Failed to load driver class com.mysql.jdbc.Driver

The answer is so embarrassing. I appended the driver line of application.properties with a semicolon ... Obviously, it did't recognize that driver.

In my case the next dependency was missing:

<dependency>
     <groupId>mysql</groupId>
     <artifactId>mysql-connector-java</artifactId>
</dependency>

In case of using IntelliJ and if you inherit from a <parent>, you can view your effective pom.xml by right clicking anywhere inside your pom.xml, then:

and search for the mysql-connector-java artifact as mentioned.