make a option for new firefox, were user will be able to use NPAPI (Java Plugin) as many websites is still using the java plugin, which is not working in forefox
I don't think it would be possible, as the NPAPI has been removed from every browser years ago, and Oracle ceased developing this plugin for any platform in Java 9.
Try searching for OpenJDK and OpenWebStart.
Why do Java, Silverlight, Adobe Acrobat and other plugins no longer work? https://support.mozilla.org/en-US/kb/npapi-plugins