There is bug in your mariadb-java-client jar version 2.4.1 that means it doesn't work within an OSGI environment when the database connections is secured with SSL/TLS using two way authentication.
When attempting a database connection you get a ClassNotFoundException javax.security.auth.x509.X509Principal.
This is due a couple of missing import statements in the pom.xml that is used to build the jar file.
You currently have this
But I have found 3 additional imports need to be added, giving this: