Do this as root
export PATH="/usr/javaj2sdk1.4.0_02/jre/bin":$PATH
that will add the java bin directory to the path, you might want to add that line to /etc/rc.d/rc.local so it does it every time you start the machine, or make a sh script like this

#!/bin/sh
echo "Starting Java..."
PATH="/usr/javaj2sdk1.4.0_02/jre/bin":$PATH
echo "Done..."

Save it as java.sh and copy it to /etc/profile.d/

Good Luck
marccd