Sonarcloud.io is the cloud offering of SonarQube.org. It offers code quality and security scanning, to help developers build maintainable and secure applications. Typically developers install a SonarLint.org plugin in their IDE, for direct feedback. Merge request decoration acts as second line of defence, to ensure no new findings make it past the merge or pull request review.
This blogpost walks you through the steps to setting up Merge request decoration on GitLab.com for Apache Maven projects. There’s a few gotcha’s around setting up merge request decoration, which could lead you to threads like these to debug what you did wrong.