doesn't work with Java 17 or above

[greenwoodma]

Partly due to stricter module encapsulation the plugin doesn't work with Java 17 and above (the latest I've had it working with is an EA version of Java 14).

Even if we open all the modules (this trick worked nicely https://dzone.com/articles/how-to-export-all-modules-to-all-modules-at-runtime-in-java) it still didn't work due to an issue with not being able to find a getClass() method on the script object. I'm guessing we need to upgrade the groovy version to something newer; note when I tried this I couldn't get the plugin to build.