Using getClass in preference to instanceof

When providing a proper version of equals, many authors use code like:

public boolean equals(final Object pObject)
{
   if ( ! (pObject instanceof Date) )
   {
      return false;
   }
   final Date tDate = (Date)pObject;
   return iYear==tDate.iYear && iMonth==tDate.iMonth && iDay==tDate.iDay;
}

This code causes problems if later inheritance is used to subclass this class and you want the subclass to override the Date's equals.
The problem is that this equals does not satisfy a rule of the contract of equals mentioned in Object's WWW pages.
For more information about this, see:
- pages 44 to 59 of the book 'Practical Java' ([11]) by Peter Haggar;
- an article by Mark Roulo entitled 'How to avoid traps and correctly override methods from java.lang.Object' ([14]).
Peter Haggar says: ‘A quick glance through the source code of the Java libraries shows the use of instanceof in equals method implementations is common. You also find the use of getClass. The Java libraries are not consistent in how they implement the equals methods of their classes, thereby making consistent equality comparisons difficult’.