Question 1

When using a list iterator, on which condition will the NoSuchElementException be thrown?

Accepted Answer

A)  Calling next when you are past the end of the list. 
B)  Calling next when the iterator points to the last element. 
C)  Calling remove after calling add. 
D)  Calling remove after calling previous. 
A)  Calling next when you are past the end of the list. 
B)  Calling next when the iterator points to the last element. 
C)  Calling remove after calling add. 
D)  Calling remove after calling previous.

Question 2

Assume that you have declared a map named myMap to hold String elements with Integer keys. Which of the following statements will correctly remove an element from myMap?

Accepted Answer

A)  myMap.get(3); 
B)  myMap.remove(3); 
C)  myMap.pop(3); 
D)  myMap.delete(3); 
A)  myMap.get(3); 
B)  myMap.remove(3); 
C)  myMap.pop(3); 
D)  myMap.delete(3);

Question 3

You have decided to store objects of a class in a TreeSet structure. Which of the following statements is correct?

Accepted Answer

A)  If the object class implements the Comparable interface, and the sort order in the compare method is acceptable, you do not have to do anything else. 
B)  If the object class implements the Comparable interface, and the sort order in the compareTo method is acceptable, you do not have to do anything else. 
C)  If the object class implements the Comparable interface, and the sort order in the compare method is acceptable, you must create a comparator object. 
D)  If the object class implements the Comparable interface, and the sort order in the compareTo method is acceptable, you must create a comparator object. 
A)  If the object class implements the Comparable interface, and the sort order in the compare method is acceptable, you do not have to do anything else. 
B)  If the object class implements the Comparable interface, and the sort order in the compareTo method is acceptable, you do not have to do anything else. 
C)  If the object class implements the Comparable interface, and the sort order in the compare method is acceptable, you must create a comparator object. 
D)  If the object class implements the Comparable interface, and the sort order in the compareTo method is acceptable, you must create a comparator object.

Question 4

You need to access values in objects by a key that is not part of the object. Which collection type should you use?

Accepted Answer

A)  Map 
B)  Hashtable 
C)  ArrayList 
D)  Queue 
A)  Map 
B)  Hashtable 
C)  ArrayList 
D)  Queue

Question 5

Which of the following statements about manipulating objects in a map is NOT correct?

Accepted Answer

A)  If you attempt to retrieve a value with a key that is not associated with any value, you will receive a null result. 
B)  You cannot change the value of an existing association in the map; you must delete it and re-add it with the new values. 
C)  Use the get method to retrieve a value associated with a key in the map. 
D)  Use the put method to add an element to the map. 
A)  If you attempt to retrieve a value with a key that is not associated with any value, you will receive a null result. 
B)  You cannot change the value of an existing association in the map; you must delete it and re-add it with the new values. 
C)  Use the get method to retrieve a value associated with a key in the map. 
D)  Use the put method to add an element to the map.

Question 6

Which of the following statements about linked lists is correct?

Accepted Answer

A)  Once you have located the correct position, adding elements in the middle of a linked list is inefficient. 
B)  Visiting the elements of a linked list in random order is efficient. 
C)  When a node is removed, all nodes after the removed node must be moved down. 
D)  Linked lists should be used when you know the correct position and need to insert and remove elements efficiently. 
A)  Once you have located the correct position, adding elements in the middle of a linked list is inefficient. 
B)  Visiting the elements of a linked list in random order is efficient. 
C)  When a node is removed, all nodes after the removed node must be moved down. 
D)  Linked lists should be used when you know the correct position and need to insert and remove elements efficiently.

Question 7

Which method is NOT part of the ListIterator generic class?

Accepted Answer

A)  hasNext 
B)  hasMore 
C)  hasPrevious 
D)  add 
A)  hasNext 
B)  hasMore 
C)  hasPrevious 
D)  add

Question 8

Suppose you push integer elements 1,2,3,4 onto a stack in that order. Then pop an element off the stack and add that element to a queue. You repeat that process three more times. In what order will you remove the elements from the queue?

Accepted Answer

A)  1,2,3,4 
B)  1,2,4,3 
C)  4,3,2,1 
D)  4,3,1,2 
A)  1,2,3,4 
B)  1,2,4,3 
C)  4,3,2,1 
D)  4,3,1,2

Question 9

Consider the following code snippet: LinkedList words = new LinkedList(); Words.addLast("abc"); Words.addLast("def"); Words.addLast("ghi"); System.out.print(words.removeLast()); System.out.print(words.removeFirst()); System.out.print(words.removeLast()); What will this code print when it is executed?

Accepted Answer

A)  abcdefghi 
B)  ghiabcdef 
C)  abcghidef 
D)  defghiabc 
A)  abcdefghi 
B)  ghiabcdef 
C)  abcghidef 
D)  defghiabc

Question 10

Consider the following code snippet: LinkedList words = new LinkedList(); Words.addFirst("abc"); Words.addLast("def"); Words.addFirst("ghi"); System.out.print(words.removeLast()); System.out.print(words.removeFirst()); System.out.print(words.removeLast()); What will this code print when it is executed?

Accepted Answer

A)  abcdefghi 
B)  ghiabcdef 
C)  abcghidef 
D)  defghiabc 
A)  abcdefghi 
B)  ghiabcdef 
C)  abcghidef 
D)  defghiabc

Question 11

What type of access does a LinkedList provide for its elements?

Accepted Answer

A)  sequential 
B)  semi-random 
C)  random 
D)  sorted 
A)  sequential 
B)  semi-random 
C)  random 
D)  sorted

Question 12

Which of the following statements about data structures is correct?

