Could you rebase this on the jruby-9.4 branch? We should fix it there as well.

I'm not sure the current state of things with 9.4 and 10. Do you want a separate PR for 9.4, or just re-target this one to 9.4?

We always merge forward so changes to 9.4 will get into master/10.

Are the .project changes necessary for the AutoCloseable? If not, what are they for? Probably should be a separate PR if it's unrelated.

Are the .project changes necessary for the AutoCloseable?

Nope, that was probably just VSCode doing something weird, and I didn't notice them when I did git commit -a.

Okay, this PR now targets 9.4, and I removed the spurious project changes.

@ccutrer Thanks for putting this together. Our CI did not rerun on jruby-9.4 for unknown reasons but this should be fine on jruby-9.4 (10 is still not quite fully green yet).