Gradle “Entry .classpath is a duplicate but no duplicate handling strategy has been set”

Similar to @korn answer, I solved mine using the EXCLUDE Strategy;

tasks.withType<Jar>() {

    duplicatesStrategy = DuplicatesStrategy.EXCLUDE

    manifest {
        attributes["Main-Class"] = "MainKt"
    }

    configurations["compileClasspath"].forEach { file: File ->
        from(zipTree(file.absoluteFile))
    }
}