I am currently creating collaboartive learning website based on the social networking ideas.

I have a Java servlet that uses HttpSession to store data.

When one user, User-A, logs in and does something on the website, User-B logs in. When User-A navigates to another page, User-B's information is shown instead of User-A's.

My Java servlet:

Code:
package control;

import java.io.IOException;
...