The goal of the ArgoUML project is to build an object oriented design tool that is:
- a joy to use
- actually helpful to designers when they are making design decisions, by offering cognitive support through critics
- completely open source Java (FreeBSD license)
- supporting everything in UML
- modular and extensible
- integrated with the web and other Tigris tools.
You can also read the Project Vision and read the list of features to learn more about what ArgoUML is capable of already.