class RepositoryBookmarkService implements BookmarkService {

    @Override
    public void removeBookmarkOfUser(User user, Project project) {
        if(userHasBookmark(user, project)) {

            // remove the bookmark and update the entity
            user.removeBookmark(project);
            userRepo.save(user);

        } else {
            throw new BookmarkNotFoundException();
        }
    }

    @Autowired public  RepositoryBookmarkService(UserRepository userRepo);

}