Use alpine's JRE instead of AdoptOpenJDK

[username-is-too-long]

AdoptOpenJDK now has a DEPRECATION NOTICE warning, and Alpine has its own packaged openjdk/jre that uses musl libc, so lines 23-35 and 55-86 could be replaced.

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[MarkEWaite]

I recommend against this change based on the comments in jenkinsci/docker#1185 and in jenkinsci/docker#1186. I'm open to reconsider based on guidance from @timja and @dduportal , but the transition to Eclipse Temurin (AdoptOpenJDK) has been a positive change. One Java provider for all our Docker images with synchronized updates across all our platforms (AMD64, Arm64, PowerPC, and s390x).

[timja]

I’ll look at this closer later but I think it might be better to take this as a temporary switch until temurin provides a musl based build,

see adoptium/containers#1 for background

[username-is-too-long]

see adoptium/containers#1 for background

Oh nice, I didn't see they were moving to musl on Alpine.

[timja]

see adoptium/containers#1 for background

Oh nice, I didn't see they were moving to musl on Alpine.

It looks like awhile away, they first need to TCK 16+ and then someone needs to backport to 11 and 8. They also need to setup some infrastructure for it.

I wouldn’t expect it to be quick but I think we can swap to this in the meantime

[timja]

@username-is-too-long the locale appears to not be set to a utf-8 one can you check it?

there was some code in the glibc section doing that, it might just be a matter of switching the locale line to:

ENV LANG C.UTF-8

but I don't think that worked last time I tried, see:
https://grrr.tech/posts/2020/add-locales-to-alpine-linux-docker-image/

[username-is-too-long]

@username-is-too-long the locale appears to not be set to a utf-8 one can you check it?

there was some code in the glibc section doing that, it might just be a matter of switching the locale line to:

/usr/glibc-compat/bin/locale doesn't exist without without glibc, I added musl-locales to provide locale, and removed that alpine case in tests.bats.

[timja]

we should still be running jlink to get a trimmed down runtime, it should be smaller than the jre

[username-is-too-long]

You're right, saved about 80mb

[timja]

(I sorted the build separately in a different PR, green now 😄 )