This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
"Is there any reason why you want to introduce Grails into that architecture?"
One of the reasons is that the development is faster in Grails. Grails has lots of plug-ins which can be used directly instead of developing the functionality from the scratch.