Setting the JProgressBar colors

You can set the progress rectangle color and remaining area color with setForeground and setBackground.
To set the color of the string drawn inside the progress bar, you have two choices (there is no trivial API method to set these colors, look at bug http://developer.java.sun.com/developer/bugParade/bugs/4226498.html.

  • Set the UIManager property values ProgressBar.selectionForeground and ProgressBar.selectionBackground before creating the JProgressBar. Beware that all your JProgressBar components will take on this color.
  • Extend the JProgressBar UI class to provide a method setSelectionForeground and setSelectionBackground

Main.java:

import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.awt.*;
 
public class Main extends JFrame {
   public Main() {
      super("JProgressBar Color Demonstration");
 
      // sets the color of the string painted inside the progressbar
      // selectionForeground is the color of the string that appears
      //    in the rectangle that shows the progress
      // selectionBackground is the color of the string that appears
      //    in the rectangle that shows the remaining area
      UIManager.put("ProgressBar.selectionForeground", Color.red);
      UIManager.put("ProgressBar.selectionBackground", Color.green);
 
      JProgressBar pb = new JProgressBar(0, 100);
      pb.setValue(50); 
      pb.setStringPainted(true);
 
      // sets the foreground color, but only the 
      // rectangle that shows the progress, not the text  
      pb.setForeground(Color.green);
 
      // sets the background color, the rectangle that  
      // shows the remaining area
      pb.setBackground(Color.red);
 
      // add the scroll pane to this window.
      getContentPane().add(pb);
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent e) {
            System.exit(0);
         }
      });
   }
 
   public static void main(String[] args) {
      Main main = new Main();
      main.pack();
      main.setVisible(true);
   }
}

Changing the foreground and background colors of JTable cells

Override the JTable’s cell renderer and set the fore- and background color. This example makes use of such a custom cell renderer. In the example, a cell item is of type ColoredItem that encapsulates an object and a Color.
Main.java:

import javax.swing.table.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
 
public class Main extends JFrame {
   JTable table;
   MyTableModel tableModel;
 
   public Main() {
      super("Colored JTable Demonstration");
 
      tableModel = new MyTableModel(10, 5);
      table = new JTable(tableModel);
 
      DefaultTableCellRenderer colorRenderer = new DefaultTableCellRenderer() {
         public void setValue(Object value) {
            if (value instanceof ColoredItem) {
               Color fcolor = ((ColoredItem) value).getForeground();
               Color bcolor = ((ColoredItem) value).getBackground();
               this.setForeground(fcolor);
               this.setBackground(bcolor);
               setText(value.toString());
            }
         }
      };
  
      table.setDefaultRenderer(Object.class, colorRenderer);
      table.setDefaultEditor(Object.class, new DefaultCellEditor(new JTextField()));
 
      JScrollPane scrollPane = new JScrollPane(table);

      getContentPane().add(scrollPane, BorderLayout.CENTER);

      JPanel radioPanel = new JPanel(new GridLayout(1, 5));
      JRadioButton redRadio = new JRadioButton("Red");
      JRadioButton greenRadio = new JRadioButton("Green");
      JRadioButton blueRadio = new JRadioButton("Blue");
      JRadioButton yellowRadio = new JRadioButton("Yellow");
      JRadioButton blackRadio = new JRadioButton("Black");

      // Group the radio buttons.
      ButtonGroup group = new ButtonGroup();
      group.add(redRadio);
      group.add(greenRadio);
      group.add(blueRadio);
      group.add(yellowRadio);
      group.add(blackRadio);

      radioPanel.add(redRadio);
      radioPanel.add(greenRadio);
      radioPanel.add(blueRadio);
      radioPanel.add(yellowRadio);
      radioPanel.add(blackRadio);
 
      RadioListener radioListener = new RadioListener();
      redRadio.addActionListener(radioListener);
      greenRadio.addActionListener(radioListener);
      blueRadio.addActionListener(radioListener);
      yellowRadio.addActionListener(radioListener);
      blackRadio.addActionListener(radioListener);
 
