Исключение Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
 
package lab5;
 
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
 
/**
 *
 * @author Alik
 */
public class AddDevice extends javax.swing.JDialog {
    /**
     * Creates new form AddDevice
     */
    public boolean ok = false;
//    public AddDevice(java.awt.Frame parent, boolean modal) {
//        super(parent, modal);
//        initComponents();        
//        jComboBox1.addItem("Клавиатура");
//        jComboBox1.addItem("Монитор");
//        jComboBox1.addItem("Мышка");
//        jComboBox1.addItem("Принтер");
//    }
 
    public AddDevice(java.awt.Frame parent, boolean modal, String component) {
        super(parent, modal);
        initComponents();
        jComboBox1.addItem("Клавиатура");
        jComboBox1.addItem("Монитор");
        jComboBox1.addItem("Мышка");
        jComboBox1.addItem("Принтер");
        jComboBox1.setSelectedItem((Object) component);
        if ("Монитор".equals(jComboBox1.getSelectedItem().toString()))
        {
            jPanel1.setVisible(true);
        }
        else {
            jPanel1.setVisible(false);
        }
        if ("Принтер".equals(jComboBox1.getSelectedItem().toString()))
        {
            jPanel2.setVisible(true);
        }
        else {
            jPanel2.setVisible(false);
        }
        jComboBox1.addActionListener(actionListener);
    }
    
    
 
    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {
 
        jComboBox1 = new javax.swing.JComboBox();
        jLabel4 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        jTextField3 = new javax.swing.JTextField();
        jLabel1 = new javax.swing.JLabel();
        jTextField2 = new javax.swing.JTextField();
        jLabel2 = new javax.swing.JLabel();
        jCheckBox1 = new javax.swing.JCheckBox();
        jButton1 = new javax.swing.JButton();
        jPanel1 = new javax.swing.JPanel();
        jLabel7 = new javax.swing.JLabel();
        jComboBox4 = new javax.swing.JComboBox();
        jComboBox3 = new javax.swing.JComboBox();
        jLabel5 = new javax.swing.JLabel();
        jPanel2 = new javax.swing.JPanel();
        jLabel6 = new javax.swing.JLabel();
        jLabel8 = new javax.swing.JLabel();
        jComboBox2 = new javax.swing.JComboBox();
        jComboBox5 = new javax.swing.JComboBox();
        jCheckBox2 = new javax.swing.JCheckBox();
 
        setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
        setPreferredSize(new java.awt.Dimension(410, 230));
        setResizable(false);
 
        jLabel4.setText("Провод:");
 
        jLabel3.setText("Цена:");
 
        jTextField3.setName("price"); // NOI18N
        jTextField3.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jTextField3ActionPerformed(evt);
            }
        });
 
        jLabel1.setText("Название:");
 
        jTextField2.setName("label"); // NOI18N
 
        jLabel2.setText("Фирма:");
 
        jCheckBox1.setName("wire"); // NOI18N
 
        jButton1.setText("Добавить");
        jButton1.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseClicked(java.awt.event.MouseEvent evt) {
                jButton1MouseClicked(evt);
            }
        });
 
        jLabel7.setText("Тип:");
 
        jComboBox4.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "15", "17", "19", "20", "21", "22", "23", "24", "25" }));
 
        jComboBox3.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "ЭЛД", "ЖК", "PDP", "OLED" }));
 
        jLabel5.setText("Диагональ:");
 
        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(jLabel5)
                    .addComponent(jLabel7))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jComboBox3, javax.swing.GroupLayout.PREFERRED_SIZE, 80, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jComboBox4, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(30, 30, 30))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel7)
                    .addComponent(jComboBox3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(23, 23, 23)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jComboBox4, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jLabel5))
                .addContainerGap(29, Short.MAX_VALUE))
        );
 
        jLabel6.setText("Тип принтера:");
 
        jLabel8.setText("Формат:");
 
        jComboBox2.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Струйный", "Лазерный", "Матричный" }));
 
        jComboBox5.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "A0", "A1", "A2", "A3", "A4", "A5" }));
 
        jCheckBox2.setText("Цветной:");
        jCheckBox2.setHorizontalTextPosition(javax.swing.SwingConstants.LEFT);
        jCheckBox2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jCheckBox2ActionPerformed(evt);
            }
        });
 
        javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
        jPanel2.setLayout(jPanel2Layout);
        jPanel2Layout.setHorizontalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel2Layout.createSequentialGroup()
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(jPanel2Layout.createSequentialGroup()
                        .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                            .addComponent(jLabel8)
                            .addComponent(jLabel6))
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                        .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addGroup(jPanel2Layout.createSequentialGroup()
                                .addComponent(jComboBox2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addContainerGap(40, Short.MAX_VALUE))
                            .addGroup(jPanel2Layout.createSequentialGroup()
                                .addComponent(jComboBox5, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addGap(0, 0, Short.MAX_VALUE))))
                    .addGroup(jPanel2Layout.createSequentialGroup()
                        .addGap(31, 31, 31)
                        .addComponent(jCheckBox2)
                        .addGap(0, 0, Short.MAX_VALUE))))
        );
        jPanel2Layout.setVerticalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel2Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel6)
                    .addComponent(jComboBox2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jComboBox5, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jLabel8))
                .addGap(18, 18, 18)
                .addComponent(jCheckBox2)
                .addContainerGap(14, Short.MAX_VALUE))
        );
 
