A while ago there was a software update from Apple that removed the Java internet plug-in. So if you accepted that update then you are likely fine.
Here is an article from the LA Times on other action by Apple.
I have a quick look under my Finder> Library> Internet Plug-ins > and it was blank (as I expected) for my MacBook Air
To disable Java go to Safari Preferences/Security and uncheck the Enable Java box. Also check out this thread to find out about security problem with Java 7.