      // add radiopanel to container
      JPanel panel = new JPanel(new GridLayout(2, 1));
      panel.add(new JLabel("Select color for selected cell:"));
      panel.add(radioPanel);     
      getContentPane().add(BorderLayout.SOUTH, panel);
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent e) {
            System.exit(0);
         }
      });
   }
 
   class RadioListener implements ActionListener {
      public void actionPerformed(ActionEvent ae) {
         int row = table.getSelectedRow();
         int column = table.getSelectedColumn();
         ColoredItem ci = (ColoredItem) tableModel.getValueAt(row, column);
 
         if (ae.getActionCommand().equals("Red"))
            ci.setForeground(Color.red);
         else if (ae.getActionCommand().equals("Green"))
            ci.setForeground(Color.green);
         else if (ae.getActionCommand().equals("Blue"))
            ci.setForeground(Color.blue);
         else if (ae.getActionCommand().equals("Yellow"))
            ci.setForeground(Color.yellow);
         else if (ae.getActionCommand().equals("Black"))
            ci.setForeground(Color.black);
 
         // necessary to cause a fireTableCellUpdated event
         tableModel.setValueAt(ci, row, column);
      }
   }
 
   private class ColoredItem {
      private Object object;
      private Color foreground;
      private Color background;
 
      public ColoredItem(Object object, Color foreground, Color background) {
         this.object = object;
         this.foreground = foreground;
         this.background = background;
      }
  
      public void setObject(Object object) {
         this.object = object;
      }
  
      public void setForeground(Color foreground) {
         this.foreground = foreground;
      }
 
      public void setBackground(Color background) {
         this.background = background;
      }
 
      public Object getObject() {
         return object;
      }
 
      public Color getForeground() {
         return foreground;
      }
 
      public Color getBackground() {
         return background;
      }
 
      public String toString() {
         return object.toString(); 
      }
   }
 
   class MyTableModel extends AbstractTableModel {
      String [] columnNames;
      Object [][] data;
 
      MyTableModel(int rows, int columns) {
         columnNames = createColumnElements(columns);
         data = createTableElements(rows, columns);         
      }
 
      public int getColumnCount() {
         return columnNames.length;
      }
        
      public int getRowCount() {
         return data.length;
      }
 
      public String getColumnName(int col) {
         return columnNames[col];
      }
 
      public Object getValueAt(int row, int col) {
         return data[row][col];
      }
 
      public Class getColumnClass(int c) {
         return getValueAt(0, c).getClass();
      }
 
      public void setValueAt(Object value, int row, int col) {
         data[row][col] = value;
         fireTableCellUpdated(row, col);
      }
 
      private String[] createColumnElements(int columns) {
         String[] data;
 
         data = new String[columns];
         for (int i=0; i<columns; i++) {
            data[i] = new String("Column " + i);
         }
 
         return data;
      }
 
      private Object[][] createTableElements(int rows, int columns) {
         ColoredItem [][]data;
         data = new ColoredItem[rows][];
         for (int i=0; i<rows; i++) {
            data[i] = new ColoredItem[columns];
            for (int j=0; j<columns; j++) {
               data[i][j] = new ColoredItem("(" + i + " , " + j + ")", Color.green, Color.white);
            }
         }
 
         return data;
      } 
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.pack();
      main.setVisible(true);
   }
}

Making the cells of a JTable transparent so that background image shows through

Author: Zafir Anjum

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
 
public class Table
{
   public static void main(String[] args) {
      JFrame frame = new JFrame("Table");
      frame.addWindowListener( new WindowAdapter() {
         public void windowClosing(WindowEvent e) {
            Window win = e.getWindow();
            win.setVisible(false);
            win.dispose();
            System.exit(0);
         }
      } );	
 
      // Create your own sub-class of JTable rather than using anonymous class
      JTable table = new JTable( 15, 3 ) {
         public Component prepareRenderer(TableCellRenderer renderer, int row, int column) {
            Component c = super.prepareRenderer( renderer, row, column);
            // We want renderer component to be transparent
            // so background image is visible
            if( c instanceof JComponent )
               ((JComponent)c).setOpaque(false);
               return c;
            }

