I wish to run a small utility ("Nightly Updater", NU) for a game called Simutrans.
NU comes in the form of a .jar file and the only system requirement for NU is Java 9.
I have Java 8 installed in my system (which it seems that I need to keep in order for other, older programs to run).
It seems that Java 9 is no longer available, but I assume that Java 12 will have backwards compatibility with Java 9 programs.
That Java 12 installation page is telling me to download a "Development Kit" that uses almost half a gigabyte of disk space, but I don't want an IDE or any other development tools so this seems to be inappropriate. I would like to download just enough to run NU as a user in Windows 7 (preferably in a user, not administrator, account) and no more.
What is the minimal Java installation necessary to run NU? Where do I find it, please?
I am using 64-bit Windows 7.