Four Pillars of Object Oriented Programming (OOP)

In this blog, I will try to explain the main four principles of Object-Oriented-Programming (OOP). Object-Oriented-Programming allows programmers to think of software development as if they are working with real-life entities. In your everyday life, people have the knowledge and can-do various works/tasks. In OOP, objects have fields to store knowledge/state/data and can-do various methods.

The Four Pillars of Object Oriented Programming:


Encapsulation is cultivated when each article keeps a private state, inside a class. Different articles cannot get to this state straightforwardly, all things being equal; they can just summon a rundown of public capacities. The item deals with its own state through these capacities and no other class can change it except if unequivocally permitted. To speak with the article, you should use the strategies gave. One way I like to consider epitome is by utilizing the case of individuals and their canines. On the off chance that we need to apply exemplification, we do as such by embodying all “canine” rationale into a Dog class. The “state” of the canine is in the private factors fun loving, hungry and energy and every one of these factors has their individual fields.

There is likewise a private strategy: bark(). The canine class can call this at whatever point it needs, and different classes cannot advise the canine when to bark. There are likewise open techniques like rest(), play() and eat() that are accessible to different classes. Every one of these capacities alters the inside condition of the Dog class and may summon bark(), when this happens the private state and public techniques are fortified.


Abstraction is an expansion of embodiment. It is the way toward choosing information from a bigger pool to show just the applicable subtleties to the article. Assume you need to make a dating application and you are approached to gather all the data about your clients. You may get the accompanying information from your client: Full name, address, telephone number, most loved food, most loved film, interests, charge data, government backed retirement number, FICO assessment.

This measure of information is incredible notwithstanding not every last bit of it is needed to make a dating profile. You just need to choose the data that is appropriate to your dating application from that pool. Information like Full name, most loved food, most loved film, and diversions bode well for a dating application. The way toward bringing/eliminating/choosing the client data from a bigger pool is alluded to as Abstraction. One of the upsides of Abstraction is having the option to apply a similar data you utilized for the dating application to different applications with next to zero adjustment.


Inheritance is the capacity of one item to gain a few/all properties of  another article. For instance, a kid acquires the qualities of his/her folks. With legacy, reusability is a significant benefit. You can reuse the fields and techniques for the current class. In Java, there are different kinds of Inheritance: single, multiple, multilevel, hierarchical, and hybrid.

For instance, Apple is a natural product so accept that we have a class Fruit and a subclass of it named Apple. Our Apple gains the properties of the Fruit class. Different characterizations could be grape, pear, and mango, and so forth Organic product characterizes a class of food varieties that are full grown ovaries of a plant, beefy, contains a huge seed inside or various little seeds. Apple the sub-class obtains these properties from Fruit and has some remarkable properties, which are not quite the same as other sub-classes of Fruit like red, round, sorrow at the top.


Polymorphism gives us an approach to utilize a class precisely like its parent so there is no disarray with blending types. This being said, every youngster sub-class keeps its own capacities/techniques as they are. In the event that we had a superclass considered Mammal that has a technique called mammal Sound().

The sub-classes of Mammals could be Dogs, whales, elephants, and ponies. Each of these would have their own emphasis of a warm blooded animal sound (canine barks, whale-clicks).

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