Using jfilechooser to select directory

Question

Ive got problem with filechooser, with taking directory path into images viewer exactly. I want to get all images from the selected directory. Ive got NullPointerException in line

String[] imagesList = selectedDirectory.list();

Here's the code:

JFileChooser wybierz = new JFileChooser();
File selectedDirectory;
String path;

int pos = 0;

public String[] getImages() {
    String[] imagesList = selectedDirectory.list();        
    return imagesList;
}

public void showImage(int index) {
    String[] imagesList = getImages();
    String imageName = imagesList[index];
    ImageIcon icon = new ImageIcon(getClass().getResource(path));
    Image image = icon.getImage().getScaledInstance(jLabel_Image.getWidth(), jLabel_Image.getHeight(), Image.SCALE_SMOOTH);
    jLabel_Image.setIcon(new ImageIcon(image));
}

public void fileChooser() {
    wybierz.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
    wybierz.setAcceptAllFileFilterUsed(false);
    wybierz.addChoosableFileFilter(new FileNameExtensionFilter("Image Files", "jpg", "png", "tif"));
    int v = wybierz.showOpenDialog(null);
    if (v == JFileChooser.APPROVE_OPTION) {
        File selectedDirectory = wybierz.getSelectedFile();
        showImage(pos);
    }
}

what's the problem?