Java error creating subclass constructor

Question

I trying to learn some Java and I've got stuck creating a subclass. I keep getting a There is no default constructor available in... error.

This is the code:

class Car 
{
    String name;
    int speed;
    int gear;
    int drivetrain;
    String direction;
    String color;
    String fuel;

    public Car(String carName, int carSpeed, String carDirection, String carColor, int carDriveTrain, int carGear)
    {
        name = carName;
        speed = carSpeed;
        gear = carGear;
        drivetrain = carDriveTrain;
        direction = carDirection;
        color = carColor;
        fuel = "Gas";
    }

    void shiftGears(int newGear){gear = newGear; }
    void accelerateSpeed(int acceleration){speed = speed + acceleration;  }
    void applyBrake(int brakingFactor){ speed = speed - brakingFactor;}
    void turnWheel(String newDirection){ direction = newDirection; }

}//end of Car class

class Suv extends Car
{

    void applyBrake(int brakingFactor)
    {
        super.applyBrake(brakingFactor);
        speed = speed - brakingFactor;

    }
}

The issue comes when I try to create the "Suv" subclass. What am I doing wrong? Thanks!

I think you need a constructor in Suv which gets the same parameters as Car. — takendarkk
– takendarkk, Commented Nov 22, 2014 at 3:27
You don't need "super.", you have to declare your methods protected. Not having a public/private/protected identifier makes them be visible only at package level. — MLProgrammer-CiM
– MLProgrammer-CiM, Commented Nov 22, 2014 at 3:29
@MLProgrammer-CiM Most of what you have said is not true. You can have multiple classes per file. Subclasses do not have to be "declared as static". Method privacy is unrelated to anything in the question. — khelwood
– khelwood, Commented Nov 22, 2014 at 3:38
@khelwood is right - and it's worth expending your comment: there can be only one public class per file, but there can be multiple non-public classes. — Nir Alfasi
– Nir Alfasi, Commented Nov 22, 2014 at 3:40

Eran · Accepted Answer · 2014-11-22 03:32:18Z

2

You probably want to create the following constructor in Suv that initialzies that parameters that the Car constructor has:

public Suv(String carName, int carSpeed, String carDirection, String carColor, int carDriveTrain, int carGear)
{
    super (carName, carSpeed, carDirection, carColor, carDriveTrain,carGear);
}

The alternative is to add the parameterless constructor to Car, in which case the default constructor of Sub would call that constructor :

public Car()
{

}

answered Nov 22, 2014 at 3:32

Eran

395k57 gold badges726 silver badges793 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Markus · Accepted Answer · 2014-11-22 03:31:19Z

2

Since "Car" has a constructor, any subclass derived from Car needs a constructor as well. So first you need to put a constructor in the Suv class.

Example:

class Suv extends Car {
    public Suv() {
        super( /* here you need to pass arguments to create a car */);
        // any other constructor code
    }
}

answered Nov 22, 2014 at 3:31

Markus

1,0161 gold badge8 silver badges23 bronze badges

Comments

Nir Alfasi · Accepted Answer · 2014-11-22 15:31:41Z

1

Add the following constructor to Car:

public Car(){}

The problem is that Suv cannot be created since in order to run Suv's default constructor the constructor of Car needs to be ran first, and Car has only a constructor that accepts arguments so it can't be used as default-constructor.

Another approach would be, as @Markus suggested, to implement a constructor in Suv that'll call super with all the required arguments. Either way, the main idea is that in order to instantiate Suv we need to be able to instantiate Car first otherwise we'll get a compiler error.

edited Nov 22, 2014 at 15:31

answered Nov 22, 2014 at 3:28

Nir Alfasi

53.6k11 gold badges94 silver badges138 bronze badges

Comments

Zulfi · Accepted Answer · 2014-11-22 03:59:50Z

0

What i would suggest is to not put the SUV class in the same file. Instead, Create another class in your current package, name it SUV, extended it and call the superclass constructor by either of the following two syntax:

super(); //calls the superclass no-argument constructor with no parameter list

or

super(parameter list); //calls the superclass constructor with a matching parameter list

answered Nov 22, 2014 at 3:59

Zulfi

133 bronze badges

Collectives™ on Stack Overflow

Java error creating subclass constructor

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related