Open a port without any service.

[Jason Long]

Hello,
I just can open and close a port that a service running on that port?
I have not any service on port 8080 and did:
# firewall-cmd --add-port=8080/tcp
success
# firewall-cmd --reload 
success
# firewall-cmd --list-ports
80/tcp 443/tcp

Why I can't see port 8080 in the list?