RFR: 8248877: Document API contract for MetaspaceObj subtypes [v2]

[Ioi Lam]

On Thu, 3 Jun 2021 14:15:45 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   @coleenp comments; clean up
>
> Looks good with some minor suggestions.

Thanks @coleenp and @yminqi for the review.

-------------

PR: https://git.openjdk.java.net/jdk/pull/4327