get the currently logged user(urgent)

Hai, I want to know the user who is currently logged in the machine.If possible post the code too,lets consider windows as the O.S.Now I want to get the user from java,where I customize the perferences for my aplication based on the user logged in.

<pre> System.out.println(System.getProperty("user.name"));</pre>
See the API for System.getProperties() for a list of other proerties you can access. Additional properties may be available on your system - this list is just the standard ones.

This works for me on Win2K:
System.getProperty("user.name")

Hi. it's working fine,but the problem is if the user is a guest it displays unknown.Is there anyway to identify the guest user too.

<pre> System.out.println("Who the heck are you?");</pre>
Seriously, if the system allows people to log in with no account or password, then you will have to ask them.

Thank you Jim,but I just wanted the system to return "Guest", instead of the username.Anyhow thank you so much.