newbie: running an example

I've successfully installed VisAD and Java3D on my NT platform and thought
I'd try to run something in \visad\examples.  "Simple" sounded like a good
start.  I ran "javac Simple.java" and got:
  Simple.class
  Simple$1.class
  Simple$2.class

then tried to run "java Simple" and get:
 Exception in thread "main" java.lang.NoClassDefFoundError: Simple

Can someone help me get started here (including comments like "Go read the
___ document")?

thanks,
--Randy