Create a Custom Fat JAR Task

Add the following to your build.gradle file:

tasks.register('customFatJar', Jar) {
    dependsOn 'clean'
    dependsOn 'build'
    tasks.named('build').get().mustRunAfter('clean')
    tasks.named('customFatJar').get().mustRunAfter('build')

    manifest {
        attributes 'Main-Class': 'com.klassconcepts.gradleSample.Main'
    }

    archiveFileName = "klass-gradle-sample-exe.jar"
    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
    from { configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) } }
    with jar
}