There is a wide variety of books published that could be of considerable use to Sakai developers. There is also a lot of trash that just isn't worth the money. The following book reviews may help you to decide where to spend your time and your money.
- Addison Wesley Writing Effective Use Cases
- core JavaServer Faces
- Head First Servlets and JSP
- Hibernate in Action
- Maven - A Developer's Notebook
- MySQL - Database Design and Tuning
- O'Reilly Java in a Nutshell
- O'Reilly JavaServer Faces
- Wiley Mastering JavaServer Faces
Please add to this list by reviewing technical books that you've read and use. You should also free free to add your own comments or follow-ons to existing reviews.