Reduce spotbugs warnings

[MarkEWaite]

Reduce spotbugs warnings

A recent settings change increased the number of spotbugs warnings by allowing higher effort and a lower threshold. Resolve several spotbugs warnings that are easy to resolve.

Checklist

• I have read the CONTRIBUTING doc
• I have referenced the Jira issue related to my changes in one or more commit messages
• I have added tests that verify my changes
• Unit tests pass locally with my changes
• I have added documentation as necessary
• No Javadoc warnings were introduced with my changes
• No spotbugs warnings were introduced with my changes
• I have interactively tested my changes
• Any dependent changes have been merged and published in upstream modules (like git-client-plugin)

Types of changes

• Refactoring to remove warnings