...the only reason I even have a system JRE installed is because it comes with the JDK which I use to run Eclipse.
I forgot: just use '-vm' and you don't need a system JRE/JDK or specify the specific one you want.
As for end-user uninstall the JRE. What for? Just disable in the browser and call it a day. If we were to uninstall all apps with holes, we wouldn't have many programs to run...but that wouldn't matter because all of us would have to nuke our OSes as well. There are pros & cons of both choices (system vs. embedded runtime) both for end-user and developers.