Paul,
I don't have any sample code handy at the moment, but your main in the Java code can accept command line arguments. You should be able to find it in the Java docs.
I find that ShellExecute, is just a whole lot easier to use than the old RUN command:
ShellExecute( 0, "open", "java", "yourclass.java your args", "", 1 )
>I'm doing some tinkering with Java at the moment and would like to know how ( if? ) I can pass a parameter to a Java.class file from VFP?
>At the moment I call the file with the RUN command.