Arrastar componente com o mouse

/*
 * LabelDnD.java is a 1.4 example that requires no other files.
 */
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingConstants;
import javax.swing.TransferHandler;
import javax.swing.border.TitledBorder;

public class LabelDnD extends JPanel {
  JTextField textField;

  JLabel label;

  public LabelDnD() {
    super(new GridLayout(2, 1));
    textField = new JTextField(40);
    textField.setDragEnabled(true);
    JPanel tfpanel = new JPanel(new GridLayout(1, 1));
    TitledBorder t1 = BorderFactory
        .createTitledBorder("JTextField: drag and drop is enabled");
    tfpanel.add(textField);
    tfpanel.setBorder(t1);

    label = new JLabel("I'm a Label!", SwingConstants.LEADING);
    label.setTransferHandler(new TransferHandler("text"));

    MouseListener listener = new DragMouseAdapter();
    label.addMouseListener(listener);
    JPanel lpanel = new JPanel(new GridLayout(1, 1));
    TitledBorder t2 = BorderFactory
        .createTitledBorder("JLabel: drag from or drop to this label");
    lpanel.add(label);
    lpanel.setBorder(t2);

    add(tfpanel);
    add(lpanel);
    setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
  }

  private class DragMouseAdapter extends MouseAdapter {
    public void mousePressed(MouseEvent e) {
      JComponent c = (JComponent) e.getSource();
      TransferHandler handler = c.getTransferHandler();
      handler.exportAsDrag(c, e, TransferHandler.COPY);
    }
  }

  /**
   * Create the GUI and show it. For thread safety, this method should be
   * invoked from the event-dispatching thread.
   */
  private static void createAndShowGUI() {
    //Make sure we have nice window decorations.
    JFrame.setDefaultLookAndFeelDecorated(true);

    //Create and set up the window.
    JFrame frame = new JFrame("LabelDnD");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    //Create and set up the content pane.
    JComponent newContentPane = new LabelDnD();
    newContentPane.setOpaque(true); //content panes must be opaque
    frame.setContentPane(newContentPane);

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

  public static void main(String[] args) {
    //Schedule a job for the event-dispatching thread:
    //creating and showing this application's GUI.
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        createAndShowGUI();
      }
    });
  }
}