Spring2.5的MVC架构与2.0的相比,有那些改进?

刚刚学习spring的MVC
还有就是
public class LoginCtrl extends AbstractCommandController {

....
protected ModelAndView handle(HttpServletRequest request,
HttpServletResponse response, Object obj, BindException e)
throws Exception {
                                             dosomething();
                                             }

}


handle方法的调用者是???
返回的ModelAndView被存放到了那里??