The Kafka Connect JDBC Connector by default does not cope so well with:

• NUMBER columns with no defined precision/scale. You may end up with apparent junk (bytes) in the output, or just errors.
• TIMESTAMP WITH LOCAL TIME ZONE. Throws JDBC type -102 not currently supported warning in the log.

Read more about NUMBER data type in the Oracle docs.

tl;dr : How do I make it work?

There are several options:

New in Confluent Platform 4.1.1 : numeric.mapping

• In the connector configuration, set "numeric.mapping":"best_fit"
• New in Confluent Platform 4.1.1 (Doc)

Avoid the problem in the first place

• Change the DDL of the source object. For example:
  • refine the NUMBER ’s precision and scale
  • Use a TIMESTAMP type that is supported

CAST the datatypes in the query

• Pull from the object directly, and use query in the JDBC connector (instead of table.whitelist)—and cast the columns appropriately: