Since SonarQube 4.2, it is possible to run an analysis on a multi-language project. To do so, the
sonar.language property just has to be removed. Conversely, if for some reason you want to perform a single language-only analysis, make sure
sonar.language is specified. By default the
sonar.sources property is set to the value of the Maven
sourceDirectory property (usually src/main/java). Therefore, for a multi-language project, the property usually has to be overridden to:
sonar.sources=src. Note that this property can only be set in the pom file. It's not possible to set it via the command line.