I made a kotlin console application and I can run it just fine inside Intellij IDE but when I build ...

# intellij

[Jeff Tycz]

I made a kotlin console application and I can run it just fine inside Intellij IDE but when I build the jar file and try to run it I get an error saying

Error: Could not find or load main class MainKt

I followed the Creating your first java application article on the jetbrains site so I dont know what the problem is.

I created a StackOverflow question with more details

[mbonnin]

To troubleshoot, you can unzip the jar file (a jar file is a zip) and look for a MainKt.class file inside

[mbonnin]

I don't see anything wrong in the setup so it should theoretically be there.

[mbonnin]

Maybe try replacing args: Array<String> with args: List<String> I don't think that'd be an issue but maybe the jvm expect a List?

[mbonnin]

If there's a MainKt.class file, you can decompile the bytecode with javap to make sure the main method is there

[Jeff Tycz]

@mbonnin If I go into build/classes/kotlin/main/com/mypackage/ in the IDE there is a MainKt.class file and it looks like this

public fun main(args: kotlin.Array<kotlin.String>): kotlin.Unit { /* compiled code */ }

[mbonnin]

Then it looks like your MainKt class is in the com.mypackage package?

[mbonnin]

Try mainClassName = 'com.mypackage.MainKt'

[mbonnin]

?

[mbonnin]

But if you really want to make sure the jar is good, it's better to unzip it directly

[Jeff Tycz]

Looking through the documents more I found this tutorial so I added the jar task

tasks.jar {
    manifest {
        attributes 'Main-Class': 'MainKt'
    }
    from {
        configurations.compile.collect {
            it.isDirectory() ? it : zipTree(it)
        }
    }
}

and deleted my other artifact coniguration and I dont get that error anymore but now I get a NoClassDefFoundError for the Mqtt library I am using but still runs fine in the Intellij