First, great book. Very valuable!
I recently purchased the Java EPI book in 10/2019, and I’m dismayed to find that you and the other authors have not provided the variant solutions in the book or Github. As you can see from 5+ years of forum posts, this is an aggravation point for a large number of your readers for many years and many revisions of the book.
I presume your team did not post those variant questions without solving them first. Therefore, I request that you post your existing solutions to github. Even if it’s in the original programming language, that would be much better than nothing