Question 1

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. C

Question 2

Which of the following indicates that a class named Class1 is a subclass of a class named Class2?

Accepted Answer

A)  public class Class1 extends Class2 
B)  public class Class1 implements Class2 
C)  public class Class2 extends Class1 
D)  public class Class2 implements Class1 
A)  public class Class1 extends Class2 
B)  public class Class1 implements Class2 
C)  public class Class2 extends Class1 
D)  public class Class2 implements Class1 A

Question 3

Consider the following code snippet: public class Motorcycle extends Vehicle
{
) . .
Public Motorcycle(int numberAxles)
{
Super(numberAxles);
}
}
What does this code do?

Accepted Answer

A)  It invokes the constructor of the Vehicle class from within the constructor of the Motorcycle class. 
B)  It invokes the constructor of the Motorcycle class from within the constructor of the Vehicle class. 
C)  It invokes a private method of the Vehicle class from within a method of the Motorcycle class. 
D)  This code will not compile. 
A)  It invokes the constructor of the Vehicle class from within the constructor of the Motorcycle class. 
B)  It invokes the constructor of the Motorcycle class from within the constructor of the Vehicle class. 
C)  It invokes a private method of the Vehicle class from within a method of the Motorcycle class. 
D)  This code will not compile. A

Question 4

Consider the following class hierarchy: public class Vehicle
{
Private String type;
Public Vehicle(String type)
{
This.type = type;
}
Public String displayInfo()
{
Return type;
}
}
Public class LandVehicle extends Vehicle
{
Public LandVehicle(String type)
{
Super(type);
}
}
Public class Auto extends LandVehicle
{
Public Auto(String type)
{
Super(type);
}
}
You have written a program to use these classes, as shown in the following code snippet:
Public class VehicleTester
{
Public static void main(String[] args)
{
Auto myAuto = new Auto("sedan");
System.out.println("MyAuto type = " + ______);
}
}
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 5

Consider the following code snippet: public class Vehicle
{
) . .
Public void setVehicleAtrributes()
{
) . .
}
}
Public class Auto extends Vehicle
{
) . .
Public void setVehicleAtrributes()
{
) . .
}
}
Which of the following statements is correct?

Accepted Answer

A)  The subclass is shadowing a superclass method. 
B)  The subclass is overloading a superclass method. 
C)  The subclass is overriding a superclass method. 
D)  This code will not compile. 
A)  The subclass is shadowing a superclass method. 
B)  The subclass is overloading a superclass method. 
C)  The subclass is overriding a superclass method. 
D)  This code will not compile.

Question 6

Which of the following indicates that the Motorcycle class is a subclass of the Vehicle class?

Accepted Answer

A)  public class Motorcycle extends Vehicle 
B)  public class Motorcycle implements Vehicle 
C)  public class Vehicle extends Motorcycle 
D)  public class Vehicle implements Motorcycle 
A)  public class Motorcycle extends Vehicle 
B)  public class Motorcycle implements Vehicle 
C)  public class Vehicle extends Motorcycle 
D)  public class Vehicle implements Motorcycle

Question 7

Consider the following code snippet: public class Vessel
{
) . .
Public void setVesselClass(double numberAxles)
{
) . .
}
}
Public class Speedboat extends Vessel
{
) . .
Public void setVesselClass(double numberAxles)
{
) . .
}
}
Which of the following statements is correct?

Accepted Answer

A)  The Speedboat class's setVesselClass method overrides the Vessel class's setVesselClass method. 
B)  The Vessel class's setVesselClass method overrides the Speedboat class's setVesselClass method. 
C)  The Speedboat class's setVesselClass method overloads the Vessel class's setVesselClass method. 
D)  The Vessel class's setVesselClass method overloads the Speedboat class's setVesselClass method. 
A)  The Speedboat class's setVesselClass method overrides the Vessel class's setVesselClass method. 
B)  The Vessel class's setVesselClass method overrides the Speedboat class's setVesselClass method. 
C)  The Speedboat class's setVesselClass method overloads the Vessel class's setVesselClass method. 
D)  The Vessel class's setVesselClass method overloads the Speedboat class's setVesselClass method.

