We are briefly describing here how to install the Java plugin for Oracle JDK/SE 7 in Firefox. This is a manual procedure, and in this case we are wanting to install the plugin for Java 7 update 10 to enable running of JavaFX apps in Firefox 17.01 on Ubuntu 12.04 x86.
Assuming we are using the full Oracle JDK and have installed it to /opt, then the Firefox/browser plugin is located at at /opt/jdk1.7.0_06/jre/lib/i386, and is the file named libnpjp2.so:
davek@mymachine:/opt/jdk1.7.0_06/jre/lib/i386$ pwd /opt/jdk1.7.0_06/jre/lib/i386 davek@mymachine:/opt/jdk1.7.0_06/jre/lib/i386$ ls -al libnpjp2.so -rwxr-xr-x 1 root root 169420 2012-08-10 15:20 libnpjp2.so
At /usr/lib/firefox/plugins create a symbolic link to this file:
davek@mymachine:/usr/lib/firefox/plugins$ pwd /usr/lib/firefox/plugins davek@mymachine:/usr/lib/firefox/plugins$ sudo ln -s /opt/jdk1.7.0_06/jre/lib/i386/libnpjp2.so . davek@mymachine:/usr/lib/firefox/plugins$ ls -al total 8 drwxr-xr-x 2 root root 4096 2012-08-15 22:19 . drwxr-xr-x 6 root root 4096 2012-05-03 00:09 .. lrwxrwxrwx 1 root root 41 2012-08-15 22:19 libnpjp2.so -> /opt/jdk1.7.0_06/jre/lib/i386/libnpjp2.so
After restarting Firefox, the Java plugin should now be available (and can be enabled and disabled accordingly):