Object Oriented Programming Features

     As we discussed before in the Features of Java , the object oriented concepts came into the picture.In this part , we will discuss that concepts in detail.             

    The object oriented programming (OOP) paradigm express computer programs in ways how people perceive the world , which is as objects.

   Firstly, we will recall the concepts of Object Oriented Programming Language(OOP ) , as disussed earlier in our Features of Java post.

Fundamental Concepts of Object Oriented:
1.Class
2.Object
3.Encapsulation
4.Abstraction
5.Inheritance
6.Polymorphism
7.Message Passing
8.Reusability

Class

• Class is a user defined data type.
• It is a fundamental packaging unit of OOP technology.
• Class can be defined as a template/blue print that describes the behaviors/states that object of its type support.

Object

• An Object is a real time entity.
• In other words , an object is an independent software entity with logically combined data and functions.
• Real-world objects share two characteristics :  They all have state and behavior.    Dogs have state (name, color) and behavior (barking, wagging tail).
• An object is an instance of class.

Encapsulation

• The mechanism of binding the code and the data it manipulates and keeping both safe from outside interference is called as encapsulation.
• In other words , the wrapping up of data and its functions into a single unit is called Encapsulation.

Abstraction

• Abstraction refers to the act of representing essential features without including the background details or explanation between them.
• Abstraction is one of the key principles of the OOAD(Object oriented analysis and Design).
• For example , a mobile phone has various features like sms,calling,music player,camera,etc. You don't need to know how this things work internally , you directly use it.This is possible because of abstraction.

    Note:It can be said that Encapsulation is the Bodyguard and Abstraction is VIP.

Inheritance

• Inheritance is the concept by which the properties of one class are made available to another.
• It allows the new classes to be built from the older instead of being rewritten from scratch.
• The concept of inheritance provides the idea of reusability and extensability.

Polymorphism

• Polymorphism is a Greek term where poly means many and morph means form.
• It simply means 'one name multiple forms'.
• The most common use of polymorphism in OOP occurs when a parent class reference is used to refer to a child class object.

Message Passing

• A message for an object is a request for execution of a procedure , and therefore will invoke a function (procedure) in the receiving object that generates the desired result. 
• Objects can send or receive message or information.
• Message passing involves name of object, name of function (message) and information to be send.
• For example, student.mark(name) .  Here student is object, mark is message, name is information.

Reusability

• Object Oriented programs are built from reusable software components.
• Reusability is nothing but re- usage of structure without changing the existing one but adding new features or characteristics to it. It is very much needed for any programmers in different situations.
• Also , as discussed above in the inheritance concept , reusability is acheived through inheritance.