1. Choose the JAR with the drivers according to your oracle’s database version and put in the lib/ directory of your web application
2. Configure your application.conf file,  located inside the conf/ directory
   • In the JPA Configuration Section you have to choose the JPA (Hibernate) dialect. In my case I was working with oracle10g so i had to insert in the configuration file:

     • jpa.dialect=org.hibernate.dialect.Oracle10gDialect

   • Now you just need to add the following lines, according to your database (including username and password).

     • db.url=jdbc:oracle:thin:@yourdatabaseserver:1521:dbname
       db.driver=oracle.jdbc.driver.OracleDriver
       db.user=yourusername
       db.pass=yourpassword

3. Now you just need to restart the server. He adds the database drivers automatically to the classpath of the project.
4. If you want, you can generate Netbeans or Eclipse projects, so you can open this projects with everything configured.

Really easy with no XMLs!