初学者hibernate编程式事务不能回滚

      public void test(){        User user=new User();        user.setUserName("lisi");        UserManager userManager=new UserManagerImpl();        userManager.addUser(user);    }

public class UserManagerImpl implements UserManager{    private LogManager logManager=new LogManagerImpl();    public void addUser(User user) {       Session session=null;       Transaction tx=null;       try {        session = HibernateSessionFactory.getSessionFactory()                .getCurrentSession();        tx=session.beginTransaction();        session.save(user);        Log log = new Log();        log.setType("anquanrizi");        Integer.parseInt("asdfasf");        log.setCont("XXX jinru xitong");        logManager.addLog(log);                tx.commit();    } catch (RuntimeException e) {        tx.rollback();    }    }            public void setLogManager(LogManager logManager) {        this.logManager = logManager;    }    }

package com.log.manager;import org.hibernate.Session;import com.HibernateSessionFactory;import com.log.entity.Log;public class LogManagerImpl implements LogManager{    public void addLog(Log log) {        Session session=null;        session = HibernateSessionFactory.getSessionFactory()                    .getCurrentSession();        session.save(log);            }}