ps is not displaying the process but lsof is showing the process is running on port?

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http://unix.stackexchange.com – I tried to grep the process id of the process by using ps -ef command, but it did not show any process . Later, I tried with lsof -i:port and it shows that the process is running. Please suggest the cause. The process I was searching is killJar it is running on port 5002 the owner for the process in not root but the other user I am able to search other process from the same user, I have permissions for that (HowTos)