In NetBeans IDE 7.3, for the first time, when you create a new Groovy class in a web (i.e., Java EE) application, whether you're in an Ant project or Maven project, the IDE will set up everything for you automatically so that the Groovy class will be compiled together with the application.
For example, in the case of Maven, the Groovy dependency will be added to the POM and the Groovy Eclipse Compiler plugin will be registered there too. And, as you can see here, a special source package root is created for Groovy, automatically when you start creating your first Groovy class in a project:
Then when the application is built, so is the Groovy class:
Related reading, which shows more good stuff for Groovy fans in NetBeans IDE 7.3: