The JPackage project may not distribute all Java related software as pre-build binaries, this is due to legalities in the Java license, you'll need to go to the Sun website and download some source files then use JPackage provided Source RPMs to build the resulting binary RPMs yourself.
This sounds like a big job but it is not really, it's very simple. First we need to prepare RedHat to be able to build RPM files, all you need is to install the rpm-build package, with yum on CentOS:
yum install rpm-build
That sets it all up for you to be able to build RPMs from source.