JApplet indiquant la classe introuvable et l'exception de classe non trouvée

Question

J'ai un problème qui me donne un message d'erreur et une applet vide apparaît. Le message d'erreur indique load: class Myapp.class not found et java.lang.ClassNotFoundException, puis une liste de lignes indiquant @ et un autre jargon. Si je cours essayer d'exécuter le programme comme une applet Jcreator comme je m'attendais à obtenir l'erreur indiquée précédemment et si je l'exécute dans une application il me donne juste l'erreur principale de méthode.

Voici mon programme:

package MyPack; 

import javax.swing.*; 
import java.awt.event.*; 
public class Myapp extends JApplet implements ItemListener{ 



JButton jbtnOne; 
JButton jbtnTwo; 
JLabel jlab; 
JComboBox comboBox; 
JComboBox comboBox_1; 
JCheckBox chckbxPizza; 
JCheckBox chckbxBurger; 
JCheckBox chckbxSalad; 
JLabel label_3; 
private JTextField textField; 
private JTextField textField_1; 
private JTextField textField_2; 
JTextArea txtrCommentsForSpecial; 
JTextArea txtrCommentsForSpecial_2; 
JTextArea txtrCommentsForSpecial_1; 
JInternalFrame internalFrame; 
public Myapp() { 
} 



    public void init() { 
     setSize(700,640); 
    // setVisible(true); 
    try { 
     SwingUtilities.invokeAndWait(new Runnable() { 
     public void run() { 
      guiInit(); // initialize the GUI 
     } 
     }); 
    } catch(Exception exc) { 
     System.out.println("Can't create because of "+ exc); 
    } 
    } 

    // Called second, after init(). Also called 
    // whenever the applet is restarted. 
    public void start() { 
    // Not used by this applet. 
    } 

    // Called when the applet is stopped. 
    public void stop() { 
    // Not used by this applet. 
    } 

    // Called when applet is terminated. This is 
    // the last method executed. 
    public void destroy() { 
    // Not used by this applet. 
    } 

    // Setup and initialize the GUI. 
    private void guiInit() { 
    // Create two buttons and a label. 
    // setLayout(null); 
     String a[] = { "Chiken Tikka", "Fajita", "Vegetable"}; 
     comboBox = new JComboBox(a); 
     comboBox.setBounds(115, 103, 100, 20); 
     comboBox.addItemListener(this); 
     getContentPane().add(comboBox); 

     String b[] = { "small", "medium","large","extra large"}; 
     comboBox_1 = new JComboBox(b); 
    // comboBox_1.addItemListener(this); 
    // comboBox_1.setEnabled(false); 
     getContentPane().add(comboBox_1); 
     comboBox_1.setBounds(290, 103, 140, 20); 
    // setSize(300, 300); 
    getContentPane().setLayout(null); 
    JLabel lblSelectMenu = new JLabel("Select Menu"); 
    lblSelectMenu.setForeground(new Color(72, 61, 139)); 
    lblSelectMenu.setFont(new Font("Segoe Script", Font.BOLD, 16)); 
    lblSelectMenu.setBounds(58, 10, 107, 34); 
    getContentPane().add(lblSelectMenu); 

    chckbxPizza = new JCheckBox("Pizza"); 
    chckbxPizza.setBounds(37, 64, 97, 23); 
    getContentPane().add(chckbxPizza); 

    JLabel lblFlavour = new JLabel("flavour"); 
    lblFlavour.setBounds(60, 103, 45, 20); 
    getContentPane().add(lblFlavour); 

    JLabel lblSize = new JLabel("size"); 
    lblSize.setBounds(253, 103, 45, 20); 
    getContentPane().add(lblSize); 

    JLabel lblQty = new JLabel("Qty"); 
    lblQty.setBounds(451, 103, 35, 20); 
    getContentPane().add(lblQty); 

    textField = new JTextField(); 
    textField.setBounds(485, 103, 86, 20); 
    getContentPane().add(textField); 
    textField.setColumns(10); 

