The Apache Doris service type: catalogs, databases, tables, columns and workload groups with Doris's own privileges and table row filters, looked up and tested through MariaDB Connector/J over the frontends' MySQL protocol. Packaged as a plugin directory (descriptor, classes and lib/) that the release ships in plugins/doris.

Loads service type plugins: built-in ones from the classpath, external ones from the plugins directory, each in its own class loader