If you use the VJ++ GUI builder or any of their Windows Foundation
Classes or other widgets, your .class files will _not_ be portable.
Also, the code that you write is not guaranteed to be portable unless
you explicitly turn off their language extensions.
In Visual J++ 6.0, go to
Projects > Properties > Compile
There should be a checkbox labeled
"Disable Microsoft Language Extensions"
Make sure it is checked for each of your projects.
FYI, Sun has a product called JavaPureCheck which verifies
whether your .class files are sound. It's freely available at:
http://java.sun.com/100percent/download/
--Craig Henderson
Rethinking CS101 Staff