I have JDeveloper 12c installed.
But yesterday, I installed 18.104.22.168 again for some old code to be enhanced and extended Webcenter extension, Integrated weblogic thrown above error.
I simply removed DefaultServer and recreated. It worked.
- copy DefaultServer path from console,
- cut DefaultDomain folder and paste somewhere for backup.
- Restart Jdeveloper
- Start Integrated Server. It will recreate server and error gone. Have fun!