关于attempt to create delete event with null entity的错误

关于attempt to create delete event with null entity的异常
在做spring和hibernate整合的时候，删除实体时有时经常报java.lang.IllegalArgumentException: attempt to create delete event with null entity这样的错误，今天用junit4做测试删除的时候报了这个错误，感谢网友的帮忙，终于解决。
解决办法是：
将

@Testpublic void deleteUser(){UserService us = (UserService) ac.getBean("userService");User user = null;if ((user = us.get(1)) != null){us.delete(user);}}