Grails or Play! for an ex-RoR developer?
I plan to start learning a Java web framework (I love the Java API) I have already used Rails and Django.
I want something close to Java but without all the complexity of J2EE.
I've found 2 frameworks that could be good for me:
Grails
Grails looks great, it uses Groovy which is better than Java for web application (I think..) but it's slower than pure-java based frameworks (Hibernate, Strut, Spring) It looks pretty simple to deploy (send .war and it's ok!), the GSP is great! It's a bit harder to debug (need to restart the server at each modification and stacktraces contain a mix of Java and Groovy traces which is not always the easiest to understand)
Play!
This framework also looks great; it's faster than Grails (It uses Java) but I don't really like how it uses Java, it modifies the source code to transform the property calls as setXXX/getXXX, I do not like that... The framework also has a caching function that Grails does not have. I don't really like the Template Engine. It's also easer to debug (no need to restart the server, stacktraces are clearer)
What do you recommend? I am looking for something easy to learn (I have a lot of Ruby experience, not so much Java experience but I love the Java API), fully featured (That's no a problem with all the Java Library available, but if it's bundle and integrated I prefer), has good scalability and is not too slow (faster than Ruby) Ideally I would like to use a framework with a decent community to easily find support.
PS: I am not interested in JRuby on Rails
Answer
I switched from Grails to Play and I never looked back. My biggest problem with Grails was overall robustness and developer usability. Most of the time I got bitten by the fact that Grails glues together the usual stack of Spring MVC and Hibernate while trying to hide this fact and giving you a Rails-like API (personal opinion of mine). The problem with this is, once something goes beyond the trivial samples, it easily broke and didnt work for me. Developing with it was like walking on eggs (for me). Whenever I googled for documentation of a feature I needed, I was not redirected to samples, tutorials, blogs, but to the Grails JIRA explaining me why the feature wouldnt work for my use case and that the bug was unresolved since two versions before the one I was using.
While that may not be the overall experience for every developer (I am not writing this to bash Grails, but to give my experiences with it here), I needed something that helped me and would not stand in my way or break down on me when I needed it the most. Thats when I found Play and I have quickly migrated my app to it after I found out about it (around the ~1.0 release).
So far it has been a great ride and for the first time in my web development career, I have stopped looking at other frameworks trying to find something that I would like better.
If I had to close with one thing that Play did better than Grails - at least for me - it would be the fact the Play is built from the ground up with developer usability in mind. It does not sacrifice ease of use for enterprise buzzwords. It has the guts to throw away what does not fit into this paradigm (e.g. ditchting Servlet-based runtimes during development for faster turnaround). It is willing to make compromises in order to guarantee awesomeness. And that is something I have only seen in communities like Rails or Django before I found Play.