More importantly, embedding very much non-trivial code in the context of an essay like this is impractical. I don't want (or need) to see an entire application

More importantly, embedding very much non-trivial code in the context of an essay like this is impractical. I don't want (or need) to see an entire application written in both Java and Ruby to get the point. Any code sample that can be reasonably inserted into the text without unduly breaking the flow is going to be simple; hello world is as good as any.