This is an application I wrote in Java to make class diagrams for a project for a course in system development. I never used it because I found something better, but I liked the challenge; I wanted to understand Swing and serialization better. The above picture is a diagram produced with the application.
The jar is not obfuscated, so you can check out the source by using a decompiler. The classes are structured as the image shows.
Contains: ClassDiagramMaker.jar and examplediagram.dgr
Size: 55 kb