Allexiel... I had the same problem as Elqueu. I for instance didn't had too much knowledge about how Java works, where I can install the aditional files and so on.
Elqueu. I can share my story with you, although I installed it on a Windows machine, but maybe it helps

.
First of all, you need to download the correct file from the
www.mysql.com website. This 'correct' file is the java connector that helps your Java VM to connect to a mysql database.
Inside this section
http://dev.mysql.com/downloads/ at the "Drivers and Connectors" you need to download the "MySQL Connector/J -- for connecting to MySQL from Java" corresponding to your installed Java version on the server.
Then (on a windows instalation of the Java environment at least) you need to copy that file to the Java path / lib / ext.
So find the folder where java is installed. Inside there should be a lib folder and inside that should be an ext folder. Copy the file "mysql-connector-java-3.1.12-bin.jar" (or whatever file you dowloaded for your version) in that folder.
After you copy the file you need to change the settings as in the doc files for your dbconnector. And I mean it like I say it. You don't need to change anything (apart from the ip, username and password

).
The driver is always named like this "org.gjt.mm.mysql.Driver"
Then, after succesfully configuring the xml file, just restart the server.
If you have problems configuring the xml file just "yell" here.