Question 1

If a class has an abstract method, which of the following statements is NOT true?

Accepted Answer

A) You can construct an object from this class. 
B) You can have an object reference whose type is this class. 
C) You can inherit from this class. 
D) All non-abstract subclasses of this class must implement this method. 
A) You can construct an object from this class. 
B) You can have an object reference whose type is this class. 
C) You can inherit from this class. 
D) All non-abstract subclasses of this class must implement this method.

Question 2

Which of the following statements about abstract methods is true?

Accepted Answer

A) An abstract method has a name, parameters, and a return type, but no code in the body of the method. 
B) An abstract method has parameters, a return type, and code in its body, but has no defined name. 
C) An abstract method has a name, a return type, and code in its body, but has no parameters. 
D) An abstract method has only a name and a return type, but no parameters or code in its body. 
A) An abstract method has a name, parameters, and a return type, but no code in the body of the method. 
B) An abstract method has parameters, a return type, and code in its body, but has no defined name. 
C) An abstract method has a name, a return type, and code in its body, but has no parameters. 
D) An abstract method has only a name and a return type, but no parameters or code in its body.

Question 3

Consider the following code snippet:   Which of the following statements is correct?

Accepted Answer

A) The toString() method of the Object class is being used to set the value of salary. 
B) The toString() method of the Double class is being used to set the value of salary. 
C) No toString() method is being used to set the value of salary. 
D) This code will not compile. 
A) The toString() method of the Object class is being used to set the value of salary. 
B) The toString() method of the Double class is being used to set the value of salary. 
C) No toString() method is being used to set the value of salary. 
D) This code will not compile.

Question 4

Consider the classes shown below:

Accepted Answer

A) -7 24 
B) 24 24 
C) -7 -7 
D) 24 -7 
A) -7 24 
B) 24 24 
C) -7 -7 
D) 24 -7

Question 5

The term for a class from which you cannot create objects is

Accepted Answer

A) Abstract class. 
B) Concrete class. 
C) Non-inheritable class. 
D) Superclass. 
A) Abstract class. 
B) Concrete class. 
C) Non-inheritable class. 
D) Superclass.

Question 6

Consider the following code snippet:

You wish to create a concrete subclass named PolisherHachine. Which of the following is the correct way to declare this subclass?

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)

Question 7

Consider the following class hierarchy:   Complete the code in this program snippet to correctly display the auto's type.

Accepted Answer

A) myAuto.displayInfo() 
B) myAuto.super.displayInfo() 
C) myAuto.super.super.displayInfo() 
D) This cannot be done unless the Auto class overrides the displayInfo method. 
A) myAuto.displayInfo() 
B) myAuto.super.displayInfo() 
C) myAuto.super.super.displayInfo() 
D) This cannot be done unless the Auto class overrides the displayInfo method.

Question 8

When the reserved word super is followed by a parenthesis, what does it indicate?

Accepted Answer

A) A call to a superclass method. 
B) A call to a superclass constructor. 
C) A call to a subclass method. 
D) A call to a subclass constructor. 
A) A call to a superclass method. 
B) A call to a superclass constructor. 
C) A call to a subclass method. 
D) A call to a subclass constructor.

Question 9

Consider the following code snippet:   Which of the following statements is NOT correct?

Accepted Answer

A) An object of type Motorcycle can call the setVehicleClass method of the Vehicle class on itself. 
B) An object of type Vehicle can call the setModelName method on itself. 
C) The Motorcycle class's SetVehicleClass method overrides the Vehicle class's setVehicleClass method. 
D) An object of type Motorcycle can call the setVehicleClass method of the Motorcycle class on itself. 
A) An object of type Motorcycle can call the setVehicleClass method of the Vehicle class on itself. 
B) An object of type Vehicle can call the setModelName method on itself. 
C) The Motorcycle class's SetVehicleClass method overrides the Vehicle class's setVehicleClass method. 
D) An object of type Motorcycle can call the setVehicleClass method of the Motorcycle class on itself.

Question 10

Which of the following is true regarding subclasses?

Accepted Answer

A) A subclass has access to private instance variables of its superclass. 
B) A subclass does not have access to public instance variables of its superclass. 
C) A subclass must specify the implicit parameter to use methods inherited from its superclass. 
D) A subclass has no access to private instance variables of its superclass. 
A) A subclass has access to private instance variables of its superclass. 
B) A subclass does not have access to public instance variables of its superclass. 
C) A subclass must specify the implicit parameter to use methods inherited from its superclass. 
D) A subclass has no access to private instance variables of its superclass.

Question 11

Consider the following class hierarchy:   Complete the code in the Auto class method named displayAutoType to return the type data.

Accepted Answer

A) super(type); 
B) super.type; 
C) super.super.type; 
D) super.displayInfo() 
A) super(type); 
B) super.type; 
C) super.super.type; 
D) super.displayInfo()

Question 12

To test whether an object belongs to a particular type, use

Accepted Answer

A) the this reserved word. 
B) the subclassOf reserved word. 
C) the instanceof operator. 
D) the equals method. 
A) the this reserved word. 
B) the subclassOf reserved word. 
C) the instanceof operator. 
D) the equals method.

Question 13

Which of the following is true regarding subclasses?

Accepted Answer

A) A subclass inherits methods from its superclass but not instance variables. 
B) A subclass inherits instance variables from its superclass but not methods. 
C) A subclass inherits methods and instance variables from its superclass. 
D) A subclass does not inherit methods or instance variables from its superclass. 
A) A subclass inherits methods from its superclass but not instance variables. 
B) A subclass inherits instance variables from its superclass but not methods. 
C) A subclass inherits methods and instance variables from its superclass. 
D) A subclass does not inherit methods or instance variables from its superclass.

