Setting the look and feel

Java has the capability to emulate many Operating Systems's look and feel
This includes

Windows
X-Window/Motif
Macintosh (only available on macintosh machines)
and the default Java look and feel

The UIManager object is used to set the look and feel
This can be done at the start of the program (before initcomponents() has been run), or dynamically in reaction to a button press or menu item choce.
Code to set it at the begining of the program (within the constructor) looks like the below. Note, the call to UIManager.getSystemLookandFeelClassName will return a Windows look and feel if you are running on Windows, a Macintosh look and feel for Macs, and a Motif look and feel for Unix:

  public class LookAndFeel extends javax.swing.JFrame {

    /** Creates new form LookAndFeel */
    public LookAndFeel() {
   try{
         String laf = UIManager.getSystemLookAndFeelClassName();
         UIManager.setLookAndFeel(laf); // tell the UIManager to change the look and feel
         System.out.println("Look and feel changed to "+laf);
        }
        catch (Exception e)
        {
System.out.println("Unable to change look and feel");
        }

        initComponents();
        setTitle("Look and Feel Demo");
        setSize(600,400);
    }

To set the code dynamically, you do the same thing, except you need to tell the frame to update its components (so they have the right look and feel). The example below forces the Windows look and feel to be used, regardless of the host system.

try{
            String laf = "com.sun.java.swing.plaf.windows.WindowsLookAndFeel";
            UIManager.setLookAndFeel(laf);
            SwingUtilities.updateComponentTreeUI(this); // tells swing to update components
            System.out.println("Look and feel changed to "+laf);
        }
        catch (Exception e)
        {
         JOptionPane.showMessageDialog(this,"Unable to set look and feel","Error",JOptionPane.ERROR_MESSAGE);
        }

The following look and feel settings can be used:

To make your program look like whatever the host system is :

String laf = UIManager.getSystemLookAndFeelClassName();
UIManager.setLookAndFeel(laf); // tell the UIManager to change the look and feel

To make your program look like a Windows program (regardless of you host system)

String laf = "com.sun.java.swing.plaf.windows.WindowsLookAndFeel";
UIManager.setLookAndFeel(laf);

To make your program use the X-Windows/Motif (Unix) look and feel

String laf = "com.sun.java.swing.plaf.motif.MotifLookAndFeel";
UIManager.setLookAndFeel(laf);

To make your program use the default Java/Metal look and feel:

String laf = UIManager.getCrossPlatformLookAndFeelClassName();
UIManager.setLookAndFeel(laf);

The following application has the ability to click on the radio buttons and dynamically change the look and feel. The other controls don't do anything (except the Exit button), but are there so you can see the difference.
Click here to download

import javax.swing.*;
/*
* LookAndFeel.java
*
* Created on October 29, 2003, 10:08 AM
*/

/**
*
* @author mpenderg
*/
public class LookAndFeel extends javax.swing.JFrame {

    /** Creates new form LookAndFeel */
    public LookAndFeel() {
       try{
         String laf = UIManager.getSystemLookAndFeelClassName();
         UIManager.setLookAndFeel(laf);
         System.out.println("Look and feel changed to "+laf);
        }
        catch (Exception e)
        {
         System.out.println("Unable to change look and feel");
        }


        initComponents();
        setTitle("Look and Feel Demo");
        setSize(600,400);
    }

    /** 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.
     */
    private void initComponents() {
        lookAndFeelGroup = new javax.swing.ButtonGroup();
        centerPanel = new javax.swing.JPanel();
        jPanel1 = new javax.swing.JPanel();
        defaultRadio = new javax.swing.JRadioButton();
        xwindowsRadio = new javax.swing.JRadioButton();
        hostRadio = new javax.swing.JRadioButton();
        windowsRadio = new javax.swing.JRadioButton();
        jTextField1 = new javax.swing.JTextField();
        jLabel1 = new javax.swing.JLabel();
        jScrollPane1 = new javax.swing.JScrollPane();
        jTextArea1 = new javax.swing.JTextArea();
        jComboBox1 = new javax.swing.JComboBox();
        toolBar = new javax.swing.JToolBar();
        exitButton = new javax.swing.JButton();
        menuBar = new javax.swing.JMenuBar();
        fileMenu = new javax.swing.JMenu();
        exitItem = new javax.swing.JMenuItem();
        editMenu = new javax.swing.JMenu();

