kotlin{
  jvm("desktop"){
    compilations.main.kotlinOptions.jvmTarget = "1.8"
  }
}

It is still using java 11, so javafx is not working :( Anyone know how can I force the compiler to use java 8?

You can’t use JavaFX 12?

Nope, tornadofx 1.x uses java 8 and I can't find tornadofx 2.0 on any repo (don't want to build it locally)

Try specifying the

jdkHome

argument: https://kotlinlang.org/docs/reference/using-gradle.html#attributes-specific-for-jvm

I think it's just because I can't target both jvm and android so something was broken (not related to java version)