The Session JSP tag library provides tags for reading
or modifying client HttpSession information.
A servlet container uses an HttpSession to store information
about a clients session on the server. By default a JSP page
will create a session for a user. The user is tied to the
session using either a Cookie or by using URL rewriting.
This is how you can tie information to a user between multiple
HTTP requests to your server.
Session Attributes are what makes it possible to store
information about a clients session between multiple HTTP
requests. A session attribute consists of a name and value.
To save information about a users session on your server use
the setattribute tag.