public Toolkit()

   public static Toolkit getDefaultToolkit()

   public class MySingleton {
     private static final MySingleton INSTANCE = 
       new MySingleton();

     private MySingleton() {
     }

     public static final MySingleton getInstance() {
       return INSTANCE;
     }
   }

  /**
   * Ensure Singleton class
   */
  private Object readResolve() throws ObjectStreamException {
    return INSTANCE;
  }

   Border line = BorderFactory.createLineBorder(Color.RED);
   JLabel label = new JLabel("Red Line");
   label.setBorder(line);

   PopupFactory factory = PopupFactory.getSharedInstance();

   Popup popup = factory.getPopup(owner, contents, x, y);

   FileInputStream fis = new FileInputStream(filename);
   CertificateFactory cf = 
      CertificateFactory.getInstance("X.509");
   Collection c = cf.generateCertificates(fis);

   ActionListener listener = new ActionListener() {
      public void actionPerformed(ActionEvent actionEvent) {
          ...
      }
   }; 
   JButton button = new JButton("Pick Me");
   button.addActionListener(listener);