http://www.oracle.com/technetwork/java/javase/manual-plugin-install-linux-136395.html

1. Exit Firefox.

2. Make sure only the latest version of Firefox and the latest version of Java is installed on the system. Use rpm -e to remove old packages and download new ones from http://www.getfirefox.com and http://java.com/en/ as necessary.

3. Create a symbolic link to the Java Plugin in the Firefox plugins directory.

# cd /usr/local/src/firefox/plugins
# ln -s /usr/java/default/lib/i386/libnpjp2.so .

4. Start Firefox

5. Open about:plugins in the URL address bar to verify Java is now seen in the browser.

6. Test with a Java verification page from java.com as necessary.