How to create a fat Jar in Gradle with Kotlin DSL and plugin

Question

I did a lot of research on how to create fat jars with Gradle. However, I can not figure out how to it with Kotlin DSL and a plugin. I have this code:

plugins {
    application
    id("org.openjfx.javafxplugin") version "0.0.9"
    id("com.github.johnrengelman.shadow") version "6.1.0"
}

repositories {
    mavenCentral()
}

dependencies {
    implementation("javax.vecmath", "vecmath", "1.5.2")
    implementation("org.apache.commons", "commons-csv", "1.8")
}

application {
    mainModule.set("de.weisbrja")
    mainClass.set("de.weisbrja.App")
}

javafx {
    modules("javafx.controls")
}

modularity.disableEffectiveArgumentsAdjustment()

But I do not know how to specify the main class for the fat jar manifest. The tutorial I followed did this:

jar {
    manifest {
        attributes "Main-Class": "com.baeldung.fatjar.Application"
    }

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

But that is Groovy DSL and not Kotlin DSL and I am not really familiar with the Kotlin DSL yet, so I do not know how to convert this to Kotlin DSL. Help very much appreciated.

Don't try to create fat jars for JavaFX programs. This does not really work for various reasons. Use a tool like jpackage instead to create a real installer bundle. — mipa, Mar 25 '21 at 09:26
@mipa also, why should I not create a fat jar of a JavaFX program? — weisbrja, Mar 25 '21 at 10:09
I don't know if JavaFX will work in a fat jar, but the tutorial you found is wrong. Instead, you can use the example in the Gradle user guide [here](https://docs.gradle.org/current/userguide/building_java_projects.html#sec:java_packaging) to get it working (be sure to select Kotlin for the code examples), and to add an entry to the manifest in Kotlin, look [here](https://docs.gradle.org/current/userguide/building_java_projects.html#sec:jar_manifest). — Bjørn Vester, Mar 25 '21 at 20:52
I can not figure out what key and value I have to add to the manifest. Can you post a code answer? — weisbrja, Mar 26 '21 at 10:51

Ryu S. · Answer 1 · 2021-07-17T03:17:39.267

try this vanilla solution in kotlin dsl (build.gradle.kts)

dependencies {
     implementation(group="org.mycomp",name="foo",version="1.0")
}

tasks {
   jar {
       //package org.mycomp.foo inside the .jar file 
       from(configurations.runtimeClasspath.get().map { if (it.isDirectory) it else zipTree(it) })
   }
}

alternatively you can use the shadowJar plugin

plugins {
    id("com.github.johnrengelman.shadow") version "7.0.0"
}

then just run ./gradlew :shadowJar

How to create a fat Jar in Gradle with Kotlin DSL and plugin

1 Answers1