Learning Kotlin? Most popular tools and frameworks for the Java-compatible programming language

If you’re an Android developer then chances are the Kotlin programming language is on your radar.

Google recently announced it will prioritize Kotlin when introducing new features for Android developers, and recommended that new Android apps are written using Kotlin.

The increasingly diverse uses of Kotlin were captured by the JetBrain’s Kotlin Census 2018, which polled almost 4,400 developers on how they use the eight-year-old language.

While the Java-compatible programming language is most commonly used by mobile developers (58% of those surveyed), a large number of web back-end developers are also turning to Kotlin (48%). That heavy use of Kotlin at the backend of web sites and services was reflected by the type of platforms developers were targeting, with the most commonly targeted platform being the Java Virtual Machine (JVM) running on web servers (67%), followed by Android (57%).

Kotlin is a modern alternative to Java that is easy to learn and use. It has been described by a Netflix senior software engineer as offering “some of the best features of other languages” combined with “interoperability with Java”, due to its ability to run on the Java Virtual Machine (JVM). Kotlin was the only JVM-targeted language to grow in popularity in this year’s RedMonk Programming Language Rankings, rising eight places to number 20.

It’s worth noting, however, that Java remains far more widely used, sitting in second place in the RedMonk rankings. Interestingly, the Census also found that Kotlin was still typically used as a side language, with most respondents saying they primarily code using Java (42%), closely followed by Kotlin (39%).

SEE: Tips for building a successful career as a software engineer (free PDF) (TechRepublic)

Not only did JetBrain’s Kotlin Census capture how the language is being used, it also shed light on the code editors and software frameworks Kotlin developers find most useful.

Most popular JetBrains’ framework

As the company behind Kotlin, JetBrains’ frameworks are core to Kotlin as a language, with the asynchronous programming-focused kotlinx.coroutines being most popular, the kotlin.test library in second place, and the Ktor framework for building asynchronous servers and clients in third.

Image: JetBrains

Most popular general Kotlin libraries and frameworks

The top three frameworks reflect the dominant usage of Kotlin for Android and web development, with Kotlin Android Extensions the most popular, just behind that is mockito-kotlin for use with the Mockito mocking framework for unit tests, and then RxKotlin for use with the asynchronous programming library RxJava.

Image: JetBrains

Most popular build tools

Topping the list for the tools used to build software from Kotlin code is Gradle, followed by Maven, and then the build system offered by JetBrain’s IntelliJ IDEA suite.

Image: JetBrains

Most popular code editors and IDEs

The programs used to write Kotlin code varied according to which platform developers were targeting, but JetBrain’s IntelliJ IDEA dominated, with a mix of the Ultimate and Community editions, and the IntelliJ-based Android Studio.


Most popular IDEs for developers targeting Android.

Image: JetBrains

Most popular IDEs for developers targeting the JVM.

Image: JetBrains

Most popular platforms to develop for

As would be expected, Android is the platform that most Kotlin developers build software for, although Linux and Apple’s iOS are not far behind.

On average Kotlin is being used to develop software for a wider range of platforms in 2018 than in 2017, up to 2.7.

Image: JetBrains

If you’re interested in learning more about Kotlin, check out TechRepublic’s guide to free resources that are available.