            // Hard coded value. In your sub-class add a function for this.
            ImageIcon image = new ImageIcon( "codeguruwm.gif" );

            public void paint( Graphics g ) {
               // First draw the background image - tiled 
               Dimension d = getSize();
               for( int x = 0; x < d.width; x += image.getIconWidth() )
                  for( int y = 0; y < d.height; y += image.getIconHeight() ) 
                     g.drawImage( image.getImage(), x, y, null, null );
               // Now let the regular paint code do it's work
               super.paint(g);
           }
      };
 
      // Set the table transparent
      table.setOpaque(false);
		
      JScrollPane sp = new JScrollPane( table );
      frame.getContentPane().add( sp );	

      frame.pack();
      frame.show();
   }
}

Changing the color of entire rows of a JTable

Write your own cell renderer. This example colors all rows green where the price of
the wine is < 55, red otherwise.

Main.java:

import javax.swing.table.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.awt.*;
 
public class Main extends JFrame {
   public Main() {
      super("TableModel Demonstration");
  
      // create our own custom TableModel
      WineTableModel wineModel = new WineTableModel();
      JTable table = new JTable(wineModel);
 
      // since we’re using values of floats and boolean here, we need
      // to set the cell renderer for every column. 
      for (int i =0; i<wineModel.getColumnCount();i++) {
         table.setDefaultRenderer(table.getColumnClass(i), new WineCellRenderer());
      }
       
      // add rows to our TableModel, each row is represented as a Wine object
      wineModel.addWine(new Wine("Chateau Meyney, St. Estephe", "1994", 18.75f, true));
      wineModel.addWine(new Wine("Chateau Montrose, St. Estephe", "1975", 54.25f, true));
      wineModel.addWine(new Wine("Chateau Gloria, St. Julien", "1993", 22.99f, false));
      wineModel.addWine(new Wine("Chateau Beychevelle, St. Julien", "1970", 61.63f, false));
      wineModel.addWine(new Wine("Chateau La Tour de Mons, Margeaux", "1975", 57.03f, true));
      wineModel.addWine(new Wine("Chateau Brane-Cantenac, Margeaux", "1978", 49.92f, false));
 
      // create the scroll pane and add the table to it. 
      JScrollPane scrollPane = new JScrollPane(table);
 
      // add the scroll pane to this window.
      getContentPane().add(scrollPane, BorderLayout.CENTER);
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent e) {
            System.exit(0);
         }
      });
   }
 
   public static void main(String[] args) {
      Main main = new Main();
      main.pack();
      main.setVisible(true);
   }
}
 
// a simple object that holds data about a particular wine
class Wine {
   private String  name;
   private String  vintage;
   private float   price;
   private boolean inStock;
 
   public Wine(String name, String vintage, float price, boolean inStock) {
      this.name = name;
      this.vintage = vintage;
      this.price = price;
      this.inStock = inStock;
   }
 
   public String getName()     { return name; }
   public String getVintage()  { return vintage; }
   public float  getPrice()    { return price; } 
   public boolean getInStock() { return inStock; }
 
   public String toString() { 
      return "[" + name + ", " + vintage + ", " + price + ", " + inStock + "]"; }
}
 
class WineTableModel extends AbstractTableModel {
   // holds the strings to be displayed in the column headers of our table
   final String[] columnNames = {"Name", "Vintage", "Price", "In stock?"};
 
   // holds the data types for all our columns
   final Class[] columnClasses = {String.class, String.class, Float.class, Boolean.class};
 
   // holds our data
   final Vector data = new Vector();
  
   // adds a row
   public void addWine(Wine w) {
      data.addElement(w);
      fireTableRowsInserted(data.size()-1, data.size()-1);
   }
 
   public int getColumnCount() {
      return columnNames.length;
   }
         
   public int getRowCount() {
      return data.size();
   }
 
   public String getColumnName(int col) {
      return columnNames[col];
   }
 
   public Class getColumnClass(int c) {
      return columnClasses1;
   }
 
   public Object getValueAt(int row, int col) {
      Wine wine = (Wine) data.elementAt(row);
      if (col == 0)      return wine.getName();
      else if (col == 1) return wine.getVintage();
      else if (col == 2) return new Float(wine.getPrice());
      else if (col == 3) return new Boolean(wine.getInStock());
      else return null;
   }
 
   public Object getValueAtRow(int row) {
      Wine wine = (Wine) data.elementAt(row);
      return wine;
   }
 
