Question 1

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

Accepted Answer

A)  Use the add method to add a new element to the map. 
B)  Use the get method to retrieve a value from the map. 
C)  Use the keyset method to get the set of keys for the map. 
D)  Use the remove method to remove a value from the map. 
A)  Use the add method to add a new element to the map. 
B)  Use the get method to retrieve a value from the map. 
C)  Use the keyset method to get the set of keys for the map. 
D)  Use the remove method to remove a value from the map.

Question 2

Select an appropriate expression to complete the following method, which is designed to visit the elements in theList and replace each occurrence of the string "hello" with the string "goodbye". public static void helloGoodbye(LinkedList theList) { ListIterator iterator = theList.listIterator(); While (iterator.hasNext()) { If (iterator.next().equals("hello")) { _____________________________ } } }

Accepted Answer

A)  iterator.replace("hello", "goodbye"); 
B)  iterator.next() = "goodbye"; 
C)  iterator.previous("goodbye"); 
D)  iterator.set("goodbye"); 
A)  iterator.replace("hello", "goodbye"); 
B)  iterator.next() = "goodbye"; 
C)  iterator.previous("goodbye"); 
D)  iterator.set("goodbye");

Question 3

Consider the following code snippet: Map<String, Integer> scores;
You expect to retrieve elements randomly by key, and want fastest retrieval times. Which of the following statements will create a structure to support this?

Accepted Answer

A) scores = new HashMap; B) scores = new TreeMap; C) scores = new Map; D) scores = new TreeSet; A) scores = new HashMap; B) scores = new TreeMap; C) scores = new Map; D) scores = new TreeSet;

Question 4

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 5

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 6

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 7

You need to access values using a key, and the keys must be sorted. Which collection type should you use?

Accepted Answer

A)  TreeMap 
B)  ArrayList 
C)  HashMap 
D)  Queue 
A)  TreeMap 
B)  ArrayList 
C)  HashMap 
D)  Queue

Question 8

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

Accepted Answer

A)  myMap.get("apple"); 
B)  myMap.peek("apple"); 
C)  myMap.get(3); 
D)  myMap.peek(3); 
A)  myMap.get("apple"); 
B)  myMap.peek("apple"); 
C)  myMap.get(3); 
D)  myMap.peek(3);

Question 9

Which of the following algorithms would be efficiently executed using a LinkedList?

Accepted Answer

A)  Tracking paths in a maze. 
B)  Binary search. 
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)  Tracking paths in a maze. 
B)  Binary search. 
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 10

Consider the following code snippet:
Map<String, Integer> scores;
If you need to visit the keys in sorted order, which of the following statements will create a structure to support this?

Accepted Answer

A) scores = new HashMap; B) scores = new TreeMap; C) scores = new Map; D) scores = new HashTable; A) scores = new HashMap; B) scores = new TreeMap; C) scores = new Map; D) scores = new HashTable;

Question 11

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

Accepted Answer

A)  Calling remove after calling next. 
B)  Calling add after calling previous. 
C)  Calling remove after calling add. 
D)  Calling previous after calling previous. 
A)  Calling remove after calling next. 
B)  Calling add after calling previous. 
C)  Calling remove after calling add. 
D)  Calling previous after calling previous.

Question 12

In a linked list data structure, when does the reference to the first node need to be updated?
I inserting into an empty list
II deleting from a list with one node
III deleting an inner node

Accepted Answer

A)  I 
B)  II 
C)  I and II 
D)  III 
A)  I 
B)  II 
C)  I and II 
D)  III

Question 13

A stack is a collection that ____.

Accepted Answer

A)  remembers the order of elements, and allows elements to be added and removed only at one end. 
B)  does not remember the order of elements but allows elements to be added in any position. 
C)  remembers the order of elements and allows elements to be inserted in any position. 
D)  remembers the order of elements and allows elements to be inserted only at one end and removed only at the other end. 
A)  remembers the order of elements, and allows elements to be added and removed only at one end. 
B)  does not remember the order of elements but allows elements to be added in any position. 
C)  remembers the order of elements and allows elements to be inserted in any position. 
D)  remembers the order of elements and allows elements to be inserted only at one end and removed only at the other end.

