We're working on a language module (fork) for the Salesforce.com language Apex. It's a proprietary language where no open grammar is available. What is available is an ANTLR based parser library under the Eclipse Public License that I would like to use.
How would we do this technically? Is there any example or tutorial on how to use a custom parser? I found only JJTree/JavaCC based code and guess some kind of adapter is needed. I can't imagine that nobody has used ANTLR with PMD before.
A little bit late, but still for completeness.
ANTLR support on PMD is in the official roadmap, but still on a very early planning stage.
On the other hand, Apex is now fully supported on PMD thanks to the works of the original poster and other talented developers.