Question 1

You have created a Motorcycle class which has a constructor with no parameters. Which of the following statements will construct an object of this class?

Accepted Answer

A)  Motorcycle myBike; 
B)  Motorcycle myBike = new Motorcycle(); 
C)  myBike.new(Motorcycle); 
D)  Motorcycle.new(myBike); 
A)  Motorcycle myBike; 
B)  Motorcycle myBike = new Motorcycle(); 
C)  myBike.new(Motorcycle); 
D)  Motorcycle.new(myBike);

Question 2

Insert the missing code in the following code fragment. This fragment is intended to initialize an instance variable.
Public class Motor
{
Private int motorSpeed;
) . .
Public Motor(int motorSpeed)
{
________
}
}

Accepted Answer

A)  Motor.motorSpeed = motorSpeed; 
B)  motorSpeed = this.motorSpeed; 
C)  this.motorSpeed = motorSpeed; 
D)  The constructor parameter variable cannot have the same name as the instance variable. 
A)  Motor.motorSpeed = motorSpeed; 
B)  motorSpeed = this.motorSpeed; 
C)  this.motorSpeed = motorSpeed; 
D)  The constructor parameter variable cannot have the same name as the instance variable.

Question 3

Consider the following code snippet:
Public class Vehicle
{
Private String type;
Private int numAxles;
Public Vehicle(String vehicleType, int VehicleAxles) { . . . }
Public Vehicle(String vehicleType) { . . . }
}
What is wrong with this code?

Accepted Answer

A)  There must be a default constructor with no arguments. 
B)  A class cannot have more than one constructor. 
C)  If a class has more than one constructor, each one should have a unique name. 
D)  There is nothing wrong with this code. 
A)  There must be a default constructor with no arguments. 
B)  A class cannot have more than one constructor. 
C)  If a class has more than one constructor, each one should have a unique name. 
D)  There is nothing wrong with this code.

Question 4

Consider the following class:
Public class Auto
{
Private String make;
Private String model;
Private String year;
Public Auto(String aMake, String aModel, String aYear)
{
Make = aMake;
Model = aModel;
Year = aYear;
}
Public String calcMileage(double milesDriven, double gasUsed)
{
Double milage = milesDriven/gasUsed;
Return mileage.toString();
}
}
Which of the following code snippets will correctly create an object of type Auto and display its mileage?

Accepted Answer

A)  myAuto = new Auto();
System.out.println(myAuto.calcMileage(246.0, 15.8)); 
B)  Auto myAuto = new Auto();
System.out.println(myAuto.calcMileage(246.0, 15.8)); 
C)  Auto myAuto = new Auto("2011", "Ford", "Focus");
System.out.println(myAuto.calcMileage(246.0, 15.8)); 
D)  Auto myAuto = new Auto("Ford", "Focus", "2011");
System.out.println(myAuto.calcMileage(246.0, 15.8)); 
A)  myAuto = new Auto();
System.out.println(myAuto.calcMileage(246.0, 15.8)); 
B)  Auto myAuto = new Auto();
System.out.println(myAuto.calcMileage(246.0, 15.8)); 
C)  Auto myAuto = new Auto("2011", "Ford", "Focus");
System.out.println(myAuto.calcMileage(246.0, 15.8)); 
D)  Auto myAuto = new Auto("Ford", "Focus", "2011");
System.out.println(myAuto.calcMileage(246.0, 15.8));

Question 5

Which choice indicates that a string variable refers to no string?

Accepted Answer

A)  nil 
B)  "" 
C)  null 
D)  empty 
A)  nil 
B)  "" 
C)  null 
D)  empty

Question 6

Which statement calls a constructor with no construction parameters?

Accepted Answer

A)  Circle c = new Circle(); 
B)  Circle c = new Circle; 
C)  Circle c = Circle() 
D)  A call to a constructor must have construction parameters. 
A)  Circle c = new Circle(); 
B)  Circle c = new Circle; 
C)  Circle c = Circle() 
D)  A call to a constructor must have construction parameters.

Question 7

Consider the following code snippet:
Public class Transaction
{
Private int transactionCount;
) . .
}
Which of the following methods would correctly keep track of the total number of transactions?

Accepted Answer

A)  public void addTransactions(int newTransactions)
{
TransactionCount = newTransactions
} 
B)  public void addTransactions(int newTransactions)
{
TransactionCount = transactionCount + newTransactions
} 
C)  public void addTransactions(int newTransactions)
{
NewTransactions = transactionCount
} 
D)  public void addTransactions(int newTransactions)
{
NewTransactions = newTransactions + transactionCount
} 
A)  public void addTransactions(int newTransactions)
{
TransactionCount = newTransactions
} 
B)  public void addTransactions(int newTransactions)
{
TransactionCount = transactionCount + newTransactions
} 
C)  public void addTransactions(int newTransactions)
{
NewTransactions = transactionCount
} 
D)  public void addTransactions(int newTransactions)
{
NewTransactions = newTransactions + transactionCount
}

Question 8

Which of the following statements about class properties is correct?

