Can't run generated JAR file with Gradle and Kotlin

Question

I have a project configured with Gradle and Kotlin. It's a command line utility and I would like to be able to run the generated jar from my terminal. However I get the following error:

Exception in thread "main" java.lang.NoClassDefFoundError: kotlin/jvm/internal/Intrinsics
    at com.autentia.impt.MainKt.main(Main.kt)
Caused by: java.lang.ClassNotFoundException: kotlin.jvm.internal.Intrinsics
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:338)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 1 more

My gradle configuration is as follows:

buildscript {
    ext.kotlin_version = '1.2.20'
    ext.junit_platform_version = '1.0.1'
    ext.junit_version = '5.0.0'
    ext.moshi_version = '1.5.0'
    ext.jna_version = '4.5.0'

    repositories {
        mavenCentral()
    }

    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath "org.junit.platform:junit-platform-gradle-plugin:$junit_platform_version"
    }
}

version '1.0-SNAPSHOT'

apply plugin: 'kotlin'
apply plugin: 'application'
apply plugin: 'org.junit.platform.gradle.plugin'

mainClassName = 'com.autentia.impt.MainKt'

repositories {
    mavenCentral()
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib"
    implementation "org.jetbrains.kotlin:kotlin-reflect"
    implementation "com.squareup.moshi:moshi:$moshi_version"
    implementation "com.squareup.moshi:moshi-kotlin:$moshi_version"
    implementation "net.java.dev.jna:jna:$jna_version"
    testImplementation("org.junit.jupiter:junit-jupiter-api:$junit_version")
    testRuntime("org.junit.jupiter:junit-jupiter-engine:$junit_version")
}

sourceSets {
    main.kotlin.srcDirs += 'src/main/kotlin'
}

task wrapper(type: Wrapper) {
    gradleVersion = '4.4.1'
}

jar {
    manifest {
        attributes "Main-Class": mainClassName
    }

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

compileKotlin {
    kotlinOptions.jvmTarget = "1.8"
}

compileTestKotlin {
    kotlinOptions.jvmTarget = "1.8"
}

The command I use to generate the jar is ./gradlew clean build and the command I use to run the jar is java -jar build/libs/impt-1.0-SNAPSHOT.jar.

I've tried following the official docs and also I've tried with these resources: 1, 2 and 3 without any luck.

it seems you don't have certain dependencies on the classpath. Is it possible you had these dependencies on the path of your IDE, instead of on that of your machine itself? — Stultuske, Jan 22 '18 at 11:15

score 5 · Accepted Answer · answered Feb 15 '18 at 18:16

Just change implementation configurations to compile. (At least for kotlin-stdlib)

The compile configuration is deprecated and should be replaced by implementation or api in Gradle plugin for Android, however for kotlin-gradle-plugin, I think you still need compile.

score -1 · Answer 2 · answered Jun 18 '18 at 03:11

Alright I had the same problem and finally figured this out:

My main class name was Main.kt and this is what I had in my build.gradle file when I was getting the same error:

jar {
    from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }
    manifest {
        attributes(
                'Class-Path': configurations.compile.collect { it.getName() }.join(' '),
                'Main-Class': "play.Main"
        )
    }
}

Although I noticed when I create the jar artifact in Intellij, it uses play.MainKt as my Main-Class name (yeah, weird naming convention), then I changed my build.gradle file to this:

jar {
    from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }
    manifest {
        attributes(
                'Class-Path': configurations.compile.collect { it.getName() }.join(' '),
                'Main-Class': "play.MainKt"
        )
    }
}

and now I am not getting that error.

Can't run generated JAR file with Gradle and Kotlin

2 Answers2