This is interesting and not what I would expect. Generally to get a java app running from github you'd install the correct JDK and that should be about it. Many projects will use maven, which will know how to obtain dependencies. Could you describe a typical issue?
That and the whole JVM fragmentation and not being able to touch Oracle because it's Oracle and they'll use it as an excuse to sue you (at least that's the impression I had, the entire lawsuits thing is why I left Java back in the day).
You can say the same about other package managers, but it's not very often that I have to add another source to apt unless I'm running in a locked-down environment.
No it doesn't. That's only if you're dealing with private maven repos and authentication etc. You don't need to do that at all for the use case in this thread, running a project from github.
Or the Go compiler fragmentation, where only the reference compiler supports everything, tinygo a subset, and gccgo left to die in Go pre-generics era.
sudo apt-get install <jdk>
sudo apt-get install maven
That isn't really a problem with other languages.