My Jenkins Server automatically starts upon Centos 7 server starts, so I need to stop it to make way for my WildFly Application Server.  What I did to stop it are as follows:

1. On my Firefox browser, go to this url : http://localhost:8080/exit

2. It will ask me to login then i have to click some button to initiate the shutdown process

I saw someone also asking about the same thing at stackoverflow: https://stackoverflow.com/questions/10238604/how-to-shutdown-my-jenkins-safely/35922474

It's that easy folks!