How to access a bean in a servlet file?

I use <jsp:useBean.... create a bean in a jsp file and set its scope to "session",when the file redirect to a servlet file,i don't know how use the instance of bean in the servlet?

I think that <jsp:useBean> action with a scope equals to "session" will put the object in the pageContext associated with the jsp page using a session scope. Therefore, this object is unavailable in the session object that you get with req.getSession() under a servlet.
Let's say you have defined an HttpSessionAttributeListener for the context, setting/unsetting session attributes in this context using jsp:setProperty will not fire any events either.
Rather ackward ain't it ?
Any comments ?