Illustrate the inheritance hierarchy

The inheritance hierarchy is independent of the containment hierarchy.

• Invoking the overridden toString method belonging to the local class B
• Using the super keyword to invoke the overridden toString method belonging to the class Y, which is the superclass of the local class B

  System.out.println("-4-");
  System.out.println(toString());
  System.out.println(super.toString());
}//end showB