After a quick research, i've ascertained that this is a Global issue, and not an issue with Java. Son, what did you do.
It seems that the Registry link to your USERAPP data folder is fubar'd. there's 2 ways of fixing this. One crappy way is to download some shady registry fixer from the interweb and fubar ur entire system
The second way involves 2 possible methods. First, tell me, do you know how to use
RegEdit? If you don't, Microsoft actually has a solution to that.
But in all honesty, i don't trust any kind of shit they make. Best to do it yerself if you know how to do it. but if not, Microsoft is a safer bet. you never know with RegEdit. One time you're trying to fix a dead registry key, the next you just deleted System32. *looks at dreaming*
@Llama yaa, i do that alot. my advice didn't make sense when i reread the OP's info.