Pretty simple. Download Java JDK 6 Update 10 from here (probably the .rpm.bin is the best one):
http://java.sun.com/javase/downloads/index.jsp
do a chmod to make give it execute privs:
chmod +x [filename].rpm.bin
run the installer:
./[filename].rpm.bin
That is it. You should be able to execute the java command to see if it the correct version:
java -version
If not follow these instructions:
http://community.wowza.com/t/-/48
Charlie