Hmm, I'd suggest that you not only allow java, but also javaw. There is a fair amount of people who run minecraft with javaw, which basically gives no error reports, but simply runs minecraft. You can find java and javaw at:
C:\Program Files (x86)\Java\jre6\bin
on a windows computer, depending on your java version.
If you have java 5, I'd imagine it be jre5.
If you have a x86 computer instead of a x64, it would probably be in Program Files instead of Program Files (x86).
I used macaffe at a time, and I never really had problems with it truthfully, then again, I never had macaffe when I started playing minecraft.
I currently use norton.