Deck 10: Introduction to Inheritance

Question 1

When a protected data field or method is created, it can be used within its own class or in any classes extended from that class; but it cannot be used by outside classes.

Answer 1

True

Question 2

Arrows used in a ____ to show inheritance relationships extend from the descendant class and point to the original class.

A) method diagram
B) UML diagram
C) virtual method call
D) composition

Answer 2

B

Question 3

____ is a mechanism that enables one class to acquire all the behaviors and attributes of another class.

A) Inheritance
B) Polymorphism
C) Encapsulation
D) Overriding

Answer 3

A

Question 4

A nonstatic method cannot  override a static member  of a parent class.

Question 5

It is useful to override the parent class members when the superclass data fields and methods are not completely appropriate for the subclass objects.

Question 6

By convention, a class diagram contains the ____ following each attribute or method.

A) data field
B) argument
C) data type
D) class

Question 7

Subclasses are more specific than the superclass they extend.

Question 8

If a programming language does not support ____, the language is not considered object-oriented.

A) syntax
B) applets
C) loops
D) polymorphism

Question 9

The class used as a basis for inheritance is the ____ class.

A) child
B) extends
C) base
D) derived

Question 10

You cannot declare a class to be final .

Question 11

____ polymorphism is the ability of one method to work appropriately for subclasses of the same parent class.

A) Subtype
B) Name
C) Supertype
D) Override

Question 12

When you create any subclass object, the subclass constructor  must execute first, and then the superclass constructor  executes.

Question 13

An error is generated by the compiler when you attempt to override a static method with a nonstatic method.

Question 14

You use the keyword ____ to achieve inheritance in Java.

A) inherit
B) extends
C) super
D) public

Question 15

The ability to use inheritance in Java makes programs easier to write, ____, and more quickly understood.

A) faster
B) more secure
C) more robust
D) less error-prone

Question 16

A class diagram consists of a rectangle divided into three sections.

Question 17

Sometimes the superclass data fields and methods are not entirely appropriate for the subclass objects; in these cases, you want to ____ the parent class members.

A) negate
B) overrule
C) override
D) hide

Question 18

When you create a class by making it inherit from another class, the new class automatically contains the data fields and _____ of the original class.

A) fonts
B) methods
C) class names
D) arrays

Question 19

In a UML diagram, an inheritance relationship is indicated with an arrow that points from the original class  to the descendant class .

Question 20

When you use the method name with a child object, the parent's version of the method is used.

Question 21

An advantage to making a method ____ is that the compiler knows there will be only one version of the method.

A) inheritable
B) private
C) final
D) derived

Question 22

When you create parent and child classes of your own, the child classes use ____ constructors.

A) two
B) three
C) four
D) six

Question 23

Programmers and analysts sometimes use a graphical language to describe classes and object-oriented processes. This language is called ____.

A) pseudocode
B) GUI
C) UML
D) Java

Question 24

Which of the following statements depicts the valid format to call a superclass constructor from a subclass constructor?

A) superclass(name, score);
B) subclass(name, score);
C) extends(name, score);
D) super(name, score);

Question 25

When you create a class and do not provide a(n) ____, Java automatically supplies you with a default one.

A) constructor
B) argument
C) header
D) name

Question 26

Which statement correctly declares a sedan object of the Car class?

A) sedan Car = new sedan();
B) Car sedan = new sedan ();
C) Car sedan = new Car();
D) new sedan() =Car ();

Question 27

The methods in a subclass can use all of the data fields and methods that belong to its parent, with one exception: ____ members of the parent class are not accessible within a child class's methods.

A) private
B) public
C) final
D) protected

Question 28

If a ____ method has the same name as a parent class method and you use the name with a child class object, the child method hides the original.

A) final
B) static
C) protected
D) private

Question 29

If jrStudent is an object of Student , which of the following statements will result in a value of true ?

A) Student = instanceof jrStudent
B) jrStudent instanceof Student
C) instanceof Student = jrStudent
D) Student instanceof jrStudent

Question 30

The term ____ means "many forms."

A) inheritance
B) polymorphism
C) UML
D) virtual

Question 31

When you employ ____, your data can be altered only by the methods you choose and only in ways that you can control.

A) virtual method calls
B) polymorphism
C) information hiding
D) inlining

Question 32

Usually, the subclass constructor only needs to initialize the ____ that are specific to the subclass.

A) objects
B) data fields
C) methods
D) constructors

Question 33

In Java, all instance method calls are ____ by default.

A) private
B) protected
C) virtual method calls
D) inherited

Question 34

The term ____ describes a "has a" relationship.

A) containment
B) owns
C) aggregation
D) superclass

Question 35

You can use the keyword ____ within a method in a derived class to access an overridden method in a base class.

