JetBrains's JVM language debuts!

Project Kotlin unveiled to the public

Chris Mayer

The aim for Kotlin – Java-compatible but faster, safer and concise. In other words, a Scala simplifier.

Just over a year since the first real steps towards their new language project, JetBrains have revealed the first public preview for Kotlin.

The statically-typed JVM-targeted programming language is now available to test via a code editor at Kotlin’s Web Demo page, allowing users to really get to grips with the nuances behind the code.

From there, you can view Hello World examples, the popular 99 Bottles of Beer examples plus some problem solving to be done, ranging from simple to complex. It’s all there to have a play with anyway. Just run your code on a JVM running on their server, so that you can use familiar JDK classes or alternatively, you compile your code to JavaScript and run it in your browser

Hello World


fun main(args : Array<String>) {
  System.out?.println("Hello, world!")


When Kotlin was announced, its place within the JVM was fairly clear. It is stated within the documentation that Kotlin was created with the following design goals in mind:

The last one is especially relevant, given recent heated discussions over where Scala should head next, now it has at least a community endeavour behind it. That’s really the next step for Kotlin – to generate enough buzz for those wanting to use it. They did state that their work on this wouldn’t affect anything to do with Scala plugin, so it is good to know that they aren’t stepping on Scala’s toes. More an interpretation of it.

It has some bold aspirations, but there’s always room for one more language. Certainly, if any team deserves to be standing alongside Scala and Groovy, it’s JetBrains.

The compiler is being created alongside the IntelliJ IDEA. Lead language designer of Kotlin, Andrey Breslav gave a little teaser into what we can expect in the near future:

  • Standard Library of extension functions that make using JDK collections and other common APIs more pleasant (things like map()/filter() and so on);
  • Code Challenge: currently we offer a few sample problems in the form of code snippets containing test data. This will be extended to contest-like automated testing system.
  • Much more examples.

Keep an eye on the demo for further updating in the coming weeks – there’s plenty more for Kotlin to show us!

Inline Feedbacks
View all comments