Question 8

Consider the classes shown below: public class Parent
{
Public void doSomething() // method 1
{ /* Implementation not shown */ }
}
Public class Child extends Parent
{
Public void doSomething(int n) // method 2
{ /* Implementation not shown */ }
Public void doSomething() // method 3
{ /* Implementation not shown */ }
}
If the variable kid is defined below, which version of the doSomething method can be called on the variable kid?
Child kid = new Child();

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 9

Suppose the class Message is partially defined as shown below public class Message
{
Private String value;
Public Message(String initial)
{
Value = initial;
}
Public String getMessage()
{
Return value;
}
}
A subclass of Message, ExcitedMessage, is defined that will behave like Message, except that it will add two exclamation points to the end of the message. Sample code that uses ExcitedMessage is shown below.
ExcitedMessage greeting = new ExcitedMessage("Hello");
System.out.print(greeting.getMessage());
// will print "Hello!!"
Which ExcitedMessage constructor will give this behavior?

Accepted Answer

A)  public ExcitedMessage(String line) {
Super(line + "!!");
} 
B)  public ExcitedMessage(String line) {
Value = line + "!!";
} 
C)  public ExcitedMessage(String line) {
Line = line + "!!";
Super(line);
} 
D)  public ExcitedMessage(String line) {
New Message(line + "!!");
} 
A)  public ExcitedMessage(String line) {
Super(line + "!!");
} 
B)  public ExcitedMessage(String line) {
Value = line + "!!";
} 
C)  public ExcitedMessage(String line) {
Line = line + "!!";
Super(line);
} 
D)  public ExcitedMessage(String line) {
New Message(line + "!!");
}

Question 10

Consider the following code snippet: Vehicle aVehicle = new Auto();
AVehicle.moveForward(200);
If the Auto class inherits from the Vehicle class, and both classes have an implementation of the moveForward method with the same set of parameters and the same return type, which statement is correct?

Accepted Answer

A)  The moveForward method of the Auto class will be executed. 
B)  The moveForward method of the Vehicle class will be executed. 
C)  You must specify in the code which class's moveForward method is to be used. 
D)  It is not possible to determine which class's method is called. 
A)  The moveForward method of the Auto class will be executed. 
B)  The moveForward method of the Vehicle class will be executed. 
C)  You must specify in the code which class's moveForward method is to be used. 
D)  It is not possible to determine which class's method is called.

Question 11

Consider the following code snippet: public class Motorcycle extends Vehicle
{
Private String model;
) . .
Public Motorcycle(int numberAxles, String modelName)
{
Model = modelName;
Super(numberAxles);
}
}
What does this code do?

Accepted Answer

A)  It invokes the constructor of the Vehicle class from within the constructor of the Motorcycle class. 
B)  It invokes the constructor of the Motorcycle class from within the constructor of the Vehicle class. 
C)  It invokes a private method of the Vehicle class from within a method of the Motorcycle class. 
D)  This code will not compile. 
A)  It invokes the constructor of the Vehicle class from within the constructor of the Motorcycle class. 
B)  It invokes the constructor of the Motorcycle class from within the constructor of the Vehicle class. 
C)  It invokes a private method of the Vehicle class from within a method of the Motorcycle class. 
D)  This code will not compile.

Question 12

Consider the following code snippet: public class Vehicle
{
) . .
Public void setVehicleClass(double numberAxles)
{
) . .
}
}
Public class Motorcycle extends Vehicle
{
) . .
Public void setModelName(String model)
{
) . .
}
Public void setVehicleClass(double numberAxles)
{
) . .
}
}
Which of the following statements is NOT correct?

Accepted Answer

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

Question 13

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 14

Consider the following code snippet: Employee programmer = new Employee(10254, "exempt");
String s = programmer.toString();
Assume that the Employee class has not implemented its own toString() method. What value will s contain when this code is executed?

Accepted Answer

A)  s will contain the values of the instance variables in programmer. 
B)  s will contain only the class name of the programmer object. 
C)  s will contain the class name of the programmer object followed by a hash code. 
D)  This code will not compile. 
A)  s will contain the values of the instance variables in programmer. 
B)  s will contain only the class name of the programmer object. 
C)  s will contain the class name of the programmer object followed by a hash code. 
D)  This code will not compile.

