I recommend the following books because I think they are fairly good.
Spring Framework Class
- Spring in Action
by Craig Walls Ryan Breidenbach
- Java Persistence with Hibernate
by Christian Bauer and Gavin King
- Pro Spring 2.5 (Pro)
from Apress. I haven’t read this one, but it covers version 2.5
- Java Persistence with Hibernate
Groovy & Grails
- Programming Groovy
- Groovy Recipes
- Groovy & Grails Recipes
- The Definitive Guide to Grails
General
- The Pragmatic Programmer
Just for full disclosure, I joined Amazon affiliate program, so if you buy any books from Amazon by following the above links, they will give me a very, very small percentage of the sale 
