Announcing KotlinConf

Over the past year we have seen significant growth in Kotlin adoption, represented not only by the lines of Kotlin code on GitHub (8M new lines of code since 1.0 release) but also by the numerous companies that have been reaching out to us about their usage, the number of talks being presented by community members at conferences, the increase in new frameworks and libraries, new user groups and meet-ups, as well as community events

To thank the wonderful Kotlin community, and to also share the most exciting things happening in Kotlin, we’re happy to announce KotlinConf, a two-day event taking place in San Francisco, November 2017.


We’ll be opening up registration soon with early-bird tickets, so make sure you sign-up for updates.

Call for Papers now open

We have keynotes lined up by Andrey Breslav and Erik Meijer, and talks by some other speakers that we’ll be announcing shortly. But this is a community event and we want you, as members of the Kotlin community to also participate in the conference. As such, there is an open Call for Papers where you can submit talks on things you’ve been doing with Kotlin and would like to share. While there is no rush, don’t delay because the call ends on the 1st of May 2017. 

If you have any questions regarding the conference, please send an email to You can also ask questions on #kotlinconf on Slack. For sponsorship enquires, please email

2017 is going to be an exciting year for Kotlin and we hope to celebrate it with you in November!

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Kotlin 1.1.1 is out

Today we’re releasing the first bugfix update for Kotlin 1.1. The primary focus of this update is to address regressions causing incorrect code generation; we wanted to get those fixes out as quickly as possible. The details are available in the changelog.

The specific changes worth highlighting are:

  • Gradle incremental compilation is now enabled by default. You can still turn it off as described in the documentation if you need to.
  • Kotlin plugins are now available in the Gradle plugin portal. See the documentation for usage instructions.
  • Using function types with receivers as parameter types of JavaScript external declarations is no longer allowed. Previously, lambdas passed to such parameters weren’t invoked with correct arguments, and there’s no easy workaround for this issue, so for now we’ve decided to disable the functionality.

We’ve also updated the Kotlin Eclipse and NetBeans plugins to include Kotlin 1.1.1, so you can enjoy the benefits of the new Kotlin version regardless of your IDE choice.

How to update

To update the IDEA plugin, use Tools | Kotlin | Configure Kotlin Plugin Updates and press the “Check for updates now” button. Also, don’t forget to update the compiler and standard library version in your Maven and Gradle build scripts.
The command-line compiler can be downloaded from the Github release page.

As usual, if you run into any problems with the new release, you’re welcome to ask for help on the forums, on Slack (get an invite here), or to report issues in the issue tracker.

Let’s Kotlin!

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Kotlin 1.1 Event

In addition to the new features that Kotlin 1.1 brings to your projects, it is also a good reason to meet up with your local community and friends to learn about new opportunities behind the release and impact on the future of Kotlin.

You can organize a Kotlin 1.1 Event together with the JetBrains team and your community on March 23. We will hold 2 live stream sessions to accommodate different time zones. You can join the live stream at 5pm or 7pm CET (9am and 11am PDT).

Let us know about your event so we can announce it at the blog.


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Kotlin 1.1 Released with JavaScript Support, Coroutines and more

Members of our community have translated this blog post into several languages:

Today we release Kotlin 1.1. It’s a big step forward enabling the use of Kotlin in many new scenarios, and we hope that you’ll enjoy it.

Kotlin 1.1

Our vision for Kotlin is to enable the use of a single expressive, performant, strongly typed language across all components of a modern application. Kotlin 1.1 makes two major steps towards this goal.

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Kotlin 1.1 Release Candidate is Here

As of today, Kotlin 1.1 has finally reached the release candidate stage. This means that most of our development work is done, we’re happy with the results, and we’ll soon publish them as a final Kotlin 1.1 release. We’ve done a lot of testing for this release internally, but the real world is always more varied than any test environment, so we need your help. Please try this build, and let us know about your experience!

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Our first book about Kotlin is out

We’re happy to announce that Kotlin in Action – a book about Kotlin written by the members of the Kotlin team – is now out, as both a eBook and a printed book. The book is written for experienced Java developers and covers all aspects of the language, without focusing on any specific problem domain. We received a lot of positive feedback about the book during Manning’s Early Access Preview program, so we hope that you’ll enjoy it too!

Kotlin in Action book

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Kotlin 1.1 Beta 2 is here

We’re happy to announce the second beta of Kotlin 1.1. Please give the new version a try – your feedback is essential for ensuring that we can deliver a quality release.

Since the first beta release, we’ve mostly been focused on stability, bugfixes, and improving the key focus areas of this release: coroutine support and the JavaScript backend. The full list of changes since 1.1 Beta can be found in the changelog. And if you’re interested in a recap of everything added in version 1.1, check out our what’s new page.

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Announcing the Support Program for Kotlin User Groups and Events

Today we are launching a new Community section at our web-site!

Explore Kotlin Community

It will provide you with the guidelines to organize Kotlin related events, and the description of support managed by JetBrains. We are now happy to announce that we have formalized the support process for User Groups and Events around Kotlin.

It is exciting to see that in 2016 about 150,000 of developers all over the world tried Kotlin. We now have an amazing community, which enables us to hold Kotlin-dedicated talks and meetups. We have also held two Kotlin Nights: the first one was in San-Francisco and the other one was in London. What is even more fantastic is that you, the community, start to organise these events, and we are here to help. It is also great to see demand for more Kotlin Nights.

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Kotlin 1.1: What’s coming in the standard library

Java 9 preparations

Java 9 is coming and brings Project Jigsaw to the table — the Java platform module system. One of the constraints it imposes is that no two modules can declare public API in the same package. The situation, when there are two modules that contribute to the same package, is called “split” package.

We face this issue with split packages in our runtime artifacts: first, kotlin-runtime and kotlin-stdlib modules share a lot of kotlin.* packages, second, kotlin-runtime and kotlin-reflect share kotlin.reflect package. What we’re going to do to make our artifacts more friendly to the module system:

  1. We merge kotlin-runtime and kotlin-stdlib into the single artifact kotlin-stdlib. Also we’re going to rename kotlin-runtime.jar, shipped in the compiler distribution, to kotlin-stdlib.jar, to reduce the amount of confusion caused by having differently named standard library in different build systems.
    That rename will happen in two stages: in 1.1 there will be both kotlin-runtime.jar and kotlin-stdlib.jar with the same content in the compiler distribution, and in 1.2 the former will be removed.

  2. In kotlin-reflect module we move all API from kotlin.reflect to kotlin.reflect.full package. Kotlin 1.1 will have the former API deprecated with the replacements suggested, and it will be removed eventually in 1.2.
    Note that this change will affect only extension functions and properties provided by kotlin-reflect for reflection interfaces and a couple of exception classes. Reflection interfaces themselves are located in the standard library and won’t be moved.

If you use maven or gradle and depend on kotlin-stdlib, you won’t need to change anything. If you depend on kotlin-runtime, you should replace that dependency with kotlin-stdlib.

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Kotlin 1.1 Beta Is Here!

Congratulations! Today Kotlin 1.1 has reached Beta, and this means that

  • it’s time to try it out,
  • there’s still time to give us your feedback (and we really need it!),
  • the release is coming fairly soon.

Kotlin 1.1 Beta

We’ve seen a lot of interest in Kotlin over the past year, and would like to thank all our users, contributors and supporters. Special thanks to early adopters of new features for their bravery and feedback to our EAP builds!

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