Give and describe an example of how the Composite pattern shows up
in the AWT or Swing user interface libraries of Java.
Solution
Swing has a JComponent class for representing items that lie within
windows, such as buttons and text fields. One subclass of JComponent is
JPanel, so it can lie within a window, and a JPanel is itself a
container of JComponents.
Thus JPanel is an example of the Composite design pattern.