Java SE (Java Platform, Standard Edition)

Ok, so I was trying to get a JTabbedPane with 'X' icons on each tab. Searched this site, and found no answers, but loads of questions on how to do it. I've done it now, and here's my code.

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

/**
 * A JTabbedPane which has a close ('X') icon on each tab.
 *
 * To add a tab, use the method addTab(String, Component)
 *
 * To have an extra icon on each tab (e.g. like in JBuilder, showing the file type) use
 * the method addTab(String, Component, Icon). Only clicking the 'X' closes the tab.
 */
public class JTabbedPaneWithCloseIcons extends JTabbedPane implements MouseListener {
  public JTabbedPaneWithCloseIcons() {
    super();
    addMouseListener(this);
  }

  public void addTab(String title, Component component) {
    this.addTab(title, component, null);
  }

  public void addTab(String title, Component component, Icon extraIcon) {
    super.addTab(title, new CloseTabIcon(extraIcon), component);
  }

  public void mouseClicked(MouseEvent e) {
    int tabNumber=getUI().tabForCoordinate(this, e.getX(), e.getY());
    if (tabNumber < 0) return;
    Rectangle rect=((CloseTabIcon)getIconAt(tabNumber)).getBounds();
    if (rect.contains(e.getX(), e.getY())) {
      //the tab is being closed
      this.removeTabAt(tabNumber);
    }
  }

  public void mouseEntered(MouseEvent e) {}
  public void mouseExited(MouseEvent e) {}
  public void mousePressed(MouseEvent e) {}
  public void mouseReleased(MouseEvent e) {}
}

/**
 * The class which generates the 'X' icon for the tabs. The constructor
 * accepts an icon which is extra to the 'X' icon, so you can have tabs
 * like in JBuilder. This value is null if no extra icon is required.
 */
class CloseTabIcon implements Icon {
  private int x_pos;
  private int y_pos;
  private int width;
  private int height;
  private Icon fileIcon;

  public CloseTabIcon(Icon fileIcon) {
    this.fileIcon=fileIcon;
    width=16;
    height=16;
  }

  public void paintIcon(Component c, Graphics g, int x, int y) {
    this.x_pos=x;
    this.y_pos=y;

    Color col=g.getColor();

    g.setColor(Color.black);
    int y_p=y+2;
    g.drawLine(x+1, y_p, x+12, y_p);
    g.drawLine(x+1, y_p+13, x+12, y_p+13);
    g.drawLine(x, y_p+1, x, y_p+12);
    g.drawLine(x+13, y_p+1, x+13, y_p+12);
    g.drawLine(x+3, y_p+3, x+10, y_p+10);
    g.drawLine(x+3, y_p+4, x+9, y_p+10);
    g.drawLine(x+4, y_p+3, x+10, y_p+9);
    g.drawLine(x+10, y_p+3, x+3, y_p+10);
    g.drawLine(x+10, y_p+4, x+4, y_p+10);
    g.drawLine(x+9, y_p+3, x+3, y_p+9);
    g.setColor(col);
    if (fileIcon != null) {
      fileIcon.paintIcon(c, g, x+width, y_p);
    }
  }

  public int getIconWidth() {
    return width + (fileIcon != null? fileIcon.getIconWidth() : 0);
  }

  public int getIconHeight() {
    return height;
  }

  public Rectangle getBounds() {
    return new Rectangle(x_pos, y_pos, width, height);
  }
}

You can also specify an extra icon to put on each tab. Read my comments on how to do it.