Error: Main.class found in top-level directory (unnamed package not allowed in module)

Question

Trying to update an application to Java 11 and after sorting through hell with modules I thought I had got rid of all the red errors and now I'm getting this one I've never seen before:

Looking around I've seen people suggest it is possible to do with the application structure:

or the module-info.java file:

Can anybody see what I need to do to get rid of this?

Edit: Error after moving Main.java to a package called 'main' and trying to run it:

Answer 1

In order for a JavaFx to launch your app, it needs access to its main class, so you need to export the package in which the main class is located.

Add export declaration to module-info:

module Game.main {
    ...

    exports main;
}