configure<MultiReleaseExtension> {
    targetVersions(defaultVersion, javaModuleVersion)
  }

  tasks.named<JavaCompile>("compileJava9Java").configure {
    val compileKotlinTask = tasks.getByName("compileKotlin") as KotlinJvmCompile
    dependsOn(compileKotlinTask)

    if (enableValidation) {
      compileKotlinTask.source(file("src/main/java9"))
    }