Abstract class in Java programing language

Abstract class in Java programing language

In this tutorial, we will discuss the OOP concept of abstract class in Java programing language.

Abstraction is one of the Oop concepts.  A class that contains at least one abstract method is known as an abstract class.

The abstract class is a class which contains at least one abstract method. That means the abstract method does not do any implementation, it just has a signature.

So abstract methods are methods that can be only declared, not defined.

The class becomes abstract if one or more of the methods are abstract.

We cannot create an object of an abstract class.

Sub class must provide an implementation for the abstract methods of the super class or themselves be declared as abstract.

What is the use of an abstract class?

Abstraction is a concept that hides implementation details and only presents the features to users.

Syntax of abstract class

abstract class A{
// abstract is a keyword
// abstract class have abstract and non-abstract methods
// implementation of abstract methods is out of the another class
// all abstract methods in abstract class must implement another class }


Syntex of the abstract method

abstract void method_name();

//no body and abstract
//only declare no define

abstract void run() – it is an abstract method, it has no implementation

void print() – It is a normal method with implementation within the class

implementation of abstract method(void run()) is provided by the override class

An abstract class can have properties as an abstract method, method, constructor, and even main() method

Related Links

Encapsulation in C++                                       Encapsulation in Java

Polymorphism in C++                                      Methodoverriding in Java

Method overloading in java                             Constructor overloading in Java

Exception Handling in Java