Some applications on Firefox require Java for working. However, you can not install regularly on CentOS. I will show you how to install Java Plugin on CentOS for Firefox.
Step 2. Close the running Firefox browser
Step 3. Add permission for *.bin before installing
chmod a+x filename_rpm.bin
./filename_rpm.bin
Step 4. add java plugin into Firefox (it depends on your installing directory)
cd .mozilla/plugins
ln -s /usr/java/jre1.6.0_24/lib/i386/libnpjp2.so
Restart your Firefox!
Have fun!
Have fun!