Fix/spotbugs issues

[lacostej]

To merge on top of #9

Testing done

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2. Ensure that the pull request title represents the desired changelog entry
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4. Link to relevant issues in GitHub or Jira
5. Link to relevant pull requests, esp. upstream and downstream changes
6. Ensure you have provided tests - that demonstrates feature works or fixes the issue

Combined with #9, this gets mvn install to pass on my machine.

[MarkEWaite]

Could anyone please replay this PR build with the updated Jenkinsfile?

Done