   public boolean isCellEditable(int row, int col) {
      return false;
   }
}
 
class WineCellRenderer extends DefaultTableCellRenderer {
   public Component getTableCellRendererComponent(
            JTable table, Object value, boolean isSelected,
            boolean hasFocus, int row, int column)
   {
      WineTableModel wtm = (WineTableModel) table.getModel();
      Wine wine = (Wine) wtm.getValueAtRow(row);
 
      if (wine.getPrice() < 55) {
         setBackground(Color.green);
      }
      else {
         setBackground(Color.red);
      }
 
      return super.getTableCellRendererComponent(table, value, isSelected, 
                                                 hasFocus, row, column);
   }
}

Adding a background image to a JTree that does not scroll

(1.3+)

Main.java:

import javax.swing.*;
import javax.swing.tree.*;
import javax.swing.event.*;
import java.awt.*;
import java.net.*;
import java.awt.event.*;
 
public class Main extends JFrame
{
   public Main() {
      DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");
      for (int i=0; i<100; i++) {
         DefaultMutableTreeNode child = new DefaultMutableTreeNode("Child " + (i+1));
         root.add(child);
      }
      JTree tree = new JTree(root);
 
      tree.setOpaque( false );
  
 
      DefaultTreeCellRenderer cr = new DefaultTreeCellRenderer();
      cr.setOpaque(false);
      cr.setBackground(new Color(0, 0, 0, 0));  
      cr.setBackgroundNonSelectionColor(null);
      tree.setCellRenderer(cr);
 
      ImageJScrollPane scrollpane = new ImageJScrollPane(tree);
      scrollpane.setBackgroundImage(new ImageIcon("mong.jpg"));
 
      getContentPane().add(scrollpane);
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.setSize(400, 400);
      main.setVisible(true);
   }
}
 
class ImageJScrollPane extends JScrollPane
{
   private ImageIcon image = null;
 
   public ImageJScrollPane() {
      this(null, VERTICAL_SCROLLBAR_AS_NEEDED, HORIZONTAL_SCROLLBAR_AS_NEEDED);
   }
 
   public ImageJScrollPane(Component view) {
      this(view, VERTICAL_SCROLLBAR_AS_NEEDED, HORIZONTAL_SCROLLBAR_AS_NEEDED);
   }
 
   public ImageJScrollPane(Component view, int vsbPolicy, int hsbPolicy) {
      super(view, vsbPolicy, hsbPolicy);
      if (view instanceof JComponent) {
         ((JComponent) view).setOpaque(false);
      }
      setOpaque(false);
      getViewport().setOpaque(false);
      getViewport().setScrollMode(JViewport.BLIT_SCROLL_MODE);
   }
 
   public ImageJScrollPane(int vsbPolicy, int hsbPolicy) {
      this(null, vsbPolicy, hsbPolicy);
   }
 
   public void setBackgroundImage(ImageIcon image) {
      this.image = image;
   }
 
   public void paint(Graphics g) {
      if (image != null) {
         Rectangle rect = getViewport().getViewRect();
         for (int x=0; x<rect.width; x+=image.getIconWidth()) {
            for (int y=0; y<rect.height; y+=image.getIconHeight()) {
               g.drawImage(image.getImage(), x, y, null, null);
            }
         }
         super.paint(g);
      }
 
   }
}

Image used:

Right-aligning a JTable column

Main.java:

import javax.swing.table.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
 
public class Main extends JFrame 
{
   public Main() {
      super("Table example, Wines from Bordeaux");
 
      Object[][] tabledata = {
            { "Chateau Meyney, St. Estephe", 	   new Integer(1994), "$18.75"},
            { "Chateau Montrose, St. Estephe", 	   new Integer(1975), "$54.25" },
            { "Chateau Gloria, St. Julien", 	   new Integer(1993), "$22.99" },
            { "Chateau Beychevelle, St. Julien",   new Integer(1970), "$61.63" },
            { "Chateau La Tour de Mons, Margeaux", new Integer(1975), "$57.03" },
            { "Chateau Brane-Cantenac, Margeaux",  new Integer(1978), "$49.92" },
      };
 
      String columnheaders[] = { "Wine", "Vintage", "Price" };
 
