If you haven't read the previous post, and would like to give it a go, skip this post.
Here is one way to print 'something nefarious' in the Groovy program:
It is clearly inspired by SQL injection. I tried using categories and some other tricks but everything else failed.
groovy ez " String() ; println 'something nefarious' ; new String"
I'm writing this right after the original post, and scheduling publication for this afternoon. I'm looking forward to seeing solutions.