4.23 Java4120r: review

Revised: Thu Apr 07 13:19:31 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 , 13 , 14 , 15 , 16
• 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 Java4120: The Comparator Interface, Part 4 .

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 a method named convertToArray , which can be called on a Collection object to "return an array containing all of the elements in this collection whose runtime type is that of the specified array" .

Answer 1

Question 2

True or False? A Comparator object can be used to sort the contents of an array containing references to objects.

Answer 2

Question 3

True or False? An array is a container that can be used to store a collection of primitive values or a collection of references to objects.

Answer 3

Question 4

Write down the output produced by the program shown in Listing 1 . Hint: There are ten lines of output.

Answer 4

Question 5

True or False? A Vector object is a Set object.

Answer 5

Question 6

True or False? Because a Vector object is a List object, it is not allowed to contain duplicate elements.

Answer 6

Question 7

True or False? Because a Vector is a List , it is an ordered collection.

Answer 7

Question 8

True or False? The position of each element in an ordered collection is determined by i ts value relative to the values of its neighbors.

Answer 8

Question 9

True or False? The add method for the Vector class simply adds each new element to the end of the list.

Answer 9

Question 10

True or False? When an iterator is used to traverse the elements in a Vector collection, the elements are delivered by the iterator in ascending index order, beginning with the element stored at index 0.

Answer 10

Question 11

True or False? The first time the iterator is applied to the Vector object in Listing 1 , the output is in ascending natural order as shown below:

BILL Bill JOE Joe TOM Tom

Answer 11

Question 12

True or False? The toArray method can be called on a Vector object to return a reference to an array object containing all of the elements in the Vector in ascending index order.

Answer 12

Question 13

True or False? The documentation for the toArray method of the Collection interface reads partially as follows:

"Returns an array containing all of the elements in this collection. If the collection makes any guarantees as to what order its elements arereturned by its iterator, this method must return the elements in the same order.