Demeter/Java allows you to write your Java programs in a much more reusable form, called the adaptive form. You reuse all your Java knowledge and learn a design language on top of Java. The two important features of the design language are: Traversals and Visitors. Demeter/Java enforces correct use of the Visitor Design pattern in complex applications. The Visitor Design pattern is directly supported in the executable design language which is on top of Java.