Accepted Answer

A)  A setter method is used to retrieve the value of a class property. 
B)  A getter method is used to assign the value of a class property. 
C)  A setter method is used to assign the value of a class property. 
D)  You cannot assign values to class properties. 
A)  A setter method is used to retrieve the value of a class property. 
B)  A getter method is used to assign the value of a class property. 
C)  A setter method is used to assign the value of a class property. 
D)  You cannot assign values to class properties.

Question 9

If you do not provide a constructor in a class, which of the following is correct?

Accepted Answer

A)  The compiler will generate a constructor with arguments for each class instance variable and will initialize all of the class instance variables. 
B)  The compiler will generate a constructor with no arguments. 
C)  The compiler will generate a constructor with arguments for each class instance variable. 
D)  The class code will not compile. 
A)  The compiler will generate a constructor with arguments for each class instance variable and will initialize all of the class instance variables. 
B)  The compiler will generate a constructor with no arguments. 
C)  The compiler will generate a constructor with arguments for each class instance variable. 
D)  The class code will not compile.

Question 10

Which of the following statements about constructors is NOT correct?

Accepted Answer

A)  A constructor must have the same name as the class name. 
B)  A call to a constructor must always have construction parameters. 
C)  A constructor initializes the instance variables of an object. 
D)  A class can have more than one constructor. 
A)  A constructor must have the same name as the class name. 
B)  A call to a constructor must always have construction parameters. 
C)  A constructor initializes the instance variables of an object. 
D)  A class can have more than one constructor.

Question 11

Consider the following code snippet:
Public class Course
{
Private int studentCount;
) . .
}
Which of the following methods would correctly keep track of the total number of enrollees in a course?

Accepted Answer

A)  public void addEnrollees(int newEnrollees)
{
StudentCount = newEnrollees
} 
B)  public void addEnrollees(int newEnrollees)
{
StudentCount = studentCount + newEnrollees
} 
C)  public void addEnrollees(int newEnrollees)
{
NewEnrollees = studentCount
} 
D)  public void addEnrollees(int newEnrollees)
{
NewEnrollees = newEnrollees + studentCount
} 
A)  public void addEnrollees(int newEnrollees)
{
StudentCount = newEnrollees
} 
B)  public void addEnrollees(int newEnrollees)
{
StudentCount = studentCount + newEnrollees
} 
C)  public void addEnrollees(int newEnrollees)
{
NewEnrollees = studentCount
} 
D)  public void addEnrollees(int newEnrollees)
{
NewEnrollees = newEnrollees + studentCount
}

Question 12

A method in a class that returns information about an object but does not change the object is called a/an ____ method.

Accepted Answer

A)  mutator 
B)  accessor 
C)  void 
D)  constructor 
A)  mutator 
B)  accessor 
C)  void 
D)  constructor

Question 13

Which of the following statements is true regarding classes?

Accepted Answer

A)  Each object of a class has a separate copy of each instance variable. 
B)  All objects created from a class share a single set of instance variables. 
C)  Private instance variables can be accessed by any user of the object. 
D)  Public instance variables can be accessed only by the object itself. 
A)  Each object of a class has a separate copy of each instance variable. 
B)  All objects created from a class share a single set of instance variables. 
C)  Private instance variables can be accessed by any user of the object. 
D)  Public instance variables can be accessed only by the object itself.

Question 14

Consider the following code snippet:
Public class Employee
{
Private String empID;
Private boolean hourly;
Public Employee(String employeeID, boolean isHourly)
{ ) . . }
}
Which of the following statements can be used to create an object of type Employee?

Accepted Answer

A)  Employee anAuto = new Employee(); 
B)  Employee anAuto = new Employee(10548, true); 
C)  Employee anAuto = new Employee("10548", true); 
D)  Employee anAuto = new Employee(10548, "true"); 
A)  Employee anAuto = new Employee(); 
B)  Employee anAuto = new Employee(10548, true); 
C)  Employee anAuto = new Employee("10548", true); 
D)  Employee anAuto = new Employee(10548, "true");

Question 15

Consider the following code snippet:
Public class Vehicle
{
Private String type;
Public String Vehicle(String type)
{
) . .
}
}
What is wrong with this code?

Accepted Answer

A)  The class instance variable type must be initialized when it is declared. 
B)  The constructor must not have any arguments. 
C)  The constructor must not have a return type declared. 
D)  The constructor's return type must be void. 
A)  The class instance variable type must be initialized when it is declared. 
B)  The constructor must not have any arguments. 
C)  The constructor must not have a return type declared. 
D)  The constructor's return type must be void.

Question 16

Which of the following statements about classes is correct?

