Java Abstraction1 min read

Data abstraction is the process of hiding the details but only displaying the relevant information to the users, which is hiding the implementation details and displaying only its functionalities. This is one of the main advantages of using abstraction.
Abstraction is one of the four major concepts behind object-oriented programming (OOP).

Take a real-life example:
Suppose a person is typing with the help of a keyboard on his/her computer. That person knows that pressing any alphabet on the keyboard, displays that alphabet on the screen of the monitor but he/she doesn’t know how the internal mechanism is working to display the alphabet.
Therefore, hiding the internal mechanism and showing only its output is an abstraction in this example.

In java, abstraction can be achieved in two ways.

Abstraction class and Abstract methods:

An abstract class is a class that is declared with an abstract keyword.
An abstract class may or may not have abstract methods.
This class cannot create objects, to access this class, it must be inherited.
Example:

Abstract methods:

It is a method that can only be used with an abstract class.
It has no body.
An abstract method is also declared with abstract keyword and ends with a semicolon(;) instead of curly braces({}).
Example:

Let us see it in an example:

Output:

Interface in Java


Encapsulation.
Polymorphism.
Inheritance.