code: public void setRunning(final boolean RUNNING) {
          running = RUNNING;
          if (RUNNING) {
              if (!CLOCK_TIMER.isRunning()) {
                  CLOCK_TIMER.start();
                  start = System.currentTimeMillis();
                  repaint(INNER_BOUNDS);
              }
          } else {
              if (CLOCK_TIMER.isRunning()) {
                  CLOCK_TIMER.stop();
              }
          }
      }
docs: Start or stop the stopwatch
  @param RUNNING