Kotlin is a programming language that was released in 2011 by JetBrains, a company that sells integrated development environments (IDEs) for programming languages. Since then, it’s become a favorite language for developers and replaced Java in many software projects.

In this article, we’ll look at why Kotlin became popular, its advantages, and what it’s used for.

What are the advantages of Kotlin?

Kotlin’s creation arose after Lead Developer Dmitry Jemerov sought features he couldn’t find in Java. Scala, another language that runs on the Java Virtual Machine (JVM), was close to what he wanted, but it took too long to compile.

Jemerov wanted a language that had all the features of more modern programming languages, would run on the JVM, and would compile as fast as Java. So he created his own language, Kotlin.

Kotlin was designed as a replacement for Java on the Android operating system. Eight years after it was released, in 2019, Google finally agreed with Jemerov and most Android developers and announced that Kotlin was the preferred language for Android app development.

Here are some reasons developers prefer Kotlin to Java:

  • Kotlin is concise, saving time that you’d otherwise spend writing boilerplate code in Java.
  • You can convert a Java file into a Kotlin file with just a script.
  • Kotlin has no runtime overhead. Sometimes, adding features to a language means it has more overhead, which lowers its performance. Not so with Kotlin.
  • Kotlin has a large community. If you ever get stuck, you can easily find other developers to help you on coding forums and social networks.
  • Kotlin streamlines asynchronous programming. Making network and database calls asynchronously in Java is clumsy and painful. Kotlin has coroutines that make asynchronous programming simple and efficient.
  • Kotlin handles nulls. A null in Java can crash a program if you haven’t prepared for it. In Kotlin, you can add a simple operator to variables that may be null to prevent these crashes.
  • Kotlin can run on multiple platforms. Kotlin can run anywhere Java runs, so you can use it to build cross-platform apps.
  • It’s easy to switch to Kotlin. Kotlin is fully compatible with Java, so you don’t have to change all your code at once. You can slowly migrate an application to use Kotlin.

Take a look at some simple Kotlin code to get a sense of its simplicity:

fun main() {
    println("Hello, Kotlin!")

What is Kotlin used for?

Kotlin is designed to run on a Java Virtual Machine and can run side by side with Java. Although Kotlin first started as a language for Android development specifically, it quickly spread through the Java community because of its features and has since been used for many types of applications.

Android development

As we mentioned, Kotlin is the preferred language for Android development as it allows developers to write more concise, expressive, and safer code. The official IDE for Android development, Android Studio, supports it completely, so you can get the same type of code completion and type checking to help you write Kotlin code as you do with Java.

Having a mobile presence is a requirement for most businesses since most people access the internet now through mobile phones. Android accounts for over 70% of the market share of mobile phones, so even if Kotlin was only for Android development, Kotlin developers would be in high demand. Still, it can be used for so much more.

Back-end web development

A lot of back-end web development is done in Java, using frameworks like Spring. But, Kotlin made inroads into server-side web development since it was so much easier for developers to work with.

The modern features of the language make it possible for Web Developers to build applications that can scale quickly on commodity hardware. Since Kotlin is interoperable with Java, you can slowly migrate an application to use Kotlin one file at a time while the rest of the application still uses Java.

Kotlin also works with Spring and other frameworks, so switching to Kotlin doesn’t mean you have to change everything you’re used to. Google, Amazon, and many other companies have already replaced Java with Kotlin in some of their server-side code.

Full-stack web development

It makes sense to use Kotlin for server-side web development. After all, Java has been used since its inception. Still, you can also use Kotlin for front-end development using Kotlin/JS.

Kotlin/JS allows developers to access powerful browser and web APIs in a type-safe fashion. Full-Stack Developers only need to know Kotlin. They can write front-end code in the same language that they used for back-end code, and it’ll be compiled to JavaScript to run in the browser.

Data science

Data Scientists have always used Java to crunch numbers, detect trends, and make predictions — so it only makes sense that Kotlin would find a home in data science as well.

Data Scientists can use all the standard Java libraries that they used for Java projects but write their own code in Kotlin. Jupyter and Zeppelin, two tools used daily by many Data Scientists for data visualization and exploratory research, also support Kotlin.

Multi-platform mobile development

Kotlin Multi-platform Mobile is intended to be a software development kit for creating cross-platform mobile applications. This means that from one Kotlin code base, you’ll be able to compile apps that run on not just Android phones but also iPhones and the Apple Watch. This project is currently in the alpha stage but has a lot of promise.

Learn more about Kotlin

Kotlin is a modern programming language that can run side by side with Java while being easier to write. If you want to develop Android apps or multi-platform applications with the JVM, you can do it quicker and simpler with Kotlin than with Java.

Ready to learn more? Our Learn Kotlin course is perfect if you’re a new developer or new to the Kotlin language. It’ll introduce you to fundamental programming concepts and teach you how to write Kotlin code.

Related courses

5 courses

Related articles

5 articles

10 Kotlin Code Challenges for Beginners

By Michael Klein

Are you learning how to develop Android apps in Kotlin? Take a look at these 10 Kotlin code challenges for beginners to put your Kotlin skills to practical use.