Question 14

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 15

A linked list ____ encapsulates a position anywhere inside the linked list.

Accepted Answer

A)  accessor 
B)  index 
C)  operation 
D)  iterator 
A)  accessor 
B)  index 
C)  operation 
D)  iterator

Question 16

A queue is a collection that ____.

Accepted Answer

A)  remembers the order of elements, and allows elements to be added and removed only at one end. 
B)  does not remember the order of elements but allows elements to be added in any position. 
C)  remembers the order of elements and allows elements to be inserted in any position. 
D)  remembers the order of elements and allows elements to be inserted only at one end and removed only at the other end. 
A)  remembers the order of elements, and allows elements to be added and removed only at one end. 
B)  does not remember the order of elements but allows elements to be added in any position. 
C)  remembers the order of elements and allows elements to be inserted in any position. 
D)  remembers the order of elements and allows elements to be inserted only at one end and removed only at the other end.

Question 17

Print jobs submitted to a printer would probably be stored in which type of data structure?

Accepted Answer

A)  queue 
B)  linked list 
C)  stack 
D)  hash table 
A)  queue 
B)  linked list 
C)  stack 
D)  hash table

Question 18

You need to write a program to build and maintain an address book. Since the program must support the possibility of having duplicate names, which data structure would be most appropriate to model this situation?

Accepted Answer

A)  map 
B)  stack 
C)  queue 
D)  linked list 
A)  map 
B)  stack 
C)  queue 
D)  linked list

Question 19

You need to write a program to manage a waiting list of patrons at a restaurant. Which data structure would be most appropriate to model this situation?

Accepted Answer

A)  map 
B)  stack 
C)  queue 
D)  linked list 
A)  map 
B)  stack 
C)  queue 
D)  linked list

Question 20

Which of the following statements about a priority queue structure is NOT correct?

Accepted Answer

A)  Elements added to a priority queue must belong to a class that implements the Comparable interface. 
B)  New elements can be inserted in any order. 
C)  The remove method is used to remove an element from the priority queue. 
D)  The insert method is used to add a new element to the priority queue. 
A)  Elements added to a priority queue must belong to a class that implements the Comparable interface. 
B)  New elements can be inserted in any order. 
C)  The remove method is used to remove an element from the priority queue. 
D)  The insert method is used to add a new element to the priority queue.

Exam 15: The Java Collections Framework

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

Consider the following code snippet: Map<String, Integer> scores; You expect to retrieve elements randomly by key, and want fastest retrieval times. Which of the following statements will create a structure to support this?

Which of the following statements about linked lists is correct?

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

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

You need to access values using a key, and the keys must be sorted. Which collection type should you use?

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

Which of the following algorithms would be efficiently executed using a LinkedList?

Consider the following code snippet: Map<String, Integer> scores; If you need to visit the keys in sorted order, which of the following statements will create a structure to support this?

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

In a linked list data structure, when does the reference to the first node need to be updated? I inserting into an empty list II deleting from a list with one node III deleting an inner node

A stack is a collection that ____.

Which of the following statements about data structures is correct?

A linked list ____ encapsulates a position anywhere inside the linked list.

A queue is a collection that ____.

Print jobs submitted to a printer would probably be stored in which type of data structure?

You need to write a program to build and maintain an address book. Since the program must support the possibility of having duplicate names, which data structure would be most appropriate to model this situation?

You need to write a program to manage a waiting list of patrons at a restaurant. Which data structure would be most appropriate to model this situation?

Which of the following statements about a priority queue structure is NOT correct?

Introduction

Using Objects

Implementing Classes

Fundamental Data Types

Decisions

Loops

Arrays and Array Lists

Designing Classes

Inheritance

Interfaces

Inputoutput and Exception Handling

Object-Oriented Design

Recursion

Sorting and Searching

Basic Data Structures

Tree Structures

Generic Classes

Graphical User Interfaces

Streams and Binary Inputoutput

Multithreading

Internet Networking

Relational Databases

XML

Web Applications

Filters