Question 1

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

Accepted Answer

A) Remove first n/ 2 elements from a list of n elements. 
B) Read n / 2 elements in random order from a list of n elements. 
C) Tracking paths in a maze. 
D) Binary search. 
A) Remove first n/ 2 elements from a list of n elements. 
B) Read n / 2 elements in random order from a list of n elements. 
C) Tracking paths in a maze. 
D) Binary search. A

Question 2

You use a(n) ____ to access elements inside a linked list.

Accepted Answer

A) queue 
B) accessor 
C) list iterator 
D) index 
A) queue 
B) accessor 
C) list iterator 
D) index C

Question 3

What is included in a linked list node?
i.a reference to its neighboring nodes
II.an array reference
III.a data element

Accepted Answer

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

Question 4

Rather than storing values in an array, a linked list uses a sequence of ____.

Accepted Answer

A) accessors 
B) nodes 
C) elements 
D) indexes 
A) accessors 
B) nodes 
C) elements 
D) indexes

Question 5

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

Question 6

Assume that you have declared a map named myMap to hold String values with Integer keys.Which of the following statements will correctly retrieve the value associated with a key from myMap?

Accepted Answer

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

Question 7

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".

Accepted Answer

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

Question 8

Select an appropriate expression to complete the following method, which is designed to return the number of elements in the parameter array numbers.If a value appears more than once, it should be counted exactly once.

Accepted Answer

A) return numbers.length - values.size(); 
B) return values.size(); 
C) return numbers.length; 
D) return values.length(); 
A) return numbers.length - values.size(); 
B) return values.size(); 
C) return numbers.length; 
D) return values.length();

Question 9

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:

Accepted Answer

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

Question 10

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

Question 11

The nodes of a(n) ____ linked list class store two links: one to the next element and one to the previous one.

Accepted Answer

A) array 
B) singly 
C) randomly 
D) doubly 
A) array 
B) singly 
C) randomly 
D) doubly

Question 12

Assume that you have declared a set named mySet to hold String elements.Which of the following statements will correctly insert an element into mySet?

Accepted Answer

A) mySet.put(apple"); 
B) mySet.insert("apple"); 
C) mySet.add("apple"); 
D) mySet.push("apple"); 
A) mySet.put(apple"); 
B) mySet.insert("apple"); 
C) mySet.add("apple"); 
D) mySet.push("apple");

Question 13

Which nodes need to be updated when we insert a new node to become the fourth node from the beginning of a doubly-linked list?

Accepted Answer

A) The current third and fourth nodes. 
B) The current fourth and fifth nodes. 
C) The current first node. 
D) The current third node. 
A) The current third and fourth nodes. 
B) The current fourth and fifth nodes. 
C) The current first node. 
D) The current third node.

Question 14

You need to access values in the order in which they were added (first in, first out), and not randomly.Which collection type should you use?

Accepted Answer

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

Question 15

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

Question 16

Which of the following statements about hash functions is NOT correct?

Accepted Answer

A) Using a prime number as a hash multiplier will produce better hash codes. 
B) If you supply your own hashCode method for a class, it must be compatible with that class's equals method. 
C) A good hash function will minimize the number of objects that are assigned the same hash code. 
D) A hash function produces a unique integer-valued hash code value for each distinct object. 
A) Using a prime number as a hash multiplier will produce better hash codes. 
B) If you supply your own hashCode method for a class, it must be compatible with that class's equals method. 
C) A good hash function will minimize the number of objects that are assigned the same hash code. 
D) A hash function produces a unique integer-valued hash code value for each distinct object.

Question 17

You intend to use a hash set with your own object class.Which of the following statements is correct?

Accepted Answer

A) You cannot override the hashCode method in the Object class. 
B) You can use the hash method of the Objects class to create your own hashCode method by combining the hash codes for the instance variables. 
C) You can override the hash method for your class provided that it is compatible with its equals method. 
D) Your class's hashCode method does not need to be compatible with its equals method. 
A) You cannot override the hashCode method in the Object class. 
B) You can use the hash method of the Objects class to create your own hashCode method by combining the hash codes for the instance variables. 
C) You can override the hash method for your class provided that it is compatible with its equals method. 
D) Your class's hashCode method does not need to be compatible with its equals method.

Question 18

Which Java package contains the LinkedList class?

Accepted Answer

A) java.lang 
B) java.io 
C) java.collections 
D) java.util 
A) java.lang 
B) java.io 
C) java.collections 
D) java.util

Question 19

You need a data structure in your program for finding a path out of a maze using backtracking.Which data structure would be most appropriate to model this situation?

Accepted Answer

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

Question 20

Consider the following code snippet:   What will be printed when this code is executed?

Accepted Answer

A) [Mary, John, Robert, Sue] 
B) [John, Robert, Sue] 
C) [Mary, Robert, Sue] 
D) [Mary, John, Sue] 
A) [Mary, John, Robert, Sue] 
B) [John, Robert, Sue] 
C) [Mary, Robert, Sue] 
D) [Mary, John, Sue]

Exam 15: The Java Collections Framework

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

You use a(n) ____ to access elements inside a linked list.

What is included in a linked list node? i.a reference to its neighboring nodes II.an array reference III.a data element

Rather than storing values in an array, a linked list uses a sequence of ____.

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.

Assume that you have declared a map named myMap to hold String values with Integer keys.Which of the following statements will correctly retrieve the value associated with a key from myMap?

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".

Select an appropriate expression to complete the following method, which is designed to return the number of elements in the parameter array numbers.If a value appears more than once, it should be counted exactly once.

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:

A queue is a collection that ____.

The nodes of a(n) ____ linked list class store two links: one to the next element and one to the previous one.

Assume that you have declared a set named mySet to hold String elements.Which of the following statements will correctly insert an element into mySet?

Which nodes need to be updated when we insert a new node to become the fourth node from the beginning of a doubly-linked list?

You need to access values in the order in which they were added (first in, first out), and not randomly.Which collection type should you use?

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?

Which of the following statements about hash functions is NOT correct?

You intend to use a hash set with your own object class.Which of the following statements is correct?

Which Java package contains the LinkedList class?

You need a data structure in your program for finding a path out of a maze using backtracking.Which data structure would be most appropriate to model this situation?

Consider the following code snippet: What will be printed when this code is executed?

Introduction

Using Objects

Implementing Classes

Fundamental Data Types

Decisions

Loops

Arrays and Array Lists

Designing Classes

Inheritance

Interfaces

Input/Output and Exception Handling

Object-Oriented Design

Recursion

Sorting and Searching

Basic Data Structures

Tree Structures

Generic Classes

Stream Processing

Graphical User Interfaces

Advanced Input/Output

Multithreading

Internet Networking

Relational Databases

XML

Filters