Hibernate has a configuration file called hibernate.properties or hibernate.cfg.xml. There you can specify the properties of database like
hibernate.connection.driver_class jdbc driver class
hibernate.connection.url jdbc URL
hibernate.connection.username database user
hibernate.connection.password database user password
hibernate.connection.pool_size maximum number of pooled connections
By default if you download the hibernate source , it will working on hsqldb.
I have tried hibernate in oracle, mysql, hsqldb