This page links to two tutorials demonstrating various aspects of the use of JAAS (Java Authentication and Authorization Service):
Explains how an application can authenticate users using JAAS.
Explains how to enforce user-based access controls using JAAS.
The authentication technology used for these tutorials is very basic, just ensuring that the user specifies a particular name and password. Thus, these tutorials can be run by everyone.
These two tutorials are a part of the Java GSS-API and JAAS sequence of tutorials that utilize Kerberos as the underlying technology for authentication and secure communication.