Creating a JTable with fixed columns

You can call the following method:

   table.getTableHeader().setResizingAllowed(false);

However, be aware that this will disable resizing for all columns, and will still resize the columns proportionally when resizing the container in which the JTable is hosted. To fix the size of one column, you have to think about what behavior you want and override the method sizeColumnsToFit().

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);
 
      // 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));
 
 
      // don't allow resizing columns
      table.getTableHeader().setResizingAllowed(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 boolean isCellEditable(int row, int col) {
      return false;
   }
}

Creating a JTable with a multi-line header

Courtesy of Nobuo Tamemasa (http://www2.gol.com/users/tame/swing/examples/JTableExamples1.html)



MultiLineHeaderExample.java:

import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
  
/**
 * @version 1.0 11/09/98
 */
public class MultiLineHeaderExample extends JFrame {
  MultiLineHeaderExample() {
    super( "Multi-Line Header Example" );
 
    DefaultTableModel dm = new DefaultTableModel();
    dm.setDataVector(new Object[][]{{"a","b","c"},
                                    {"A","B","C"}},
                     new Object[]{"1stnalpha","2ndnbeta","3rdngamma"});
 
    JTable table = new JTable( dm );
    MultiLineHeaderRenderer renderer = new MultiLineHeaderRenderer();
    Enumeration enum = table.getColumnModel().getColumns();
    while (enum.hasMoreElements()) {
      ((TableColumn)enum.nextElement()).setHeaderRenderer(renderer);
    }   
    JScrollPane scroll = new JScrollPane( table );
    getContentPane().add( scroll );
    setSize( 400, 110 );
    setVisible(true);
  }
 
  public static void main(String[] args) {
    MultiLineHeaderExample frame = new MultiLineHeaderExample();
    frame.addWindowListener( new WindowAdapter() {
      public void windowClosing( WindowEvent e ) {
        System.exit(0);
      }
    });
  }
}

MultiLineHeaderRenderer.java:

import java.io.*;
import java.util.*;
import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;


/**
 * @version 1.0 11/09/98
 */
public class MultiLineHeaderRenderer extends JList implements TableCellRenderer {
  public MultiLineHeaderRenderer() {
    setOpaque(true);
    setForeground(UIManager.getColor("TableHeader.foreground"));
    setBackground(UIManager.getColor("TableHeader.background"));
    setBorder(UIManager.getBorder("TableHeader.cellBorder"));
    ListCellRenderer renderer = getCellRenderer();
    ((JLabel)renderer).setHorizontalAlignment(JLabel.CENTER);
    setCellRenderer(renderer);
  }
 
  public Component getTableCellRendererComponent(JTable table, Object value,
                   boolean isSelected, boolean hasFocus, int row, int column) {
    setFont(table.getFont());
    String str = (value == null) ? "" : value.toString();
    BufferedReader br = new BufferedReader(new StringReader(str));
    String line;
    Vector v = new Vector();
    try {
      while ((line = br.readLine()) != null) {
        v.addElement(line);
      }
    } catch (IOException ex) {
      ex.printStackTrace();
    }
    setListData(v);
    return this;
  }
}

Preventing a particular JTable column from being edited

Decide what column should not be editable using the method isCellEditable.
This example allows you to modify any of the cells except the column Vintage.

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("Color Row Demonstration");
  
      // create our own custom TableModel
      WineTableModel wineModel = new WineTableModel();
      JTable table = new JTable(wineModel);
  
      // 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 void setName(String name)        { this.name = name; }
   public void setVintage(String vintage)  { this.vintage = vintage; }
   public void setPrice(float price)       { this.price = price; }
   public void setInStock(boolean inStock) { this.inStock = 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 void setValueAt(Object value, int row, int col) {
      Wine wine = (Wine) data.elementAt(row);
      if (col ==0)       wine.setName(""+value);
      else if (col == 1) wine.setVintage(""+value);
      else if (col == 2) wine.setPrice(new Float(""+value).floatValue());
      else if (col == 3) wine.setInStock(((Boolean) value).booleanValue());
   }
 
   public boolean isCellEditable(int row, int col) {
      if (col == 1) return false;
 
      return true;
   }
}

Creating a JTree without node icons

Set the OpenIcon, ClosedIcon and LeafIcon to null in a DefaultTreeCellRenderer.

