need advice about out parameter settings while calling stored procedure in Java code

Hi ,

I am migrating from Oracle to Postgresql, and have encountered below issue while calling stored procedure via the latest PG JDBC (postgresql-9.4-1201.jdbc4.jar).

Here is the procedure snippet:

----------start------------

PROCEDURE p_myprocedure(a character varying, b character varying, c character varying,d character varying, OUT o1 text, OUT o2 text) IS

  BEGIN

Blalabla;

END;

----------end-------------

In my Java code, I have to set the value of the out parameters like input as bellowing:

stmt = con.prepareCall("{call xxx. p_myprocedure(?,?,?,?,?,?)}");

                  stmt.setString(1, "x1");

                  stmt.setString(2, "x21");

                  stmt.setString(3, "x3");

                  stmt.setString(4, "x4");

                  stmt.setString (5,"");//need to set the output value

                  stmt.setString (6,""); //need to set the output value

before invoking the ‘stmt.execute();’;

Otherwise, it will throw error like:

ERROR: function p_myprocedure (character varying, character varying, character varying, character varying) does not exist

  Hint: No function matches the given name and argument types. You might need to add explicit type casts.

But setting output  is unnecessary if I use Oracle DB or access Postgresql DB via EDB jdbc driver.

Is there any possible way to avoid such out parameter settings ?

Thanks & regards,

Alex