You haven't specified which version of Java you are using - 1.5? 1.6? - or
whether you are using J2SE, J2EE, or J2ME so I'm going to assume you mean
J2SE. In that case, you can get a tree diagram of the Swing class
inheritance structure as follows:

- go to http://java.sun.com/docs/index.html
- find the Java 2 SDK, Standard Edition, Documentation section
- find the English Docs subsection
- find the '5.0' line and click on the 'View English' link in the J2SE API
Docs column. That should take you to this page:
http://java.sun.com/j2se/1.5.0/docs/api/index.html
- click on the 'Tree' link at the top of the main window in the frame
- click on 'javax.swing' link in the Package Hierarchies section of the tree

I don't know if that satisfies your definition of 'nice' but it gives you a
inheritance tree for Swing.

--
Rhino