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 = createNodes();
      JTree tree = new JTree(root);
 
      DefaultTreeCellRenderer cr = new DefaultTreeCellRenderer();
      cr.setOpenIcon(null);
      cr.setClosedIcon(null);
      cr.setLeafIcon(null);
  
      tree.setCellRenderer(cr);
 
      getContentPane().add(new JScrollPane(tree));
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
   }
 
   public static DefaultMutableTreeNode createNodes() {
      DefaultMutableTreeNode root = new DefaultMutableTreeNode("Java");
      
      DefaultMutableTreeNode j2se = new DefaultMutableTreeNode("J2SE");
      DefaultMutableTreeNode j2ee = new DefaultMutableTreeNode("J2EE");
      DefaultMutableTreeNode j2me = new DefaultMutableTreeNode("J2ME");
 
      j2se.add(new DefaultMutableTreeNode("http://java.sun.com/j2se/"));
      j2ee.add(new DefaultMutableTreeNode("http://java.sun.com/j2ee/"));
      j2me.add(new DefaultMutableTreeNode("http://java.sun.com/j2me/"));
 
      root.add(j2se);
      root.add(j2ee);
      root.add(j2me);
 
      return root;
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.setSize(400, 400);
      main.setVisible(true);
   }
}

Creating an underlined JLabel without using HTML

Main.java:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
 
public class Main extends JFrame
{
   public Main() {
      getContentPane().setLayout(new GridLayout(1, 2));
      JPanel panel1 = new JPanel();
      panel1.setLayout(new GridLayout(5, 1));
      panel1.add(new JLabel("JLabel/icon/LEFT", 
                           new ImageIcon("tiffIcon.gif"), SwingConstants.LEFT));
      panel1.add(new JLabel("JLabel/icon/CENTER", 
                           new ImageIcon("tiffIcon.gif"), SwingConstants.CENTER));
      panel1.add(new JLabel("JLabel/icon/RIGHT", 
                           new ImageIcon("tiffIcon.gif"), SwingConstants.RIGHT));
      panel1.add(new JLabel("JLabel/icon/LEADING", 
                           new ImageIcon("tiffIcon.gif"), SwingConstants.LEADING));
      panel1.add(new JLabel("JLabel/icon/TRAILING", 
                           new ImageIcon("tiffIcon.gif"), SwingConstants.TRAILING));
 
      getContentPane().add(new JScrollPane(panel1));
 
      JPanel panel2 = new JPanel();
      panel2.setLayout(new GridLayout(5, 1));
      panel2.add(new UnderlinedJLabel("JLabel/icon/LEFT", 
                                      new ImageIcon("tiffIcon.gif"), SwingConstants.LEFT));
      panel2.add(new UnderlinedJLabel("JLabel/icon/CENTER", 
                                      new ImageIcon("tiffIcon.gif"), SwingConstants.CENTER));
      panel2.add(new UnderlinedJLabel("JLabel/icon/RIGHT", 
                                      new ImageIcon("tiffIcon.gif"), SwingConstants.RIGHT));
      panel2.add(new UnderlinedJLabel("JLabel/icon/LEADING", 
                                      new ImageIcon("tiffIcon.gif"), SwingConstants.LEADING));
      panel2.add(new UnderlinedJLabel("JLabel/icon/TRAILING", 
                                      new ImageIcon("tiffIcon.gif"), SwingConstants.TRAILING));
 
      getContentPane().add(new JScrollPane(panel2));
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(1);
         }
      });
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.setSize(300, 150);
      main.setVisible(true);   
   }
}
 
class UnderlinedJLabel extends JLabel
{
   public UnderlinedJLabel() {
   }
 
   public UnderlinedJLabel(Icon image) {
      super(image);
   }
 
   public UnderlinedJLabel(Icon image, int horizontalAlignment) {
      super(image, horizontalAlignment);
   }
 
   public UnderlinedJLabel(String text) {
      super(text);
   }

   public UnderlinedJLabel(String text, Icon icon, int horizontalAlignment) {
      super(text, icon, horizontalAlignment);
   }
 
   public UnderlinedJLabel(String text, int horizontalAlignment) {
      super(text, horizontalAlignment);
   }
 
   public void paint(Graphics g) {
      super.paint(g);
      underline(g);
   }
 
   protected void underline(Graphics g) {
      Insets insets = getInsets();
      FontMetrics fm = g.getFontMetrics();
      Rectangle textR = new Rectangle();
      Rectangle viewR = new Rectangle(
                                  insets.left, 
                                  insets.top, 
                                  getWidth() - (insets.right + insets.left), 
                                  getHeight() - (insets.bottom + insets.top));
  
