Getting the source code
The library source code can be freely download from the CVS repository hosted at dev.java.net.
From a terminal, first authenticate with the CVS repository:

cvs -d:pserver:guest@cvs.dev.java.net:/cvs login

when prompted for a password, hit ENTER. Then get the source code:

cvs -d:pserver:guest@cvs.dev.java.net:/cvs co l2fprod-common

Contributing code to the project
Several developers have already subscribed to the project and are regularly contributing code. If you want to be part of this community, join the project at https://l2fprod-common.dev.java.net.

Making donation to the project
The library is free for commercial and non-commercial applications. The project is accepting donations through a paypal account, just click on the following picture.