Building a self-executable jar with Gradle and Kotlin

None of the above solution worked for me while building Artifact.

IDE version IntelliJ IDEA 2019.1.1.

To fix the issue, do the following

Steps

Step 1 - Create Artifact

1. Go to File -> Project Structure -> Artifacts

2. Click the + -> JAR -> From modules with dependencies

3. Select your program's Main Class

Step 2 - Change MANIFEST Path

4. Change value of Directory for META-INF/MANIFEST.MF to your project root.

   For example , from /your/project/directory/src/main/kotlin to /your/project/directory

5. Press OK,then Press Apply and OK.

Step 3 - Build Artifact

6. Finally, Go to Build -> Build Artifacts -> [your-artifact-name] -> Build.

The generated JAR file can be found in the out/artifact/[your-artifact-name] directory. (y)

Add the plugin application, then set the mainClassName as

mainClassName = '[your_namespace].[your_arctifact]Kt'

For instance, suppose you have placed the following code in a file named main.kt:

package net.mydomain.kotlinlearn

import kotlin
import java.util.ArrayList

fun main(args: Array<String>) {

    println("Hello!")

}

your build.gradle should be:

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

mainClassName = "net.mydomain.kotlinlearn.MainKt"

In fact Kotlin is building a class to encapsulate your main function named with the same name of your file - with Title Case.

I've found the workaround (thanks to MkYong website)

1. The gradle script needed the kotlin-compiler artifact as a dependency
2. The gradle script needed a way to collect all kotlin files and put them into the jar.

So i get with the following gradle script :

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
       classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:1.0.1-2'
    }
}

apply plugin: "kotlin"

repositories {
    mavenCentral()
}

dependencies {
    compile 'org.jetbrains.kotlin:kotlin-stdlib:1.0.1-2'
}

jar {
    manifest {
        attributes 'Main-Class': 'com.loloof64.kotlin.exps.MultideclarationsKT'
    }

    // NEW LINE HERE !!!
    from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }
}