Welcome to the forum, @joukj!
Sorry for my ignorance, but does OpenVMS include a POSIX-compliant shell? If so, I suggest using the
ImageJ.sh launch script. And in that case, the instructions for the Raspberry Pi are probably pretty close to on target for OpenVMS as well. If they work for you, let's create an OpenVMS page in
Category:Platforms and add it to that section of the wiki.
Yes, the invocation you already tried simply runs ImageJ 1.x, without the ImageJ2 parts.
If you need a very simple one-liner, you could try this:
java -cp 'jars/*:jars/bio-formats/*:plugins/*' net.imagej.Main