Is there some BDD framework for Java Swing? Something like Cucumber working with Maven and Sonar could help a lot.
Potentially you could use Cucumber-JVM for this which works great with Maven.
For example you could say,
When I click this button
Then this should happen
This may be possible but it will depend on how you have designed the project and if the swing interface is abstracted from the business layer. Not really sure what you wan't to do with Sonar.