Design patterns are widely recognized as important software development methods. Their use as software understanding tools, though generally acknowledged has been scarcely explored. Patterns are most useful in understanding software when they are well documented. Sometimes they are described separately from code as design comments. Nevertheless they hold a strong relationship to the source code and thus they should be documented at the source level too. Unfortunately there is no agreement on how to document pattern use. This paper describes a structured approach to document pattern use in the Java language. Our solution is based on the standard Javadoc tool and it is able to generate HTML documentation. The approach has been implemented and tested with software that uses patterns.