feat: add jre8 slices for Jammy

[cjdcordeiro]

These new slice definitions files constitute the minimal set of packages and files necessary to build a functional headless java 8 runtime filesystem.

[vpa1977]

Maybe we need tools slice and misc properties slice.

When adding websphere liberty/tomcat support I've stumbled on the fact that sometimes launcher scripts want to run keytool or access logging.properties that we've decided to map in.
In those cases we are happy with defaults, so we can add a separate slice for that/

[cjdcordeiro]

Maybe we need tools slice and misc properties slice.

When adding websphere liberty/tomcat support I've stumbled on the fact that sometimes launcher scripts want to run keytool or access logging.properties that we've decided to map in. In those cases we are happy with defaults, so we can add a separate slice for that/

So, that would be something like:

tools:
  /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/keytool:
  /usr/lib/jvm/java-8-openjdk-amd64/bin/keytool:

Is that right? What would they depend on? Libs?

As for properties, there's already a slice, but it only contains a handful of properties. Should I add them all?

[vpa1977]

tools:
  /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/keytool:
  /usr/lib/jvm/java-8-openjdk-amd64/bin/keytool:

Is that right? What would they depend on? Libs?
yes, needs libjli and jvm to work.

As for properties, there's already a slice, but it only contains a handful of properties. Should I add them all?
Probably, they do not take much space and its possible to replace/override them.

[cjdcordeiro]

alright, thanks @vpa1977 . Done

[vpa1977]

I was doing comparison with corretto, and I've found that they do not add glib libraries.

Looking into openjdk source code, the only downside is that those cause java to always think that it connects directly to internet.
Maybe those should be in a separate optional slice.

[cjdcordeiro]

I was doing comparison with corretto, and I've found that they do not add glib libraries.

Looking into openjdk source code, the only downside is that those cause java to always think that it connects directly to internet. Maybe those should be in a separate optional slice.

👍 this should be addressed in rockcrafters/chiselled-jre#50

[cjdcordeiro]

Bringing this PR back to draft mode. @vpa1977 I'll need your help to make some design changes on these slices, driven by the following feedback from @niemeyer (summarized):

creating slices with basis on the file format, although logical for some pkgs, doesn't really help much from a functional standpoint (eg. it doesn't make sense to always install all the Java properties together, as they are probably meant for different functional units). Maybe a better way to slice this would be to split slices based on their functional purpose, i.e. jars and properties (and other paths) can easily belong to the same slice, if they are part of the same functional unit.

So basically, the questions we need to ask ourselves are:

• do these jars function by themselves? or do they expect certain properties files to coexist in the same filesystem?
• are slices being overdesigned to include all paths of the same type, even though some of those are not generally needed?
• in practice, for this specific Java example: "where are .properties (and others) used? they might be a functional dependency of some code in some other slice...so if that code is in a jar and that jar can't function without that .property, then let's put them together in the same slice. An even more functional approach would be to group .properties by jar, ie. each .jar has its own .properties, in a dedicated sliced"

[vpa1977]

Bringing this PR back to draft mode. @vpa1977 I'll need your help to make some design changes on these slices, driven by the following feedback from @niemeyer (summarized):

I think main point that we need to address here is separate security dependencies (nss3 ) and awt dependencies (fontconfig). Those make sense as separate slices and provide ~4/5 mb savings of the image size. Rest of the items does not provide such benefit, but we might do them in the same manner just for consistency.

[woky]

Will leave the rest for tomorrow. The shared library paths should be changed though.

[niemeyer]

Lots of slices, but looks quite clean. Thanks for the reorg on the JRE slices.

[cjdcordeiro]

Thanks for the approvals ;)

I'll merge it