> I have a question about CallableStatement in JDBC Driver.
> There is the stored procedure with 2 in parameters and 2 out
> parameters (RETURNS ...).
> What should I write in connection.prepareCall() method?
> I use connection.prepareCall("{call sp_procedure (?,?,?,?)}") and
> get SQLException with message:
> "GDSException: org.firebirdsql.gds.GDSException: Dynamic SQL Error
> parameter mismatch for procedure SP_PROCEDURE"
>
> What is wrong?

This is bug in driver, but I have no idea how to correct it. When you
issue this procedure call, at this time driver has no information
about what parameter is in and what is out. Driver transforms {call
sp_procedure(?,?,?,?)} into EXECUTE PROCEDURE sp_procedure(?,?,?,?),
which is incorrect because you have only 2 in params.

So, you have to use {call sp_procedure(?,?)} and set values only for
in parameters, and then access out params using getXXX methods.

> P.S. Is there the documentation for JDBC Driver

No.

Best regards,
Roman Rokytskyy