The SQL extension uses ServiceLoader to load table providers: https://github.com/apache/beam/blob/v2.22.0/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/BeamCalciteSchemaFactory.java#L85
And the IOs used in the built-in table providers (e.g. pubsub json, avro, parquet, ...) are included as provided dependencies, not compile. This means that we are able to build the sql extension jar, and AutoService picks them up and records them in META-INF/services. However because they are provided dependencies, the necessary IO modules are not marked as dependencies for the SQL extension.
This means consumers of :sdks:java:extensions:sql (like :sdks:java:extensions:sql:jdbc) can end up with ServiceLoader registering a TableProvider that will fail with ClassDefNotFoundError, unless they add the necessary dependency.
Possible solution: Refactor TableProvider to beam core (or another shared module) in order to solve Service Loader errors with SchemaCapableIOTableProviderWrapper. Remove getTableType overrides of SchemaCapableIOProviderWrapper when fixed.