Q: How do I install java in linux for use with Mozilla Firefox?
A: This howto assumes CentOS 5.3 i386, Firefox 3.0.14 and JRE 1.6.0.16.
1. Follow the steps on http://linuxadminzone.com/install-java-plugin-for-firefox/.
2. After having installed JRE, your java-stuff is found in /usr/java/1.6.0_16/i386/ns7. The path may change with newer versions of JRE.
3. Testdrive your java-installation on http://www.javatester.org.
4. Done.
Additional notes: How to enable java in Firefox is described in the following FAQ; Installing java for Firefox in linux.