Migrated from Kotlin script to Groovy as couldn't figure out how to create fat jar with Kotlin script

EpcQrCodeJavaFxApp/build.gradle

@@ -0,0 +1,49 @@
+apply plugin: 'kotlin'
+apply plugin: 'application'
+
+
+group = "net.codinux.banking.epcqrcode.javafx"
+
+mainClassName = "net.codinux.banking.epcqrcode.EpcQrCodeJavaFxAppKt"
+
+
+sourceCompatibility = JavaVersion.VERSION_1_8
+targetCompatibility = JavaVersion.VERSION_1_8
+
+compileKotlin {
+    kotlinOptions.jvmTarget = JavaVersion.VERSION_1_8
+}
+compileTestKotlin {
+    kotlinOptions.jvmTarget = JavaVersion.VERSION_1_8
+}
+
+
+dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlinVersion"
+
+    api project(":EpcQrCode")
+
+    implementation "net.dankito.utils:java-fx-utils:1.0.8"
+}
+
+
+
+jar {
+    zip64 = true
+
+    // If one of the source JARs is signed, merging it into one fat jar destroys the signature -> remove signatures
+    // (but may runs into problems with jars that require a valid signature like BouncyCastle, see
+    // https://stackoverflow.com/questions/51455197/gradle-fatjar-could-not-find-or-load-main-class)
+    exclude("META-INF/*.RSA", "META-INF/*.SF", "META-INF/*.DSA")
+
+    manifest {
+        attributes  'Main-Class': mainClassName,
+                'Implementation-Title': "EPC QR Code",
+                'Implementation-Version': "1.0.0-SNAPSHOT"
+    }
+
+    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+
+    from { configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) } }
+
+}

EpcQrCodeJavaFxApp/build.gradle.kts

@@ -1,71 +0,0 @@
-import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
-
-plugins {
-    kotlin("jvm")
-    application
-}
-
-group = "net.codinux.banking.epcqrcode.javafx"
-
-val mainClassName = "net.codinux.banking.epcqrcode.EpcQrCodeJavaFxAppKt"
-
-
-val compileKotlin: KotlinCompile by tasks
-compileKotlin.kotlinOptions {
-    jvmTarget = "1.8"
-}
-val compileTestKotlin: KotlinCompile by tasks
-compileTestKotlin.kotlinOptions {
-    jvmTarget = "1.8"
-}
-
-java {
-    sourceCompatibility = JavaVersion.VERSION_1_8
-    targetCompatibility = JavaVersion.VERSION_1_8
-}
-
-tasks.withType<KotlinCompile>() {
-    kotlinOptions.jvmTarget = "1.8"
-}
-
-
-dependencies {
-    implementation(kotlin("stdlib-jdk8"))
-
-    api(project(":EpcQrCode"))
-
-    implementation("net.dankito.utils:java-fx-utils:1.0.8")
-}
-
-
-application {
-    mainClassName = mainClassName
-}
-
-
-tasks.withType<Jar> {
-    isZip64 = true
-
-    // If one of the source JARs is signed, merging it into one fat jar destroys the signature -> remove signatures
-    // (but may runs into problems with jars that require a valid signature like BouncyCastle, see
-    // https://stackoverflow.com/questions/51455197/gradle-fatjar-could-not-find-or-load-main-class)
-    exclude("META-INF/*.RSA", "META-INF/*.SF", "META-INF/*.DSA")
-
-    manifest {
-        attributes(mapOf(
-            "Main-Class" to mainClassName,
-            "Implementation-Title" to "EPC QR Code",
-            "Implementation-Version" to "1.0.0-SNAPSHOT"
-        ))
-    }
-
-    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
-
-    // To add all of the dependencies
-    from(sourceSets.main.get().output)
-
-    dependsOn(configurations.runtimeClasspath)
-    from({
-        configurations.runtimeClasspath.get().filter { it.name.endsWith("jar") }.map { zipTree(it) }
-    })
-}

gradle.properties

@@ -3,4 +3,6 @@ kotlin.js.generate.executable.default=false
 xcodeproj=./EpcQrCodeiOSApp
 
 
+kotlinVersion=1.4.10
+
 quarkusVersion=1.8.2.Final