Jasper + ireport mais um sofrendo na mão do jasper

Exception in thread “main” java.lang.NullPointerException

at net.sf.jasperreports.engine.JRPropertiesMap.readObject(JRPropertiesMap.java:185)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

at java.lang.reflect.Method.invoke(Unknown Source)

at java.io.ObjectStreamClass.invokeReadObject(Unknown Source)

at java.io.ObjectInputStream.readSerialData(Unknown Source)

at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)

at java.io.ObjectInputStream.readObject0(Unknown Source)

at java.io.ObjectInputStream.defaultReadFields(Unknown Source)

at java.io.ObjectInputStream.readSerialData(Unknown Source)

at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)

at java.io.ObjectInputStream.readObject0(Unknown Source)

at java.io.ObjectInputStream.readArray(Unknown Source)

at java.io.ObjectInputStream.readObject0(Unknown Source)

at java.io.ObjectInputStream.defaultReadFields(Unknown Source)

at java.io.ObjectInputStream.readSerialData(Unknown Source)

at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)

at java.io.ObjectInputStream.readObject0(Unknown Source)

at java.io.ObjectInputStream.defaultReadFields(Unknown Source)

at java.io.ObjectInputStream.readSerialData(Unknown Source)

at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)

at java.io.ObjectInputStream.readObject0(Unknown Source)

at java.io.ObjectInputStream.readObject(Unknown Source)

at net.sf.jasperreports.engine.util.JRLoader.loadObject(JRLoader.java:88)

at net.sf.jasperreports.engine.JasperFillManager.fillReportToFile(JasperFillManager.java:443)

at RelatorioBibliotecaPessoal.geraRelatorio(RelatorioBibliotecaPessoal.java:40)

at RelatorioBibliotecaPessoal.main(RelatorioBibliotecaPessoal.java:49)

import java.sql.*;   
import java.util.*;   
  
import net.sf.jasperreports.engine.JRException;   
import net.sf.jasperreports.engine.JRResultSetDataSource;   
import net.sf.jasperreports.engine.JasperExportManager;   
import net.sf.jasperreports.engine.JasperFillManager;   
import net.sf.jasperreports.engine.JasperPrint;
import net.sf.jasperreports.engine.JasperRunManager;
import net.sf.jasperreports.view.JasperViewer;   
  
  
  
  
public class RelatorioBibliotecaPessoal {   
  
private static Connection getConnection( ) throws   
ClassNotFoundException, SQLException   
{   
String driver = "org.gjt.mm.mysql.Driver";   
String url = "jdbc:mysql://localhost:3306/humanus";   
String user = "root";   
String password = "w2gh59o_";   
Class.forName(driver);   
Connection con = DriverManager.getConnection( url, user, password );   
return con;   
}   
/* Gera Relatorio e visualiza-o */   
public void geraRelatorio( ) throws JRException, Exception   
{   
Connection con = getConnection( );   
Statement stm = con.createStatement( );   
String query = "select * from alunos";   
ResultSet rs = stm.executeQuery( query );   
/* implementação da interface JRDataSource para DataSource ResultSet */   
JRResultSetDataSource jrRS = new JRResultSetDataSource( rs );   
/* HashMap de parametros utilizados no relatório. Sempre instanciados */   
Map parameters = new HashMap();   
// parameters.put("COLUNA", valor);   
/* Preenche o relatório com os dados. Gera o arquivo BibliotecaPessoal.jrprint */   

  
/* Exporta para o formato PDF */   

 
JasperPrint jpt = JasperFillManager.fillReport("relatorio.jasper", parameters, jrRS);  
JasperRunManager.runReportToPdfFile("relatorio.jasper",parameters, jrRS);   
JasperViewer.viewReport( jpt, false );   
}   
public static void main(String[] args) throws JRException, Exception   
{   
new RelatorioBibliotecaPessoal().geraRelatorio();   
}   
}