      JTable table = new JTable(tabledata, columnheaders);
      table.setPreferredScrollableViewportSize(new Dimension(500, 70));
 
      // right align 2nd column
      TableColumnModel columnModel = table.getColumnModel();
      TableColumn column = columnModel.getColumn(1);  
      DefaultTableCellRenderer renderer = new DefaultTableCellRenderer();
      renderer.setHorizontalAlignment(JLabel.RIGHT);
      column.setCellRenderer(renderer);
 
      // right align 2nd column when editing
      JTextField tf = new JTextField();
      tf.setHorizontalAlignment(JTextField.RIGHT);
      column.setCellEditor(new DefaultCellEditor(tf));
 
      JScrollPane scrollPane = new JScrollPane(table);
      getContentPane().add(scrollPane);
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
 
      pack();
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.show();
   }
}

Creating a JList with icons and text

Main.java:

import java.awt.image.*;
import javax.swing.*;
import java.util.*;
import java.awt.*;
  
public class Main 
{
   public static void main(String args[]) {
      JFrame frame = new JFrame("JList ImageIcon Demonstration");
 
      DefaultListModel dlm = new DefaultListModel();
      dlm.addElement(new ListEntry("Audio", new ImageIcon("audio.gif")));
      dlm.addElement(new ListEntry("Control Panel", new ImageIcon("controlpanel.gif")));
      dlm.addElement(new ListEntry("Folder", new ImageIcon("folder.gif")));
      dlm.addElement(new ListEntry("Local Disk (C:)", new ImageIcon("mycomp.gif")));
      dlm.addElement(new ListEntry("doc on '192.168.0.1' (Z:)", new ImageIcon("network.gif")));
 
      JList list = new JList(dlm);
      list.setCellRenderer(new ListEntryCellRenderer());
         
      frame.getContentPane().add(BorderLayout.CENTER, new JScrollPane(list)); 
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.pack();
      frame.setVisible(true);
   }
}
 
class ListEntry 
{
   private String value;
   private ImageIcon icon;
 
   public ListEntry(String value, ImageIcon icon) {
      this.value = value;
      this.icon = icon;
   }
 
   public String getValue() {
      return value;
   }
 
   public ImageIcon getIcon() {
      return icon;
   }
 
   public String toString() {
      return value;
   }
}
 
class ListEntryCellRenderer
 extends JLabel implements ListCellRenderer
{
   private JLabel label;
 
   public Component getListCellRendererComponent(JList list, Object value,
                                                 int index, boolean isSelected,
                                                 boolean cellHasFocus) {
      ListEntry entry = (ListEntry) value;
 
      setText(value.toString());
      setIcon(entry.getIcon());
  
      if (isSelected) {
         setBackground(list.getSelectionBackground());
         setForeground(list.getSelectionForeground());
      }
      else {
         setBackground(list.getBackground());
         setForeground(list.getForeground());
      } 
 
      setEnabled(list.isEnabled());
      setFont(list.getFont());
      setOpaque(true);
 
      return this;
   }
}

Adding a JPanel with a null layout to a JScrollPane

Make sure you set the preferredSize of the JPanel. Invoke the method setViewportView on JScrollPane.

Main.java:

import java.awt.event.*;
import javax.swing.border.*;
import javax.swing.*;
import java.awt.*;
 
public class Main extends JFrame 
{
   public Main() {
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
 
      JPanel panel = createContactPanel();
 
      JScrollPane sp = new JScrollPane();
      sp.setViewportView(panel);
 
      getContentPane().setLayout(new BorderLayout());
      getContentPane().add(sp, BorderLayout.CENTER); 
   }
 
   public JPanel createContactPanel() {
      JLabel titleLbl      = new JLabel("Title");
      JLabel firstNameLbl  = new JLabel("First name");
      JLabel lastNameLbl   = new JLabel("Last name");
      JLabel addressLbl    = new JLabel("Address");
      JLabel cityLbl       = new JLabel("City");
      JLabel zipLbl        = new JLabel("Postal code");
      JLabel countryLbl    = new JLabel("Country");
      JLabel phoneLbl      = new JLabel("Phone number");
      JLabel faxLbl        = new JLabel("Fax number");
      JLabel emailLbl      = new JLabel("E-mail");
      JLabel birthdayLbl   = new JLabel("Birthdate");
      JLabel pickchoiceLbl = new JLabel("Pick a choice");
      JLabel creditCardTypeLbl     = new JLabel("Credit card type");
      JLabel creditCardNumberLbl   = new JLabel("Credit card number");
      JLabel expirationLbl         = new JLabel("Expiration date");
 