Question 15

Consider the following class hierarchy: public class Vehicle
{
Private String type;
Public Vehicle(String type)
{
This.type = type;
}
Public String displayInfo()
{
Return type;
}
}
Public class LandVehicle extends Vehicle
{
Public LandVehicle(String type)
{
Super(type);
}
}
Public class Auto extends LandVehicle
{
Public Auto(String type)
{
_________;
}
}
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 the Auto declares an instance variable named type. 
A)  super(type); 
B)  super(super(type)); 
C)  super.super(type); 
D)  This cannot be done unless the Auto declares an instance variable named type.

Question 16

Consider the following code snippet: double salary = 45000.00;
String sal = "Current salary is " + salary;
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 17

What must a subclass do to modify a private superclass instance variable?

Accepted Answer

A)  The subclass must simply use the name of the superclass instance variable. 
B)  The subclass must declare its own instance variable with the same name as the superclass instance variable. 
C)  The subclass must use a public method of the superclass (if it exists) to update the superclass's private instance variable. 
D)  The subclass must have its own public method to update the superclass's private instance variable. 
A)  The subclass must simply use the name of the superclass instance variable. 
B)  The subclass must declare its own instance variable with the same name as the superclass instance variable. 
C)  The subclass must use a public method of the superclass (if it exists) to update the superclass's private instance variable. 
D)  The subclass must have its own public method to update the superclass's private instance variable.

Question 18

The ____ reserved word in a class definition ensures that subclasses cannot be created from this class.

Accepted Answer

A)  abstract 
B)  anonymous 
C)  final 
D)  static 
A)  abstract 
B)  anonymous 
C)  final 
D)  static

Question 19

Consider the following code snippet: public abstract class Machine
{
Public abstract void setRPMs();
) . .
}
You wish to create a concrete subclass named PolisherMachine. Which of the following is the correct way to declare this subclass?

Accepted Answer

A)  public class PolisherMachine implements Machine
{
Public void setRPMs() { . . . }
} 
B)  public class PolisherMachine extends Machine
{
Void setRPMs() { . . . }
} 
C)  public class PolisherMachine implements Machine
{
Void setRPMs() { . . . }
} 
D)  public class PolisherMachine extends Machine
{
Public void setRPMs() { . . . }
} 
A)  public class PolisherMachine implements Machine
{
Public void setRPMs() { . . . }
} 
B)  public class PolisherMachine extends Machine
{
Void setRPMs() { . . . }
} 
C)  public class PolisherMachine implements Machine
{
Void setRPMs() { . . . }
} 
D)  public class PolisherMachine extends Machine
{
Public void setRPMs() { . . . }
}

Question 20

Which of the following indicates that a class named ClassA class is a superclass of the ClassB class?

Accepted Answer

A)  public class ClassB extends ClassA 
B)  public class ClassB implements ClassA 
C)  public class ClassA extends ClassB 
D)  public class ClassA implements ClassB 
A)  public class ClassB extends ClassA 
B)  public class ClassB implements ClassA 
C)  public class ClassA extends ClassB 
D)  public class ClassA implements ClassB

Which of the following is true regarding subclasses?

Which of the following indicates that a class named Class1 is a subclass of a class named Class2?

Consider the following code snippet: public class Motorcycle extends Vehicle { ) . . Public Motorcycle(int numberAxles) { Super(numberAxles); } } What does this code do?

Consider the following code snippet: public class Vehicle { ) . . Public void setVehicleAtrributes() { ) . . } } Public class Auto extends Vehicle { ) . . Public void setVehicleAtrributes() { ) . . } } Which of the following statements is correct?

Which of the following indicates that the Motorcycle class is a subclass of the Vehicle class?

Consider the following code snippet: public class Vessel { ) . . Public void setVesselClass(double numberAxles) { ) . . } } Public class Speedboat extends Vessel { ) . . Public void setVesselClass(double numberAxles) { ) . . } } Which of the following statements is correct?

