Let me start by saying I am not a RHEL person, I have always used deb based OS's, and the server that I had to install Jenkins on is one I inherited.
The problem that I encountered is that I assumed that YUM would check for and install all dependencies.
I had a bit of confusion when I tried to run it and java was not found.
Now I know that there are licenceing isses with the distro and Java. But the install should check for java and if its not there and point to some documentation about how to install java.
Just my 2 cents