Errors like this:
2014-07-26 21:06:11 [Server Watchdog/FATAL]: A single server tick took 35.28 seconds (should be max 0.05)
2014-07-26 21:06:11 [Server Watchdog/FATAL]: Considering it to be crashed, server will forcibly shutdown.
May be resolved by this:
To set the server watchdog to a higher time or switch it off:
Set max-tick-time in server.properties to a value higher than 60000 or to -1
Watchdog shuts down server