      JComboBox titleCombo = new JComboBox(
             new String[] { "-", "Mr", "Mrs", "Miss" });
      JTextField firstNameTf    = new JTextField();
      JTextField lastNameTf     = new JTextField();
      JTextField address1Tf     = new JTextField();
      JTextField address2Tf     = new JTextField();
      JTextField cityTf         = new JTextField();
      JTextField zipTf          = new JTextField();
      JTextField countryTf      = new JTextField();
      JTextField phoneTf        = new JTextField();
      JTextField faxTf          = new JTextField();
      JTextField emailTf        = new JTextField();
      JComboBox bd1Combo = new JComboBox();
      for (int i=1; i<=12; i++) bd1Combo.addItem(""+i);
      JComboBox bd2Combo = new JComboBox();
      for (int i=1; i<=31; i++) bd2Combo.addItem(""+i);
      JComboBox bd3Combo = new JComboBox();
      for (int i=1900; i<2000; i++) bd3Combo.addItem(""+i);
      JComboBox referCombo = new JComboBox();
      referCombo.addItem("Friend");
      referCombo.addItem("Search engine");
      referCombo.addItem("Print Media");
      referCombo.addItem("Banner Add");
      referCombo.addItem("Other");
      JComboBox creditCardTypeCombo = new JComboBox();
      creditCardTypeCombo.addItem("VISA");
      creditCardTypeCombo.addItem("MasterCard");
      creditCardTypeCombo.addItem("American Express");
      JTextField creditCardNumberTf = new JTextField();
      JComboBox expiration1Combo = new JComboBox();
      for (int i=1; i<=12; i++) expiration1Combo.addItem(""+i);
      JComboBox expiration2Combo = new JComboBox();
      for (int i=1; i<=31; i++) expiration2Combo.addItem(""+i);
      JComboBox expiration3Combo = new JComboBox();
      for (int i=1900; i<=2000; i++) expiration3Combo.addItem(""+i);
 
      JPanel panelGeneral = new JPanel();
      panelGeneral.setLayout(null);
      panelGeneral.add(titleLbl);
      panelGeneral.setBorder(new TitledBorder("General Information"));
      titleLbl.setBounds(20, 20, 150, 20);
      panelGeneral.add(firstNameLbl);
      firstNameLbl.setBounds(20, 50, 150, 20);
      panelGeneral.add(lastNameLbl);
      lastNameLbl.setBounds(20, 80, 150, 20);
      panelGeneral.add(addressLbl);
      addressLbl.setBounds(20, 110, 150, 20);
      panelGeneral.add(cityLbl);
      cityLbl.setBounds(20, 170, 150, 20);
      panelGeneral.add(zipLbl);
      zipLbl.setBounds(20, 200, 150, 20);
      panelGeneral.add(countryLbl);
      countryLbl.setBounds(20, 230, 150, 20);
      panelGeneral.add(phoneLbl);
      phoneLbl.setBounds(20, 260, 150, 20);
      panelGeneral.add(faxLbl);
      faxLbl.setBounds(20, 290, 150, 20);
      panelGeneral.add(emailLbl);
      emailLbl.setBounds(20, 320, 150, 20);
      panelGeneral.add(birthdayLbl);
      birthdayLbl.setBounds(20, 350, 150, 20); 
      panelGeneral.add(titleCombo);
      titleCombo.setBounds(150, 20, 60, 20);
      panelGeneral.add(firstNameTf);
      firstNameTf.setBounds(150, 50, 200, 20);
      panelGeneral.add(lastNameTf);
      lastNameTf.setBounds(150, 80, 200, 20);
      panelGeneral.add(address1Tf);
      address1Tf.setBounds(150, 110, 200, 20);  
      panelGeneral.add(address2Tf);
      address2Tf.setBounds(150, 140, 200, 20);  
      panelGeneral.add(cityTf);
      cityTf.setBounds(150, 170, 200, 20);
      panelGeneral.add(zipTf);
      zipTf.setBounds(150, 200, 200, 20);
      panelGeneral.add(countryTf);
      countryTf.setBounds(150, 230, 200, 20);
      panelGeneral.add(phoneTf);
      phoneTf.setBounds(150, 260, 200, 20);
      panelGeneral.add(faxTf);
      faxTf.setBounds(150, 290, 200, 20);
      panelGeneral.add(emailTf);
      emailTf.setBounds(150, 320, 200, 20);
      panelGeneral.add(bd1Combo);
      bd1Combo.setBounds(150, 350, 60, 20);
      panelGeneral.add(bd2Combo);
      bd2Combo.setBounds(220, 350, 60, 20);
      panelGeneral.add(bd3Combo);
      bd3Combo.setBounds(290, 350, 60, 20);
 
