As is the much older Jackpot (https://bitbucket.org/jlahoda/jackpot30/wiki/RulesLanguage). I believe James Gosling worked on the project, which is now integrated with NetBeans.

What's cool is that you can distribute the rules file alongside your new version of a library with its API changes, and NetBeans will automatically detect the rules if the user updates the dependency, and ask the user if they want to apply them. The downside is that not many people use NetBeans (or Jackpot for that matter).