I don't know but it is a good point. Have you asked on their issues tracker or ML ? https://issues.guix.gnu.org/ I am also looking at guix and trying to use it. It seems it still has ways to go before it reaches maturity. Debian solves this problem by introducing pseudo-packages ?! (not sure about the name). The idea is jdk source packages provide a pseudo package like openjdk-jre or openjdk-jdk . Packages will depend on this pseudo package instead of the hardcoded version. Not sure if guix offers this capability.

Turns out it isn't hard at all; Just need to install openjdk at whatever version you're after. The reason it didn't work for me at first was because I was using guix install and guix-home at the same time, so the path resolved the icedtea (java 8) version I had in the home config first.

great to hear that

I did check the package definition and I did not see a direct dependency on Java package - but was not sure if that was the case