When configured with MySQL Community Server 8.0.11 DB, XWiki 10.3 does not start and the browser gets HTTP ERROR 500.
Was used JDBC connector 'mysql-connector-java-8.0.11.jar' from https://dev.mysql.com/get/Downloads/Connector-J/mysql-connector-java-8.0.11.zip.
Also, the server was installed using the Legacy Authentication Method (Retain MySQL 5.x Compatibility).
Please find attached the log containing the stacktrace.
The issue was also reproduced by Manuel.