Patch for spotbugs bugs

[krisstern]

Description

Fixed three SpotBugs bugs encountered while running mvn verify, all of them NPE type errors.

Checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests - that demonstrates feature works or fixes the issue

[Wadeck]

Thanks for the PR, I will integrate them next time I am working on the plugin. There are some small things that I wanted to adjust after the recent internship :-)

[krisstern]

You are welcome! And sure, no problem.