Here's an interesting e-mail I received last night:
I see AppFuse's strong points is in integrating a lot of oss in a
synergistic manner, which is really great and helpful. Just wondering
whether there is any chance of integrating AppFuse with groovy and
I also just found out about grails 0.1 and it looks really promising, for a 0.1 release.
I just feel that it has some synergy there, a java ruby on rails combines with the best oss integration available.
I think Grails and AppFuse are more likely competitors rather than compatible. Grails uses Spring, Spring MVC and Hibernate under-the-covers, whereas AppFuse uses the raw frameworks. Of course, it would be cool to allow different classes w/in AppFuse to be written in Groovy or JRuby. At this point, I think it's probably better for users to choose one or the other.
Grails definitely looks cool, and a lot like Rails. However, I think using Groovy is a pretty big step for the majority of Java Developers out there. If you're reading this post, you're probably not in the majority.