Deck 9: Inheritance

Question 1

Which of the following statements declares Salaried as a subclass of PayType?

A) public class Salaried implements PayType
B) public class PayType derives Salaried
C) public class Salaried extends PayType
D) public class Salaried derivedFrom(Paytype)

Answer 1

C

Question 2

In object-oriented programming, ________ allows you to extend the capabilities of a class by creating another class that is a specialized version of it.

A) prototyping
B) code reusability
C) inheritance
D) data hiding

Answer 2

C

Question 3

When one object is a specialized version of another object, there is this type of relationship between them.

A) "is a"
B) "contains a"
C) "has a"
D) "consists of"

Answer 3

A

Question 4

If a subclass constructor does not explicitly call a superclass constructor,

A) the superclass's fields will be set to the default values for their data types.
B) Java will automatically call the superclass's default constructor immediately after the code in the subclass's constructor executes.
C) it must include the code necessary to initialize the superclass fields.
D) Java will automatically call the superclass's default constructor just before the code in the subclass's constructor executes.

Question 5

When an "is a" relationship exists between objects, it means that the specialized object has

A) some of the characteristics of the general class, but not all, plus additional characteristics.
B) some of the characteristics of the general object, but not all.
C) none of the characteristics of the general object.
D) all the characteristics of the general object, plus additional characteristics that make it special.

Question 6

A(n) ________ is a method that appears in a superclass, but expects to be overridden in a subclass.

A) abstract method
B) protected method
C) static method
D) overloaded method

Question 7

In the following statement, which is the subclass?
Public class ClassA extends ClassB implements ClassC

A) ClassA
B) ClassB
C) ClassC
D) ClassB and ClassC

Question 8

This shows the inheritance relationships among classes in a manner that is similar to a family tree.

A) UML diagram
B) CRC card
C) flowchart
D) class hierarchy

Question 9

In a class hierarchy,

A) the more general classes are toward the right of the tree and the more specialized classes are toward the left.
B) the more general classes are toward the left of the tree and the more specialized classes are toward the right.
C) the more general classes are toward the bottom of the tree and the more specialized classes are toward the top.
D) the more general classes are toward the top of the tree and the more specialized classes are toward the bottom.

Question 10

A class becomes abstract when you place the ________ key word in the class definition.

A) super
B) extends
C) final
D) abstract

Question 11

You can use this operator to determine whether an object is an instance of a particular class.

A) equals
B) instanceof
C) >>
D) isa

Question 12

All fields declared in an interface

A) have protected access.
B) must be initialized in the class implementing the interface.
C) have private access.
D) are treated as final and static.

Question 13

A ________ member's access is somewhere between private and public.

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

Question 14

A subclass can directly access

A) only protected and private members of the superclass.
B) all members of the superclass.
C) only public and private members of the superclass.
D) only public and protected members of the superclass.

Question 15

When a class does not use the extends key word to inherit from another class, Java automatically extends it from the ________ class.

A) Object
B) subclass
C) superclass
D) public

Question 16

If you do not provide an access specifier for a class member, the class member is given ________ access by default.

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

Question 17

When a method is declared with the ________ modifier, it cannot be overridden in a subclass.

A) final
B) super
C) void
D) public

Question 18

In the following statement, which is the superclass?
Public class ClassA extends ClassB implements ClassC

A) ClassA
B) ClassB
C) ClassC
D) ClassB and ClassC

Question 19

This key word indicates that a class inherits from another class.

A) final
B) super
C) implements
D) extends

Question 20

In Java, a reference variable is ________ because it can reference objects of types different from its own, as long as those types are related to its type through inheritance.

A) static
B) dynamic
C) polymorphic
D) public

Question 21

In ________, inheritance is shown with a line that has an open arrowhead at one end that points to the superclass.

A) pseudocode
B) UML diagrams
C) CRC cards
D) hierarchy charts

Question 22

You show inheritance in a UML diagram by connecting two classes with a line that has an open arrowhead that points to the subclass.

Question 23

You can write a super statement that calls a superclass constructor, but only in the subclass's constructor.

Question 24

All methods specified by an interface are

A) private.
B) public.
C) protected.
D) static.

Question 25

Because the subclass is more specialized than the superclass, it is sometimes necessary for the subclass to replace inadequate superclass methods with more suitable ones.

Question 26

If a method in a subclass has the same signature as a method in the superclass, the subclass method ________ the superclass method.

A) inherits
B) overrides
C) overloads
D) implements

Question 27

Which of the following statements correctly specifies two interfaces?

A) public class ClassA implements [Interface1, Interface2]
B) public class ClassA implements (Interface1, Interface2)
C) public class ClassA implements Interface1 | Interface2
D) public class ClassA implements Interface1, Interface2

Question 28

In a UML diagram, you show a realization relationship by connecting a class and an interface with a

A) dashed line that has an open arrowhead at one end.
B) line that has an open diamond at one end.
C) dashed line.
D) line that has an open arrowhead at one end.

Question 29

An abstract class is not instantiated itself, but serves as a superclass for other classes.

Question 30

When an "is a" relationship exists between objects, it means that the specialized object has all of the characteristics of the general object, plus additional characteristics that make it special.

Question 31

When a subclass overrides a superclass method, only the subclass's version of the method can be called with a subclass object.

Question 32

Because every class directly or indirectly inherits from the Object class, every class inherits the Object class's members.

Question 33

When a class implements an interface, an inheritance relationship known as ________ is established.

A) implemented heritage
B) interface inheritance
C) realized inheritance
D) abstract inheritance

Question 34

A protected member of a class may be directly accessed by

A) methods of the same class.
B) methods of a subclass.
C) methods in the same package.
D) All of the above

Question 35

When a class contains an abstract method, you cannot create an instance of the class.

Question 36

In an inheritance relationship, the subclass constructor always executes before the superclass constructor.

Question 37

If a method in a subclass has the same signature as a method in the superclass, the subclass method overrides the superclass method.

Question 38

In the following statement, which is the interface?
Public class ClassA extends ClassB implements ClassC

A) ClassA
B) ClassB
C) ClassC
D) ClassA, ClassB, and ClassC

Question 39

Protected class members can be denoted in a UML diagram with the ________ symbol.

A) +
B) -
C) *
D) #

Question 40

If ClassC is derived from ClassB, which is derived from ClassA, this would be an example of

A) a chain of inheritance.
B) linear inheritance.
C) multiple interfaces.
D) cascading classes.