hibernate中Configuration和AnnotationConfiguration区别?

hibernate中Configuration config=new Configuration()和Configuration config=new AnnotationConfiguration()的区别?
工具类里面能共用在注解和映射xml文件的getSession()方法是怎样写的?
在注解的方法下运行,就报错:
An AnnotationConfiguration instance is required to use

final StandardServiceRegistry registry=
new StandardServiceRegistryBuilder().configure().build();

    SessionFactory sessionFactory=
            new MetadataSources(registry).buildMetadata().buildSessionFactory();
    Session sess=sessionFactory.openSession();