[Backport 2.x] Restore support for Java 8

[opensearch-trigger-bot]

Backport f8ec75e from #795 and #777, closes #778, #156

[dblock]

@reta Backport most of this and comment out CI or let's open an issue to re-add JDK8 to 2.x and link this and other PRs?

[reta]

@reta Backport most of this and comment out CI or let's open an issue to re-add JDK8 to 2.x and link this and other PRs?

@dblock reopened this one #778

[reta]

Blocking till 2.12.0. release is out (@dblock @VachaShah fyi)

[cb-pankajk]

Hi @dblock / @VachaShah,
when will this be released? I am currently using 1.0.0 (java 8 compatible) with a bug fixed in 2.1.0 (java 8 incompatible). If possible, can we backport the fix on 1.x?

[reta]

when will this be released? I am currently using 1.0.0 (java 8 compatible) with a bug fixed in 2.1.0 (java 8 incompatible). If possible, can we backport the fix on 1.x?

Hi @cb-pankajk it will be released right after OpenSearch 2.12.0 release (the planned release date as of today is Feb 20), thank you

[dblock]

If possible, can we backport the fix on 1.x?

@cb-pankajk I don't think we want to maintain/re-release a 1.x unless it's a security vulnerability, but maybe @reta or @VachaShah feel otherwise? Either way you'll have to do the backport work.

[reta]

@dblock @VachaShah we should be all set for 2.x now :)

[VachaShah]

@dblock @VachaShah we should be all set for 2.x now :)

Awesome!