[AryanRG]

Summary

JDBC interprets a zero-second validation timeout as unlimited. A positive sub-second Duration currently truncates to zero, so validation can run without the requested bound.

Round positive sub-second values up to one JDBC second in both the validation-query and Connection.isValid paths. Preserve zero/negative values as the existing no-timeout behavior, document the conversion, add regressions for both paths, and add the DBCP-600 change entry.

Jira: https://issues.apache.org/jira/browse/DBCP-600

Validation

• The validation-query regression failed on pristine base and passed with this patch.
• Focused tests and mvn -q verify passed locally.
• The default Maven build (mvn) passed locally on this exact tree, including a fresh run before publication.

Contributor checklist

• Read the project contribution guidelines.
• Read the ASF Generative Tooling Guidance.
• AI assistance used: Kiro Opus 5.5 helped identify the defect, prepare code/tests/documentation, and perform an independent automated review. The Maven results above were checked locally.
• Run the default Maven build.
• Add unit tests for the behavioral change.
• Explain the what, how, and why of the change.
• Use a meaningful issue-linked commit subject and body.