I already wrote a post about it but I think I was not clear and easy to find enough. So let me make another post about and add some information…
Ok, are you facing a “java.sql.SQLException: ORA-28040: No matching authentication protocol” after upgrade your database to 12c?
It’s related to old jdbc driver version in your application. Please review matrix available in this post and check your application. The MOS noted below have good information about it…
1) 12c: ORA-28040 After Upgrade: No Matching Authentication Protocol (Doc ID 1957995.1)
2) 10.2.0.5 DBCA Fails With ORA-28040: No matching authentication protocal (Doc ID 1637514.1)
As per second MOS document:
“In 12.1, the default value for the SQLNET.ALLOWED_LOGON_VERSION parameter has been updated to “11”. This means that database clients using pre-11g JDBC thin drivers cannot authenticate to 12.1 database servers unless the SQLNET.ALLOWED_LOGON_VERSION parameter is set to the old default of “8”.
In this case, if not able to adjust driver immediately, a possible option to work around it is to set “SQLNET.ALLOWED_LOGON_VERSION=8” in sqlnet.ora.
Other similar parameters you might evaluate are: