Oracle SEPS Wallet Resolution Across Mixed OCI and JDBC Thin Test Clients

An integration test suite needs to connect to an Oracle test database without embedding production-style passwords in source control. The plan is to use Oracle Secure External Password Store (SEPS) with an auto-login wallet so that non-interactive CI jobs can authenticate via the /@db_alias syntax.

The environment mixes Oracle client drivers—OCI tools such as SQL*Plus and JDBC Thin connections from a test harness—running on Oracle 19c or later. Documentation describes wallet discovery through SQLNET.WALLET_OVERRIDE or a default filesystem path, yet the precedence and fallback behavior when the override is present but inaccessible is not clearly bounded across drivers. Auto-login is required for scripted runs, but the exact failure mode when it is missing remains a design uncertainty.

What documented behavior governs wallet lookup order for OCI versus JDBC Thin in 19c and later? Does SQLNET.WALLET_OVERRIDE always take precedence, or can clients silently fall back to the default wallet directory? Are there version-specific limits on which client drivers honor the override parameter in non-interactive integration tests?