        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowClosing(java.awt.event.WindowEvent evt) {
                exitForm(evt);
            }
        });

        centerPanel.setLayout(null);

        centerPanel.setMinimumSize(new java.awt.Dimension(0, 0));
        jPanel1.setLayout(new java.awt.GridLayout(2, 2));

        jPanel1.setBorder(new javax.swing.border.TitledBorder(new javax.swing.border.EtchedBorder(), "Look and Feel"));
        jPanel1.setPreferredSize(new java.awt.Dimension(400, 400));
        defaultRadio.setText("Default (Java)");
        lookAndFeelGroup.add(defaultRadio);
        defaultRadio.addItemListener(new java.awt.event.ItemListener() {
            public void itemStateChanged(java.awt.event.ItemEvent evt) {
                defaultRadioItemStateChanged(evt);
            }
        });

        jPanel1.add(defaultRadio);

        xwindowsRadio.setText("Unix Motif");
        lookAndFeelGroup.add(xwindowsRadio);
        xwindowsRadio.addItemListener(new java.awt.event.ItemListener() {
            public void itemStateChanged(java.awt.event.ItemEvent evt) {
                xwindowsRadioItemStateChanged(evt);
            }
        });

        jPanel1.add(xwindowsRadio);

        hostRadio.setSelected(true);
        hostRadio.setText("Host System");
        lookAndFeelGroup.add(hostRadio);
        hostRadio.addItemListener(new java.awt.event.ItemListener() {
            public void itemStateChanged(java.awt.event.ItemEvent evt) {
                hostRadioItemStateChanged(evt);
            }
        });

        jPanel1.add(hostRadio);

        windowsRadio.setText("Windows");
        lookAndFeelGroup.add(windowsRadio);
        windowsRadio.addItemListener(new java.awt.event.ItemListener() {
            public void itemStateChanged(java.awt.event.ItemEvent evt) {
                windowsRadioItemStateChanged(evt);
            }
        });

        jPanel1.add(windowsRadio);

        centerPanel.add(jPanel1);
        jPanel1.setBounds(10, 20, 240, 90);

        jTextField1.setColumns(20);
        jTextField1.setToolTipText("null");
        centerPanel.add(jTextField1);
        jTextField1.setBounds(80, 120, 140, 20);

        jLabel1.setText("Name :");
        jLabel1.setToolTipText("null");
        centerPanel.add(jLabel1);
        jLabel1.setBounds(20, 120, 39, 20);

        jScrollPane1.setHorizontalScrollBarPolicy(javax.swing.JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
        jScrollPane1.setVerticalScrollBarPolicy(javax.swing.JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
        jScrollPane1.setViewportView(jTextArea1);

        centerPanel.add(jScrollPane1);
        jScrollPane1.setBounds(20, 160, 330, 80);

        jComboBox1.setMaximumRowCount(5);
        jComboBox1.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" }));
        jComboBox1.setToolTipText("null");
        centerPanel.add(jComboBox1);
        jComboBox1.setBounds(270, 30, 100, 25);

        getContentPane().add(centerPanel, java.awt.BorderLayout.CENTER);

        exitButton.setText("Exit");
        exitButton.setToolTipText("Exit Program");
        exitButton.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                exitButtonActionPerformed(evt);
            }
        });

        toolBar.add(exitButton);

        getContentPane().add(toolBar, java.awt.BorderLayout.NORTH);

        fileMenu.setMnemonic('f');
        fileMenu.setText("File");
        exitItem.setMnemonic('x');
        exitItem.setText("Exit");
        exitItem.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                exitItemActionPerformed(evt);
            }
        });

