Question 1

"Shadowing" is the term used to describe how the field name is hidden by the name of a local or parameter variable.

Accepted Answer

Shadowing occurs when a local variable in a method or a block has the same name as a field, effectively hiding the field within that method or block's scope.

Question 2

Which symbol indicates that a member is public in a UML diagram?
A) -
B) *
C) #
D) +

Accepted Answer

The "+" symbol indicates that a member is public in a UML diagram.

Question 3

You should not define a class that is dependent on the values of other class fields
A) in order to keep it current
B) because it is redundant
C) in order to avoid having stale data
D) because it should be defined in another class

Accepted Answer

Defining a class that is dependent on the values of other class fields can lead to issues with stale data if those fields change and the dependent class is not updated accordingly. This can result in inconsistencies and bugs in the software.

Question 4

A method that stores a value in a class's field or in some other way changes the value of a field is known as a mutator method.

Accepted Answer

This is correct definition of a mutator method.

Question 5

Using the blueprint/house analogy, you can think of a class as a blueprint that describes a house and __________ as instances of the house built from the blueprint.
A) methods
B) fields
C) objects
D) attributes

Accepted Answer

Objects are instances of a class, much like houses built from a blueprint. Each object is an instance of its class, with its own unique set of properties and behaviors defined by the class blueprint.

Question 6

The java.lang package is automatically imported into all Java programs.

Accepted Answer

The java.lang package is automatically imported into all Java programs, along with a few other commonly used packages such as java.util and java.io.

Question 7

The public access specifier for a field indicates that the field may not be accessed by statements outside the class.

Accepted Answer

The public access specifier allows the field to be accessed by statements outside the class. The correct statement would be "The private access specifier for a field indicates that the field may not be accessed by statements outside the class."

Question 8

A method that gets a value from a class's field but does not change it is known as a mutator method.

Accepted Answer

A method that gets a value from a class's field but does not change it is known as an accessor method. A mutator method, on the other hand, is a method that changes the value of a class's field.

Question 9

A group of related classes is called a(n)
A) archive
B) package
C) collection
D) attachment

Accepted Answer

A group of related classes is typically referred to as a package in object-oriented programming. A package is a namespace that organizes a set of related classes and interfaces. Packages help in avoiding naming conflicts, provide code isolation, and improve the readability of the code.

Question 10

Class objects normally have __________ that perform useful operations on their data, but primitive variables do not.
A) fields
B) relationships
C) methods
D) instances

Accepted Answer

Class objects have methods that can perform operations on their data, while primitive variables do not have any methods. Fields are variables that hold data within a class instance, relationships refer to how objects interact with each other, and instances are objects that are created from a class.

Question 11

An access specifier indicates how a class may be accessed.

Accepted Answer

An access specifier such as public, private, or protected determines how the members of a class can be accessed by other code.

Question 12

When an object is created, the attributes associated with the object are called
A) instance fields
B) class instances
C) instance methods
D) fixed attributes

Accepted Answer

Instance fields are variables that are associated with an instance of a class, meaning they have a specific value for each object that is created. They are also often referred to as instance variables or member variables.

Question 13

The term "default constructor" is applied to the first constructor written by the author of the class.

Accepted Answer

A default constructor is a constructor that is automatically generated by the compiler if no constructor is specified by the author of the class. Therefore, the term "default constructor" is not applied to the first constructor written by the author of the class, but rather to the constructor automatically generated by the compiler.

Question 14

When a local variable in an instance method has the same name as an instance field, the instance field hides the local variable.

Accepted Answer

When a local variable in an instance method has the same name as an instance field, the local variable shadows the instance field within the scope of the method.

Question 15

Data hiding (which means that critical data stored inside the object is protected from code outside the object) is accomplished in Java by
A) using the public access specifier on the class methods
B) using the private access specifier on the class methods
C) using the private access specifier on the class fields
D) using the private access specifier on the class definition

Accepted Answer

Data hiding is accomplished in Java by using the private access specifier on the class fields. This restricts the access to the data to only the methods inside the class, and not to any code outside the class, ensuring that the critical data is protected from unauthorized access and modification.

Question 16

A class's responsibilities include
A) the things a class is responsible for knowing
B) the things a class is responsible for doing
C) both of these
D) neither of these

Accepted Answer

A class's responsibilities include both the things it is responsible for knowing and the things it is responsible for doing. It encapsulates data and behavior, meaning it has attributes (the things it knows or is responsible for knowing) and methods (the things it does or is responsible for doing).

Question 17

Methods that operate on an object's fields are called
A) instance methods
B) instance variables
C) private methods
D) public methods

Accepted Answer

Instance methods operate on an object's fields, and are called as such because they are invoked on an instance of the class rather than on the class itself. Instance variables are the fields themselves and not the methods that operate on them. Private methods are methods within a class that can only be accessed within that class, while public methods are accessible from outside the class. However, the question specifically asks about methods that operate on an object's fields, making instance methods the best choice.

Question 18

Another term for an object of a class is a(n)
A) access specifier
B) instance
C) member
D) method

Accepted Answer

An instance refers to a specific object created from a class. The other options listed are not interchangeable with the term "object of a class."

Question 19

The term "no-arg constructor" is applied to any constructor that does not accept arguments.

Accepted Answer

The definition of a no-arg constructor is a constructor that does not accept arguments. Therefore, the statement is true.

Question 20

A constructor is a method that is automatically called when an object is created.

Accepted Answer

This is true. When an object is created, the constructor method is automatically called to initialize the object.

Quiz 3: A First Look at Classes and Objects

"Shadowing" is the term used to describe how the field name is hidden by the name of a local or parameter variable.

Which symbol indicates that a member is public in a UML diagram?

You should not define a class that is dependent on the values of other class fields

A method that stores a value in a class's field or in some other way changes the value of a field is known as a mutator method.

Using the blueprint/house analogy, you can think of a class as a blueprint that describes a house and __________ as instances of the house built from the blueprint.

The java.lang package is automatically imported into all Java programs.

The public access specifier for a field indicates that the field may not be accessed by statements outside the class.

A method that gets a value from a class's field but does not change it is known as a mutator method.

A group of related classes is called a(n)

Class objects normally have __________ that perform useful operations on their data, but primitive variables do not.

An access specifier indicates how a class may be accessed.

When an object is created, the attributes associated with the object are called

The term "default constructor" is applied to the first constructor written by the author of the class.

When a local variable in an instance method has the same name as an instance field, the instance field hides the local variable.

Data hiding (which means that critical data stored inside the object is protected from code outside the object) is accomplished in Java by

A class's responsibilities include

Methods that operate on an object's fields are called

Another term for an object of a class is a(n)

The term "no-arg constructor" is applied to any constructor that does not accept arguments.

A constructor is a method that is automatically called when an object is created.