Jacuzzi works around java.sql.Connection and it is all you need to provide. Jacuzzi don't use any configuration files and uses just a few annotations. It doesn't take care about abstract cross-database query language, use native SQL to write queries or methods from GenericDaoImpl? to interact with database.

Usage

Domain class:

public class User {
    @Id
    private long id;

    private String name;

    private String login;

    // ...
    // Getters and setters are here
    // ...

Interface:

public interface UserDao {
    List<User> findByName(String name);
    void insert(User user);
    User findByLogin(String login);
    User find(long id);
    void delete(User user);
}

Implementation:

public class UserDaoImpl extends GenericDaoImpl<User, Long> implements UserDao {
    public UserDaoImpl(DataSource source) {
        super(source);
    }

    @Override
    public List<User> findByName(String name) {
        return findBy("name=?", name);
    }

    @Override
    public User findByLogin(String login) {
        return findOnlyBy(true, "login=?", login);
    }

    @Override
    public User find(long id) {
        return super.find(id);
    }
}