Abstraction: Abstraction is act of representing data without including background details.
In java it can be achieved by using abstract classes/interfaces.
Hiding information can be achieved by modifiers.
Example for Abstract method:
abstract void function();
Example of abstract class:
abstract class TestAbstract{
abstract void fun1();
public void fun2(){
statements
}
abstract classes contain abstract methods and normal methods.
Abstract Class Example:
package com.oops;
abstract class Area{
int side;
Area(int a){
side=a;
}
abstract int area();
public void nonAbstractMethod(){
System.out.println("Non abstract Method");
}
}
class Square extends Area{
Square(int a) {
super(a);
}
@Override
int area() {
System.out.println("Square Area");
return side*side;
}
}
class Rect extends Area{
public Rect(int a) {
super(a);
// TODO Auto-generated constructor stub
}
@Override
int area() {
// TODO Auto-generated method stub
System.out.println("Area of Triangle");
return side*side;
}
}
public class AbstractClassExample {
public static void main(String args[]){
Square sq=new Square(3);
Rect rt=new Rect(5);
Area ar;
ar=sq;
System.out.println("Square Area"+ar.area());
ar=rt;
System.out.println("Rectangle area"+ar.area());
}
}
Output:
============
Square Area
Square Area9
Area of Triangle
Rectangle area25