      // compute and return location of the icons origin,
      // the location of the text baseline, and a possibly clipped
      // version of the compound label string.  Locations are computed 
      // relative to the viewR rectangle.
      String text = SwingUtilities.layoutCompoundLabel(
                         this,                        // this JLabel
                         fm,                          // current FontMetrics
                         getText(),                   // text
                         getIcon(),                   // icon
                         getVerticalAlignment(),      
                         getHorizontalAlignment(),
                         getVerticalTextPosition(),
                         getHorizontalTextPosition(), 
                         viewR,                       
                         new Rectangle(),             // don't care about icon rectangle
                         textR,                       // resulting text locations
                         getText() == null ? 0 : 
                            ((Integer)UIManager.get("Button.textIconGap")).intValue());
 
      // draw line
      int textShiftOffset = ((Integer) UIManager.get("Button.textShiftOffset")).intValue();
      g.fillRect(textR.x +
                 textShiftOffset - 4,
                 textR.y + fm.getAscent() + textShiftOffset + 2,
                 textR.width, 
                 1);
   }
}

Creating a JFormattedTextField that only accepts dates

Main.java and JFormattedDateTextField:

import javax.swing.text.*;
import java.awt.event.*;
import javax.swing.*;
import java.text.*;
import java.awt.*;
import java.util.*;
 
public class Main extends JFrame 
{
   public Main() throws Exception
   {
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(1);
         }
      });
  
 
      final JFormattedDateTextField formattedTf =
                   new JFormattedDateTextField();
      formattedTf.setValue(new Date()); 
 
      final JTextField normalTf = new JTextField(25);
      JButton button = new JButton("Get value");
      button.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) { 
            normalTf.setText(""+formattedTf.getValue());
         }
      });
 
      getContentPane().setLayout(new FlowLayout(FlowLayout.LEFT));
      getContentPane().add(formattedTf);
      getContentPane().add(button);
      getContentPane().add(normalTf);
 
      formattedTf.setPreferredSize(normalTf.getPreferredSize());
   }
  
   public static void main(String args[]) throws Exception 
   {
      Main main = new Main();
      main.setSize(300, 150);
      main.setVisible(true);
   }
}
 
class JFormattedDateTextField extends JFormattedTextField {
   Format format = new SimpleDateFormat("MM/dd/yyyy"); 
 
   public JFormattedDateTextField() {
      super();
      MaskFormatter maskFormatter = null;
      try {
         maskFormatter = new MaskFormatter("##/##/####");
      } catch (ParseException e) {
         e.printStackTrace();
      }
 
      maskFormatter.setPlaceholderCharacter('_');
      setFormatterFactory(new DefaultFormatterFactory(maskFormatter));
      this.addFocusListener(new FocusAdapter() {
         public void focusGained(FocusEvent e) {
            if (getFocusLostBehavior() == JFormattedTextField.PERSIST)
               setFocusLostBehavior(JFormattedTextField.COMMIT_OR_REVERT);
            }
  
            public void focusLost(FocusEvent e) {
               try {
                  Date date = (Date) format.parseObject(getText());
                  setValue(format.format(date));
               } catch (ParseException pe) {
                  setFocusLostBehavior(JFormattedTextField.PERSIST);
                  setText("");
                  setValue(null);
               }
            }
      });
   }
 
   public void setValue(Date date) {
      super.setValue(toString(date));
   }
 
   private Date toDate(String sDate) {
      Date date = null;
      if (sDate == null) return null;
      try {
         date = (Date) format.parseObject(sDate);
      }
      catch (ParseException pe) {
         // ignore
      }
 
      return date;
   } 
 
   private String toString(Date date) {
      try {
         return format.format(date);
      } catch (Exception e) {
         return "";
      }
   }
}

