should not be done immediately, but with an delay of 1 minute. If another client also requests to reload the configuration in the same minute, this request should be ignored. </p>
  
  <p>My idea is to schedule a task with a ScheduledExecutorService like: </p>
  
  <pre><code> ScheduledExecutorService service = Executors.newSingleThreadScheduledExecutor();
   service.schedule(new LoadConfigurationTask(), 1, TimeUnit.MINUTES);
  
   public class LoadConfigurationTask Runnable {
      public void run() {
        // LoadConfiguration
      }
   }
  </code></pre>
  
  <p>How can I check if a LoadConfigurationTask has been scheduled, but not executed yet, to be able to ignore further requests until the configuration is reloaded ?</p>