I have run the local GAE app server (dev_appserver.py) from Eclipse and then Eclipse crashed. So I had to kill Eclipse and restart it. However, when Eclipse restarted, it lost connection to the still running GAE server and I cannot figure how to shut it down.
You have to kill the process of the devserver. This is os dependent. On linux use:
ps aux| grep java
kill -9 <process id>
On windows you can use tasklist and taskkill.