    JLabel lblComments = new JLabel("comments"); 
    lblComments.setBounds(139, 154, 76, 20); 
    getContentPane().add(lblComments); 

    txtrCommentsForSpecial = new JTextArea(); 
    txtrCommentsForSpecial.setForeground(new Color(220, 220, 220)); 
    txtrCommentsForSpecial.setText("comments for special features"); 
    txtrCommentsForSpecial.setBounds(210, 154, 268, 61); 
    getContentPane().add(txtrCommentsForSpecial); 

    chckbxBurger = new JCheckBox("Burger"); 
    chckbxBurger.setBounds(37, 236, 97, 23); 
    getContentPane().add(chckbxBurger); 

    JLabel label = new JLabel("flavour"); 
    label.setBounds(60, 286, 45, 20); 
    getContentPane().add(label); 

    String c[] = { "Fish", "Vegetable", "Chicken"}; 
    JComboBox comboBox_2 = new JComboBox(c); 
    comboBox_2.setBounds(115, 286, 100, 20); 
    getContentPane().add(comboBox_2); 

    JLabel label_1 = new JLabel("size"); 
    label_1.setBounds(253, 286, 45, 20); 
    getContentPane().add(label_1); 

    JComboBox comboBox_3 = new JComboBox(b); 
    comboBox_3.setBounds(290, 286, 110, 20); 
    getContentPane().add(comboBox_3); 

    JLabel label_2 = new JLabel("Qty"); 
    label_2.setBounds(451, 286, 35, 20); 
    getContentPane().add(label_2); 

    textField_1 = new JTextField(); 
    textField_1.setBounds(485, 286, 86, 20); 
    getContentPane().add(textField_1); 
    textField_1.setColumns(10); 

    label_3  = new JLabel("comments"); 
    label_3.setBounds(139, 340, 76, 20); 
    getContentPane().add(label_3); 

    txtrCommentsForSpecial_1 = new JTextArea(); 
    txtrCommentsForSpecial_1.setForeground(new Color(220, 220, 220)); 
    txtrCommentsForSpecial_1.setText("comments for special features"); 
    txtrCommentsForSpecial_1.setBounds(210, 340, 268, 61); 
    getContentPane().add(txtrCommentsForSpecial_1); 

    chckbxSalad = new JCheckBox("Soft Drink"); 
    chckbxSalad.setBounds(37, 424, 97, 23); 
    getContentPane().add(chckbxSalad); 

    JLabel label_4 = new JLabel("flavour"); 
    label_4.setBounds(60, 475, 45, 20); 
    getContentPane().add(label_4); 

    String f[] = { "Pepsi", "Coca Cola", "Sprite","7up"}; 
    JComboBox comboBox_4 = new JComboBox(f); 
    comboBox_4.setBounds(115, 475, 86, 20); 
    getContentPane().add(comboBox_4); 

    JLabel label_5 = new JLabel("size"); 
    label_5.setBounds(253, 475, 45, 20); 
    getContentPane().add(label_5); 

    JComboBox comboBox_5 = new JComboBox(b); 
    comboBox_5.setBounds(290, 475, 110, 20); 
    getContentPane().add(comboBox_5); 

    JLabel label_6 = new JLabel("Qty"); 
    label_6.setBounds(451, 475, 35, 20); 
    getContentPane().add(label_6); 

    textField_2 = new JTextField(); 
    textField_2.setBounds(485, 475, 86, 20); 
    getContentPane().add(textField_2); 
    textField_2.setColumns(10); 

    JLabel label_7 = new JLabel("comments"); 
    label_7.setBounds(139, 546, 76, 20); 
    getContentPane().add(label_7); 

    txtrCommentsForSpecial_2 = new JTextArea(); 
    txtrCommentsForSpecial_2.setForeground(new Color(220, 220, 220)); 
    txtrCommentsForSpecial_2.setText("comments for special features"); 
    txtrCommentsForSpecial_2.setBounds(210, 546, 268, 61); 
    getContentPane().add(txtrCommentsForSpecial_2); 

    JButton btnNewButton = new JButton("Ok"); 
    btnNewButton.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent e) { 
       internalFrame = new JInternalFrame("Order Details"); 
      internalFrame.setBounds(100, 80, 450, 300); 
      internalFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
      internalFrame.getContentPane().setLayout(null); 
      internalFrame.setVisible(true); 
       JTextArea textArea = new JTextArea(); 
       textArea.setBounds(67, 52, 270, 149); 
       internalFrame.getContentPane().add(textArea); 

