python socket.error: [Errno 98] Address already in use -

when setup application.py, shows socket.error: [errno 98] address in use.

traceback (most recent call last): file "application.py", line 121, in <module> main() file "application.py", line 117, in main http_server.listen(options.port) file "/usr/local/lib/python2.7/site-packages/tornado-3.1-py2.7.egg/tornado/tcpserver.py", line 117, in listen sockets = bind_sockets(port, address=address) file "/usr/local/lib/python2.7/site-packages/tornado-3.1-py2.7.egg/tornado/netutil.py", line 90, in bind_sockets sock.bind(sockaddr) file "/usr/local/lib/python2.7/socket.py", line 224, in meth return getattr(self._sock,name)(*args) socket.error: [errno 98] address in use 

there process listening on port. might find out process using following command:

$ lsof -i :8000 

or change tornado app's port. tornado's error info not explicitly on this.