None. I usually rely on the source code + javadocs. I might be biased but I find that most Java source code and documentations tend to be easier to read due to common practices employed by newer projects.

I can only give you pointers to JavaEE 6 books (overall).

Beginning GF3 is an OK introduction to JavaEE 6: http://www.amazon.com/Beginning-GlassFish-Experts-Voice-Tech...

Oracle Tutorial (formerly SUN tutorial) for JavaEE 6 is another OK one (reviews were meh, but you've got limited choice so...) http://docs.oracle.com/javaee/6/tutorial/doc/

I saw Amazon has the print edition and another one to be in stock by mid 2012 (Advanced Java EE 6...)

Here's another book covering Java EE6 (intro):

http://www.amazon.com/Java-EE-GlassFish-Application-Server/d...

Seems to cover Servlet more than Apress book (first book).

You probably would need to know JPA 2.0 (ORM) as well.

And some more "best practices/real world-ish" tutorials:

http://www.amazon.com/World-Night-Hacks-Dissecting-Business/...

Good luck.

http://www.amazon.com/Pro-JPA-Mastering-Persistence-Technolo...