The student is assumed to have completed the basic Robo sequence which introduces fundamental programming concepts, top-down structured design ideas and the rationale for them. This should have been followed by a sequence on algorithms and on the basic computer architecture needed to run them, and on the mechanism by which this is achieved.
Ideally, students should also be familiar with the notions of Java compiler, virtual machine, applet, etc., and have the software and ability be able to take the examples and play with them by modifying the source code, then compiling and running them.