The JEdit installer (jedit5.1.0install.jar) seems to work okay. I did not try the CMD file. I used the method that I always use. The program starts okay, but it seems that trying to open a file causes the file open routine to concatenate every drive and directory, that it ever saw.
My conclusions are:
Our JAVA 16 (latest from the eCS Software Subscription, with the latest ODIN) is working as it should.
JAlbum works, as it should (but I didn't try the installer, which has never worked, for me).
The JEdit 5.1.0 file open dialog is badly broken, making the program unusable.