Kotlin K2 compiler

The JetBrains team is excited to announce the stabilization of the K2 compiler with Kotlin 2.0.0. The K2 compiler is now the default and stable for all platforms: JVM, Native, Wasm, and JS. It offers major performance improvements, faster language feature development, unified platform support, and better architecture for multiplatform projects.

To ensure quality, JetBrains compiled 10 million lines of code from various projects and involved 18,000 developers in testing, covering 80,000 projects.

The initialization phase is up to 488% faster using the K2 compiler.

How to configure gradle project:

import org.jetbrains.kotlin.gradle.tasks.KotlinCompile

plugins {
    id("org.springframework.boot") version "3.2.0" apply false
    id("io.spring.dependency-management") version "1.1.4" apply false
    kotlin("jvm") version "2.0.0" apply false
    kotlin("plugin.spring") version "2.0.0" apply false
}

group = "com.kss"
version = "1.0-SNAPSHOT"

allprojects {
    repositories {
        mavenCentral()
    }
    apply(plugin = "org.jetbrains.kotlin.jvm")

    configure<org.jetbrains.kotlin.gradle.dsl.KotlinJvmProjectExtension> {
        jvmToolchain {
            languageVersion.set(JavaLanguageVersion.of(21))
        }
    }

    tasks.named("compileKotlin", org.jetbrains.kotlin.gradle.tasks.KotlinCompilationTask::class.java) {
        compilerOptions {
            freeCompilerArgs.add("-Xexport-kdoc")
        }
    }

    tasks.withType<KotlinCompile> {
        compilerOptions{
            apiVersion.set(org.jetbrains.kotlin.gradle.dsl.KotlinVersion.KOTLIN_2_0)
        }
    }
    tasks.withType<Test> {
        useJUnitPlatform()
    }
}

There is whole description of how to configure gradle project.

How to enabled compiler in Intellij Idea

We need to enabled K2 mode in settings

Or there is path how to find it

Settings -> Languages & Frameworks -> Kotlin -> Enabled K2 Kotlin Mode