Kotlin 1.8.0 beta introduces experimental features

Published on Dec 03, 2022

A new version of the Kotlin programming language adds support for Java 19 and introduces experimental functions for the JVM to recursively copy and delete directory contents.

Kotlin 1.8.0, an upgrade to the JetBrains-developed, statically typed language for mobile, web, and native development, is now available as a beta. New experimental functions have been added to the JVM in the new version.

There are new experimental functions added to the standard library in Kotlin 1.8.0 for java.nio.file.path that can recursively copy or delete directory content. Furthermore, experimental functionality has been added to TimeMarks, allowing elapseNow to read from multiple TimeMarks simultaneously. Both sets of new functionality require opt-in. As part of Kotlin 1.8.0, java.util.Optional extension functions have been stabilised.

As announced on November 23, Kotlin 1.8.0 also adds support for Gradle 7.3, but removes support for the old JVM back end, with the -Xuse-old-backend compiler option no longer available. Please refer to kotlinlang.org for instructions on how to update to the beta version.

The Kotlin 1.8.0 beta also contains the following new features and improvements:

Kotlin/JVM supports Java 19 bytecode.

For Kotlin/JS, the IR (intermediate representation) compiler has been stabilised, and incremental compilation has been set as the default. We have deprecated the old Kotlin/JS backend.

Kotlin Multiplatform now supports an Android source set layout that can be enabled in the Gradle plugin by setting kotlin.mpp.androidSourceSetLayoutVersion=2. A new naming schema has also been added for KotlinSourceSet entities.

As part of Kotlin Native, support has been added for the Xcode 14 IDE for Apple development, as well as for the watchosDeviceArm64 target. Annotations are supported to improve interoperability between Objective-C and Swift.