Wow, I didn’t realise this. I can see Oracle has documented it though. And Java 10 (18.3) is only supported until September 2018:
** Java SE 9 will be a short term release, and users should immediately transition to the next release (18.3) when available.
*** Oracle has proposed a new version scheme for Oracle based builds (YY.M) starting in March, 2018. Java SE 10 (18.3) will be a short term release and users should transition to the next release when available.
Release notes: http://www.oracle.com/technetwork/java/javase/10-relnote-issues-4108729.html
And, of course, this means Java 9 is already end of life. No more updates. Not even security updates.
Wow, I didn’t realise this. I can see Oracle has documented it though. And Java 10 (18.3) is only supported until September 2018: