public Optional<User> activateRegistration(String key) { log.debug("Activating user for activation key {}", key); userRepository .findOneByActivationKey(key) .map( user -> { // activate given user for the registration key. user.setActivated(true); user.setActivationKey(null); userRepository.save(user); log.debug("Activated user: {}", user); return user; }); return Optional.empty(); }