Reinventing wheels?

Although the sample code implemented tick synchronization between worker thread and robot thread, the use of token may not be necessary, since Java already had similar mechanism.

    worker = new Thread(() -> {
      try {
        while (true) {
          Thread.sleep(1000);
        }
      } catch (InterruptedException e) {
        Thread.currentThread().interrupt();
      }
    });

call worker.interrupt() whenever you don't need it anymore, or just wait robocode to call that method for you.