Accepted Answer

A)  Inserting and removing elements that have already been located is faster with a list than with a set. 
B)  Accessing elements in a linked list in a random fashion is efficient. 
C)  Adding and removing already-located elements in the middle of a linked list is efficient. 
D)  A set is an ordered collection of unique elements. 
A)  Inserting and removing elements that have already been located is faster with a list than with a set. 
B)  Accessing elements in a linked list in a random fashion is efficient. 
C)  Adding and removing already-located elements in the middle of a linked list is efficient. 
D)  A set is an ordered collection of unique elements.

Question 13

Which of the following algorithms would be efficiently executed on an ArrayList?

Accepted Answer

A)  add 1 element to the middle of a list with n elements 
B)  add n / 2 elements to a list with n / 2 elements 
C)  remove first n / 2 elements from a list of n elements 
D)  read n / 2 elements in random order from a list of n elements 
A)  add 1 element to the middle of a list with n elements 
B)  add n / 2 elements to a list with n / 2 elements 
C)  remove first n / 2 elements from a list of n elements 
D)  read n / 2 elements in random order from a list of n elements

Question 14

What operation is least efficient in a LinkedList?

Accepted Answer

A)  Adding an element in a position that has already been located. 
B)  Linear traversal step. 
C)  Removing an element when the element's position has already been located. 
D)  Random access of an element. 
A)  Adding an element in a position that has already been located. 
B)  Linear traversal step. 
C)  Removing an element when the element's position has already been located. 
D)  Random access of an element.

Question 15

A collection that remembers the order of items, and allows items to be added and removed only at one end is called a ____.

Accepted Answer

A)  list 
B)  stack 
C)  set 
D)  queue 
A)  list 
B)  stack 
C)  set 
D)  queue

Question 16

What can a generic class be parameterized for?

Accepted Answer

A)  properties 
B)  iterators 
C)  type 
D)  methods 
A)  properties 
B)  iterators 
C)  type 
D)  methods

Question 17

Assume you are using a doubly-linked list data structure with many nodes. What is the minimum number of node references that are required to be modified to remove a node from the middle of the list? Consider the neighboring nodes.

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
A)  1 
B)  2 
C)  3 
D)  4

Question 18

Which of the following statements about the TreeSet class is NOT correct?

Accepted Answer

A)  Elements are stored in sorted order. 
B)  Elements are arranged in linear fashion. 
C)  Elements are stored in nodes. 
D)  To use a TreeSet, it must be possible to compare the elements. 
A)  Elements are stored in sorted order. 
B)  Elements are arranged in linear fashion. 
C)  Elements are stored in nodes. 
D)  To use a TreeSet, it must be possible to compare the elements.

Question 19

Complete the following code, which is intended to print out all key/value pairs in a map named myMap that contains String data for student IDs and names: Map myMap = new HashMap(); ) . . Set mapKeySet = myMap.keySet(); For (String aKey : mapKeySet) { ___________________________; System.out.println("ID: " + aKey + "->" + name); }

Accepted Answer

A)  String name = myMap.get(aKey); 
B)  String name = myMap.next(aKey); 
C)  String name = MapKeySet.get(aKey); 
D)  String name = MapKeySet.next(aKey); 
A)  String name = myMap.get(aKey); 
B)  String name = myMap.next(aKey); 
C)  String name = MapKeySet.get(aKey); 
D)  String name = MapKeySet.next(aKey);

Question 20

Complete the following code snippet, which is intended to determine if a specific value in a variable named targetWord appears in a set of String values named mySet:
For (String aWord : mySet)
{
_______________________
{
System.out.println ("The word " + targetWord + " was found.");
}
)

Accepted Answer

A)  if (mySet.equalsIgnoreCase(targetWord)) 
B)  if (mySet == targetWord) 
C)  if (mySet.contains(targetWord)) 
D)  if (mySet.get(targetWord)) 
A)  if (mySet.equalsIgnoreCase(targetWord)) 
B)  if (mySet == targetWord) 
C)  if (mySet.contains(targetWord)) 
D)  if (mySet.get(targetWord))

Exam 15: The Java Collections Framework

When using a list iterator, on which condition will the NoSuchElementException be thrown?

Assume that you have declared a map named myMap to hold String elements with Integer keys. Which of the following statements will correctly remove an element from myMap?

You have decided to store objects of a class in a TreeSet structure. Which of the following statements is correct?

You need to access values in objects by a key that is not part of the object. Which collection type should you use?

Which of the following statements about manipulating objects in a map is NOT correct?

Which of the following statements about linked lists is correct?

Which method is NOT part of the ListIterator generic class?

Suppose you push integer elements 1,2,3,4 onto a stack in that order. Then pop an element off the stack and add that element to a queue. You repeat that process three more times. In what order will you remove the elements from the queue?

What type of access does a LinkedList provide for its elements?

Which of the following statements about data structures is correct?

Which of the following algorithms would be efficiently executed on an ArrayList?

What operation is least efficient in a LinkedList?

A collection that remembers the order of items, and allows items to be added and removed only at one end is called a ____.

What can a generic class be parameterized for?

Assume you are using a doubly-linked list data structure with many nodes. What is the minimum number of node references that are required to be modified to remove a node from the middle of the list? Consider the neighboring nodes.

Which of the following statements about the TreeSet class is NOT correct?

Complete the following code snippet, which is intended to determine if a specific value in a variable named targetWord appears in a set of String values named mySet: For (String aWord : mySet) { _______________________ { System.out.println ("The word " + targetWord + " was found."); } )

Introduction

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