Firefox 8: Where's the Java?

I noticed that Java wasn't working in my browser anymore. After some research I found that Firefox decided to "blocklist" the sun-java6 plugin.

One message said it was due to a security flaw, the other said it was because the plugin was causing browser crashes. The Java plugin never crashed the browser on my Ubuntu system.

The Solution

How to fix it? After considerable research and trial & error, the solution is simple. I'll describe the steps I did to fix two Ubuntu Linux systems.

First, make sure the plugin is installed:

sudo apt-get install sun-java6-plugin

Next, make sure firefox is not running - close/kill it if it is. Put a symbolic link to the plugin library, into the Firefox plugin directory:

ln -s /usr/lib/jvm/java-6-sun/jre/lib/i386/libnpjp2.so /usr/lib/firefox-addons/plugins

Solution Details

First I read the Orcle solution linked above. Then I poked around the filesystem to better understand the solution. I found 5 different places the Firefox plugins might live:

/usr/lib/firefox/plugins

/usr/lib/firefox-8.0/plugins

/usr/lib/firefox-addons/plugins

/usr/lib/mozilla/plugins

/usr/lib/mozilla-firefox/plugins

Really only 4 as the 2nd is a link to the 3rd. I added the plugin (via symlink) to all 5 and it started working. Then I removed it from each one by one to find it was the 3rd location that really matters.