> Can the handling of Boolean types be configured?

As far as I remember - no. JDBC standard does not define any mapping
between boolean and SMALLINT/CHAR/etc, only between boolean and BIT data
type. JayBird supports 'Y'/'N', "true"/"false", 'T'/'F' and 1/0 mappings.

So far there were no request to make this configurable, therefore the
mappings are hardcoded. It is not hard to add such feature, but it better
be solved on server by introducing the BIT data type.

Roman