Install a JDK

Sadly that didn't work either. I suspect it would be fine if you knew exactly which file to pinpoint.

Touch wood I have now been JDK free for several hours after going through the steps outlined here. Like the author I have no idea which step solved the issue, though I deleted an Open DNS updater, several Adobe plists (I use Affinity now), a Facebook plist and a Kensington trackball updater.

Thanks Leroy and Viking OSX,

After posting that, my son came round and we (or rather he) solved it (I made the tea and popped the Digestive biscuits on a plate).

The issue was an old Facebook video chat updater plist file. The advice below removes the file. We chose to edit it and turned True to False so that it does not launch on startup.

Best wishes,

Will

The solution was found here. Screensnap below.

For people wondering how to see "invisible" files on the Mac, use Command + Shift + Period.

Update to my post. My son's solution *reduced* the number of JDK messages but it didn't stop them. Presumably the Facebook plist was just one of the issues. I am now trying Leroy's Terminal solution. Will let people know how I get on.

Thank you, Leroy. See below.