A) sub
B) this
C) protected
D) super

Question 36

Using the keyword ____ provides you with an intermediate level of security between public and private access.

A) protected
B) this
C) super
D) secure

Question 37

You can use the ____ modifier with methods when you don't want the method to be overridden.

A) override
B) access
C) final
D) end

Question 38

Which of the following statements will create a class named Red that is based on the class Color ?

A) public class Red extends Color
B) public Red class extends Color
C) public Color class expands Red
D) public extend Red class Color

Question 39

You are never aware that ____ is taking place; the compiler chooses to use this procedure to save the overhead of calling a method.

A) information hiding
B) polymorphism
C) overriding
D) inlining

Question 40

In most Java classes, the keywo rd ____ precedes each data field, and the keyword ____ precedes each method.

A) public , public
B) private , private
C) public , private
D) private , public

Question 44

What is the difference between derived classes and base classes when considering two classes that inherit from each other?

Question 45

What does polymorphism mean in Java programming?

Question 46

How are real-life examples of inheritance similar to object-oriented programming inheritance?

Question 52

What are the parts of a class diagram and how would you use them?

Question 55

When you instantiate an object that is a member of a subclass, how many constructors are called?

Question 61

What are the three types of methods that you cannot override in a subclass?

Question 62

Use the above code and sections labeled 1, 2, and 3 to answer the following:
Identify the labeled section that is the constructor for the Bicycle class, identify the section of fields of the Bicycle class, and identify the Bicycle class methods.

Question 63

​ public class ASuperClass
{
   public ASuperClass()
   {
      System.out.println("In superclass constructor");
   }
}
public class ASubClass extends ASuperClass
{
   public ASubClass()
   {
      System.out.println("In subclass constructor");
   }
}
public class DemoConstructors
{
   public static void main(String[] args)
   {
      ASubClass child = new ASubClass();
   }
}
​
Given the above code, what will the output be when DemoConstructors executes?

Question 64

Create a class named Student that contains methods getGPA() , setIDNum() , and setGPA() . Be sure to declare variables and methods appropriately as public or private.

Question 65

What is the process of inlining and how is it accomplished in Java?

Question 66

You have a Student class with a constructor that requires two arguments: a character "F" for Freshman and an integer "2020" for the year. Create a Freshman class that is a subclass of Student with a constructor for Freshman . Include the initial super() statement and include a comment that reads "//Other statements go here".

Question 67

What is information hiding and how is it used?

Question 68

class InstanceofDemo
{
    public static void main(String[] args)
   {
        Parent object1 = new Parent();
        Parent object2 = new Child();
        System.out.println("object1 instanceof Parent: "
            + (obj1 instanceof Parent));
        System.out.println("object1 instanceof Child: "
            + (obj1 instanceof Child));
        System.out.println("object1 instanceof MyInterface: "
            + (obj1 instanceof MyInterface));
        System.out.println("object2 instanceof Parent: "
            + (obj2 instanceof Parent));
        System.out.println("object2 instanceof Child: "
            + (obj2 instanceof Child));
        System.out.println("object2 instanceof MyInterface: "
            + (obj2 instanceof MyInterface));
     }
}
The above code defines a parent class (named Parent ), a simple interface (named MyInterface ), and a child class (named Child ) that inherits from the parent and implements the interface.
Following program execution, what will be the output of the six println statements?

Question 69

class Vehicle {}
public class Car extends Vehicle
{
   public static void main(String args[])
   {
      Vehicle myCar = new Car();
      boolean result =  myCar instanceof Car;
      System.out.println(result);
   }
}
The above code uses the instanceof operator to determine whether an object is a member of a class. What will be the output following execution?

Question 70

How is the keyword protected used?

Question 71

Using a class named Student , write the statement to create a yearOne object of the Student class.

Question 72

What are virtual method calls?

Question 73

The UML diagram above derives a subclass called EmployeeWithTerritory from the superclass Employee . Describe what variables and methods the class EmployeeWithTerritory  inherits from the superclass Employee. Also, describe any variables and public methods defined by the subclass EmployeeWithTerritory .

Question 74

public HourlyEmployee(char dept, double rate, int hours)
{
​
     ---- code here ----
​
}
​Given the overloaded constructor above, write the appropriate statement that calls the superclass constructor  and passes the indicated arguments to the superclass constructor.

Question 75

Will the above code compile correctly? Why or why not? Explain your answer.

Question 76

Write the statement to create a class header with a superclass-subclass relationship, with Vehicle as the superclass and Subaru as the subclass.

Question 77

What happens when you write your own constructor in Java and what must you pay attention to?

Question 78

The above code will generate an error message when compiling. Explain the error message and why it occurs.