Sometimes multiple Java Console extensions will appear in the Firefox > Tools > Add-ons list.
Ideally uninstalling redundant versions of Java should also remove redundant Java Consoles in Firefox. But this is not the case: uninstalling older versions of JRE may not uninstall the Java Console for that version, causing Firefox to accumulate multiple Java Console extensions.
How to remove these outdated Java Consoles can be found
here.
