As a matter of interest, which class(es) do those methods belong to? Are they in the Java API?
I would try to test it now if I were further advanced in my Java studies, but will have to wait until i know a few more things. I have not learnt how to call SQL in Java yet, nor do I know how to read a file or write to a file yet.
It actually isn't important for me to know the answers, as I said before, I was just curious to see how Java programming handles commit and rollback.