Got a fresh jdev 11gR2 (220.127.116.11.0, studio) on an existing oracle client home 18.104.22.168.0 and tried to create a connection to an oracle database based on the oci8 option (thick instead of thin driver) in the Create Database Connection dialogue. The result on some test (test connection button) was a:
Test failed: oracle.jdbc.driver.T2CConnection.getLibraryVersionNumber()I
The resolution trick seems to comprise of a copy of the
ojdbc6.jar of the oracle client installation, here in
d:\Programme\Oracle\product\11.1.0\client_1\jdbc\lib\, to the jdeveloper app server lib path, here in
My reference to the problem solution was: this thread entry on the oracle forums.