Two-and-a-half years ago, I developed my assignment under Win98. Before submitting, I tested under Windows NT and found that I had some rather horrible repaint issues that made the application unusable. These were due both to subtle differences between the behaviour of the JVM on different platforms, and to bugs in the Swing toolkit at the time.
So the answer is: according to the WORA (Write Once Run Anywhere)
philosophy,
you should be fine. However, practice can be more like WODE (Write Once Debug Everywhere). You're best off testing on as many platforms as you can, since you don't know what OS the assessor is going to use. But if you can't, you can't, and have to take the (small) risk.
- Peter