Adding a menu bar to a JSplitPane

Main.java:

 
import javax.swing.plaf.basic.*;
import java.awt.event.*;
import javax.swing.*;
import java.beans.*;
import java.awt.*;
 
public class Main extends JFrame
{
   JSplitPane splitPane;
  
   public Main() {
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
 
      splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, 
                                 new JPanel(), new JPanel());
      splitPane.setDividerSize(20);
  
      splitPane.setUI(new MenuDividerUI(getMainMenuBar()));
 
      getContentPane().add(splitPane);
 
      addComponentListener(new ComponentAdapter() {
         public void componentShown(ComponentEvent event) {
            splitPane.setDividerLocation(0.5);  
                
            removeComponentListener(this);
         }
      });
   }
 
   public JMenuBar getMainMenuBar() {
      JMenuBar mainBar = new JMenuBar();
      JMenu menu = new JMenu("JSplitPane");
      JMenuItem item1 = new JMenuItem("HORIZONTAL_SPLIT");
      JMenuItem item2 = new JMenuItem("VERTICAL_SPLIT");
      menu.add(item1);
      menu.add(item2);
      mainBar.add(menu);
  
      item1.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            splitPane.setOrientation(JSplitPane.HORIZONTAL_SPLIT);
         }
      });
 
      item2.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            splitPane.setOrientation(JSplitPane.VERTICAL_SPLIT);
         }
      });
 
      return mainBar;
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.setSize(300, 300);
      main.setVisible(true);
   }
}
 
class MenuDividerUI extends BasicSplitPaneUI
{
   protected JMenuBar menuBar;
 
   public MenuDividerUI(JMenuBar menuBar) {
      this.menuBar = menuBar;
   }
 
   public BasicSplitPaneDivider createDefaultDivider() {
      BasicSplitPaneDivider divider = new BasicSplitPaneDivider(this) {
         public int getDividerSize() { return menuBar.getPreferredSize().height; }
      };
      divider.setLayout(new BorderLayout());
      divider.add(BorderLayout.NORTH, menuBar);
 
      return divider;
   }
}

Programmatically closing a JInternalFrame

Use this:

   frame.getDesktopPane().getDesktopManager().closeFrame(frame);

Main.java:

import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.awt.*;
import java.net.*;
 
public class Main extends JFrame {
   JDesktopPane desktop;
   int nframes = 0;
 
   JMenu internalFrameMenu;
   Action closeAction = new CloseAction();
 
   public Main() {
      desktop = new JDesktopPane(); 
      setContentPane(desktop);
      setJMenuBar(createMenuBar());
      createInternalFrame(); 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
   }
 
   protected JMenuBar createMenuBar() {
      JMenuBar menuBar = new JMenuBar();
 
      JMenu createMenu = new JMenu("Create");
      createMenu.setMnemonic(KeyEvent.VK_C);
      JMenuItem newMenuItem = new JMenuItem("New");
      newMenuItem.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            createInternalFrame();
         }
      }); 
      newMenuItem.setMnemonic(KeyEvent.VK_N);
      createMenu.add(newMenuItem);
      menuBar.add(createMenu);
 
      internalFrameMenu = new JMenu("Close");
      internalFrameMenu.setMnemonic(KeyEvent.VK_C);
  
      menuBar.add(internalFrameMenu);     
 
      return menuBar;
   }
 
   protected void createInternalFrame() {
      nframes++;
      String title = "JInternalFrame #" + nframes;
      JInternalFrame frame = new JInternalFrame(title,
         true,    // resizable
         true,    // closable
         true,    // maximizable
         true);   // iconifiable
      frame.setVisible(true); 
      desktop.add(frame);
      frame.setSize(200, 200);
      frame.setLocation(30*nframes, 30*nframes);
      try {
         frame.setSelected(true);
      } catch (java.beans.PropertyVetoException e) {}
 
