Question 1

Consider the following code snippet: public class Employee
{
) . .
Public void setDepartment(String deptName)
{
) . .
}
}
Public class Programmer extends Employee
{
) . .
Public void setProjectName(String projName)
{
) . .
}
Public void setDepartment(String deptName)
{
) . .
}
}
Which of the following statements is NOT correct?
A) The Programmer class can call the setDepartment method of the Employee class.
B) The Employee class can call the setProjectName method.
C) The Programmer class's setDepartment method overrides the Employee class's setDepartment method.
D) The Programmer class can call the setDepartment method of the Programmer class.

Accepted Answer

The Employee class cannot call the setProjectName method because it is not defined in the Employee class or any of its superclasses. It is specific to the Programmer class.

Question 2

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?
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.

Accepted Answer

The Speedboat class's setVesselClass method overrides the Vessel class's setVesselClass method because it provides a new implementation of the method in a subclass.

Question 3

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?
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.

Accepted Answer

The Vehicle class cannot call the setModelName method because it is not defined in the Vehicle class; it is defined in the Motorcycle class.

Question 4

If a subclass uses the same method name but different parameter types for a method that appears in its superclass, ____.
A) the subclass method has overloaded its superclass's method.
B) the subclass method has overridden its superclass's method.
C) the subclass has implemented its superclass's method.
D) a compiler error will occur.

Accepted Answer

Overloading occurs when two or more methods in the same class or subclass have the same name but different parameter lists.

Question 5

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

Accepted Answer

The code snippet uses the `super` keyword to invoke the constructor of the `Vehicle` class from within the constructor of the `Motorcycle` class.

Question 6

If a subclass defines the same method name and the same parameter types for a method that appears in its superclass, ____.
A) the subclass method overloads the superclass method.
B) the subclass method overrides the superclass method.
C) the subclass has implemented its superclass's method.
D) a compiler error will occur.

Accepted Answer

The subclass method overrides the superclass method because it provides a new implementation for the method with the same name and parameter types.

Question 7

Consider the following code snippet: public class Vehicle
{
) . .
Public void setVehicleClass(double numberAxles)
{
) . .
}
}
Public class Motorcycle extends Vehicle
{
) . .
Public void setVehicleClass(double numberAxles)
{
) . .
}
}
Which of the following statements is correct? (I changed the wording below, because methods override methods. . .classes don't override methods)
A) The Motorcycle class's setVehicleClass method overrides the Vehicle class's setVehicleClass method.
B) The Vehicle class's setVehicleClass method overrides the Motorcycle class's setVehicleClass method.
C) The Motorcycle class's setVehicleClass method overloads the Vehicle class's setVehicleClass method.
D) The Vehicle class's setVehicleClass method overloads the Motorcycle class's setVehicleClass method.

Accepted Answer

The Motorcycle class's setVehicleClass method overrides the Vehicle class's setVehicleClass method because it provides a new implementation for the method in the subclass.

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

Accepted Answer

The answer of Consider the classes shown below: public class...

Question 9

Consider the following code snippet: public class Motorcycle extends Vehicle
{
) . .
Public Motorcycle(int numberAxles)
{
Super(numberAxles); //line #1
}
}
If the line marked "//line #1" was missing, which of these statements would be correct?
A) The Motorcycle class constructor would invoke the constructor of the Vehicle class with no parameters.
B) The Vehicle class constructor would invoke the constructor of the Motorcycle class with no parameters.
C) The Motorcycle class constructor would invoke the constructor of the Vehicle class with a parameter value of 0.
D) This code would not compile.

Accepted Answer

In Java, if a constructor does not explicitly call a superclass constructor, the default no-argument constructor of the superclass is called automatically.

Question 10

If a subclass contains a method with the same name as a method in its superclass, but with different parameter types, the subclass method is said to ____ the method of the superclass.
A) implement
B) inherit
C) override
D) overload

Accepted Answer

When a subclass contains a method with the same name as a method in its superclass but with different parameter types, it is said to overload the method of the superclass. Overloading involves having multiple methods with the same name but different parameter lists within the same class or subclass.

Question 11

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

Accepted Answer

The answer of Consider the following code snippet: public class...

Question 12

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?
Parent kid = new Child();
A) Method 1 only
B) Methods 2 and 3 only
C) Methods 1 and 2 only
D) Methods 1, 2, and 3

Accepted Answer

The answer of Consider the classes shown below: public class...

