Is it a bug in 1.4.2_04

Question

public class MainFrame extends JFrame implements ActionListener
JLabel jLable = new JLabel();
static int i = 0;
public MainFrame()
jLabel.setText("sometext");
//some button defined here and added actionlistener.
public void actionPerformed(ActionEvent e)
jLabel.setText(++i);
I click on the button, the text on the jLable is 0, but at the second and also the following clicks on the button to triggle the actionPerformed method, the text on the jLabel doesn't change, still remaining 0. I'm confused, so I changed javax.swing.JLabel to java.awt.Label, everything appears just as I expected. Eaching clicking makes the number on the label increase by 1. Is it a bug of javax.swing.JLabel of 1.4.2_04?

Answer 1

Thank you very much for your advice, and below is my real codes. I'm sorry the JLabel in my real codes was added to a panel, not the JFrame. I didn't believe it was a bug until I compared it with in java.awt.Label.
* Created on 2004-6-5
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
package com.jpdragon.product;
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.FlowLayout;
//import java.awt.Label;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JLabel;
* @author elgs
* TODO To change the template for this generated type comment go to Window -
* Preferences - Java - Code Style - Code Templates
public class MainFrame extends JFrame implements ActionListener
     Connection               connection;
     PreparedStatement     pstatement;
     ResultSet               rs;
     Container               content               = getContentPane();
     JPanel                    pn                    = new JPanel();
     JPanel                    pc                    = new JPanel();
     JPanel                    ps                    = new JPanel();
     JPanel                    pt                    = new JPanel();
     (J)Label                    lr                    = new Label();
     LabelPanel               labelPanel          = new LabelPanel("No.）",
                                                            "0000000000", 7);
     JButton                    addButton          = new JButton("Add *");
     JButton                    removeButton     = new JButton("Remove *");
     Properties               p                    = new Properties();
     JTable                    t                    = new JTable();
     JScrollPane               s                    = new JScrollPane();
     String[]               names               =
                                                  {"code", "name"};
     TableModel               tableModel          = new TableModel();
     public MainFrame() throws ClassNotFoundException, FileNotFoundException,
               IOException, SQLException
          p.load(new FileInputStream("star.properties"));
          Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
          labelPanel.getTheField().selectAll();
          setTitle("2004-06-06");
          content.setLayout(new BorderLayout());
          pc.setLayout(new BorderLayout());
          ps.setLayout(new FlowLayout());
          content.add(pn, BorderLayout.NORTH);
          content.add(pc, BorderLayout.CENTER);
          content.add(ps, BorderLayout.SOUTH);
          addButton.addActionListener(this);
          removeButton.addActionListener(this);
          pn.add(labelPanel);
          ps.add(addButton);
          ps.add(removeButton);
          s.setViewportView(t);
          pt.add(s);
          lr.setText("Total: " + 0);
          pc.add(pt, BorderLayout.CENTER);
          pc.add(lr, BorderLayout.SOUTH);
          String url = p.getProperty("url");
          String username = p.getProperty("username");
          String password = p.getProperty("password");
          connection = DriverManager.getConnection(url, username, password);
          pstatement = connection
                    .prepareStatement("select max(num) from prcadj where cls='lprice'");
          ResultSet rs = pstatement.executeQuery();
          if (rs.next())
               labelPanel.setField(rs.getString(1).trim());
          pstatement.close();
          pack();
     * (non-Javadoc)
     * @see java.awt.event.ActionListener#actionPerformed(java.awt.event.ActionEvent)
     public void actionPerformed(ActionEvent e)
          addButton.setEnabled(false);
          removeButton.setEnabled(false);
          String sql_view = "";
          String sql_exe = "";
          String title = "";
          String msg_view = "";
          String msg_exe = "";
          String no = labelPanel.getText().trim();
          Component src = (Component) e.getSource();
          if (src == addButton)
               sql_view = "select g.code,g.name from prcadjdtl p,goods g "
                         + "where num = ? and cls ='lprice' "
                         + "and p.gdgid = g.gid and g.name not like '*%'";
               title = "Add *";
               msg_view = "Are you sure to add *?";
               msg_exe = "items have been added with *";
               sql_exe = "update goods set name = '*'+ name from prcadjdtl p,goods g "
                         + "where num = ? and cls ='lprice' "
                         + "and p.gdgid = g.gid "
                         + "and g.name not like '*%'";
          if (src == removeButton)
               sql_view = "select g.code,g.name from prcadjdtl p,goods g "
                         + "where num = ? and cls ='lprice' "
                         + "and p.gdgid = g.gid and g.name like '*%'";
               title = "Remove *";
               msg_view = "Are you sure to remove *?";
               msg_exe = "items have been removed *";
               sql_exe = "update goods set name = substring(name,2,len(name)-1) from prcadjdtl p,goods g "
                         + "where num = ? and cls ='lprice' "
                         + "and p.gdgid = g.gid "
                         + "and g.name like '*%'";
          try
               pstatement = connection.prepareStatement(sql_view,
                         ResultSet.TYPE_SCROLL_INSENSITIVE,
                         ResultSet.CONCUR_READ_ONLY);
               pstatement.setString(1, no);
               rs = pstatement.executeQuery();
               tableModel.set(rs);
               tableModel.setName(names);
               t.setModel(tableModel);
               s.setViewportView(t);
               pt.add(s);
               lr.setText("total: " + tableModel.getRowCount());
               pstatement.close();
               pack();
               int answer = JOptionPane.showConfirmDialog((Component) content,
                         msg_view, title, JOptionPane.YES_NO_OPTION);
               if (answer == JOptionPane.YES_OPTION)
                    pstatement = connection.prepareStatement(sql_exe);
                    pstatement.setString(1, no);
                    int rowsAffected = pstatement.executeUpdate();
                    t.setModel(new TableModel());
                    JOptionPane.showMessageDialog((Component) content, rowsAffected
                              + msg_exe, title, JOptionPane.INFORMATION_MESSAGE);
               addButton.setEnabled(true);
               removeButton.setEnabled(true);
               pack();
          catch (SQLException e1)
               System.out.println(e1);
}