build.gradle

buildscript {
  ext.kotlin_version = '1.1.4-3'
  repositories {
    mavenCentral()
  }
  dependencies {
    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
  }
}

apply plugin: 'kotlin'
apply plugin: 'application'

mainClassName = 'demo.HelloWorld'

defaultTasks 'run'

repositories {
  mavenCentral()
}

dependencies {
  compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
  compile "com.sparkjava:spark-core:2.7.2"
  compile "org.json:json:20180813"
  compile group: 'ch.qos.logback', name: 'logback-core', version: '1.2.3'
  compile group: 'ch.qos.logback', name: 'logback-classic', version: '1.2.3'
  testCompile 'junit:junit:4.11'
  testCompile "org.jetbrains.kotlin:kotlin-test-junit:$kotlin_version"
}

task wrapper(type: Wrapper) {
  gradleVersion = "4.1"
}

jar {
  manifest {
    attributes "Main-Class": "demo.HelloWorld"
  }

  from {
    configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
  }
}