RFR: JEP 360: Sealed Types (Preview)

[Vicente Romero]

Hi all,

The sealed types JEP was already reviewed a while back when we were 
planning to include it in JDK14. It finally fell off that boat but it is 
being considered now for JDK15. There have been some changes since then 
mostly related to subtypes of a sealed type. Before we were planning to 
infer finality, sealness or non-sealness in the subtypes. We steered 
away from that direction in favor of explicit declaration at the 
subtype. I would like to ask for another review of the current version 
of the JEP that reflects these changes. The JEP is at [1] and the last 
version of the spec is at [2],

Thanks,
Vicente

[1] https://bugs.openjdk.java.net/browse/JDK-8227043
[2] 
http://cr.openjdk.java.net/~gbierman/jep360/jep360-20200228/specs/sealed-types-jls.html