> I have upgraded web application from Interbase (open source 6 with
> interclient) to the latest Firebird and FirebirdSQL driver..

Which version of InterClient have you used?

> I'm encountering some code that no longer works..
>
> String _sSql = "{call sp_do_due_date}"
> CallableStatement _stmt = this.g_con.prepareCall(arg_sSql);
> _stmt.executeQuery();
>
> The stored procedure has NO inputs or outputs..

In this case you should have used stmt.execute() method. The executeQuery()
call should be used only with selectable procedures, since only selectable
procedures can return result sets. See javadoc for
FirebirdCallableStatement.setSelectable(boolean) method.

The error you see most likely is a bug in escaped call parser, but I have
tested it with JayBird 2.0 RC3a and it works (or more correctly, it fails,
but with the error message "No result set for sql", which is correct in this
case). If you have tried it with this version of driver, please create a
test case, so I can reproduce the error.

Roman