DAO

• Data Access Object, to save Model/Domain into the database.
• Dao interface could look like this:

public interface Dao<T> {
    
    Optional<T> get(long id);
    
    List<T> getAll();
    
    void save(T t);
    
    void update(T t, String[] params);
    
    void delete(T t);
}

• And you have to implement this interface, for example

public class UserDao implements Dao<User> {
    private final EntityManager entityManager;

	public void create(User user) {
		entityManager.persist(user);
	}
}

Note:

• DAO is different than Repository Pattern. In a way such repository pattern can implement multiple DAOs and contains business logic.
• DAO is purely just for data fetching