```
 $ java --module-path /Users/headius/Downloads/javafx-sdk-15/lib --add-modules javafx.controls -Djruby.home=`pwd` -cp lib/jruby.jar org.jruby.Main javafx.rb
Unhandled Java exception: java.lang.RuntimeException: Error: class jdk.internal.reflect.NativeMethodAccessorImpl is not a subclass of javafx.application.Application
java.lang.RuntimeException: Error: class jdk.internal.reflect.NativeMethodAccessorImpl is not a subclass of javafx.application.Application
                             launch at javafx/application/Application.java:298
```