This happens is because the correct symbolic link is missing from the folder /usr/lib/mozilla/plugins.
There should be a symbolic link named "libjavaplugin.so".
This usually points to another symbolic link named "moxilla-plugin.so" in the folder /etc/alternatives.
This symbolic link (mozilla-plugin.so) is then pointing to the java shared object "libnpjp2.so".
The shared object is in the folder "/usr/lib/jvm/java-6-sun/jre/lib/amd64".
This happens is because the correct symbolic link is missing from the folder /usr/lib/ mozilla/ plugins. jvm/java- 6-sun/jre/ lib/amd64" .
There should be a symbolic link named "libjavaplugin.so".
This usually points to another symbolic link named "moxilla-plugin.so" in the folder /etc/alternatives.
This symbolic link (mozilla-plugin.so) is then pointing to the java shared object "libnpjp2.so".
The shared object is in the folder "/usr/lib/