Some people have wondered why CDI requires an explicit @Named annotation before a bean can be accessed using EL? Why not just give all beans names by default?

Well, the reason is that EL has a single flat namespace. There's no notion of qualified names in EL. Experience in the JSF community is that avoiding duplicate names is harder than it looks, especially when the application includes multiple modules maintained by different teams. Remember that not all CDI beans are intended to form part of the user interface layer. A Java EE 6 application might include modules defining an independent business layer, whose beans should always be accessed via typesafe dependency injection instead of non-typesafe EL names. Beans in these modules should not have EL names, in order to avoid polluting the namespace of the UI layer.

Still, the combination @Named @RequestScoped is going to be super-common in JSF applications. So CDI includes a built-in stereotype that encapsulates these defaults. The @Model stereotype refers to the M role in the MVC pattern. We recommend that all JSF user-interface-oriented beans be annotated @Model to both save a little typing (one annotation instead of two), and, more importantly, to make clear their architectural role in the system.

Indeed, even when you have a UI model bean that's not @RequestScoped, I recommend annotating it @ConversationScoped @Model rather than @Named @ConversationScoped. The two options have the same functional effect, but the first combination communicates more information to someone reading your code later, and makes it easy to quickly search for all UI model beans.

(Of course, if, for whatever reason, you don't like @Model, you can always define your own stereotype to fulfil a similar purpose. The CDI container doesn't treat @Model in any special way.)

Congratulations to the whole AS team on the release of version 6! JBoss AS 6 is a Java EE 6 compliant application server, so it includes built-in support for many of the technologies we talk about here: CDI, JPA 2, Bean Validation, EJB 3.1, JSF 2.0, Servlets 3.0, along with many major enhancements in other areas.

Since the release of Weld and Java EE 6, there's been a heap of activity in the Weld user forum, and especially a lot of questions about problems related to framework development. You can do some kinds of generic programming in CDI just using managed beans, producer methods and InjectionPoint. But if you want to get serious, you're eventually going to have to embrace the portable extension SPI. Here's a couple of examples of how people are using this SPI.

Steven Verborgh has written a nice tutorial showing how to implement a custom JSF view scope for CDI. Henri Chen has integrated the ZK framework with CDI (hopefully other web frameworks won't be far behind). Matt Corey has been experimenting with environment configuration via JNDI.

Meanwhile, I've been working on compiling user feedback into a list of enhancements to the SPI. We plan to roll the most important items into the first CDI maintenance release.

UPDATE: for completeness, I should also link Pete Royle's Quartz scheduling extension.

As I'm sure you've all seen, Java EE 6 has gone final. You can now download the Final Release of the Contexts and Dependency Injection, Bean Validation, Java Persistence API 2 and Java Servlet 3 specifications from jcp.org, and read the linked javadoc for the entire platform. It's also a good chance to check out the Java API for RESTful Web Services specification, which now includes CDI integration, if you havn't already.

Sun have also published a three-part overview of the new platform and the Java EE 6 tutorial and sample applications.

It's just fantastic to finally see the fruits of all that work :-)

The Java EE 6 platform, along with Contexts and Dependency Injection, Bean Validation, EJB 3.1, JPA 2 and Servlet 3 have just been approved by the JCP EC. This completely changes the landscape for people developing web and enterprise applications in Java. There's just so much to digest here, and so many problems that are finally solved. EE 6 is something of a new start, and the beginning of a whole new ecosystem. Congratulations!