Question 14

All rodents are mammals and all canines are mammals.No canines are rodents and no rodents are canines.What hierarchy best captures this information?

Accepted Answer

A) Mammal is a superclass of Rodent and Mammal 
B) Rodent is a superclass of Mammal and Canine is a superclass of Mammal 
C) Mammal is a superclass of Rodent and Rodent is a superclass of Canine 
D) Mammal is a superclass of Canine and Canine is a superclass of Rodent 
A) Mammal is a superclass of Rodent and Mammal 
B) Rodent is a superclass of Mammal and Canine is a superclass of Mammal 
C) Mammal is a superclass of Rodent and Rodent is a superclass of Canine 
D) Mammal is a superclass of Canine and Canine is a superclass of Rodent

Question 15

Which of the following is true regarding subclasses?

Accepted Answer

A) A subclass that inherits methods from its superclass may not override the methods. 
B) A subclass that inherits instance variables from its superclass may not declare additional instance variables. 
C) A subclass may inherit methods or instance variables from its superclass but not both. 
D) A subclass may inherit methods and instance variables from its superclass, and may also implement its own methods and declare its own instance variables. 
A) A subclass that inherits methods from its superclass may not override the methods. 
B) A subclass that inherits instance variables from its superclass may not declare additional instance variables. 
C) A subclass may inherit methods or instance variables from its superclass but not both. 
D) A subclass may inherit methods and instance variables from its superclass, and may also implement its own methods and declare its own instance variables.

Question 16

Consider the classes shown below:

Accepted Answer

A) Methods 1 and 2 only 
B) Method 2 only 
C) Methods 2 and 3 only 
D) Methods 1, 2, and 3 
A) Methods 1 and 2 only 
B) Method 2 only 
C) Methods 2 and 3 only 
D) Methods 1, 2, and 3

Question 17

Insert the missing code in the following code fragment.This fragment is intended to call the Vehicle class's method.

Accepted Answer

A) Motorcyle.setVehicleClass(2.0); 
B) Vehicle.setVehicleClass(2.0); 
C) numberAxles = 2.0; 
D) setVehicleClass(2.0); 
A) Motorcyle.setVehicleClass(2.0); 
B) Vehicle.setVehicleClass(2.0); 
C) numberAxles = 2.0; 
D) setVehicleClass(2.0);

Question 18

Consider the following code snippet, which is meant to override the equals() method of the Object class:   What is wrong with this code?

Accepted Answer

A) A class cannot override the equals() method of the Object class. 
B) The equals() method must be declared as private. 
C) A class cannot change the parameters of a superclass method when overriding it. 
D) There is nothing wrong with this code. 
A) A class cannot override the equals() method of the Object class. 
B) The equals() method must be declared as private. 
C) A class cannot change the parameters of a superclass method when overriding it. 
D) There is nothing wrong with this code.

Question 19

Consider the following code snippet:   Assume that the Auto class inherits from the Vehicle class, and neither class has an implementation of the toString() method.Which of the following statements is correct?

Accepted Answer

A) The toString() method of the Object class will be used when this code is executed. 
B) The toString() method of the String class will be used when this code is executed. 
C) This code will not compile because there is no toString() method in the Vehicle class. 
D) This code will not compile because there is no toString() method in the Auto class. 
A) The toString() method of the Object class will be used when this code is executed. 
B) The toString() method of the String class will be used when this code is executed. 
C) This code will not compile because there is no toString() method in the Vehicle class. 
D) This code will not compile because there is no toString() method in the Auto class.

Question 20

Consider the following class hierarchy:   Complete the code in the Auto class constructor to store the type data.

Accepted Answer

A) super(type); 
B) super(super(type)); 
C) super.super(type); 
D) This cannot be done unless Auto declares an instance variable named type. 
A) super(type); 
B) super(super(type)); 
C) super.super(type); 
D) This cannot be done unless Auto declares an instance variable named type.

Exam 9: Inheritance

If a class has an abstract method, which of the following statements is NOT true?

Which of the following statements about abstract methods is true?

Consider the following code snippet: Which of the following statements is correct?

Consider the classes shown below:

The term for a class from which you cannot create objects is

Consider the following code snippet: You wish to create a concrete subclass named PolisherHachine. Which of the following is the correct way to declare this subclass?

Consider the following class hierarchy: Complete the code in this program snippet to correctly display the auto's type.

When the reserved word super is followed by a parenthesis, what does it indicate?

Consider the following code snippet: Which of the following statements is NOT correct?

Which of the following is true regarding subclasses?

Consider the following class hierarchy: Complete the code in the Auto class method named displayAutoType to return the type data.

To test whether an object belongs to a particular type, use

Which of the following is true regarding subclasses?

All rodents are mammals and all canines are mammals.No canines are rodents and no rodents are canines.What hierarchy best captures this information?

Which of the following is true regarding subclasses?

Consider the classes shown below:

Insert the missing code in the following code fragment.This fragment is intended to call the Vehicle class's method.

Consider the following code snippet, which is meant to override the equals() method of the Object class: What is wrong with this code?

Consider the following code snippet: Assume that the Auto class inherits from the Vehicle class, and neither class has an implementation of the toString() method.Which of the following statements is correct?

Consider the following class hierarchy: Complete the code in the Auto class constructor to store the type data.

Introduction

Using Objects

Implementing Classes

Fundamental Data Types

Decisions

Loops

Arrays and Array Lists

Designing Classes

Interfaces

Input/Output and Exception Handling

Object-Oriented Design

Recursion

Sorting and Searching

The Java Collections Framework

Basic Data Structures

Tree Structures

Generic Classes

Stream Processing

Graphical User Interfaces

Advanced Input/Output

Multithreading

Internet Networking

Relational Databases

XML

Filters