Servlet and Filter pluggability from servlet 3.0

public class MyListener implements ServletContextListener{
    public void contextInitialized(ServletContextEvent sce) {
        ServletContext sc = sce.getServletContext();
        sc.addServlet("myServlet", "Sample servlet", "foo.bar.MyServlet",
                        null, -1);
        sc.addServletMapping("myServlet", new String[] {"/urlpattern/*"});
        sc.addFilter("myFilter", "Sample Filter", "foo.bar.MyFilter",
                        null);
        sc.addFilterMapping("myFilter", new String[] {"/urlpattern/*"},
                        “myServlet”, DispatcherType.REQUEST, false);
    }
}