Constructors in Inheritance in Java

Constructors in Inheritance:

• When a drived class is extended from the base class, the constructor of the base class is executed first followed by the constructor of the derived class. For the following Inheritance hierarchy , the constructors are executed in the order:

1. C1- Parent
2. C2 - Child
3. C3 - Grandchild

Constructors during constructor overloading :

• When there are multiple constructors in the parent class, the constructor without any parameters is called from the child class.
• If we want to call the constructor with parameters from the parent class, we can use the super keyword.
• super(a, b) calls the constructor from the parent class which takes 2 variables

class Base1{
    Base1(){
        System.out.println("I am a constructor");
    }
    Base1(int x){
        System.out.println("I am an overloaded constructor with value of x as: " + x);
    }
}

class Derived1 extends Base1{
    Derived1(){
        //super(0);
        System.out.println("I am a derived class constructor");
    }
    Derived1(int x, int y){
        super(x);
        System.out.println("I am an overloaded constructor of Derived with value of y as: " + y);
    }
}

class ChildOfDerived extends  Derived1{
    ChildOfDerived(){
        System.out.println("I am a child of derived constructor");
    }
    ChildOfDerived(int x, int y, int z){
        super(x, y);
        System.out.println("I am an overloaded constructor of Derived with value of z as: " + z);
    }
}
public class cwh_46_constructors_in_inheritance {
    public static void main(String[] args) {
        // Base1 b = new Base1();
        // Derived1 d = new Derived1();
        // Derived1 d = new Derived1(14, 9);
        // ChildOfDerived cd = new ChildOfDerived();
        ChildOfDerived cd = new ChildOfDerived(12, 13, 15);
    }
}

Handwritten Notes: Click to Download

Ultimate Java Cheatsheet: Click To Download