I’ve recently done a complete OSMC reinstall on my Vero 4K+, and the option to install Java is present in MyOSMC without enabling test builds. The installation does error, and you get a fresh error every time you do an update - I sorted that thanks to a suggestion from joakim_s:
I haven’t actually got around to testing this on a disc menu yet!
EDIT: ninja’ed by Sam. Oh well.