@Data
@AllArgsConstructor
@Entity
@Table(name = "cities")
public class City {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    private String name;
    private int population = 0;

    public City(String name, int population) {
        this.name = name;
        this.population = population;
    }
}

@Repository
public interface CityRepository extends CrudRepository<City, Long> {
    List<City> findByName(String name);
}