I installed MariaDB with yum in CentOS 7.
SonarQube throws this exception:
org.sonar.api.utils.MessageException: Unsupported mysql version: 5.5. Mini
MariaDB is not supported by SonarQube, see requirements.
Like Nicolas said, MariaDB is not supported by SonarQube - still in v7.
The Solution to run SonarQube in combination with XAMPP is to change the database from MariaDB to MySQL. Here you'll find the steps for changing it:
https://gist.github.com/odan/c799417460470c3776ffa8adce57eece