Find the "application data" folder?

[NeuroFuzzy]

Well... What I really need is a primer on java file handling. What I want to do is find the .minecraft directory on a computer using java. Normally this would be in (rootdrive):\Documents and Settings\<user>\Application Data\.minecraft

So... Obviously some program got that folder there, so I can... but I don't know how! Any help? And, since this is a java program, and therefore supposed to be cross-platform - how can I find that .minecraft folder on other OSes?

[travishein]

Probably using the system property for the current user's home directory, e.g.

File mineCraftFolder = new File(System.getProperty("user.home"), ".minecraft");