|We used jGRASP in a recent Introduction to Coding with Java class. It is not a production type IDE such as Netbeans or Eclipse but we have found it a good tool for introductory classes aimed more at casual users, beginning computer science students, etc. It has a lot of interesting features such as generation of UML diagrams, an interactions pane like the Visual Basic immediate window, object viewers, side by side columns for editing multiple class files, etc. It is lightweight and very quick to load. It will also handle Python, C, etc. But we have not yet explored that in any depth. Although we have used it for simple Python scripts.
On the downside it does not have a "smart editor" with intellisense type capabilities beyond simple syntax highlighting.