Kotlin 1.2.60 Early Access Preview


We’re happy to announce the Early Access Preview (EAP) build for Kotlin 1.2.60!

What’s new

The full changelog is available here.

How to get the EAP build

For IntelliJ IDEA

You can configure Early Access Preview channel in ToolsKotlinConfigure Kotlin Plugin Updates. Change the update channel to ‘Early Access Preview 1.2.x’ and press Check for updates now.

For Maven or Gradle

Add the https://dl.bintray.com/kotlin/kotlin-eap repository URL to the list of project repositories. Here is how to do this in Gradle:

buildscript {
    ext.kotlin_version = '1.2.60-eap-7'

    repositories {
        maven { url 'https://dl.bintray.com/kotlin/kotlin-eap' }

    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"

apply plugin: "kotlin"

repositories {
    maven { url 'https://dl.bintray.com/kotlin/kotlin-eap' }

dependencies {
    compile "org.jetbrains.kotlin:kotlin-stdlib"

Change the version of Kotlin dependencies (compiler and stdlib) to 1.2.60-eap-7.

Please provide feedback and report issues to our issue tracker. Please don’t forget to specify your IDE/build system Kotlin plugin versions.

JsName and JVMName cannot be used in the same project

The changelog mentions inline class. Is there a way to enable it?


Inline classes are actually a feature of an upcoming 1.3 (https://github.com/Kotlin/KEEP/issues/104), which is being developed in the master branch under a separate compiler argument for simplicity. You can enable the feature with the compiler argument -XXLanguage:+InlineClasses. Note that this will mark your compiled code as “pre-release”, so that it’d be impossible to use it as a library when using “release” Kotlin versions (less than 1.3 at the moment).

Enable inline classes

I’m a bit sad that the REPL got no love. It could be such a useful tool …


I am using beakerx with kotlin kernel. Works like charm. Of course you need python runtime for that.



The new build 1.2.60-eap-27 has been published. The changelog (relative to the previous build) is available here.


The new build 1.2.60-eap-44 has been published. The changelog (relative to the previous build) is available here.


Gradle crashes with kotlinx.serialization plugin (v0.5.1)

* What went wrong:
A problem occurred configuring project ':caves'.
> Failed to notify project evaluation listener.
   > java.lang.AbstractMethodError (no error message)
   > java.lang.AbstractMethodError (no error message)


There’s a note on github page of kotlinx.serialization that 1.2.60-eap-* works only with 0.5.2-SNAPSHOT version of plugin


Woops, my bad :blush: