spring data jpa:插入而不是删除

我有一个基本的SpringBoot应用程序。使用spring初始化器、jpa、嵌入式tomcat、thymeleaf模板引擎,并将其打包为一个可执行的jar文件。我已创建此存储库类:

@Repository
public interface MenuRepository extends CrudRepository<Menu, Long> {

      @Cacheable("menus")
      @Query("select cur from Menu cur where cur.MenuId = ?1")
      Menu findMenuByMenuId (String MenuId);

      @Cacheable("menus")
      @Query("select cur from Menu cur where lower (cur.symbol) = lower (?1) ")
      Menu findMenuBySymbol (String symbol);

这项服务:

@Service
public class MenuService {

        @Autowired
    protected MenuRepository menuRepository;    

    @Autowired
    MenuPriceService menuPriceService;


     @Transactional
     public Menu save (Menu menu) {              
         return menuRepository.save (menu);
     }


     @Transactional
     public void delete (Menu menu) {
         menuRepository.delete  (menu);
     }
     ..
}


}

这个junit测试:

    @Test
    @Transactional
    public void testDelete () {

        String menuName = System.currentTimeMillis()+"";

        Menu menu = new Menu(); 
        menu.setMenuId(menuName);
        menuService.delete (menu);
}

但这是我在控制台上看到的

Hibernate: 
    insert 
    into
        t_menu
        (...) 
    values
        (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)