Gram is a simple xdoclet-like tool for processing doclet tags or Java 5 annotations in source code or bytecode and auto-generating files, data or resources.
Gram = Groovy + JAM. JAM does all the hard work of abstracting away the details between annotations and doclet tags and handling Java 1.4 and 5 compliance. Groovy takes care of the scripting, code generation & templating. Gram is the little tidy bit of code in between.
The sources can be found here : Gram
You can use the Gram class as a main() and run it from your IDE if you wish. There is a GramTask as well for using it inside Ant.
Often since JAM depends on Sun's doclet stuff, you can have issues running the GramTask inside Maven and sometimes Ant. So I tend to run the Gram command line tool from inside an Ant build. e.g.
Here's a simple example which just lists all the hibernate peristent classes in your source code
Gram depends on:
You might find some more documentation in the form of blog posts by Andres Almiray: