What "grails package" actually does?

Considering moving a big app from Spring MVC/JPA/Maven/Jetty Plugin to Grails for productivity reasons. To those familiar with both: is it worth it?

• We aren't so much interested in a big architectural change, just cutting down on lost development time due to rebuilding. We looked at various steps to speed up or replace Maven (including Buildr and Gradle), but it seems like Grails has the complete package (including a plugin for JPA instead of GORM) and since it's built on Spring MVC, it doesn't seem like we'd need to replace our existing controllers with Groovy ones - we could just straight-up switch. We already use GSPs for our views (via EasyGSP) and Spring Security, which also has a Grails plugin. It's a multi-module Maven app, but from what I've read it looks like we can achieve that same architecture by conceptualizing your modules as Grails plugins and using in-place plugin development. I'm most interested to know if Grails actually get you more productive even if you aren't using things like GORM or their built-in controller setup, and are essentially just using it as a more streamlined replacement for Maven.

• Answer:

  Grails doesn't always play nice or keeps up with latest versions of other "major" third-party tools. For example, Grails is only finally catching up to Hibernate 3.6 sometime in "near future" in next 1.4 release. So you may be stuck on "older" versions of Hibernate/etc once you migrate to Grails completely... In our case, we wanted to move our "main app" backend to later version of Hibernate but couldn't do so b/c the Grails front-end could only connect to older versions of Hibernate. your mileage may vary, of course