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Java program to call a superclass constructor from sub/child class

Learn how to call a superclass constructor from sub/child class in Java?
Submitted by Nidhi, on March 23, 2022

Problem statement

In this program, we will inherit a class into another class using the "extends" keyword. Then we will call Superclass constructor from child/subclass constructor using the 'super' keyword.

Java program to call a superclass constructor from sub/child class

The source code to call a superclass constructor from sub/child class is given below. The given program is compiled and executed successfully.

// Java program to call a superclass constructor 
// from sub/child class

class Super {
  Super() {
    System.out.println("Super class constructor called.");
  }
}

class Sub extends Super {
  Sub() {
    super();
    System.out.println("Sub class constructor called.");
  }
}

public class Main {
  public static void main(String[] args) {
    Sub obj = new Sub();
  }
}

Output

Super class constructor called.
Sub class constructor called.

Explanation

In the above program, we created 3 classes Super, Sub, and Main. The Super and Subclass contain a constructor. Here, we inherited the Superclass into Sub class using the "extends" keyword.  In the Sub Class constructor, we accessed the superclass constructor using the super keyword.

The Main class contains a method main(). The main() method is the entry point for the program, here we created the object of Subclass and called both class constructors, and printed the messages.

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