       JButton btnOk = new JButton("Ok"); 
       btnOk.addActionListener(new ActionListener() { 
        public void actionPerformed(ActionEvent e) { 
         internalFrame.setVisible(false); 
        } 
       }); 
       btnOk.setBounds(164, 212, 89, 23); 
       internalFrame.getContentPane().add(btnOk); 

       JLabel lblOrderYouPlaced = new JLabel("Order You Placed"); 
       lblOrderYouPlaced.setBounds(67, 26, 98, 14); 
       internalFrame.getContentPane().add(lblOrderYouPlaced); 

       getContentPane().add(internalFrame); 

     } 
    }); 
    btnNewButton.setBounds(162, 616, 89, 23); 
    getContentPane().add(btnNewButton); 

    JButton btnNewButton_1 = new JButton("Reset"); 
    btnNewButton_1.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent e) { 
      textField.setText(""); 
      textField_1.setText(""); 
      textField_2.setText(""); 
      chckbxPizza.setText(""); 
       chckbxBurger.setText(""); 
       chckbxSalad.setText(""); 
       txtrCommentsForSpecial.setText(""); 
       txtrCommentsForSpecial_2.setText(""); 
       txtrCommentsForSpecial_1.setText(""); 
     } 
    }); 
    btnNewButton_1.setBounds(279, 616, 89, 23); 
    getContentPane().add(btnNewButton_1); 

    JButton btnNewButton_2 = new JButton("Cancel"); 
    btnNewButton_2.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent e) { 
      System.exit(0); 
     } 
    }); 
    btnNewButton_2.setBounds(389, 616, 89, 23); 
    getContentPane().add(btnNewButton_2); 

    } 
    public void itemStateChanged(ItemEvent e) { 
     String b[] = { "Chikken Tikka", "Fajita" }; 
     String c[] = { "Fish", "Vegetable", "Chicken"}; 
     String d[] = { "Russian Salad", "Fruit Salad", "Beans Salad"}; 
     String f[] = { "Pepsi", "Coca Cola", "Sprite","7up"}; 

     if (e.getSource() == comboBox) { 
       if (comboBox.getSelectedItem().equals("Select")) { 
         comboBox_1.setEnabled(false); 
       } else if (comboBox.getSelectedItem().equals("Pizza")) { 
        comboBox_1.setEnabled(true); 
        comboBox_1.removeAllItems(); 
         for (int i = 0; i < b.length; i++) { 
          comboBox_1.addItem(b[i]); 
         } 
       } else if (comboBox.getSelectedItem().equals("Burger")) { 
        comboBox_1.setEnabled(true); 
        comboBox_1.removeAllItems(); 
         for (int i = 0; i < c.length; i++) { 
          comboBox_1.removeItem(c[i]); 
          comboBox_1.addItem(c[i]); 
         } 
       } else if (comboBox.getSelectedItem().equals("Salad")) { 
        comboBox_1.setEnabled(true); 
        comboBox_1.removeAllItems(); 
         for (int i = 0; i < d.length; i++) { 
          comboBox_1.addItem(d[i]); 
         } 
       }else if (comboBox.getSelectedItem().equals("Soft Drink")) { 
        comboBox_1.setEnabled(true); 
        comboBox_1.removeAllItems(); 
         for (int i = 0; i < f.length; i++) { 
          comboBox_1.addItem(f[i]); 
         } 
     } 


} 

    } 
} 

Answer 1

Écrivez le ItemListener avec une lettre captial comme celui-ci

public class Myapp extends JApplet implements ItemListener{ 

et importer tous ces paquets:

import java.awt.Color; 
import java.awt.Font; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.awt.event.ItemEvent; 
import java.awt.event.ItemListener; 

import javax.swing.JApplet; 
import javax.swing.JButton; 
import javax.swing.JCheckBox; 
import javax.swing.JComboBox; 
import javax.swing.JFrame; 
import javax.swing.JInternalFrame; 
import javax.swing.JLabel; 
import javax.swing.JTextArea; 
import javax.swing.JTextField; 
import javax.swing.SwingUtilities;