Assuming Firefox is already installed, go to the Firefox plugin directory while you’re still in the console. To get the Java plugin to work in Firefox, you have to create a symbolic link within the plugins directory for Firefox
Once you find the plugin directory from within the console you have to create a symbolic link back to the original Java directory. In this case for my Mandrake 10.1 Official install, my java plugins are located in /usr/java/jre1.5.0_02/plugin/i386/ns7/libjavaplugin_oji.so.
Assuming you have not compiled with gcc (most standard installs will not be) use the libjavaplugin_oji.so file within the /ns7 directory. The command you’ll use is ln –s.
Your total command from within the Firefox plugins directory should look similar to this:
ln –s /usr/java/jre1.5.0_02/plugin/i386/ns7/libjavaplugin_oji.so
Run the command and the symbolic link will be created. To see if the symbolic link was created, type in ls. It should be listed.
Another way to check is to run Firefox and type in the address bar: about
You should be able to scroll down and see a listening for JRE 1.5.0_02.
A symbolic link must be created and not just simply copied from the Java plugins folder. If you just copy the file, Firefox will crash when you try to run a Java plugin.