How to setup session scope in servlet?

Question

bean tag can be used in jsp to setup its scop, like
<jsp:usebean id="abc" class="def" scope="session"/>
but is it possible to setup session scope to divide two users in order not to use the same bean? becuase i encounter a problem that, when using bean in servlet, seemly A user would access the data that B user just store in; at first, i try to compare if session == null or session.isNew(), but finally find out that their session.getId() is difference, thus i suppose that if i am able to decide via users' session id to limit their access to the bean just as jsp:usebean does!
is that right? or in what way is better?(i am now to rewrite my original code, it's a little bit complicate for some reasons, so i think, if possible, that via compare session id, that i do not know how, would be a better way!)
thanks in advice,

Answer 1

If each user has a separate session, then each one
should get their own instance of the bean. Is it
possible that that you store and retrieve a reference
to the bean in a servlet instance variable? That
would cause the problem you describe.do you mean by putting variable in situation like A) ; yes i did, but if i put bean in the body of doPost method, each time when bean are "new"ed, there may be error occurred, accounting for i hope to instantize with default value, but default constructor do nothing; thus if by only construct with default constructor, error would occurred and so a new constructor with parameters i put in the position you refferred to! would you like to tell me what's the right way for i am not so familiar with servlet.
thanks in advice,
A)
public class MyClassName extends HttpServlet {
BeanClass myBean = new BeanClass();
... doGet(...){}
... doPost(...){...}