how do you set

sourceCompatibility = 8
targetCompatibility = 8

if you use

jvm { withJava() }

?

i just use this:

configure<JavaPluginConvention> {
    sourceCompatibility = JavaVersion.VERSION_1_8
}

I use:

jvm {
        compilations.all {
            kotlinOptions.jvmTarget = "1.8"

It corresponds to

targetCompatibility

. I don't think

sourceCompatibility

has any meaning with respect to kotlin source (assuming you don't write native Java).

Thanks, I have Java files, so I am going to try out christoph's solution. I am already using jvmTarget for Kotlin