Structure101

Structure101 is a rich, interactive, visual environment that provides the user with a deep understanding of their software architecture (or "structure"). Structure101 lets you analyze, measure and control the quality of your software architecture.
"Structure101 analyzes codebases to elicit the kind of information that good developers hold in their head for small projects, great ones juggle for large projects, and only the likes of Richard Stallman and Bill Joy can master for enterprise-scale projects."
Rick Wayne, Dr. Dobb's Journal.

Requirements:

Java Runtime 1.5 or greater