http://c25o7knygjm3m67jy27yuynvv4pkfi25naucscmh4ubq2ggiig3v57ad.onion/en/supporting-java-modules-in-guix.html
Unfortunately, the build failed very quickly for the first package, as it
threw an error when encountering the unknown module keyword: [javac] /tmp/guix-build-java-jakarta-json-2.1.3.drv-0/source/api/src/main/java/module-info.java:20: error: class, interface, or enum expected
[javac] module jakarta.json {
[javac] ^
[javac] /tmp/guix-build-java-jakarta-json-2.1.3.drv-0/source/api/src/main/java/module-info.java:22: error: class, interface, or enum expected
...