We can crash BlueJ by entering one character into BlueJ. Repeatable on two systems (Asus Eee with Win 7 Starter, iMac 27" 10.5.8)
- Create a new Applet.
- Call it anything you like.
- Scroll down to the paint method.
- in g.drawString, add a backslash character ('\')
- Wait. Or, perhaps, don't. If it doesn't take the first time, try again.
- Kill BlueJ.
See the 3.5 MB screencast; you can download it from drop.io:
I've claimed this is "critical" and part of the "Editor," as that seems reasonable.