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ABSTRACT CLASS
MOHIT AGARWAL �C (161080107026)

INTRODUCTION
? ��Abstraction�� is a process of hiding the implementation
details and showing only functionality to the user.
? It shows only essential things to the user and hides the
internal details.
? There are two ways to achieve abstraction in java
1) Abstract class (0 to 100%)
2) Interface (100%)

ABSTRACT CLASS & METHOD
? An abstract class is a class that is declared ��abstract�� it may or may
not include abstract methods.
? A method which is declared as ��abstract�� and does not have
implementation is known as an abstract method.
? Syntax :
modifier abstract class className
{
abstract dataType methodName();
}
modifier class childClass extends className
{
dataType methodName(){}
}

? An abstract class must be declared with an abstract keyword.
? It can have abstract and non-abstract methods.
? It cannot be instantiated.
? It can have constructors and static methods also.
? It can have final methods which will force the subclass not to
change the body of the method.
? Any class which contains an abstract method must also be abstract.
POINTS TO REMEMBER

Abstract Class & Abstract Method in Core Java

abstract class Animal //Abstract Class Declaration
{
public abstract void sound(); //Abstract Method Declaration
}
public class Dog extends Animal //Dog inherits from Animal
{
public void sound()
{
System.out.println("Woof");
}
public static void main(String args[])
{
Animal obj = new Dog();
obj.sound();
}
}
OUTPUT : Woof

abstract class MyClass
{
public void disp()
{
System.out.println("Concrete method of parent class");
}
abstract public void disp2();
}
class Demo extends MyClass
{
public void disp2()
{
System.out.println("overriding abstract method");
}
public static void main(String args[])
{
Demo obj = new Demo();
obj.disp2();
}
}
OUTPUT : overriding abstract method

? To share code among several closely related classes.
? If classes that extend your abstract class have many common
methods or fields or require access modifiers other than public
(such as protected and private).
? You want to declare non-static or non-final fields. This enables
you to define methods that can access and modify the state of
the object to which they belong.
USE OF ABSTRACT CLASS

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Abstract Class & Abstract Method in Core Java

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Abstract Class & Abstract Method in Core Java