      JPanel panelReferral = new JPanel();
      panelReferral.setLayout(null);
      panelReferral.setBorder(new TitledBorder("Where did you hear about us?"));
      panelReferral.add(pickchoiceLbl);
      pickchoiceLbl.setBounds(20, 20, 150, 20);
      panelReferral.add(referCombo);
      referCombo.setBounds(150, 20, 100, 20);
 
      JPanel panelCreditCard = new JPanel();
      panelCreditCard.setLayout(null);
      panelCreditCard.setBorder(new TitledBorder("Payment method"));
      panelCreditCard.add(creditCardTypeLbl);
      creditCardTypeLbl.setBounds(20, 20, 150, 20);
      panelCreditCard.add(creditCardNumberLbl);
      creditCardNumberLbl.setBounds(20, 50, 150, 20);
      panelCreditCard.add(expirationLbl);
      expirationLbl.setBounds(20, 80, 150, 20);
 
      panelCreditCard.add(creditCardTypeCombo);
      creditCardTypeCombo.setBounds(150, 20, 100, 20);
      panelCreditCard.add(creditCardNumberTf);
      creditCardNumberTf.setBounds(150, 50, 150, 20);
      panelCreditCard.add(expiration2Combo);
      expiration2Combo.setBounds(220, 80, 60, 20);
      panelCreditCard.add(expiration3Combo);
      expiration3Combo.setBounds(290, 80, 60, 20);
 
      JPanel panel = new JPanel();
      panel.setLayout(null);
      panel.add(panelGeneral);
      panelGeneral.setBounds(10, 20, 370, 400);
      panel.add(panelReferral);
      panelReferral.setBounds(10, 430, 370, 50);
      panel.add(panelCreditCard);
      panelCreditCard.setBounds(10, 490, 370, 120);
      
      panel.setPreferredSize(new Dimension(380, 620)); 
 
      return panel;
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.setSize(400, 400);
      main.setVisible(true);
   }
}

Setting the top-left icon of a JInternalFrame

Use setFrameIcon():

JInternalFrame frame = new JInternalFrame("Test",false,false,false,false);

try {
  URL url = new URL("http://localhost/images/icon.gif");
  ImageIcon icon = new ImageIcon(url);
  frame.setFrameIcon(icon);
} catch (MalformedURLException me) {}

...

Detecting a selection change on a JComboBox

Use an ActionListener.

Main.java:

import java.awt.image.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.awt.*;
 
public class Main extends JFrame { 
   public Main() {
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(1);
         }
      }); 
 
      Vector v = new Vector();
      v.add(&quot;first element&quot;);
      v.add(&quot;second element&quot;);
      v.add(&quot;third element&quot;);
      v.add(&quot;fourth element&quot;);
      v.add(&quot;fifth element&quot;);
 
      final JComboBox cb = new JComboBox(v);
      cb.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            System.out.println(cb.getSelectedItem());
         }
      });
      getContentPane().setLayout(new FlowLayout(FlowLayout.LEFT, 10, 10));
      getContentPane().add(new JLabel(&quot;Select element:&quot;));
      getContentPane().add(cb);
   } 
 
   public static void main(String []args) {
      Main main = new Main();
      main.setVisible(true);
      main.setSize(300, 150);
   }
}