Java Database Connectivity (JDBC)

Hello,

I'm getting this java.sql.SQLException: No ResultSet was produced.
I use J2SE 1.4.1, Jakarta Tomcat, Sybase ASE ODBC driver, Windows 2000. The code makes use of a CollableStatement to execute a stored procedure on Sybase, similar to the following:

    CallableStatement cs = connection.prepareCall( 
      "{call sp(?,?)}" );
    cs.setInt( 1, intvalue );
    cs.setString( 2, stringvalue );
    ResultSet rs = cs.executeQuery();
    return rs;

I tried with

cs.execute(); return cs.getResultSet();

in which case the ResultSet returned is null. The stored procedure is supposed to return a result set and nothing else. If I execute the sp for the same particular instance, it does actually also return a few records in the result set, so I'm really puzzle to what the cause might be. The db driver? Using too many CallableStatementS and ResultSetS at the same time? Any small suggestion on this is very much appreciated.

Thank you