Build (and publish) a jpackage-d "native" (not really) executable

[vorburger]

https://www.baeldung.com/java14-jpackage

https://www.baeldung.com/jar-windows-executables

https://www.baeldung.com/jlink

[vorburger]

https://medium.com/azulsystems/using-jlink-to-build-java-runtimes-for-non-modular-applications-9568c5e70ef4

[vorburger]

I've dabbled with this a bit today, something like this actually works:

$ ~/.cache/bazel/_bazel_vorburger/a3c...bf4/external/remotejdk21_linux/bin/jlink \
        --no-header-files --no-man-pages --compress=zip-9 --strip-debug \
        --add-modules java.logging,java.xml --output site/download/latest/jre

$ site/download/latest/jre/bin/java -jar bazel-bin/java/dev/enola/cli/enola_deploy.jar -V

$  du -h site/download/latest/jre/
43M

Note that this smaller JRE does NOT (seem to) improve JRE boot start-up speed; it actually seems to be slightly slower, for some reason, for me:

$ time ~/.cache/bazel/_bazel_vorburger/a3c...bf4/external/remotejdk21_linux/bin/java -jar bazel-bin/java/dev/enola/cli/enola_deploy.jar -V
~240ms

$ time site/download/latest/jre/bin/java -jar bazel-bin/java/dev/enola/cli/enola_deploy.jar -V
~310ms

BTW jpackage apparently only builds (a DMG or PKG for Mac, MSI or EXE for Win, or) DEB and RPM - that's not the point of interest, here. (That should be done by distros.)

As far as I understand, there isn't really any way to "build (and publish) a jpackage-d (not really) 'native' executable".

What could be done with this is to re-distribute such a minimal JDK together with the (existing) single JAR.

This could be in different (and possibly several) formats, including:

• ZIP, or any other such archive; for end-users to download & unpack, to launch
• 7z -sfx (or https://github.com/pts/pts-tiny-7z-sfx; but why use that instead?!)
• AppImage

[vorburger]

https://stackoverflow.com/q/61612710/421602 FYI

https://appimage.github.io/apps/

An AppImage is fun because it can include an icon, and importantly a .desktop with which we could ./enola server && xdg-open http://localhost - neat!

https://github.com/AppImage/AppImageKit/wiki/Bundling-Java-apps

https://docs.appimage.org/packaging-guide/manual.html

https://docs.appimage.org/introduction/software-overview.html#ref-appimagetool

https://docs.appimage.org/packaging-guide/from-source/linuxdeploy-user-guide.html#ref-linuxdeploy

https://github.com/probonopd/go-appimage ?

https://docs.appimage.org/packaging-guide/testing.html#using-the-docker-based-appimage-testsuite

[vorburger]

https://github.com/bitshifted/launchcode is another tool in this space, see #1157.

jpackage might actually not be a bad idea... jpackage -h shows that it uses jlink itself.

#1159 makes a start! With that, I'm closing this. #1158 has a (low priority) possible future follow-up.

PS: Error: Invalid or unsupported type: [rpm] just means (confusingly) that (on Fedora) you need to sudo dnf install rpm-build. But that's only if you don't specify --type app-image, which is what I really wanted here. (RPM & DEB that are not on and thus autoupdating from a repo are kind of pointless IMHO; an archive, without requiring sudo, seems simpler & better here.)