4.31 Java4160r: review

Revised: Fri Apr 08 13:36:43 CDT 2016

This page is included in the following Books:

• ITSE 2321 - Object-Oriented Programming (Java)
• Object-Oriented Programming (OOP) with Java

Table of contents

• Preface
• Questions
  • 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12
• Figures
• Listings
• Answers
• Complete program listing
• Miscellaneous

Preface

This module is one in a collection of modules on Java Collections designed for teaching ITSE2321 - Object-Oriented Programming (Java) at Austin Community College in Austin, TX.

This module contains review questions and answers keyed to the module titled Java4160: The toArray Method, Part 2 .

Once you study that module, you should be able to answer the review questions in this module.

The questions and the answers in this module are connected by hyperlinks to make it easy for you to navigate from the question to the answer and back again.

Questions

Question 1 .

True or False? The Collection interface declares the following two versions of the toArray method (with generics syntax omitted because generics is beyond the scope of this course) .

public Object[] toArray()

public Object[] toArray(Object[]a)

Answer 1

Question 2

Write down the output produced by the program shown in Listing 1 .

Answer 2

Question 3

True or False? The Collections class (as opposed to the Collection interface) , provides static methods that operate on collections.

Answer 3

Question 4

True or False? TreeSet is a class in the Java Collections Framework .

Answer 4

Question 5

True or False? A SortedMap is a Map that maintains its entries in ascending order, sorted according to the values'natural ordering, or according to a Comparator provided at the time of the SortedMap creation.

Answer 5

Question 6

True or False? An object of type SortedSet is a Set that, by default, maintains its elements in descending order.

Answer 6

Question 7

True or False? An object of type Map is an object that maps keys to values. Such an object can contain duplicate keys but cannot containduplicate values.

Answer 7

Question 8

True or False? An object of type Deque allows elements to be inserted, retrieved, and removed at both ends.

Answer 8

Question 9

True or False? Objects of type List allow duplicates..

Answer 9

Question 10

True or False? Objects of type Set allow duplicates..

Answer 10

Question 11

True or False? Set is an interface in the Collections Framework .

Answer 11

Question 12

True or False? Collection is the class that forms the root of the Collections Framework hierarchy.

Answer 12

Figures

• Figure 1 . Answer 2.

Listings

• Listing 1 . ToArray02.java.

What is the meaning of the following two images?

These images were inserted here simply to insert some space between the questions and the answers to keep them from being visible on the screen at thesame time.

This image was also inserted for the purpose of inserting space between the questions and the answers.

Answers

Answer 12

False. Collection is an interface, not a class.

Back to Question 12

Answer 11

True.

Back to Question 11

Answer 10

False. Objects of type Set do not allow duplicates.