This summary provides a comprehensive overview of the different error messages and scenarios that can occur when connecting to an Oracle database, including JDBC Thin and OCI drivers. It highlights the importance of troubleshooting complex connection issues and provides guidance on how to resolve them using various methods, such as modifying the tnsnames.ora file, setting environment variables, and using Java KeyStore or the Oracle Wallet. The summary also emphasizes the need for thorough testing and error handling when migrating from Oracle to YugabyteDB with YugabyteDB Voyager.