Mozilla Firefox plugins (Ubuntu)

Last year, I started to use Ubuntu 7.10 on a DELL inspiron 1420 and recently ran into problems around firefox plugins and thought it'll be useful to share these experiences here.

1) First of all, there are a few different folders for the plugins (based on how mozilla and firefox got installed):

- /usr/lib/mozilla/plugins
- /usr/lib/mozilla-firefox/plugins
- /usr/lib/firefox/plugins
It is important to make sure that you know which folder your browser uses. One way to tell is by typing about: plugins in the browser address bar and checking which plugins are listed (they should correspond to the so files in the folder). In my case it was /usr/lib/firefox/plugins

2) Secondly, I was having problems not being able to run certain java applets (especially the ones for web conferencing from webex, yugma etc.). Their system requirements indicated that I should have JRE >=1.5 installed as a plugin for firefox. I did that by doing the following:

cd /usr/lib/firefox/plugins
sudo ln -s /usr/lib/jvm/java-1.5.0-sun/jre/plugin/i386/ns7/libjavaplugin_oji.so .

and I then restarted the browser.

However, these applets still refused to work (bad error reporting though: they kept saying Java was not "enabled" even though it was enabled in the Edit/Preferences/Content tab of the browser preferences).

I then noticed that there was another link to another java plugin sitting in that folder: libgcjwebplugin.so. I removed that link, restarted the browser and was able to run the applets I wanted to run!