Deck 9: Inheritance

Question 1

Which of the following shows the inheritance relationships among classes in a manner similar to that of a family tree.

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

Answer 1

D

Question 2

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

Answer 2

True

Question 3

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

Answer 3

True

Question 4

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

Question 5

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

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

Question 6

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

Question 7

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

Question 8

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

Question 9

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

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

Question 10

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

Question 11

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 12

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

Question 13

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 14

What type of relationship exists between two objects when one object is a specialized version of another object?

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

Question 15

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

Question 16

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

Question 17

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

A) some of the characteristics of the general class, but not all, plus additional characteristics
B) some, but not all, of the characteristics of the general object
C) none of the characteristics of the general object
D) all of the characteristics of the general object plus additional characteristics

Question 18

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 19

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 20

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 21

All methods specified by an interface are

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

Question 22

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

A) dashed line with an open arrowhead at one end
B) line with an open diamond at one end
C) dashed line
D) line with an open arrowhead at one end

Question 23

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

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

Question 24

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 25

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

Question 26

Which of the following is the operator used to determine whether an object is an instance of a particular class?

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

Question 27

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

A) ClassA
B) ClassB
C) ClassC
D) both ClassB and ClassC are superclasses

Question 28

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

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

Question 29

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) Any of these

Question 30

Which key word indicates that a class inherits from another class?

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

Question 31

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

Question 32

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)

Question 33

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

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

Question 34

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) overloads
C) overrides
D) implements

Question 35

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

A) ClassA
B) ClassB
C) ClassC
D) both ClassB and ClassC are subclasses

Question 36

If you don't 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 37

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

A) pseudocode
B) a UML diagram
C) a CRC card
D) a hierarchy chart

Question 38

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

A) ClassA
B) ClassB
C) ClassC
D) all are interfaces

Question 39

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 40

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

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