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class CalendarSubclass extends Calendar {
  @Override public boolean after(Object when) {
    if(when instanceof Calendar && super.compareTo((Calendar)when) == 0)
        // correctly calls Calendar.compareTo()
      return true;
    return super.after(when); // calls CalendarSubclass.compareTo() due to polymorphism
  }
	
  @Override public int compareTo(Calendar anotherCalendar) {
    // This method is erroneously invoked by Calendar.after()
    return compareTo(anotherCalendar.getFirstDayOfWeek(),anotherCalendar);
  }

  private int compareTo(int firstDayOfWeek, Calendar c) {
    int thisTime = c.get(Calendar.DAY_OF_WEEK);
    return (thisTime > firstDayOfWeek) ? 1 : (thisTime == firstDayOfWeek) ? 0 : -1;
  }

  public static void main(String[] args) {
    CalendarSubclass cs1 = new CalendarSubclass();
    CalendarSubclass cs2 = new CalendarSubclass();
    cs1.setTime(new Date());
    System.out.println(cs1.after(cs2));  // prints false
  }

/* Implementation of other abstract methods */
}

// The implementation of java.util.Calendar.after() method is shown below
public boolean after(Object when) {
  return when instanceof Calendar && compareTo((Calendar)when) > 0;
     // forwards to the subclass's implementation erroneously
}

// The CalendarImplementation object is a concrete implementation of the abstract Calendar class
// Class ForwardingCalendar
public class ForwardingCalendar {
  private final CalendarImplementation c;

  public ForwardingCalendar(CalendarImplementation c) {
    this.c = c;
  }

  public boolean after(Object when) {
    return c.after(when);
  }

  public int compareTo(Calendar anotherCalendar) {
    // ForwardingCalendar's compareTo() will be called
    return c.compareTo(anotherCalendar);
  }
}

//Class CompositeCalendar
class CompositeCalendar extends ForwardingCalendar {
  public CompositeCalendar(CalendarImplementation ci) {
    super(ci);  
  }
  
  @Override public boolean after(Object when) {
    if(when instanceof Calendar && super.compareTo((Calendar)when) == 0)
          // this will call the overridden version
          // i.e. CompositeClass.compareTo();
          // return true if it is the first day of week
      return true;
    return super.after(when); // does not compare with first day of week anymore;
                              // uses default comparison with epoch
  }
	
  @Override public int compareTo(Calendar anotherCalendar) {
     // CompositeCalendarcompareTo() will not be called now
     return compareTo(anotherCalendar.getFirstDayOfWeek(),anotherCalendar);
  }

  private int compareTo(int firstDayOfWeek, Calendar c) {
    int thisTime = c.get(Calendar.DAY_OF_WEEK);
    return (thisTime > firstDayOfWeek) ? 1 : (thisTime == firstDayOfWeek) ? 0 : -1;
  }

  public static void main(String[] args) {
    CalendarImplementation ci1 = new CalendarImplementation();
    CalendarImplementation ci2 = new CalendarImplementation();
    CompositeCalendar c = new CompositeCalendar(ci1);
    ci1.setTime(new Date());
    System.out.println(c.after(ci2)); // prints true 
  }
}