build.gradle

buildscript {
    ext.kotlin_version = '1.2.31'

    repositories {
        mavenCentral()
    }
    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

group 'com.github.shakram02'
version '0.0.1'

apply plugin: 'java'
apply plugin: 'kotlin'

sourceCompatibility = 1.8

repositories {
    mavenCentral()
}


configurations {
    provided
    compile.extendsFrom provided
}

dependencies {
    provided "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
    testCompile group: 'junit', name: 'junit', version: '4.12'
}

compileKotlin {
    kotlinOptions.jvmTarget = "1.8"
}
compileTestKotlin {
    kotlinOptions.jvmTarget = "1.8"
}


jar {
    from sourceSets.main.allSource

    // This line of code recursively collects and copies all of a project's files
    // and adds them to the JAR itself. One can extend this task, to skip certain
    // files or particular types at will
    // Use provided to declare already present library that will be provided by the runtime
    // I marked the kotlin-runtiume as provided
    from {
        (configurations.runtime - configurations.provided).collect {
            it.isDirectory() ? it : zipTree(it)
        }
    }
}