Accepted Answer

A)  When programmers work with an object of a class, they do not need to know how the object stores its data or how its methods are implemented. 
B)  When programmers work with an object of a class, they must understand how the object stores its data and how its methods are implemented. 
C)  When programmers work with an object of a class, they must understand only how the object stores its data. 
D)  When programmers work with an object of a class, they must understand only how the object's methods are implemented. 
A)  When programmers work with an object of a class, they do not need to know how the object stores its data or how its methods are implemented. 
B)  When programmers work with an object of a class, they must understand how the object stores its data and how its methods are implemented. 
C)  When programmers work with an object of a class, they must understand only how the object stores its data. 
D)  When programmers work with an object of a class, they must understand only how the object's methods are implemented.

Question 17

When an object is created from a class, the object is called a/an ____ of the class.

Accepted Answer

A)  child 
B)  constructor 
C)  instance 
D)  subclass 
A)  child 
B)  constructor 
C)  instance 
D)  subclass

Question 18

You have created a Fruit class and a ShoppingCart class. Which of the following methods will correctly add a Fruit object to an array list named fruits in the ShoppingCart class?

Accepted Answer

A)  public void add(Fruit aFruit)
{
Fruits.add(new Fruit(aFruit));
} 
B)  public void add(Fruit aFruit)
{
Fruits.add(aFruit);
} 
C)  public void add(Fruit aFruit)
{
Fruits.addItem(new Fruit(aFruit));
} 
D)  public void add(Fruit aFruit)
{
Fruits.addItem(aFruit);
} 
A)  public void add(Fruit aFruit)
{
Fruits.add(new Fruit(aFruit));
} 
B)  public void add(Fruit aFruit)
{
Fruits.add(aFruit);
} 
C)  public void add(Fruit aFruit)
{
Fruits.addItem(new Fruit(aFruit));
} 
D)  public void add(Fruit aFruit)
{
Fruits.addItem(aFruit);
}

Question 19

Insert the missing code in the following code fragment. This fragment is intended to initialize an instance variable.
Public class Vehicle
{
Int numAxles;
Public Vehicle(int axles)
{
NumAxles = axles;
}
Public Vehicle()
{
_________;
}
}
Which of the following lines of code will allow the second constructor to call the first constructor?

Accepted Answer

A)  this. numAxles(0); 
B)  this(0); 
C)  this(axles); 
D)  this(numAxles); 
A)  this. numAxles(0); 
B)  this(0); 
C)  this(axles); 
D)  this(numAxles);

Question 20

A constructor is invoked when ___ to create an object.

Accepted Answer

A)  the class keyword is used 
B)  the class is defined as public 
C)  the new keyword is used 
D)  the class is defined as private 
A)  the class keyword is used 
B)  the class is defined as public 
C)  the new keyword is used 
D)  the class is defined as private

Exam 8: Objects and Classes

You have created a Motorcycle class which has a constructor with no parameters. Which of the following statements will construct an object of this class?

Insert the missing code in the following code fragment. This fragment is intended to initialize an instance variable. Public class Motor { Private int motorSpeed; ) . . Public Motor(int motorSpeed) { ________ } }

Consider the following code snippet: Public class Vehicle { Private String type; Private int numAxles; Public Vehicle(String vehicleType, int VehicleAxles) { . . . } Public Vehicle(String vehicleType) { . . . } } What is wrong with this code?

Which choice indicates that a string variable refers to no string?

Which statement calls a constructor with no construction parameters?

Consider the following code snippet: Public class Transaction { Private int transactionCount; ) . . } Which of the following methods would correctly keep track of the total number of transactions?

Which of the following statements about class properties is correct?

If you do not provide a constructor in a class, which of the following is correct?

Which of the following statements about constructors is NOT correct?

Consider the following code snippet: Public class Course { Private int studentCount; ) . . } Which of the following methods would correctly keep track of the total number of enrollees in a course?

A method in a class that returns information about an object but does not change the object is called a/an ____ method.

Which of the following statements is true regarding classes?

Consider the following code snippet: Public class Employee { Private String empID; Private boolean hourly; Public Employee(String employeeID, boolean isHourly) { ) . . } } Which of the following statements can be used to create an object of type Employee?

Consider the following code snippet: Public class Vehicle { Private String type; Public String Vehicle(String type) { ) . . } } What is wrong with this code?

Which of the following statements about classes is correct?

When an object is created from a class, the object is called a/an ____ of the class.

You have created a Fruit class and a ShoppingCart class. Which of the following methods will correctly add a Fruit object to an array list named fruits in the ShoppingCart class?

A constructor is invoked when ___ to create an object.

Introduction

Fundamental Data Types

Decisionseasy

Loops

Methods

Arrays and Arraylists

Inputoutput and Exception Handling

Inheritance and Interfaces

Graphical User Interfaces

Advanced User Interfaces

Object-Oriented Design

Recursion

Sorting and Searching

The Java Collections Framework

Basic Data Structures

Tree Structures

Generic Classes

Streams and Binary Inputoutput

Multithreading

Internet Networking

Relational Databases

XML

Web Applications

Filters