apply plugin: "java" apply plugin: "kotlin" sourceCompatibility = 1.5 version = '1.0' dependencies { testCompile group: 'junit', name: 'junit', version: '4.11' } buildscript { repositories { mavenCentral() } dependencies { classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version" } } sourceSets { main.java.srcDirs += 'src/main/kotlin' }