        fileMenu.add(exitItem);
        menuBar.add(fileMenu);
        editMenu.setMnemonic('e');
        editMenu.setText("Edit");
        menuBar.add(editMenu);
        setJMenuBar(menuBar);

        pack();
    }

    private void exitItemActionPerformed(java.awt.event.ActionEvent evt) {
        // Add your handling code here:
        System.exit(0);
    }

    private void exitButtonActionPerformed(java.awt.event.ActionEvent evt) {
        // Add your handling code here:
        System.exit(0);
    }

    private void xwindowsRadioItemStateChanged(java.awt.event.ItemEvent evt) {
        // Add your handling code here:

      if(!xwindowsRadio.isSelected())
           return;
      try{
            String laf = "com.sun.java.swing.plaf.motif.MotifLookAndFeel";
            UIManager.setLookAndFeel(laf);
            SwingUtilities.updateComponentTreeUI(this); // tells swing to update components
            System.out.println("Look and feel changed to "+laf);
        }
        catch (Exception e)
        {
         JOptionPane.showMessageDialog(this,"Unable to set look and feel","Error",JOptionPane.ERROR_MESSAGE);
        }
    }

    private void windowsRadioItemStateChanged(java.awt.event.ItemEvent evt) {
        // Add your handling code here:
      if(!windowsRadio.isSelected())
           return;
      try{
            String laf = "com.sun.java.swing.plaf.windows.WindowsLookAndFeel";
            UIManager.setLookAndFeel(laf);
            SwingUtilities.updateComponentTreeUI(this); // tells swing to update components
            System.out.println("Look and feel changed to "+laf);
        }
        catch (Exception e)
        {
         JOptionPane.showMessageDialog(this,"Unable to set look and feel","Error",JOptionPane.ERROR_MESSAGE);
        }

    }

    private void defaultRadioItemStateChanged(java.awt.event.ItemEvent evt) {
        // Add your handling code here:
     if(!defaultRadio.isSelected())
           return;
      try{
            String laf = UIManager.getCrossPlatformLookAndFeelClassName();
            UIManager.setLookAndFeel(laf);
            SwingUtilities.updateComponentTreeUI(this); // tells swing to update components
        System.out.println("look and feel changed to "+laf);
        }
        catch (Exception e)
        {
         JOptionPane.showMessageDialog(this,"Unable to set look and feel","Error",JOptionPane.ERROR_MESSAGE);
        }
    }

    private void hostRadioItemStateChanged(java.awt.event.ItemEvent evt) {
        // Add your handling code here:
        if(!hostRadio.isSelected())
           return;
        try{
            String laf = UIManager.getSystemLookAndFeelClassName();
            UIManager.setLookAndFeel(laf);
            SwingUtilities.updateComponentTreeUI(this); // tells swing to update components
            System.out.println("look and feel changed to "+laf);
        }
        catch (Exception e)
        {
         JOptionPane.showMessageDialog(this,"Unable to set look and feel","Error",JOptionPane.ERROR_MESSAGE);
        }
    }

    /** Exit the Application */
    private void exitForm(java.awt.event.WindowEvent evt) {
        System.exit(0);
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        new LookAndFeel().show();
    }


    // Variables declaration - do not modify
    private javax.swing.JMenu fileMenu;
    private javax.swing.JRadioButton defaultRadio;
    private javax.swing.JRadioButton windowsRadio;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JMenuBar menuBar;
    private javax.swing.JRadioButton hostRadio;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JButton exitButton;
    private javax.swing.JRadioButton xwindowsRadio;
    private javax.swing.JPanel centerPanel;
    private javax.swing.JComboBox jComboBox1;
    private javax.swing.ButtonGroup lookAndFeelGroup;
    private javax.swing.JToolBar toolBar;
    private javax.swing.JMenuItem exitItem;
    private javax.swing.JTextField jTextField1;
    private javax.swing.JTextArea jTextArea1;
    private javax.swing.JMenu editMenu;
    private javax.swing.JLabel jLabel1;
    // End of variables declaration

}