Abstract Class

Abstract Class

Abstract class

Example :

abstract class Animal

{

abstract void eat();

void show()

{

System.out.println("This is Animal show");

}

}

class Demo

{

public static void main(String as[])

{

Animal a=new Animal(); //not allowed.

a.show();

}

}

Explanation :

» When you are unable to implement the method (Without body)

declare the method as abstract.

» When you declare one (or) more methods as abstract you must

declare the class also abstract.

» When class is abstract it can't be instantiated.

» In an abstract class we can have both abstract method and concrete

methods.

» In abstract class we can have only concrete methods also.

» When class is abstract we should write a subclass for that (or)

subclass is responsible to implement the abstract class with

subclass object only.

» We can call the subclass methods as well as abstract class concrete

methods.

» When you extend any abstract class we should override all the

abstract methods in subclass, otherwise declare the subclass

as abstract.