Hi,
Personally I don't think, that such a training with code like this would help you score higher in OCAJ exam. OCAJ exam is not about such a things how logic of the program should flow. It is more about the
Java language itself, technical part of it, compiler behaviour - in different words, unusual situations, corners of the language.
Do you have an exam preparation book? Have you looked at it?
About that code you posted:
Probably it more shows how the code shouldn't be written.
I mean (do you notice what's possibly wrong with it?):
And there are many more problems. Usually such a situations suggests one thing - bin it and start over.
Likely with a pencil and piece of paper by writing down the logical steps in simple english what has to be done (by omitting "how" part).