I tested Kerberos a for an older release the usecases were:
1/OCI/Thick with okinit no username password
2/Thin principal + password provided
Settings in tools->Preferences->database->Advanced
I was running SQL Developer from a shared drive. But now I have copied it into C:\ drive and tried connecting. Now I get a different error:
An error was encountered performing the requested operation:
Client not found in Kerberos database (6)
Vendor code 0
Are you using Microsoft Active Directory? (I have not tested kerberos support with Microsoft Active Directory.
Confirm your changed setup with sqlplus [with okinit].
Try: OCI/Thick with okinit no username/password [It has minimum custon SQLDeveloper code and is most similar to SQLPLUS]
I think the settings are all in .ora (eg sqlnet.ora) files.
I moved to Windows XP and it works fine.
Looks like some issue with Windows 7. I tried the OCI/Thick with okinit as well but got an error for asking me to use 32-bit Java.