Question: Is it possible to develop an application in groovy using GWT components?

Luis

Answer: 
If you want to use Groovy on the server-side and GWT for the UI, that is certainly possible. You can use Grails (a Groovy web framework on the server), and the [Grails GWT plugin](http://www.grails.org/plugin/gwt) to help you integrate GWT with this framework.
I don't think so, because the GWT compiler is basically a [Java to JavaScript *source*](http://java.dzone.com/news/understanding-gwt-compiler) compiler (it would be possible if the GWT compiler needed Java bytecode). You can use Groovy on the server side though.