Minimal TornadoFX setup with Gradle

build.gradle

//File build.gradle
plugins {
    id "org.jetbrains.kotlin.jvm" version "1.2.41"
    id "application"
}

mainClassName = "HelloWorldKt"

repositories {
   jcenter()
}

compileKotlin {
    kotlinOptions.jvmTarget= "1.8"
}

dependencies {
   compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
   compile 'no.tornado:tornadofx:1.7.16'

}

HelloWorld.kt

//File src/main/kotlin/HelloWorld.kt
import tornadofx.*

class HelloWorld : View() {
    override val root = hbox {
        label("Hello world")
    }
}

class MyApp : App(HelloWorld::class)

fun main(args: Array<String>) {
  launch<MyApp>(args)
}