Recently, a patch was added in order to make it possible to build prismlauncher with openjdk:21. It still allows building with openjdk:17, but doing so requires changing the system configuration. I don't want to change the system's default java implementation, but want to be able to build this program with an older version of java. Hence, my request: would it be possible to add java_target_openjdk{17,21} USE flags? I realize that unlike PYTHON_TARGETS there isn't a USE_EXPAND for this yet, but I feel it'd be helpful.
I think you might be able to accomplish setting the java version for just one package using package.env, but I have not tried this myself. What is the reason you want to build prismlauncher with java 7 suppport? Note that there are patches/mods available for older versions of minecraft that bump the java compatibility to more recent/reasonable versions. This is usually a better option then sticking with old java, it gives you a small performance boost as a side effect.
Since writing this bug report, I've been using prismlauncher happily and haven't encountered any issues. Since I'm specifically going through the alpha and beta versions of minecraft, when I read the messages reported by "elog" in the ebuild, I expected to encounter problems with it. I'm not sure what prismlauncher is building that requires the java compiler, and I'm still not sure of what issues the elog messages are refering to. I just felt that, since it's something that upstream has deliberately avoided changing, and it's apparently important/complicated enough to get a relatively wordy message in the build logs, it might be better suited as a USE flag, so people don't accidentally get incorrect builds when they forget to change the java-config for this specific package. At the end of the day, prism has its own configuration and heurestics to select the java version, it sometimes just downloads one from microsoft. I'm using java 8 for these old versions (pre-1.0), I'm not aware of ways to run them with modern java. I just want to avoid hitting the problems upstream is aware of. But yeah, I intend this ticket to merely be a suggestion. I'm not entirely sure how any of this works, so I might be wrong on a few things. Feel free to close the issue if you disagree.
