How to add close button to a JTabbedPane Tab?

Essentially, you're going to need to supply a "renderer" for the tab. Take a look at JTabbedPane.setTabComponentAt(...) for more information.

The basic idea is to supply a component that will be laid out on the tab.

I typically create a JPanel, onto which I add a JLabel (for the title) and, depending on what I want to display, some kind of control that acts as the close action.

tabPane.addTab(title, tabBody);
int index = tabPane.indexOfTab(title);
JPanel pnlTab = new JPanel(new GridBagLayout());
pnlTab.setOpaque(false);
JLabel lblTitle = new JLabel(title);
JButton btnClose = new JButton("x");

GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
gbc.weightx = 1;

pnlTab.add(lblTitle, gbc);

gbc.gridx++;
gbc.weightx = 0;
pnlTab.add(btnClose, gbc);

tabPane.setTabComponentAt(index, pnlTab);

btnClose.addActionListener(myCloseActionHandler);

Now somewhere else, I establish the action handler...

public class MyCloseActionHandler implements ActionListener {

    public void actionPerformed(ActionEvent evt) {

        Component selected = tabPane.getSelectedComponent();
        if (selected != null) {

            tabPane.remove(selected);
            // It would probably be worthwhile getting the source
            // casting it back to a JButton and removing
            // the action handler reference ;)

        }

    }

}

Now, you just as easily use any component you like and attach a mouse listener to it and monitor the mouse clicks...

Updated

The above example will only remove the currently active tab, there are a couple of ways to fix this.

The best is to probably provide some means for the action to find the tab it's associated with...

public class MyCloseActionHandler implements ActionListener {

    private String tabName;

    public MyCloseActionHandler(String tabName) {
        this.tabName = tabName;
    }

    public String getTabName() {
        return tabName;
    }

    public void actionPerformed(ActionEvent evt) {

        int index = tabPane.indexOfTab(getTabName());
        if (index >= 0) {

            tabPane.removeTabAt(index);
            // It would probably be worthwhile getting the source
            // casting it back to a JButton and removing
            // the action handler reference ;)

        }

    }

}   

This uses the name of tab (as used with JTabbedPane#addTab) to find and then remove the tab and its associated component...

I found a tab example (from the java site) that appears to do that, at least in theirs. (Though I thought, when I tried it in the past, that it also closed the currently selected tab, though it works properly when you run their example, though I think when I updated it to work on a tabbed java notepad, it was closing the currently selected tab, though maybe I did it wrong.

http://docs.oracle.com/javase/tutorial/displayCode.html?code=http://docs.oracle.com/javase/tutorial/uiswing/examples/components/TabComponentsDemoProject/src/components/ButtonTabComponent.java

Yes, my thing is working now! This WILL work for the actual tab, rather than the currently selected tab!

Hopefully you have got the answer to your question. I want to give a link that was very useful for me.

JTabbedPane with a close button

Here is some code as well.

public static void createAndShowGUI()
{
    JFrame frame = new JFrame("Tabs");
    frame.setMinimumSize(new Dimension(500, 200));
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JTabbedPane tabbedPane = new JTabbedPane();

    JPanel panel = new JPanel();
    panel.setOpaque(false);
    tabbedPane.add(panel);
    tabbedPane.setTabComponentAt(tabbedPane.indexOfComponent(panel), getTitlePanel(tabbedPane, panel, "Tab1"));

    JPanel panel1 = new JPanel();
    panel1.setOpaque(false);
    tabbedPane.add(panel1);
    tabbedPane.setTabComponentAt(tabbedPane.indexOfComponent(panel1), getTitlePanel(tabbedPane, panel1, "Tab2"));

    JPanel panel2 = new JPanel();
    panel2.setOpaque(false);
    tabbedPane.add(panel2);
    tabbedPane.setTabComponentAt(tabbedPane.indexOfComponent(panel2), getTitlePanel(tabbedPane, panel2, "Tab3"));

    JPanel panel3 = new JPanel();
    panel3.setOpaque(false);
    tabbedPane.add(panel3);
    tabbedPane.setTabComponentAt(tabbedPane.indexOfComponent(panel3), getTitlePanel(tabbedPane, panel3, "Tab4"));

    frame.add(tabbedPane);

    // Display the window.
    frame.pack();
    frame.setVisible(true);
}