Unable to reserve the .lok file for Integrated WebLogic Server (IntegratedWebLogicServer).

You might have noticed below error message from Jdeveloper after closing unexpectedly. You can follow below steps to recover your integrated server from this situation.

Error Message: Unable to reserve the .lok file for Integrated WebLogic Server (IntegratedWebLogicServer).

Jdeveloper Version: 12.2.1.3

1. Close Jdeveloper
2. Open Task Manager and stop java from  process list.
3. Delete below files from your default WLS domain location.
       <Install Location>\DefaultDomain\tmp\DefaultServer.lok
       <Install Location>\DefaultDomain\edit.lok
4. Open Jdeveloper and start WLS.