This interface should be implemented by writers of Java extensions to JRuby. The basicLoad method will get called exactly once, the first time this extension gets loaded. It is therefore prudent that it established the environment the extension wants to have. For example, creating new Modules and Classes, adding methods to these and describe which implementation will get used. This interface details the standard load mechanism for easy extensions. Implement the interface in a class outlined in the JavaDoc for LoadService, put the class into a jar-file and put it on JRuby's load path, and you're set to go.