[aardvark179]

This is not just a hypothetical proposal, I believe there is a working prototype and a lot of thought has gone into this. More things are coming, but pattern matching is a low hanging fruit that doesn't have difficult interactions with the type system or VM. Value classes need a lot of language enhancement to be really useful, and those things are likely to land before value classes themselves.

[pdpi]

Project Valhalla (featuring value classes) is scheduled for Java 10 — so it'll probably arrive in production around 2020.

[aardvark179]

I cannot comment on the Java release schedule, but Project Valhalla will be done when it's done, and it is not a small task. Project Amber is intended for smaller changes that may have been investigated as part of Valhalla and can be released earlier.