Actually you can hack Runescape. Like I know some Java and it would be very very diffcult, and would take a lot of work. There is a way to turn any item into another, but that would cost a lot work and bypasses and firewalls and a bunch of proxys and you would have to have a looooooot of experience in Java. Runescape has a whole team 100+ programers who has spent most of their life doing coding. It would be a waste of time trying to hack it...
On runescape 1 guy almost did. Shut down runescape for 1 night, but in the matter of minutes they blocked him, kicked him, banned him, fixed hole, everything...