To use findbugs-slf4j with SonarQube (Sonar ver. 7.9 or later), please put sonar-findbugs-slf4j-plugin-*.jar to ${SONAR_HOME}/extensions/plugin. After restarting SonarQube, you can use FindBugsSlf4j plugin. Note that you also need to put findbugs-plugin version 3.11 or later.