High-performance Java is indeed basically writing C in Java, including using you own byte array for memory. It's amazingly un-idiomatic though, and you'll get (rightly) roasted by fellow Java developers for doing it without a clear and compelling need.
In other words, you've missed the whole point of the article. Just because you can do it, doesn't mean you'll end up doing it.
In other words, you've missed the whole point of the article. Just because you can do it, doesn't mean you'll end up doing it.