What is Abstraction with detailed explanation and example program

Question

Explain abtraction, abstract class and interface

Answer 1

Abstraction in Object Oriented Design :

https://en.wikipedia.org/wiki/Abstraction_(software_engineering)#Abstraction_in_object_oriented_programming

Abstract classes VS. Interfaces :

https://beginnersbook.com/2013/05/abstract-class-vs-interface-in-java/

Start by those, and feel free to ask if something is unclear to you. Good reading!