WebLogic server Error: Could not obtain an exclusive lock for directory.

Steps to make your  OAM Admin Server Start:

1.  Shutdown the Admin Server.
2.  Delete the lok file from <domain-home>/servers/<server-name>/tmp/.

      AdminServer.lok
3.  Now start the Admin Server.
4.  If the server still fails to start then we need to kill the the process which    is still running on the server 

      using following commands.

ps -ef | grep 'weblogic'

kill -9 PID

4.    Now start again the Admin Server.