Aplicação de Relatorio não aceita execução

public Connection getConnection()
    {
        try{
               Class.forName ("oracle.jdbc.driver.OracleDriver");
               //String Driver = "jdbc:oracle:thin:@127.0.0.1:1521:xe";
               //Connection con = DriverManager.getConnection(driver, "igm", "igm");
               return con;
            } catch (Exception e) {
                e.printStackTrace();
            }
                return null;
    }

package laboratorioac;

import java.sql.Connection;
import java.util.Map;
import net.sf.jasperreports.engine.JasperExportManager;
import net.sf.jasperreports.engine.JasperFillManager;
import net.sf.jasperreports.engine.JasperPrint;
import net.sf.jasperreports.view.JasperViewer;

/**
 *
 * @author Elcio
 */
public class Mapatrab extends javax.swing.JFrame {

    private static class Hashmap {

        public Hashmap() {
        }
    }

    /** Creates new form Mapatrab */
    public Mapatrab() {
        initComponents();

    }

private void visualisarActionPerformed(java.awt.event.ActionEvent evt) {                                           
        // TODO add your handling code here:
        try{
            Connection con = new Facade().getConnection();
            Hashmap parametros = new Hashmap();
            JasperPrint jp = JasperFillManager.fillReport("./jasper/Mapatrab.jasper", (Map) parametros, con);
            JasperViewer jrv = new JasperViewer (jp);
            jrv.setVisible(true);
        }   catch (Exception e) {
            e.printStackTrace();
        }
}                                          

    private void pdfActionPerformed(java.awt.event.ActionEvent evt) {                                    
        // TODO add your handling code here:
        try{
            Connection con = new Facade().getConnection();
            Hashmap parametros = new Hashmap();
            JasperPrint jp = JasperFillManager.fillReport("./jasper/Mapatrab.jasper", (Map) parametros, con);
            JasperExportManager.exportReportToPdfFile(jp, "./Mapatrab.pdf");
        }   catch (Exception e) {
            e.printStackTrace();
        }
    }                                   

    private void htmlActionPerformed(java.awt.event.ActionEvent evt) {                                     
        // TODO add your handling code here:
        try{
            Connection con = new Facade().getConnection();
            Hashmap parametros = new Hashmap();
            JasperPrint jp = JasperFillManager.fillReport("./jasper/Mapatrab.jasper", (Map) parametros, con);
            JasperExportManager.exportReportToHtmlFile(jp, "./Mapatrab.pdf");
        }   catch (Exception e) {
            e.printStackTrace();
        }
    }                                    

    /**
    * @param args the command line arguments
    */
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Mapatrab().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton html;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JPanel jPanel2;
    private javax.swing.JPanel jPanel3;
    private javax.swing.JButton pdf;
    private javax.swing.JButton visualisar;
    // End of variables declaration 
}