What I understood by more searching is that this class is not meant for public use. That's why there is no Javadoc. I found this article in W3 Spot
https://www.w3spot.com/2020/07/diffe...va-thread.html. Though it is not an official doc, but it explains why performance is better for Unsafe.park method & the difference with Object.wait method. Anyways it also says that I should go with Object.wait method as an application developer which makes sense. I am parking my thought of using Unsafe.park for now.