Captures what the user types and writes to a .TXT

I made a program in JFrame, basically it captures what the user types and writes to a txt, but when I go to see the contents of the file is written, the following "null". What could be happening?

importjava.io.BufferedWriter;importjava.io.File;importjava.io.FileWriter;importjava.io.IOException;importjava.util.*;importjava.util.logging.Level;importjava.util.logging.Logger;publicclasstestedabeta07extendsjavax.swing.JFrame{Scannerscan=newScanner(System.in);Scannern;publictestedabeta07(){initComponents();}@SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jInternalFrame1 = new javax.swing.JInternalFrame();
        jPanel1 = new javax.swing.JPanel();
        panel1 = new java.awt.Panel();
        jFrame1 = new javax.swing.JFrame();
        Jcampo2 = new javax.swing.JTextField();
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        Bconfirmar = new javax.swing.JButton();
        Bsair = new javax.swing.JButton();
        Jcampo1 = new javax.swing.JTextField();

        jInternalFrame1.setVisible(true);

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setBounds(new java.awt.Rectangle(5, 5, 10, 10));
        setCursor(new java.awt.Cursor(java.awt.Cursor.DEFAULT_CURSOR));
        setMinimumSize(new java.awt.Dimension(360, 237));
        getContentPane().setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());

        Jcampo2.setFont(new java.awt.Font("Tahoma", 1, 11)); // NOI18N
        Jcampo2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                Jcampo2ActionPerformed(evt);
            }
        });
        getContentPane().add(Jcampo2, new org.netbeans.lib.awtextra.AbsoluteConstraints(80, 120, 240, -1));

        jLabel1.setText("Chegada");
        getContentPane().add(jLabel1, new org.netbeans.lib.awtextra.AbsoluteConstraints(20, 70, -1, -1));

        jLabel2.setText("Saída");
        getContentPane().add(jLabel2, new org.netbeans.lib.awtextra.AbsoluteConstraints(30, 120, -1, -1));

        jLabel3.setFont(new java.awt.Font("Trebuchet MS", 0, 24)); // NOI18N
        jLabel3.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
        jLabel3.setText("HALKINGS");
        getContentPane().add(jLabel3, new org.netbeans.lib.awtextra.AbsoluteConstraints(120, 20, -1, -1));

        Bconfirmar.setText("Confirmar");
        Bconfirmar.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                BconfirmarActionPerformed(evt);
            }
        });
        getContentPane().add(Bconfirmar, new org.netbeans.lib.awtextra.AbsoluteConstraints(80, 160, -1, -1));

        Bsair.setText("Sair");
        Bsair.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                BsairActionPerformed(evt);
            }
        });
        getContentPane().add(Bsair, new org.netbeans.lib.awtextra.AbsoluteConstraints(190, 160, -1, -1));

        Jcampo1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                Jcampo1ActionPerformed(evt);
            }
        });
        getContentPane().add(Jcampo1, new org.netbeans.lib.awtextra.AbsoluteConstraints(80, 70, 240, -1));

        setSize(new java.awt.Dimension(359, 249));
        setLocationRelativeTo(null);
    }// </editor-fold>                        

    private void BconfirmarActionPerformed(java.awt.event.ActionEvent evt) {                                           
                     File Ponto = new File ("C:\Users\W\Desktop\Ponto\funcionarios.txt");


  try{

  FileWriter fw = new FileWriter(Ponto, true);
  BufferedWriter bw = new BufferedWriter (fw);

  bw.write("" +n);
  bw.newLine();

  bw.close();
  fw.close();

  }catch(IOException ex){
  }

    }                                          

    private void BsairActionPerformed(java.awt.event.ActionEvent evt) {                                      
        System.exit(0);
    }                                     

    private void Jcampo1ActionPerformed(java.awt.event.ActionEvent evt) {                                        

    }                                       

    private void Jcampo2ActionPerformed(java.awt.event.ActionEvent evt) {                                        
        // TODO add your handling code here:
    }                                       

    public static void main(String args[]) {

        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new testedabeta07().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton Bconfirmar;
    private javax.swing.JButton Bsair;
    private javax.swing.JTextField Jcampo1;
    private javax.swing.JTextField Jcampo2;
    private javax.swing.JFrame jFrame1;
    private javax.swing.JInternalFrame jInternalFrame1;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JPanel jPanel1;
    private java.awt.Panel panel1;
    // End of variables declaration                   
}