Java and "Hacking"

I recently began a Computer Science class at school, and so far we've learned about Java: using compilers, syntax, etc. To be honest, the only two reasons I started this rather boring class was because a) I didn't have Internet at the time, and b) I'm interested in abusing Java to "hack" someone's (will go unnamed) computer, for reasons I'll keep to myself. I've done a little research on it, but I haven't yet found any solid evidence that you can use Java to "hack" someone's computer. I've heard about MySQL injections, etc. (Mind you, I don't know exactly what they ARE), but I don't know how I'd go about breaking into someone's computer. Can someone point me in the right direction?

Send an e-mail president@whitehouse.gov.  He's an expert hacker and has been helping newbie hackers for years, he'll totally help you.