Thanks for looking into this, however could you please file a github PR so the system tests the change against different PostgreSQL / Java versions?
Could you add a test case that explores ResultSet.getClob as well?
I think something similar is needed for PgPreparedStatement as well, but I did not find a way to check the type of a column the way it's done in PgResultSet. It seems that ParameterList.getTypeOIDs() would provide that information, but I don't know how to use that. If someone points me in the right direction I can add that as well.