Scan /nix/store for JDKs

[msgilligan]

I am finding the Nix package manager very useful these days. Especially since I am using JDK 22 + Panama to interface to a native 'C" library.

It would be nice if JDK-Updater could know about and display JDKs installed via Nix.

p.s. I'm not sure how this can be done efficiently. Maybe there should be some mechanism for JDKs installed via Nix to register somehow.

[HanSolo]

JDKUpdater in principle simply scans the disk and tries to identify JVM‘s it found. Because some installer like sdkman use their own folders to manage installed software, JDKUpdater can identify the installer too. Meaning to say, if you can tell me where Nix does install JDK‘s, I can add this location to the search path and display them as installed by Nix. If Nix offers a mechanism to install JDK‘s via shell commands I might even be able to offer an update procedure but that’s probably not possible. In case Nix installs the JDK‘s in the default folder /Library/Java/JavaVirtualMachines, I won’t be able to figure where the JDK was „coming“ from.

[HanSolo]

Just did a quick check and if I‘m right, the Nix package manager stores it‘s pkgs in /nix/store. Is that also true for JDK‘s? In that case I could scan this path to find JVM‘s.

[msgilligan]

Yes, JDKs are also in /nix/store, for example: /nix/store/6amvs3wxc0lv382igpryc25dfcmgfcyv-graalvm-ce-22.0.0/ and
/nix/store/cvmim67ikqj3wd42ys6vrdslyfmjgbcz-zulu-ca-jdk-22.0.0/. Because of the way Nix manages dependencies (similar in some ways to local Maven repos) there can be quite a few JDKs in /nix/store including multiple copies of the same version (but with different hashes).

As far as I know, Nix JDKs are not put into /Library/Java/JavaVirtualMachines, but there might be an add-on somewhere that does that. (Nix has a lot of add-ons, it seems)

[msgilligan]

Nix is powerful, exciting and frustrating. I would recommend this article for getting started:
https://tonyfinn.com/blog/nix-from-first-principles-flake-edition/

It's best to set experimental-features = nix-command flakes and use the new commands and flakes features, but the frustrating part is that most of the documentation doesn't cover this.

[HanSolo]

Added scanning for the /nix/store path. Will come with the next release. Please let me know if it works once it will be available.

[msgilligan]

Added scanning for the /nix/store path. Will come with the next release. Please let me know if it works once it will be available.

Can I install from source?

[HanSolo]

Nope, there is only the dmg or pkg available atm

[msgilligan]

Nope, there is only the dmg or pkg available atm

I'm still running macOS 13, so I'll have to wait until I upgrade (which should be soon) to give it a try.

[HanSolo]

Check 👍🏻