I haven't used Java in that context, so feel free to correct me if I'm wrong -- but isn't running jars in the browser just about impossible with the last couple years of security updates?
It used to be done by wrapping the jar as an applet, until Edge & Chrome blocked Java applets completely. Firefox is on the same path. As a result, Oracle announced it would stop supporting the feature completely in future updates.
But maybe there's another way to run Java in-browser that I'm not aware of?
Edit: Whoops, I see TerraCottaFrog beat me to it on another thread haha.