super() in Java

Question

Is super() used to call the parent constructor? Please explain super().

Answer 1

As stated, inside the default constructor there is an implicit super() called on the first line of the constructor.

This super() automatically calls a chain of constructors starting at the top of the class hierarchy and moves down the hierarchy .

If there were more than two classes in the class hierarchy of the program, the top class default constructor would get called first.

Here is an example of this:

class A {
    A() {
    System.out.println("Constructor A");
    }
}

class B extends A{

    public B() {
    System.out.println("Constructor B");
    }
}

class C extends B{ 

    public C() {
    System.out.println("Constructor C");
    }

    public static void main(String[] args) {
    C c1 = new C();
    }
} 

The above would output:

Constructor A
Constructor B
Constructor C