Hi @Jaff ,
Thanks for the sample projects. I scanned your helloworld project with SonarQube 8.9.1 (with latest version of Sonar scanner CLI) with this command:
sonar-scanner -Dsonar.projectKey=play-helloworld -Dsonar.login=<INSERT-USER-TOKEN> -Dsonar.host.url=http://localhost:9000 -Dsonar.java.binaries=tmp/classes -Dsonar.java.libraries=lib
If you are not using Maven or Gradle, then you need to use sonar-scanner CLI and ensure you set sonar.java.binaries (see Java | SonarQube Docs for more information). You may need to adjust sonar.java.binaries and sonar.java.libraries (and set proper sonar.exclusions also).