Student Jens J. Jensen writes:
I'm interested in taking your course this semester, but I noticed you require familiarity with a programming language. How familiar do I have to be? I know Maple and Java, but my knowledge of Java is very limited.
It is up to you what you use, as long as you can program - most people in the past wrote in fortran, c, basic, matlab, maple, mathematica, java, as you can see on ChaosBook/extras collection of programs. It would be cute to contribute some java applets. Learning how to do numerical work is a necessary skill no matter what you do later, as long as you do not turn into a lawyer.