Tuesday, July 20, 2010

The Use of Super in Java Programs

The Java keyword super has  a special use in the application of inheritance. When we pass parameters to our constructors, we also perform the same thing for parents and child classes. A child class may access the parent class' fields through the use of super to pass parameters to parent class.

See the sample below for the illustration.

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/*with super in constructor*/
import javax.swing.*;
public class SampleInheritance4{

public static void main (String args[]){
String myname=JOptionPane.showInputDialog("Input a student name: ");
String myaddress=JOptionPane.showInputDialog("Input a student's address: ");
String mycourse=JOptionPane.showInputDialog("Input a student's college course: ");

College2 obj1=new College2(myname,myaddress);

JOptionPane.showMessageDialog(null,"object of the child class");
JOptionPane.showMessageDialog(null,"Student's Info: "+"\n""\n"+obj1.getaddress()+"\n"+obj1.getcourse());



class Student2{
protected String name;
protected String address;

String getname()

String getaddress()
{return this.address;}


class College2 extends Student2{

College2(String xname,String xaddress){; // passing the values of xname and xaddress to parent variables names and address

String course;

void setcourse(String xcourse)

String getcourse()
{return this.course;}