The groovy rule set, available by setting abuild.rules to ['java', 'groovy'], adds the ability to build Groovy code to the functionality of the java rules. The basic functionality is that all .groovy files in the src/groovy and abuild-java/src/groovy directories are compiled to .class files and written to the abuild-java/classes directory. The order in which Java and Groovy sources are compiled is determined by the order in which java and groovy are added to abuild.rules, but you must include java if you include groovy. If you have a build item that builds both Java and Groovy code, you should avoid having circular dependencies between your Java and Groovy code. If your Groovy classes make calls into your Java code, list java in your abuild.rules parameter first. If your Java code makes calls to your Groovy code, then include groovy first. For additional information on how to customize compilation of Groovy code, refer to abuild's online help for the groovy rules. This help text is included in Section E.7, “abuild --help rules rule:groovy”.