Issue present in...
Windows 10.0 2.2.7265
Tuesday, November 2, 2021, 2:47:51 PM
Launcher version 2.2.3555 just got pushed to me on Windows 10, and reverted the work-around (as expected). Re-applying the work-around worked.
I can also confirm for 2.2.3201 on Windows 10, trying to use Java JDK 16.0.1 to play Optifine 1.16.5, which I had been doing successfully since the Java 16 requirement for 1.17 was announced. I signed up for an account here to report this, but will instead throw in with this issue report.
EDIT to add: I applied the workaround by renaming JavaCheck.jar to JavaCheck.jar.disabled, and that's got it working again.
I then wondered if creating an empty folder named JavaCheck.jar would block updates from re-breaking it, or if that would cause errors, so I tried it. I got an "Unable to access jarfile" error complaining about it when I click Play, but the game launched fine otherwise. I decided it was too annoying so I deleted the empty folder. No idea if it would have blocked updates of the jar file. I'm just going to hope this issue is fixed by the next Launcher update.
Also affected version 10.0 2.2.7447 just now. Work-around still working.