code: public static void waitUntilJobEnded(Key jobkey, int pollingIntervalMillis) {
      while (true) {
        if (Job.isEnded(jobkey)) {
          return;
        }
  
        try { Thread.sleep (pollingIntervalMillis); } catch (Exception ignore) {}
      }
    }
docs: Block synchronously waiting for a job to end, success or not.
  @param jobkey Job to wait for.
  @param pollingIntervalMillis Polling interval sleep time.