Where can I find info on the status of G1GC in Lucene and ES?

[jeroen1]

Because G1 stability left a lot to be desired in earlier JDK versions and we found serious bugs in G1. See e.g.: A Heap of Trouble: Managing Elasticsearch's Managed Heap | Elastic Blog.

These are arguments from 2016. Yes, back then CG1 was experimental, buggy and not recomendable. Since then (2016), the issues were fixed and since Java 9 (2017) G1 is the standard carbage collector. So G1 is not a experimental CG but the standard. So the 'buggy' argument is no longer valid.

We take performance very seriously but if we know that such bugs cause index corruption it would be irresponsible and a disservice to our users if we would claim to support it.

Index corruption as the result of Jaba bugs: that was 2016 and if fixed. Why support G1 in Java 10+ but not in 8? I'm sure the G1 bugfixes are backported. Is this decision based on recent tests - and thus valid arguments in 2018 - or based on old data from 2016?

I think many professional parties run ES on LTS OSs. LTS OS versions typically support one major version over the lifetime of the OS. Java 11 is the first LTS Java since 8 and brand new. So it's not included in any LTS OS yet. That is why I think including offical G1 support for Java 8 by Elastic would be a big plus.