There are several ways to enable user authentication for web based applications, like .htaccess files, plain tekst files, databases, LDAP, etc. They all have their pros and cons. In case a central, flexible solution is needed, either a database or LDAP solution can be used.
According to the PrimeFaces website, "PrimeFaces is an open source component suite for Java Server Faces featuring 70+ Ajax powered rich set of JSF components. Additional TouchFaces module features a UI kit for developing mobile web applications.".
In the past few month several Java EE 6 related JSRs (Java Specification Requests) have been finalized. The final ballot for them ended on November 30 and all were approved. Today, December 10, 2009, Java EE 6 and GlassFish v3, THE reference implementation of Java EE6, are released.