Object-oriented programming is such a fundamental part of software development that it's hard to remember a time when people used any other approach. However, when objected-oriented programming, or OOP, first appeared in the 1980s, it was a radical leap forward from the traditional top-down method.
You may be used to breaking down large problems into sub-problems and solving them in separate units of code. Or you may have experience with functional programming, which treats elements of code as precise mathematical functions, and prevents them from affecting other elements - that is, no side effects. Come to grips with OOP, however, and you'll see that it offers a whole new way of solving problems.
With OOP, instead of writing a program, you create classes. A class contains both data and functions. When you want to create something in memory, you create an object, which is an instance of that class. So, for example, you can declare a Customer class, which holds data and functions related to customers. If you then want your program to create a customer in memory, you create a new object of the Customer class.
The advantages of object-oriented programming lie in this kind of encapsulation. Here's a look at some of OOP's top benefits:
1. Modularity for easier troubleshooting
When working with object-oriented programming languages, you know exactly where to look when something goes wrong. "Oh, the car object broke down? The problem must be in the Car class!" You don't have to go line-by-line through all your code.
That's the beauty of encapsulation. Objects are self-contained, and each bit of functionality does its own thing while leaving the other bits alone. Also, this modularity allows an IT team to work on multiple objects simultaneously while minimizing the chance that one person might duplicate someone else's functionality.
2. Reuse of code through inheritance
Suppose that in addition to your Car object, one colleague needs a RaceCar object, and another needs a Limousine object. Everyone builds their objects separately but discover commonalities between them. In fact, each object is just a different kind of Car. This is where the inheritance technique saves time: Create one generic class (Car), and then define the subclasses (RaceCar and Limousine) that are to inherit the generic class's traits.
Of course, Limousine and RaceCar still have their unique attributes and functions. If the RaceCar object needs a method to "fireAfterBurners" and the Limousine object requires a Chauffeur, each class could implement separate functions just for itself. However, because both classes inherit key aspects from the Car class, for example the "drive" or "fillUpGas" methods, your inheriting classes can simply reuse existing code instead of writing these functions all over again.
What if you want to make a change to all Car objects, regardless of type? This is another advantage of the OOP approach. Make a change to your Car class, and all car objects will simply inherit the new code.
3. Flexibility through polymorphism
Riffing on this example, you now need just a few drivers, or functions, like "driveCar," driveRaceCar" and "DriveLimousine." RaceCarDrivers share some traits with LimousineDrivers, but other things, like RaceHelmets and BeverageSponsorships, are unique.
This is where object-oriented programming's polymorphism comes into play. Because a single function can shape-shift to adapt to whichever class it's in, you could create one function in the parent Car class called "drive" - not "driveCar" or "driveRaceCar," but just "drive." This one function would work with the RaceCarDriver, LimousineDriver and so on. In fact, you could even have "raceCar.drive(myRaceCarDriver)" or "limo.drive(myChauffeur)."
4. Effective problem solving
Many people avoid learning OOP because the learning curve seems steeper than that for top-down programming. But take the time to master OOP and you'll find it's the easier, more intuitive approach for developing big projects.
Object-oriented programming is ultimately about taking a huge problem and breaking it down to solvable chunks. For each mini-problem, you write a class that does what you require. And then - best of all - you can reuse those classes, which makes it even quicker to solve the next problem.
This isn't to say that OOP is the only way to write software. But there's a reason that languages like C++, C# and Java are the go-to options for serious software development.
What to know about OOP developer jobs
There's an insatiable demand right now for talented software developers with experience using C# and Java. Employers are also keen for OOP programmers with other qualifications, such as Certified Information Security Manager (CISM) or AWS-Certified Cloud Practitioner.
Industries with the highest demand for OOP developers include:
Retail and e-commerce
As reported in the the latest Robert Half Salary Guide, the national average starting salary for software developers is $122,250, while experienced software developers can command starting salaries averaging $142,750. (You can use our Salary Calculator to see what market rates are like in your area.)
If you've worked exclusively with top-down languages so far, it might be hard to land a position as an OOP developer. Here are some steps you can take to build up your object-oriented programming skills:
Teach yourself an OOP language: The Java SDK is free to download and use. You will also find a wide range of free programming tutorials available online.
Attend a boot camp: Boot camps are intended to help coders learn new skills, fast. They are usually intensive courses with a project at the end that shows what you've learned.
Work on a solo project: The best way to learn is by doing, of course. Use your new skills to build software demos and test out new concepts. Android apps run on Java, so you can build a mobile application and release it to the world.
Join coding forums: There are many online communities where you can network with more experienced developers. The pros you connect with in these forums can offer advice on ways to hone your skills and strengthen your resume.
Once you understand how to use classes and objects, you'll wonder why you ever used anything else. And when you are able to start your career as an OOP developer, you'll never look back.