Yes, the jar file needs to be generated at least once.
One option would be to save the precreated jar file and pass it for future
invocations of the same job (with same table structure). Please see the
We also added a mechanism for some of the connectors to declare that they
don't need the generated files (useful in the case of direct mode
connectors which dump text data). Netezza connector is an example of the
one which does that.