Not able to install java plugin with latest firefox on Ubuntu
extract Java Plugin on /usr/java/jre1.8.0_91. run chmod 777 on above path set JAVA_HOME in .bashrc file
create symbolic link to <jre>/lib/i386/libnpjp2.so to ~/mozilla/plugins
but still JAVA plugin is not visible on about:addons > Plugins page.
Alle svar (1)
Hmm it appears you are trying to use the 32-bit Java Plugin when you have 64-bit Firefox.
http://www.oracle.com/technetwork/java/javase/manual-plugin-install-linux-136395.html
Also use the about:plugins so Firefox will scan for any Plugin updates, especially if Firefox was running when you added Plugins.