How to find the procss using specific port and kill it

I am using PyDev in Eclipse on CentOS. Eclipse crashes sometimes and leaves python still using port 8000. Before you can restart the development server, you have to kill the previous process, to do so,
$ sudo /usr/sbin/lsof -w -n -i tcp:8000
which will list the process pid using port 8000

COMMAND    PID  USER   FD   TYPE DEVICE SIZE NODE NAME
python2.7 6211 htang    3u  IPv4 157102       TCP 127.0.0.1:irdmi (LISTEN)

$ sudo kill 6211
which will kill process 6211.