Fatal error: Uncaught Error: Class "Drupal\Core\Config\Entity\ConfigEntityBase" not found in /home/www/drupal8/test/core/modules/rdf/src/Entity/RdfMapping.php:35 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/rdf/src/Entity/RdfMapping.php on line 35