Ensure your tnsnames.ora file is correctly mapped in the preferences.
You are using third-party tools that require a standalone JAR file. Where to Download the Oracle JDBC Driver oracle sql developer jdbc driver download
By default, SQL Developer uses the "Thin" driver. If you require advanced features like TAO (Transparent Application Failover), you may need to install the full Oracle Client and use the OCI driver. Summary of Key Files Driver Name Recommended Java Version ojdbc8.jar Legacy systems and standard 19c setups ojdbc10.jar Intermediate environments ojdbc11.jar Java 11, 17, 21 Modern 21c/23c cloud and on-premise setups Ensure your tnsnames
Search for "Oracle JDBC Drivers" on the Oracle website. If you require advanced features like TAO (Transparent
💡 Always match your JDBC driver version to your JDK version rather than just the database version to avoid "Unsupported Class Version" errors. Troubleshooting Common Connection Issues