@Override
  public Ball createNewBall(Ball ball) {
    if (ball.getRadius().compareTo(100D) > 0) {
      logger.error("Ball radius > 100.");
      throw new AppException("Ball radius > 100.");
    }

    logger.debug("Adding new ball. color={} radius={}", ball.getColor(), ball.getRadius());
    return ballDao.save(ball);
  }
 @Override
 public List<Ball> findAllBalls() {
   logger.debug("Getting list of all balls.");
   return ballDao.findAll();
 }