Question 13

Consider the following code snippet: public class Auto extends Vehicle
{
) . .
Public Auto(int numberAxles)
{
Super(numberAxles);
}
}
What does this code do?
A) It invokes the constructor of the Vehicle class from within the constructor of the Auto class.
B) It invokes the constructor of the Auto 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 Auto class.
D) This code will not compile.

Accepted Answer

The code snippet uses the `super` keyword to call the constructor of the superclass `Vehicle` from the constructor of the subclass `Auto`, passing `numberAxles` as an argument.

Question 14

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

Accepted Answer

The code uses the `super` keyword to call the constructor of the superclass `Vehicle` from the constructor of the subclass `Motorcycle`.

Question 15

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?
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.

Accepted Answer

The answer of Consider the following code snippet: public class...

Question 16

To override a superclass method in a subclass, the subclass method ____.
A) Must use a different method name.
B) Must use the same method name and the same parameter types.
C) Must use a different method name and the same parameter types.
D) Must use a different method name and different parameter types.

Accepted Answer

The subclass method must use the same method name and the same parameter types as the superclass method in order to override it.

Question 17

Consider the following code snippet that appears in a subclass: public void deposit(double amount)
{
TransactionCount ++;
Deposit(amount);
}
Which of the following statements is true?
A) This method will call itself.
B) This method calls a public method in its subclass.
C) This method calls a private method in its superclass
D) This method calls a public method in its superclass.

Accepted Answer

The answer of Consider the following code snippet that appears...

Question 18

Consider the following code snippet: public class Vehicle
{
) . .
Public void setVehicleClass(double numberAxles)
{
) . .
}
}
Public class Auto extends Vehicle
{
) . .
Public void setVehicleClass(int numberAxles)
{
) . .
}
}
Which of the following statements is correct?
A) The Auto class overrides the setVehicleClass method.
B) The Vehicle class overrides the setVehicleClass method.
C) The Auto class overloads the setVehicleClass method.
D) The Vehicle class overloads the setVehicleClass method.

Accepted Answer

The Auto class overloads the setVehicleClass method because it provides a method with the same name but a different parameter type (int instead of double).

Question 19

Which reserved word must be used to call a method of a superclass?
A) this
B) my
C) parent
D) super

Accepted Answer

The reserved word "super" is used to call a method of a superclass. This is necessary when a subclass inherits from a superclass and wants to utilize the methods of the superclass.

Question 20

Consider the following code snippet: public class Employee
{
) . .
Public void setEmployeeDept(String deptNum)
{
) . .
}
}
Public class Programmer extends Employee
{
) . .
Public void setEmployeeDept(int deptNum)
{
) . .
}
}
Which of the following statements is correct?
A) The Programmer class overrides the setEmployeeDept method.
B) The Employee class overrides the setEmployeeDept method.
C) The Programmer class overloads the setEmployeeDept method.
D) The Employee class overloads the setEmployeeDept method.

Accepted Answer

The Programmer class overloads the setEmployeeDept method because it provides a method with the same name but a different parameter type (int instead of String) compared to the method in the Employee class.

Quiz 9: Inheritance

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?

If a subclass uses the same method name but different parameter types for a method that appears in its superclass, ____.

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

If a subclass defines the same method name and the same parameter types for a method that appears in its superclass, ____.

Consider the following code snippet: public class Motorcycle extends Vehicle { ) . . Public Motorcycle(int numberAxles) { Super(numberAxles) ; //line #1 } } If the line marked "//line #1" was missing, which of these statements would be correct?

If a subclass contains a method with the same name as a method in its superclass, but with different parameter types, the subclass method is said to ____ the method of the superclass.

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 Auto extends Vehicle { ) . . Public Auto(int numberAxles) { Super(numberAxles) ; } } What does this code do?

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 Motorcycle extends Vehicle { Private String model; ) . . Public Motorcycle(int numberAxles, String modelName) { Model = modelName; Super(numberAxles) ; } } What does this code do?

To override a superclass method in a subclass, the subclass method ____.

Consider the following code snippet that appears in a subclass: public void deposit(double amount) { TransactionCount ++; Deposit(amount) ; } Which of the following statements is true?

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

Which reserved word must be used to call a method of a superclass?

Consider the following code snippet: public class Employee { ) . . Public void setEmployeeDept(String deptNum) { ) . . } } Public class Programmer extends Employee { ) . . Public void setEmployeeDept(int deptNum) { ) . . } } Which of the following statements is correct?