If you architect many secure Web applications, authentication and authorization are always important concerns. Defining an architecture so that users can sign on to many n-tier Web applications only once—regardless of who built the applications, when they were built, or what kind of OSs and application servers they run on—is always a big challenge. Here, Jian Zhong and Mike Lehr present a single sign-on (SSO) architecture using their real-world experience in developing n-tier Web applications for the Energy Information Administration (EIA) of the US Department of Energy. Discover how they solved this business problem using cutting-edge Java 2 Platform, Enterprise Edition (J2EE) technologies. (2,500 words)

In this article, Steven Gould introduces the 13 core technologies of the Java 2 Platform, Enterprise Edition (J2EE): JDBC, JNDI, EJBs, RMI, JSP, Java servlets, XML, JMS, Java IDL, JTS, JTA, JavaMail, and JAF. To ground things in the real world, Gould explains J2EE in context of one of the its major implementations, BEA Systems' WebLogic Server. (3,200 words)

Creating the client tier of an n-tier Web architecture is extremely time-consuming, with an immense chance for error. In this article, Jason Cai, Ranjit Kapila, and Gaurav Pal explain HMVC -- an industrial-strength design pattern that can significantly lower the risks and costs associated with developing a Java-based client tier. The authors outline HMVC's design philosophy and some key aspects of it; they also provide a lucid example of how you can apply it. HMVC is applicable to both Java applets and applications; indeed, any object-oriented language could take advantage of this architecture. (3,000 words) The task of designing and developing the client tier of an n-tier Web architecture often challenges developers. This is particularly true in the Web world, where the sheer variety of servers, deployment platforms, and protocols turns the challenge into a headache. A client-tier architect must address a number of questions:

• How should I structure my GUI?
• How will users interact with my GUI?
• How should I separate server-side/transport data formats from my GUI?
• How should I provide sound mechanisms for event management, application flows, and widget control?