Oh, that's the JRE software version - that's
completely different from the language version.
For the JRE, I want to say that they stuck with the 1.version.minor numbering (although the last version with a minor other zero was I think the Very Popular And Probably Still In Prod 1.4.2), with updates suffixed with "u" + number through the Java 8 series, but then with 9 they switched to version.minor.update instead.
It's completely incomprehensible; not even Oracle can keep it straight.