Developing Web Applications with Servlets and JSPs - Java EE 5 Development with NetBeans 6 - page 90

It also displays session properties such as the session ID, the session creation date,
the date the session was last accessed, and the allowed time of inactivity (in seconds)
allowed before the session expires.
The session tab also shows session attributes that existed before the request (if any)
and session attributes that were created during the request (if any).
The Context tab displays context information, including context attributes and
initialization parameters.
We can once again see attributes that were set by the application server. Had our
code stored objects as context attributes, they would be shown on this tab as well.
We can also see some initialization parameters that were added by the application
server. We can add initialization parameters by modifying the application's
web.xml deployment descriptor. Adding the following lines to our application's
web.xml would result in an initialzation parameter named admin_email with a
value of [e-mail] to be added to the servlet context.
<context-param>
<param-name>admin_email</param-name>
<param-value>[e-mail]</param-value>
</context-param>