Invoking stored procedure - is catalog name ever required?

[Mike Norman]

I've seen the stored procedure invocation documented as:

   {call demoSp(?, ?)}

I'm building up my invocation string from JDBC metadata.
The PROCEDURE_CAT column is populated with the name of the database

    url: jdbc:mysql://localhost:3306/emp
                                   ^^^ database name

    // useful fields in databaseMetaData.getProcedures() ResultSet
    public static final int PROCS_INFO_CATALOG = 1;//catalog (may be null)
    ...
    ResultSet procsInfo = databaseMetaData.getProcedures(catalogPattern,
        schemaPattern, procedurePattern);
    String actualCatalogName = procsInfo.getString(PROCS_INFO_CATALOG);
           ^^^^^^^^^^^^^^^^^ contains "emp"

Thus, my invocation string becomes:

   {call emp.demoSp(?, ?)}

In older versions of the Connector, this seemed to work; however, in
version 5.1.13 of Connector/J, I'm getting an exception:

    Parameter index of n is out of range (a, b)  {values n, a, b vary based on
                                                  number of arguments}

(and yes, I've opened a bug on this http://bugs.mysql.com/bug.php?id=57183)

I can change my code to not include the catalog name ... but is there ever
any circumstance under which it does becomes required?

Thanks in advance,
Mike Norman