Restrict multiple instances of an application in java

Question

I want to prevent multiple instances of application being launched in java. I know 2 methods for this:

1. locking file
2. locking socket

But

Answer 1

File lock is better way to do- imo. When you create the file in User's Home directory, this will still work in a multi-user environment.

I came across - JUnique - haven't had a chance to use it http://www.sauronsoftware.it/projects/junique/manual.php