Deck 8: Polymorphism and Abstract Classes

Question 1

Early binding enables the compiler to be more efficient.

Answer 1

True

Question 2

You cannot create an object using a/an:

A)superclass constructor
B)subclass constructor
C)ancestor class constructor
D)abstract class constructor

Answer 2

D

Question 3

The clone method return type is:

A)the same as the cloned object
B)Object
C)String
D)none of the above

Answer 3

B

Question 4

____________ refers to the process of associating a method definition with a method invocation.

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

Question 5

A class that has at least one abstract method is called an:

A)concrete class
B)encapsulated class
C)abstract class
D)private class

Question 6

Polymorphism refers to the ability to associate many meanings to one method through dynamic binding.

Question 7

Java does not use late binding for methods marked as:

A)final
B)static
C)private
D)all of the above

Question 8

If you choose to use the method clone in your code,you must ___________ the clone method.

A)overload
B)encapsulate
C)override
D)protect

Question 9

__________ refers to the ability to associate many meanings to one method name by means of the late binding mechanism.

A)Inheritance
B)Encapsulation
C)Polymorphism
D)None of the above

Question 10

Assigning an object of a derived class to a variable of a base class is called:

A)static binding
B)dynamic binding
C)upcasting
D)downcasting

Question 11

__________ binding refers to the method definition being associated with the method invocation when the code is compiled.

A)Dynamic
B)Late
C)Early
D)None of the above

Question 12

An abstract class must have the modifier ___________ included in the class heading.

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

Question 13

The principals of object oriented programming include:

A)encapsulation
B)inheritance
C)polymorphism
D)all of the above

Question 14

Late binding refers to the method definition being associated with the method invocation when the method is invoked at run time.

Question 15

The clone method has ________ parameters.

A)zero
B)one
C)two
D)three

Question 16

An abstract method cannot be modified by:

A)public
B)protected
C)private
D)none of the above

Question 17

A class with no abstract methods is called a

A)concrete class
B)encapsulated class
C)abstract class
D)private class

Question 18

Assigning an object of an ancestor class to a descendent class is called:

A)static binding
B)dynamic binding
C)upcasting
D)downcasting

Question 19

A method marked as final means the compiler uses ________ binding.

A)dynamic
B)early
C)late
D)none of the above

Question 20

Java allows an instance of an abstract class to be instantiated.

Question 21

An abstract method serves as a placeholder for a method that must be defined in all derived classes.

Question 22

Draw an inheritance hierarchy to represent a shoe object.The base class should have derived classes of Dress Shoes,Tennis Shoes and Boots.

Question 23

Describe the limitations of the copy constructor.

Question 24

Downcasting should be used only in situations where it makes sense.

Question 25

What is wrong with the following method definition?
public abstract void doSomethingint count)

Question 26

The method clone has one parameter and should return a copy of the calling object.

Question 27

The type of the variable naming an object determines which method names can be used in an invocation with that calling object.

Question 28

Why should the instanceOf operator be used in conjunction with downcasting?

Question 29

What is polymorphism and how does it relate to late binding?

Question 30

The final modifier is included before the definition of the method,then the method can be redefined in a derived class.

Question 31

Explain the difference between early and late binding.

Question 32

Derive a class named Dress Shoes from the base class created in number 9 above.

Question 33

An abstract class is a class that has some methods without complete definitions.

Question 34

Java uses late binding with private methods,methods marked final,or static methods.

Question 35

What are the advantages of polymorphism?

Question 36

Derive a class named Boots from the base class created in number 9 above.

Question 37

Implement the base class in the shoe hierarchy in number 8 above.

Question 38

Write a decision statement to determine if an object should be downcast.

Question 39

Derive a class named Tennis Shoes from the base class created in number 9 above.

Question 40

What is an abstract method?

Question 41

Override the clone method inherited in the Boots class created in number 12 above.

Question 42

Override the clone method inherited in the Tennis Shoes class created in number 11 above.

Question 43

Override the clone method inherited in the Dress Shoes class created in number 10 above.