Congrats on launching the early access! I'm familiar with data-oriented programming from Clojure and F#, and I'm interested in seeing how you approach it in Java, so I just picked up a copy (ebook). Wish you all the best on completing the book!
I can highly recommend excellent Domain Modeling Made Functional by Scott Wlaschin for an F# book that touches on a lot of the ideas which back data-oriented programming (namely, representing your domain as strongly typed data).
