issues with java driver setDate() on function call

I have a function declared as follows
CREATE OR REPLACE FUNCTION insertaegreso(usuario1 integer, importepago1 numeric, fechapago1 DATE, concepto1 character varying, tipopagonomina1 character varying, comentarios1 character varying)
RETURNS integer AS....implementation....

notice the field "fechapago1 DATE"

the function is working just fine, I tried it from pgadmin3 and it works,
but when I try to call it using java's PreparedStatement pst;
pst.setDate(3, date);
I get this error, (note: "no existe la función" means "the function .... doesn't exists")

org.postgresql.util.PSQLException: ERROR: no existe la función insertaegreso(integer, double precision, unknown, character varying, character varying, character varying)

it puts "unknown" instead of date

is there a workaround for it that doesn't involve creating a function with VARCHAR instead of DATE?

because also when I try to do something like

String sql1 = "SELECT EXTRACT (YEAR FROM ?)";
PreparedStatement pst = con.getPreparedStatement(sql1);
pst.setDate(1, date);

I get this error:

(the function....isn't unique)
org.postgresql.util.PSQLException: ERROR: la función pg_catalog.date_part(unknown, unknown) no es única

tanks in advance
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