I have created a Java Desktop Application Database Application to work on a table "prova" using PostgreSQL 8.2.5.
When running the application, the "double" type columns are correctly visualized into italian format (decimal point 
comma), whereas the "numeric" type columns are incorrect (decimal point is not comma).
When trying to insert a new row I can't use the comma as a decimal point, but I have to use the decimal point.
When trying to enter a character in a "date" type column I get the error:
Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException

Connection parameters are
Basic settings
Name PostgreSQL
Driver org.postgresql.Driver
Database URL jdbc:postgresql://localhost:5432/test
User Name postgres

Advanced
Select schema public

The steps to create the application are
New Project
Java Desktop Application
Database Application
Database Connection jdbc:postgresql://localhost:5432/test [postgres on public]
Database Table prova
All columns included

SQL scripts are

CREATE TABLE prova
(
  id serial NOT NULL,
  stringa character varying,
  carattere character(1),
  doppia double precision,
  numero numeric(10,2),
  data date,
  timemod timestamp without time zone,
  CONSTRAINT prova_pkey PRIMARY KEY (id)
) 
WITHOUT OIDS;
ALTER TABLE prova OWNER TO postgres;