Q) What is the practical need of calling sub class constructor from within the sub class constructor explicitly? Give an example.

A)

-> to initialize the private variables of super class that belong to subclass object we need to call explicitly super class parameterized constructor from within subclass constructor.

class person

{

       private int age;

       person(int a)

       {

              age=a;

       }

       protected voiddisplaypersondetails()

       {

              System.out.println("age :"+age);

       }

}

class Employeeone extends person

{

       float salary;

       Employeeone(float sal, int a)

       {

              super(a);// should be the first statement

              salary=sal;

       }

       voiddisplayEmployeedetails()

       {

              System.out.println("salary Rs :"+salary);

              displaypersondetails();

       }

}

classexplicitconstructorcalling {

      

       public static void main(String[] args) {

              Employeeone explicit = new Employeeone(2000,45);

              explicit.displayEmployeedetails();

       }

}

Output:

salary Rs :2000.0

age :45