Method overloading example in java (dynamic polymorphism)

public class First {

public static void main(String[] args) {
// TODO Auto-generated method stub
Second obj = new Second();
obj.show();

}

}

public class Second {

int i,k;

float j;

void show(){

System.out.println("No argument method");

}

void show(int k){

this.k=k;

System.out.println("The value of k is " +k);

}

void show(int i,float j){

this.j=j;

this.i=i;

System.out.println("The value of i,j is " +i +j);

}

}

output:-

No argument method

Dynamic overriding example in java (dynamic polymorphism)

public class First {

public static void main(String[] args) {
// TODO Auto-generated method stub
Second obj = new Second();
Third  obj1 = new Third();
obj.show();
obj1.show();
}
}



public class Second {

void show(){
System.out.println("Parent");

}

}

class Third extends Second{
void show(){


System.out.println("Child");

}


}

Output:-
Parent
Child

"Super" keyword usage example in Java

public class First {

public static void main(String[] args) {
// TODO Auto-generated method stub
Third obj=new Third();
}

}

public class Second {

int i;

Second(int i){

this.i=i;

System.out.println("This is super class param constructor");

}

}

class Third extends Second{

Third(){

super(20);

System.out.println("The value of super calss variable i is " +super.i);

}

}

output:-

This is super class param constructor

The value of super calss variable i is 20

"This" keyword usage in Java

public class Acceptt {

 public static void main(String[] args) {
  // TODO Auto-generated method stub
  Third obj = new Third(10,20);
  obj.show();
  }

}



class Second {

 void show(){
 
  System.out.println("I am Parent");
 }

}


class Third extends Second{
 int i,j;

 void show(){

  System.out.println("I am child");
 }
 Third(){
  System.out.println("Third constructor");
 }

 Third(int i,int j){
  this();
  this.i=i;
  this.j=j;
  System.out.println("The values are "+i  +j);
  }

 void display(){
  this.show();
 }

}


output:-
Third constructor
The values are 1020
I am child

Java Inheritance example

public class Inheritance {

public static void main(String[] args) {
// TODO Auto-generated method stub
Second obj = new Second();
First obj1 = new First();
obj.setage(10);
obj1.setage(20);
System.out.println("The value is " +obj.i);
System.out.println("The value is " +obj1.i);
}

}

public class First {

int i;

String S;

void setage(int i){

this.i=i;

}

void setname (String S){

this.S=S;

}

int getage(){

return i;

}

String getname(){

return S;

}

}

class Second extends First{

int j;

void setrollno(int i){

j=i;

}

}

output:-

Test one

Test Two

Java Program Example to demonstrtae First parent constructor is called followed by chiled class constructor

/**
 *
 */

/**
 *
 *
 */
public class Second {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
First obj = new First();
}

}

public class Demo {

Demo(){

System.out.println("Test one");

}

}

class First extends Demo{

First(){

System.out.println("Test Two");

}

}

Output:-

Test one

Test Two

Java Inheritance example Program

public class Demo {

public static void main(String[] args) {
// TODO Auto-generated method stub

SubClass obj = new SubClass();

obj.display();

}

}

public class First {

protected String str;

First() {

str = "Java ";

}

}

 

class SubClass extends First {

SubClass() {

str = str.concat("Is My World ...!!!");

}

void display()

{

System.out.println(str);

}

}

output:-

Java Is My World ...!!!