Jasper " O relatório vem em branco "

Relatórios   
  
commons-collection-2-a.jar   
commons-javaflow-20060411.jar   
commons-logging-api-1.0.2.jar   
ireport.jar   
jasperreports-1.3.3.jar   
  
GeradorRelatorio.java   
  
  
package javaapplication1;   
  
import java.sql.Connection;   
import java.sql.DriverManager;   
import net.sf.jasperreports.engine.JasperFillManager;   
import net.sf.jasperreports.engine.JasperPrint;   
import net.sf.jasperreports.engine.JRException;   
import java.util.HashMap;   
  
public class GeradorRelatorio {   
    public JasperPrint gerarRelatoriosClientes() throws Exception{   
        JasperPrint rel=null;   
  
    try{   
           
                    Class.forName("com.mysql.jdbc.Driver");   
               Connection con =    
                  DriverManager.getConnection   
                  ("jdbc:mysql://localhost/bd?user=root&password=");   
  
         HashMap map= new HashMap();   
         String arquivoJasper= "teste.jasper";   
         rel=JasperFillManager.fillReport(arquivoJasper,map,con);   
    }catch (JRException e){   
        e.printStackTrace();   
    }   
        return rel;   
    }   
       
       
}   
  
  
  
  
  
  
  
  
Button   
  
   GeradorRelatorio rep=new GeradorRelatorio();   
        JasperPrint relat;   
        try{   
            relat=rep.gerarRelatoriosClientes();   
            JasperViewer.viewReport(relat,false);   
        }catch (Exception e){   
            e.printStackTrace();   
        }