JAAS Reference Guide in the JDK 8 documentation describes Java Authentication and Authorization Service (JAAS), which enables you to authenticate users and securely determine who is currently executing Java code, and authorize users to ensure that they have the access control rights, or permissions, required to do the actions performed.
JAAS Tutorials in the JDK 8 documentation provides tutorials about Java Authentication and Authorization Service (JAAS) authentication and authorization.
Java Authentication and Authorization Service (JAAS): LoginModule Developer's Guide shows you how to implement the LoginModule interface, which you plug into an application to provide a particular type of authentication.