Brent Sordyl's blog

The sample application described here demonstrates using LDAP with the JBoss Security Extension (JBossSX), and describes a simple API for managing users, roles, and groups in LDAP. In addition, this article demonstrates the use of the Abstract Factory pattern to implement pluggable persistence.

An Abstract Factory is used to decouple the LDAP access classes in order that LDAP can easily be replaced with another type of storage. This is useful if you are building multiple web applications for different clients, some requiring LDAP storage, and others requiring a database.
(Link: Introduction to Securing Web Applications with JBoss and LDAP — Developer.com)

JBoss includes several bundled login modules suitable for most user management needs. JBoss can read user information from a relational database, an LDAP server or flat files. In addition to these core login modules, JBoss provides several other login modules that provide user information for very customized needs in JBoss. Before we explore the individual login modules, let’s take a look at a few login module configuration options that are common to multiple modules.
(Link: 8.5.3. Using JBoss Login Modules)