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Introducing Object-Oriented Programming Languages: A Guide

Ethan Scully - June 18, 2022

Object-Oriented Programming languages use objects that contain both data and code. The principles of object-oriented programming are encapsulation, abstraction, polymorphism, and inheritance.

Object-oriented programming (OOP) languages are everywhere we look. Many of the most widely used coding languages that make up the computing world today are object-oriented. In fact, many computer programs and much of the content on the web is built on high-level, object-oriented languages . Understanding how object-oriented languages work and why they are useful is important for almost every career in computing.

In this article, we’re going to take a look at what object-oriented languages are and examine their pros and cons. We’ll also take a look at a shortlist of some of the most popular OOP languages in use today.

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What is a Programming Language?

A programming language is a set of rules and procedures that allow programmers to give computers a set of instructions to execute. Every programming language has its own syntax, which, once learned, allows you to tell a computer what tasks it should perform.

Think about it this way. English is a language that allows you to communicate with English speakers. When you know the basic rules of English, you can talk with anyone else who understands those same rules. But, computers cannot understand English or any other “traditional” language for that matter.

What are Object-Oriented Programming Languages?

Computers are powerful machines. With a computer, we can calculate numbers extremely quickly, and we are able to produce amazing programs for many applications. However, to take advantage of this power, we need to communicate with the computer is something less painful than manually typing ones and zeros.

Therefore, we have programming languages, which are propped up by machine code that’s already been written. However, the further removed we get from machine code the more abstract and specialized languages become in handling data. This is why we have so many languages; no one language is perfect, and they all have different and overlapping applications.

Programming Paradigms

To this note, programming languages are often separated by their programming paradigm . A programming paradigm is one way of looking at and accessing data. The two primary paradigms are Object-Oriented and Functional , although there are many more (including some that are underlying principles for the above).

Object-Oriented programming is built around objects, which are data structures that contain both data (properties or attributes) and code (procedures or methods). Objects are able to modify themselves with ‘this’ or ‘self.’ In most OOP languages, almost everything is an object that can have both values and executable code. Each object is unique, and though it may be a copy of another object, its variables can be different from any other object’s variables.

The objects in object-oriented software design can be thought of like actual objects. Think of an object, like a watch. That watch has properties. It’s made of metal, it’s black, it has a specific weight. But that object also does things. It displays the time, and it also can affect itself by spinning gears to change the position of its hands.

Another feature of objects is that we don’t always need to know how the watch functions to get it to function. Assuming the watch is well-built it will reliably tell time, without us having to interfere with its inner workings.

Object-oriented languages have objects similar to real-world objects. They can have properties and functions. They also tend to follow a certain set of principles.

Object-Oriented Programming Principles

Object-oriented languages come with four principles. These four principles are common properties that define them and make them significantly more efficient. Some people call them the four pillars of object-oriented programming.

The four pillars of object-oriented programming are:

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  1. Encapsulation
  2. Abstraction
  3. Inheritance
  4. Polymorphism

The Four Principles

Let’s explore these four principles in greater depth.

  • Encapsulation – Encapsulation is the concept of binding data to functions, which work as a security function to keep that data safe. For example, many OOP languages prevent anything other than specific methods in the class owning the data to access that data. This is often done explicitly to keep certain data safe.
  • Abstraction – Abstraction is the idea that if you’re doing one thing too often, it should be its own entity. For example, if a programmer is repeatedly rewriting the same function for different objects, that function could be abstracted to become its own entity.
  • Inheritance – Inheritance is what it sounds like, and is most often defined as a “is a” relationship. It lets certain classes be under the umbrella of other classes. These classes can inherit information and functionality from that class, while also being able to expand on that functionality. It lets us reuse code that we’ve already typed in other classes.
  • Polymorphism – Polymorphism means ‘to take more than one shape.’ In the sense of OOP languages, it refers to the ability to handle objects differently depending on what they are. It allows us to define different methods for handling objects based on their derived class. For example, if we needed to find the size of something, we might change how we measure it based on what it is. If it’s a plank of wood, I would measure it in inches. This is as opposed to a volume of water, which I would measure by weight. If we utilize polymorphism, we can create a function that can accept either object and still give us a sane measurement.

