jdbc:oracle:thin:@//mydbhostname:1521/mydbservicename
This is fundamentally different than the URL
jdbc:oracle:thin:@//mydbhostname
Note the slash vs the colon separating the last component.
If I create a new connection using the wizard everything goes fine. It connects and I can work as expected. However if I restart and attempt to load the connection information from the registered .odb file several things are wrong.
1) It thinks the ServiceName is a SID and so tries to reconstruct the URL with a colon.
2) It messes up the "Name of the Oracle database" which it thinks is "1521/mydbservicename"
3) It messes up the "Host Name" which it thinks is "//mydbhostname"
I couldn't figure out how to file a bug so I hope this finds a developer who can fix it.