ABSTRACT CLASSES AND INTERFACES - Introduction to Java Programming: Comprehensive Version - page 529

8.

The java.lang.Cloneable interface is a marker interface . An object of the class that
implements the Cloneable interface is cloneable.

9.

A class can extend only one superclass but can implement one or more interfaces.

10.

An interface can extend one or more interfaces.

Q UIZ

Answer the quiz for this chapter online at www.cs.armstrong.edu/liang/intro10e/quiz.html .

P ROGRAMMING E XERCISES

Sections 13.2-13.3
**13.1

( Triangle class ) Design a new Triangle class that extends the abstract
GeometricObject class. Draw the UML diagram for the classes Triangle
and GeometricObject and then implement the Triangle class. Write a test
program that prompts the user to enter three sides of the triangle, a color, and a
Boolean value to indicate whether the triangle is filled. The program should create
a Triangle object with these sides and set the color and filled properties using
the input. The program should display the area, perimeter, color, and true or false
to indicate whether it is filled or not.

*13.2

( Shuffle ArrayList ) Write the following method that shuffles an ArrayList of
numbers:

public static void shuffle(ArrayList<Number> list)

*13.3

( Sort ArrayList ) Write the following method that sorts an ArrayList of numbers.

public static void sort(ArrayList<Number> list)

**13.4

( Display calendars ) Rewrite the PrintCalendar class in Listing 6.12 to display
a calendar for a specified month using the Calendar and GregorianCalendar
classes. Your program receives the month and year from the command line. For
example:

java Exercise13_04 5 2016

This displays the calendar shown in Figure 13.9.

F IGURE 13.9

The program displays a calendar for May 2016.