Implementation of "update" method in a "in memory" repository.

VehicleRepositoryImpl.java

@Override
public Vehicle update(Long id, UpdateVehicleDto dto) {
    Vehicle vehicleToUpdate = findById(id).orElse(null);
    if (vehicleToUpdate == null) {
        return null;
    }
    // method 1
    if (dto.getBrand() != null) vehicleToUpdate.setBrand(dto.getBrand());
    if (dto.getModel() != null) vehicleToUpdate.setModel(dto.getModel());
    if (dto.getRegistration() != null) vehicleToUpdate.setRegistration(dto.getRegistration());
    if (dto.getColor() != null) vehicleToUpdate.setColor(dto.getColor());
    if (dto.getYear() != null) vehicleToUpdate.setYear(dto.getYear());
    if (dto.getMax_speed() != null) vehicleToUpdate.setMax_speed(dto.getMax_speed());
    if (dto.getPassengers() != null) vehicleToUpdate.setPassengers(dto.getPassengers());
    if (dto.getFuel_type() != null) vehicleToUpdate.setFuel_type(dto.getFuel_type());
    if (dto.getTransmission() != null) vehicleToUpdate.setTransmission(dto.getTransmission());
    if (dto.getLength() != null) vehicleToUpdate.setLength(dto.getLength());
    if (dto.getWidth() != null) vehicleToUpdate.setWidth(dto.getWidth());
    if (dto.getWeight() != null) vehicleToUpdate.setWeight(dto.getWeight());

    // method 2
    dto.iterable(false)
            .forEach(
                    (key, newValue) -> {
                        System.out.printf("==========\n%s: %s%n", key, newValue);
                        switch (key) {
                            case "brand":
                                vehicleToUpdate.setBrand(newValue.toString());
                                break;
                            case "model":
                                vehicleToUpdate.setModel(newValue.toString());
                                break;
                            case "registration":
                                vehicleToUpdate.setRegistration(newValue.toString());
                                break;
                            case "color":
                                vehicleToUpdate.setColor(newValue.toString());
                                break;
                            case "year":
                                vehicleToUpdate.setYear(Integer.parseInt(newValue.toString()));
                                break;
                            case "max_speed":
                                vehicleToUpdate.setMax_speed(newValue.toString());
                                break;
                            case "passengers":
                                vehicleToUpdate.setPassengers(Integer.parseInt(newValue.toString()));
                                break;
                            case "fuel_type":
                                vehicleToUpdate.setFuel_type(newValue.toString());
                                break;
                            case "transmission":
                                vehicleToUpdate.setTransmission(newValue.toString());
                                break;
                            case "length":
                                vehicleToUpdate.setLength(Double.valueOf(newValue.toString()));
                                break;
                            case "width":
                                vehicleToUpdate.setWidth(Double.valueOf(newValue.toString()));
                                break;
                            case "weight":
                                vehicleToUpdate.setWeight(Double.valueOf(newValue.toString()));
                                break;
                        }
                    }
            );

    return vehicleToUpdate;
}

DTO Should have that method .iterable

public Map<String, ?> iterable(boolean getNullValues) {
        Map<String, ?> m = new HashMap<>() {{
            put("brand", brand);
            put("model", model);
            put("registration", registration);
            put("color", color);
            put("year", year);
            put("max_speed", max_speed);
            put("passengers", passengers);
            put("fuel_type", fuel_type);
            put("transmission", transmission);
            put("length", length);
            put("width", width);
            put("weight", weight);
        }};

        if (!getNullValues) {
            m.values().removeIf(Objects::isNull);
        }

        return m;
    }

Yep, this is a overengineering.

Study purposes