Java, Python, C++, Lisp, and Perl are all examples of popular object-oriented programming languages. They support programming using the classes and objects paradigm.

Five of the most popular object-oriented languages include:

  1. Java
  2. Python
  3. C++
  4. Ruby
  5. C#
  • Java Java is everywhere, and it is one of the most used and in-demand languages of all time. Java’s motto is ‘write once, run anywhere,’ and that is reflected in the number of platforms it runs on and places it’s used.
  • Python Python is general-purpose and used in many places. However, Python has a strong foothold in machine learning and data science. It’s one of the preferred languages for that new and ever-growing field.
  • C++ – C++has the speed of C with the functionality of classes and an object-oriented paradigm. It’s a compiled, reliable, and powerful language. In fact, it’s even used to build compilers and interpreters for other languages.
  • Ruby – Ruby is another general-purpose programming language. It was built for simplicity. With that said, Ruby is an incredibly powerful language. The creator of Ruby, Yukihiro “Matz” Matsumoto, has said, “Ruby is very simple in appearance, but is very complex inside, just like our human body.”
  • C# – C# is a programming language designed by Microsoft. It was designed to improve upon existing concepts in C. C# powers the Microsoft .NET framework alongside many web apps, games, desktop apps, and mobile apps.

There are other object-oriented languages that we haven’t covered above. Perl, Objective-C, Dart, Lisp, JavaScript, and PHP are all object-oriented too or support object-oriented principles.

The Pros and Cons of Object-Oriented Programming Languages

While OOP languages can be powerful, they aren’t useful for every situation and come with some baggage that must be considered.



Object-oriented code is extremely modular by design. Because of polymorphism and abstraction, you can make one function that can be used over and over again. You can also copy information and functionality that’s already been written with inheritance. This saves time, reduces complexity, saves space, and makes coding a lighter load on our fingers.

Parallel Development

There is enough groundwork for parts of the program to be developed separately from each other and still function under object-oriented principles. This makes concurrent development much easier for larger development teams.


Because most, if not all, of our code is in one place, being called and reused, that code is much easier to maintain. Instead of having to individually fix a hundred different instances where a function is called, we can fix the one modular and polymorphic function.


While most languages have some security, object-oriented languages are convenient because security is built-in with encapsulation. Other methods and classes cannot access private data by default, and programs written in OOP languages are more secure for it.


Object-oriented programming languages break down an application into objects and classes. This is beneficial because it gives your application a more modular structure. Modular code is easier to read. Therefore, it is easier to maintain.


Often Messy

Because object-oriented languages are so customizable and scalable, it can be easy to lose an understanding of how the code works. OOP code can function in many ways. There are many methodologies for programming in OOP that don’t work well with other methodologies, are inefficient, or are difficult to use.

Requires More Planning

Because these languages are so modular and scalable, going in without a clear design ahead of time is a recipe for disaster. Creating an efficient program requires a solid plan, more so than with other programming paradigms.


This is as much a pro as it is a con. Objects and functions can operate independently. They can take in information and (usually) return reliable results. As a result, they can end up being black boxes, meaning that what they do isn’t always apparent. While the programmer probably created that object and knows what it does, OOP languages simply aren’t as transparent as other languages.


Object-oriented languages often take a performance hit. Programs made in OOP languages are often larger and require more computational effort to run than functional languages. However, this isn’t always true or important. C++ is an OOP language, but it’s one of the fastest languages available. On the same note, speed isn’t always important. The difference in speed only becomes apparent when processing huge or complex calculations or in instances where extreme speed is required.

Now you have a firm grasp of what an object-oriented language is, what it’s good for, and which are the most popular. You should also have a better understanding of what coding is and how it works. Programming in these languages can be as enjoyable as it is profitable, and your career in development is only a few steps away.

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Ethan Scully

About the author: Ethan Scully is a writer, editor, and game developer who manages Career Karma's content partnership initiatives and is currently based in Istanbul. His relationships with coding bootcamps give him particular insight into these new job training programs. Before joining the Career Karma team, Scully worked in IT support, graphic design, and as an editor for Cambodia's Khmer Times.

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