I swear I googled this like 2 months ago and the first 2 or 3 links weren't helpful so I gave up. Thanks!
See https://openjdk.java.net/jeps/223#Dropping-the-initial-1-ele...
PS: had to edit, was really just a note about the numbers not the content of the versions!!!
In the end the case was settled out of court and MS agreed to pay more then 1 billion dollar to Sun. MS also agreed to license a whole slew of patents for use with .net.
[1] https://www.pinsentmasons.com/out-law/news/sun-sues-microsof...
.net didn't add support for macOS on ARM64 years ago. .net also didn't implement 2D rendering on macOS via Metal. etc. As a matter of fact .net didn't even support any other platform then Windows until recently.
Meaning .net has nowhere near the "write once, run anywhere" support Java has.
I always assumed this was because .net (arguably it's main competitor) was churning fast through version numbers and they "wanted to keep up".