Erro no ResultSet na classe que gera Relatorio IReport/Jaspe

import net.sf.jasperreports.engine.*;
import net.sf.jasperreports.engine.design.JasperDesign;
import net.sf.jasperreports.view.*;
import java.sql.*;
import java.util.*;
try
        {
            con.IniciaConexao();
            String query = "select * from OPERACAO";
            ResultSet rs = con.st.executeQuery(query);
            
            JRResultSetDataSource jrRS = new JRResultSetDataSource( rs );
                    
            Map parameters = new HashMap();
            
            parameters.put("CODIGO", ""+rs.getInt("CODIGO"));            
            parameters.put("DESCRICAO", ""+rs.getString("DESCRICAO"));
            
            JasperPrint jprint = JasperManager.fillReport("RelatorioOperacao.jasper", parameters, jrRS);
            JasperViewer.viewReport(jprint,false);
           
            con.FechaConexao();
            
        }
        catch(SQLException e)
        {
		System.out.println("Erro no SQL"+e);
	}
}