Java tutorial
import java.awt.Dimension; import java.awt.Graphics; import java.beans.PropertyChangeEvent; import java.beans.PropertyChangeListener; import java.io.File; import javax.swing.JComponent; import javax.swing.JFileChooser; public class Main { public static void main(String[] argv) { JFileChooser chooser = new JFileChooser(); chooser.setAccessory(new MyAccessory(chooser)); chooser.showOpenDialog(null); } } class MyAccessory extends JComponent implements PropertyChangeListener { public MyAccessory(JFileChooser chooser) { chooser.addPropertyChangeListener(this); setPreferredSize(new Dimension(50, 50)); } public void propertyChange(PropertyChangeEvent evt) { if (JFileChooser.SELECTED_FILE_CHANGED_PROPERTY.equals(evt.getPropertyName())) { JFileChooser chooser = (JFileChooser) evt.getSource(); // Get the new selected file File newFile = (File) evt.getNewValue(); repaint(); } } public void paint(Graphics g) { // Paint a preview of the selected file } }