buildscript { ext.kotlin_version = '1.2.51' repositories { jcenter() } dependencies { classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version" } } apply plugin: 'kotlin' compileKotlin { kotlinOptions.jvmTarget= "1.8" } repositories { mavenLocal() jcenter() } dependencies { compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version" compile 'no.tornado:tornadofx:1.7.16' testCompile "junit:junit:4.11" testCompile 'org.assertj:assertj-core:3.9.0' testCompile "org.jetbrains.kotlin:kotlin-test-junit:$kotlin_version" } task wrapper(type: Wrapper) { gradleVersion = "4.6" }