RFR: 8284036: Make ConcurrentHashMap.CollectionView a sealed hierarchy

[Stuart Marks]

On Mon, 4 Apr 2022 06:55:10 GMT, Jaikiran Pai <jpai at openjdk.org> wrote:

> Can I please get a review of this change which now marks `CollectionView` as a `sealed` class with only `EntrySetView`, `KeySetView` and  `ValuesView` as the sub-classes? This change corresponds to https://bugs.openjdk.java.net/browse/JDK-8284036.
> 
> A CSR has also been drafted for this change https://bugs.openjdk.java.net/browse/JDK-8284272. As noted in the CSR, marking this class as `sealed` and marking `KeySetView` as `final` shouldn't have any impact in general and also in context of serialization/de-serialization.
> 
> tier1, tier2, tier3 tests have been run successfully with this change.

LGTM

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Marked as reviewed by smarks (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/8085