      JMenuItem menuItem = new JMenuItem(title);
      internalFrameMenu.add(menuItem);
      menuItem.addActionListener(closeAction);
      frames.put(title, frame);
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.setSize(500, 300);
      main.setVisible(true);
   }
 
   public class CloseAction extends AbstractAction
   {
      public CloseAction() {
         super("Close Action");
      }
 
      public void actionPerformed(ActionEvent ae) {
         JMenuItem menuItem = ((JMenuItem) ae.getSource());
         JInternalFrame frame = (JInternalFrame) frames.get(menuItem.getText());
         // close the frame
         frame.getDesktopPane().getDesktopManager().closeFrame(frame);
         // remove JMenuItem from JMenu
         JMenu parent = (JMenu) ((JPopupMenu) menuItem.getParent()).getInvoker();
         parent.remove(menuItem);
      }
   }
}

Putting a JButton inside a JComboBox

Here’s an example:

import javax.swing.plaf.basic.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.awt.*;
    
public class Main extends JFrame
{ 
   public Main() {
      getContentPane().setLayout(new FlowLayout());
      
      final JButton buttonOk = new JButton("OK");
      buttonOk.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            System.out.println(ae.getActionCommand() + " clicked!");
         }
      });
      final JButton buttonCancel = new JButton("Cancel");
      buttonCancel.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            System.out.println(ae.getActionCommand() + " clicked!");
         }
      });
 
      final JComboBox combobox = 
         new JComboBox(new Object[] {
               "Item 1",
               "Item 2",
               "Item 3",
               buttonOk,
               "Item 4",
               "Item 5",
               buttonCancel
            }
         );
 
      getContentPane().add(combobox);
      combobox.setRenderer(new ButtonComboBoxRenderer());
      combobox.addActionListener(new ButtonComboBoxListener(this, combobox));
  
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(1);
         }
      });      
   
      setSize(new Dimension(200, 200));
   } 
 
   public static void main(String[] args) throws Exception {
      Main main = new Main();
      main.setVisible(true);
   }
}
 
class ButtonComboBoxRenderer extends BasicComboBoxRenderer implements ListCellRenderer
{
   public ButtonComboBoxRenderer() {
      super();
   }
   
   public Component getListCellRendererComponent( JList list, 
           Object value, int index, boolean isSelected, boolean cellHasFocus) {
      if (isSelected) {
          setBackground(list.getSelectionBackground());
          setForeground(list.getSelectionForeground());
      }
      else {
          setBackground(list.getBackground());
          setForeground(list.getForeground());
      }
 
      setFont(list.getFont());
      if (value instanceof Icon) {
         setIcon((Icon)value);
      }
      if (value instanceof JButton) {
         return (Component) value;
      }
      else {
         setText((value == null) ? "" : value.toString());
      }
 
      return this;
  }  
}
 
class ButtonComboBoxListener implements ActionListener {
   JComboBox combobox;
   JFrame frame;
 
   ButtonComboBoxListener(JFrame frame, JComboBox combobox) {
      this.frame = frame;
      this.combobox = combobox;
      combobox.setSelectedIndex(0);
   }
     
   public void actionPerformed(ActionEvent e) {
      Object selectedItem = combobox.getSelectedItem();
      if (selectedItem instanceof JButton) {
         ((JButton) selectedItem).doClick();
      }
   }
}

Showing a tooltip on a individual items of JList

Override the JList method getToolTipText, determine the particular JList item the mouse is pointed on and show the appropriate text. Here’s an example:

import javax.swing.event.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.awt.*;
  
public class Main extends JFrame {
 
   public Main() {
      getContentPane().setLayout(new FlowLayout());
 
      Vector v = new Vector();
      for (int i=0; i<50; i++) {
         v.addElement("Item #" + i);
      }
      final JList list = new JList(v) {
         public String getToolTipText(MouseEvent me) {
            int index = locationToIndex(me.getPoint());
            if (index > -1) {
               String item = (String) getModel().getElementAt(index);
               return "Tooltip for " + item;
            }
            return null;
         }
      };
 
      // necessary to activate tooltips for this JList!
      list.setToolTipText("");
 
      getContentPane().add(new JScrollPane(list));    
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent event) {
            System.exit(0);   
         }      
      });
 
      setSize(200, 230);
   }
   
   public static void main(String[] args) {
      (new Main()).show();
   }
}