With Mill build tool that I'm working on, you don't need to install Java at all! (https://mill-build.org/blog/16-zero-setup.html). Instead, it gets bootstrapped automatically when you launch the `./mill` script like any other third-party dependency. You can use any version you want just by editing the config file and it'll be downloaded and cached on demand, and if you wipe out the caches it'll just re-download it again next time you run a command. You can also configure different JVM versions to use in different Java modules without worrying about conflicts between them.

You don't need to globally install Apache-Commons, nor is there a "Apache Commons Version Manager" that you need to first install to then manage your different versions of Apache Commons. So why should the JVM need such a thing?

Happy sdkman user for many years.