Inheritance in Java - Part 2

The keyword used for inheritance is extends.

Syntax:

	class derived_class extends base_class    {                //members and methods     }

 

super : reference variable that is used to refer parent class objects. 

In the example given below the Base Class is Employee and the Derived Class is Manager : 

public class Employee {

int empid;

String empname;

double salary;

public Employee() {

System.out.println("Default constructor of Emp class");

empid = 1;

empname = "Ram";

salary = 10000;

}

public Employee(int empid, String empname, double salary) {

System.out.println("Parameterized constructor of Emp class");

this.empid = empid;

this.empname = empname;

this.salary = salary;

}

@Override

public String toString() {

return empid + " " + empname + " " + salary;

}

public  double calSalary() {

return salary;

}

protected String showName(){

return empname;

}

}

­­­­­­­­

public class Manager extends Employee {

int ptallow, fdallow, incentive;

public Manager(int empid, String empname, double salary, int ptallow, int fdallow, int incentive) {

super(empid, empname, salary);

System.out.println("Parameterized constructor of Manager class");

this.fdallow = fdallow;

this.ptallow = ptallow;

this.incentive = incentive;

}

@Override

public String toString() {

return empid + " " + empname + " " + salary + " " + ptallow + " " + fdallow + " " + incentive;

}

@Override

public double calSalary() {

// TODO Auto-generated method stub

return super.calSalary() + ptallow + fdallow;

}

}

//Driver code

public class TestMain {

public static void main(String[] args) {

Employee  e1 = new Empoyee(100,"Smruti",10000);  //object of Employee

Manager m1 = new Manager(101,"Swapna",25000,100,100,100); //object of Manager

System.out.println(e1.showName());

System.out.println(e1.calSalary());

System.out.println(m1.showName());

System.out.println(m1.calSalary());

}

}

Output:

Smruti

10000

Swapna

25200

Smruti Khire

K38