不能添加數據到表中，報錯java.lang.ClassCastException

Question

                                Students s1 = new Students("S0000001","张三丰","男",new Date(),"武当山"); Students s2 = new Students("S0000002","郭靖","男",new Date(),"桃花岛"); Students s3 = new Students("S0000003","黄蓉","女",new Date(),"桃花岛"); session.save(s1)；                                session.save(s2); session.save(s3); tran.commit();                                sessionFactory.close();什麼回事啊？誰能解答一下。