        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addComponent(jLabel1, javax.swing.GroupLayout.Alignment.TRAILING)
                            .addComponent(jLabel2, javax.swing.GroupLayout.Alignment.TRAILING)
                            .addComponent(jLabel3, javax.swing.GroupLayout.Alignment.TRAILING)
                            .addComponent(jLabel4, javax.swing.GroupLayout.Alignment.TRAILING))
                        .addGap(18, 18, 18)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(jCheckBox1)
                            .addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, 100, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(jTextField3, javax.swing.GroupLayout.PREFERRED_SIZE, 100, javax.swing.GroupLayout.PREFERRED_SIZE)))
                    .addComponent(jButton1))
                .addGap(18, 18, 18)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addGroup(layout.createSequentialGroup()
                        .addGap(10, 10, 10)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(jLabel1))
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(jLabel2))
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jTextField3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(jLabel3))
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addComponent(jCheckBox1)
                            .addComponent(jLabel4))
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                        .addComponent(jButton1))
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                        .addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
 
        pack();
    }// </editor-fold>
 
    private void jTextField3ActionPerformed(java.awt.event.ActionEvent evt) {                                            
        // TODO add your handling code here:
    }                                           
 
    private void jButton1MouseClicked(java.awt.event.MouseEvent evt) {                                      
       ok = true;
       switch(jComboBox1.getSelectedItem().toString())
       {
           case "Клавиатура": 
           {
               boolean wire = jCheckBox1.isSelected();
               Keyboard tmp = new Keyboard("Клавиатура", this.jTextField2.getText(), Integer.parseInt(this.jTextField3.getText()), wire);
               Lab5.collection.add(tmp);
           }
           case "Монитор": 
           {
               boolean wire = jCheckBox1.isSelected();
               Monitor tmp = new Monitor("Монитор", this.jTextField2.getText(), Integer.parseInt(this.jTextField3.getText()), wire,Integer.parseInt(this.jComboBox4.getSelectedItem().toString()),this.jComboBox3.getSelectedItem().toString());
               Lab5.collection.add(tmp);
           }
           case "Мышка": 
           {
               boolean wire = jCheckBox1.isSelected();
               Mouse tmp = new Mouse("Мышка", this.jTextField2.getText(), Integer.parseInt(this.jTextField3.getText()), wire);
               Lab5.collection.add(tmp);
           }
           case "Принтер": 
           {
               boolean wire = jCheckBox1.isSelected();
               boolean color = this.jCheckBox2.isSelected();
               Printer tmp = new Printer("Принтер", this.jTextField2.getText(), Integer.parseInt(this.jTextField3.getText()), wire, this.jComboBox2.getSelectedItem().toString(), this.jComboBox5.getSelectedItem().toString(), color);
               Lab5.collection.add(tmp);
           }                   
       }
       this.dispose();
    }                                     
 
      ActionListener actionListener = new ActionListener() {
          @Override
            public void actionPerformed(ActionEvent e) {
                if ("Монитор".equals(jComboBox1.getSelectedItem().toString()))
                {
                    jPanel1.setVisible(true);
                    jPanel2.setVisible(false);
                }
                else if ("Принтер".equals(jComboBox1.getSelectedItem().toString())) 
                {
                    jPanel1.setVisible(false);
                    jPanel2.setVisible(true);                    
                }
                else {
                    jPanel2.setVisible(false);
                    jPanel1.setVisible(false);
                }
                
            }
        };
      
 
 
    private void jCheckBox2ActionPerformed(java.awt.event.ActionEvent evt) {                                           
        // TODO add your handling code here:
    }                                          
 
    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see [url]http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html[/url] 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(AddDevice.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(AddDevice.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(AddDevice.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(AddDevice.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>
 
        /* Create and display the dialog */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                AddDevice dialog = new AddDevice(new javax.swing.JFrame(), true, null);
                dialog.addWindowListener(new java.awt.event.WindowAdapter() {
                    @Override
                    public void windowClosing(java.awt.event.WindowEvent e) {
                        System.exit(0);
                    }
                });
                dialog.setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JButton jButton1;
    private javax.swing.JCheckBox jCheckBox1;
    private javax.swing.JCheckBox jCheckBox2;
    private javax.swing.JComboBox jComboBox1;
    private javax.swing.JComboBox jComboBox2;
    private javax.swing.JComboBox jComboBox3;
    private javax.swing.JComboBox jComboBox4;
    private javax.swing.JComboBox jComboBox5;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JLabel jLabel5;
    private javax.swing.JLabel jLabel6;
    private javax.swing.JLabel jLabel7;
    private javax.swing.JLabel jLabel8;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JPanel jPanel2;
    private javax.swing.JTextField jTextField2;
    private javax.swing.JTextField jTextField3;
    // End of variables declaration
 
//        @Override
//        public void actionPerformed(ActionEvent e) {
//            throw new UnsupportedOperationException("Not supported yet.");
//        }
    }

    Lab5.collection.add(tmp);