Consider the following code snippet: Vehicle aVehicle = new Auto(); AVehicle.moveForward(200); If the Auto class inherits from the Vehicle class, and both classes have an implementation of the moveForward method with the same set of parameters and the same return type, which statement is correct?

Consider the following code snippet: public class Motorcycle extends Vehicle { Private String model; ) . . Public Motorcycle(int numberAxles, String modelName) { Model = modelName; Super(numberAxles); } } What does this code do?

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

Consider the following code snippet: Employee programmer = new Employee(10254, "exempt"); String s = programmer.toString(); Assume that the Employee class has not implemented its own toString() method. What value will s contain when this code is executed?

Consider the following code snippet: double salary = 45000.00; String sal = "Current salary is " + salary; Which of the following statements is correct?

What must a subclass do to modify a private superclass instance variable?

The ____ reserved word in a class definition ensures that subclasses cannot be created from this class.

Consider the following code snippet: public abstract class Machine { Public abstract void setRPMs(); ) . . } You wish to create a concrete subclass named PolisherMachine. Which of the following is the correct way to declare this subclass?

Which of the following indicates that a class named ClassA class is a superclass of the ClassB class?

Introduction

Using Objects

Implementing Classes

Fundamental Data Types

Decisions

Loops

Arrays and Array Lists

Designing Classes

Interfaces

Inputoutput and Exception Handling

Object-Oriented Design

Recursion

Sorting and Searching

The Java Collections Framework

Basic Data Structures

Tree Structures

Generic Classes

Graphical User Interfaces

Streams and Binary Inputoutput

Multithreading

Internet Networking

Relational Databases

XML

Web Applications

Filters

Exam 9: Inheritance

Which of the following is true regarding subclasses?

Which of the following indicates that a class named Class1 is a subclass of a class named Class2?

Consider the following code snippet: public class Motorcycle extends Vehicle { ) . . Public Motorcycle(int numberAxles) { Super(numberAxles); } } What does this code do?

Consider the following code snippet: public class Vehicle { ) . . Public void setVehicleAtrributes() { ) . . } } Public class Auto extends Vehicle { ) . . Public void setVehicleAtrributes() { ) . . } } Which of the following statements is correct?

Which of the following indicates that the Motorcycle class is a subclass of the Vehicle class?

Consider the following code snippet: public class Vessel { ) . . Public void setVesselClass(double numberAxles) { ) . . } } Public class Speedboat extends Vessel { ) . . Public void setVesselClass(double numberAxles) { ) . . } } Which of the following statements is correct?

Consider the following code snippet: Vehicle aVehicle = new Auto(); AVehicle.moveForward(200); If the Auto class inherits from the Vehicle class, and both classes have an implementation of the moveForward method with the same set of parameters and the same return type, which statement is correct?

Consider the following code snippet: public class Motorcycle extends Vehicle { Private String model; ) . . Public Motorcycle(int numberAxles, String modelName) { Model = modelName; Super(numberAxles); } } What does this code do?

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

Consider the following code snippet: Employee programmer = new Employee(10254, "exempt"); String s = programmer.toString(); Assume that the Employee class has not implemented its own toString() method. What value will s contain when this code is executed?

Consider the following code snippet: double salary = 45000.00; String sal = "Current salary is " + salary; Which of the following statements is correct?

What must a subclass do to modify a private superclass instance variable?

The ____ reserved word in a class definition ensures that subclasses cannot be created from this class.

Consider the following code snippet: public abstract class Machine { Public abstract void setRPMs(); ) . . } You wish to create a concrete subclass named PolisherMachine. Which of the following is the correct way to declare this subclass?

Which of the following indicates that a class named ClassA class is a superclass of the ClassB class?

Introduction

Using Objects

Implementing Classes

Fundamental Data Types

Decisions

Loops

Arrays and Array Lists

Designing Classes

Interfaces

Inputoutput and Exception Handling

Object-Oriented Design

Recursion

Sorting and Searching

The Java Collections Framework

Basic Data Structures

Tree Structures

Generic Classes

Graphical User Interfaces

Streams and Binary Inputoutput

Multithreading

Internet Networking

Relational Databases

XML

Web Applications

Filters