JDepend4Eclipse plugin for Eclipse is a wrapper for running JDepend from within Eclipse.

- What is JDepend? (from www.clarkware.com):

JDepend traverses Java class file directories and generates design quality metrics for each Java package. JDepend allows you to automatically measure the quality of a design in terms of its extensibility, reusability, and maintainability to manage package dependencies effectively.

Advanced JDepend documantation are available as online help in Eclipse (press F1 key) or on the JDepend creator's site (please do not ask me what JDepend metrics are - ask Mike:)