Runescape client work on PPC?

I just got an iMac G5 on version 10.5.8 and its a PPC, I realize now this computer is **** for games and im wondering if ATLEAST runescape works on this? I understand I can't play on the website because I don't have an up to date Java and i know I cant get Java.. So I thought maybe the runescape client would work.. I downloaded it fine but went to click on it and it jumps around a little bit on my dock then disappears. Ive tried putting it in my application folder, and my desktop , etc. but nothings working. Id like to know if there is anyone who plays Runescape on the same computer as me. I have 2 GB RAM. All i need is helpful answers. Thank you so much. I'm legit willing to pay someone $50 via paypal to help me if I have to.