Help with key Logger in java

Hi, Basically, I need to know how that Java could be used to record the keystrokes of a user and then store them into an external file. Or even whether or not that Java can actually do this?
More importantly the software needs to work when it is not the active program running on the PC (i.e. it is not the active window), and it needs to install discreetly on the users computer.

If anyone can help me I'd be extremely grateful, as I am truly stuck.
Thanks.

A key logging application that needs to install discretely and is a hidden application?

Yes you can log key events with Java, but if the window is out of focus then I'm not sure if you can. KeyEvent I think is the standard keystroke event class but I've never used it personally.

Greetings.