3. Swing containment hierarchy

• 
      javax.awt.JFrame
  
      javax.awt.JDialog
  
      javax.awt.JApplet
  
  

• Each of the above classes start a single containment hierarchy.

• AWT is the Abstract Window Toolkit, Java's original platform-independent windowing, graphics, and user-interface widget toolkit.

• The AWT is part of the Java Foundation Classes (JFC) - the standard Java GUI API.