Could you remind me how to add JavaExec task to mutliplatform? I believe it was answered several times, but I forgot again.

With

1.3.40

you can now use the application gradle plugin.

Oh? I think I've missed that. I will try it, thanks

Or otherwise you can copy what you need from here https://github.com/Dominaezzz/kgl-vulkan-samples/blob/e3da64b07ef2b1d7feb1b5db6525c59316d77a4a/build.gradle.kts#L142

I've already solved the problem with

tasks.register<JavaExec>("runSwing") {
    group = "run"
    val target = kotlin.targets["jvm"]
    val compilation: KotlinCompilationToRunnableFiles<KotlinCommonOptions> =
        target.compilations["main"] as KotlinCompilationToRunnableFiles<KotlinCommonOptions>

    val classes = files(
        compilation.runtimeDependencyFiles,
        compilation.output.allOutputs
    )
    classpath = classes


    main = "ru.mipt.phys.diffraction.AppFrameKt"
}

but application is better.