Deck 3: A First Look at Classes and Objects

Question 1

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

Answer 1

True

Question 2

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

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

Answer 2

D

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

Answer 3

C

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.

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

Question 6

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

Question 7

The public 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.

Question 9

A group of related classes is called a(n)

A) archive
B) package
C) collection
D) attachment

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

Question 11

An access specifier indicates how a class may be accessed.

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

Question 13

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

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.

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

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

Question 17

Methods that operate on an object's fields are called

A) instance methods
B) instance variables
C) private methods
D) public methods

Question 18

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

A) access specifier
B) instance
C) member
D) method

Question 19

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

Question 20

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

Question 21

Which symbol indicates that a member is private a UML diagram?

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

Question 22

One or more objects may be created from a(n)

A) field
B) method
C) instance
D) class

Question 23

UML diagrams do not contain

A) fields
B) methods
C) class names
D) object names

Question 24

To indicate the data type of a variable in a UML diagram you specify

A) the variable name followed by the data type
B) the class name followed by the variable name followed by the data type
C) the variable name followed by a colon and the data type
D) the data type followed by the variable name

Question 25

For the following code, which statement is not true?
public class Sphere
{
Private double radius;
Public double x;
Private double y;
Private double z;
}

A) The z field is available to code written outside the Sphere class.
B) The radius field is not available to code written outside the Sphere class.
C) The radius, x, y, and z fields are members of the Sphere class.
D) The x field is available to code that is written outside the Sphere class.

Question 26

Which is the key word used to import a class?

A) import
B) assume
C) use
D) link

Question 27

A constructor is a method that

A) returns an object of the class
B) never receives any arguments
C) performs initialization or setup operations
D) removes the object from memory

Question 28

What does the following UML diagram entry mean? + setHeight(h : double) : void

A) a public method with a parameter of data type double that does not return a value
B) a private field called setHeight that is a double data type
C) a private method with no parameters that returns a double data type
D) a public field called Height that is a double data type

Question 29

When an argument is passed by value

A) the parameter variable holds the address of the argument
B) the parameter variable cannot be changed
C) the parameter variable holds a copy of the value passed to it
D) changes can be made to the argument variable

Question 30

For the following code, which statement is not true?
public class Circle
{
Private double radius;
Public double x;
Private double y;
}

A) The y field is available to code written outside the Circle class.
B) The radius field is not available to code written outside the Circle class.
C) The radius, x, and y fields are members of the Circle class.
D) The x field is available to code that is written outside the Circle class.

Question 31

If you do not provide initialization values for a class's numeric fields, they will

A) cause a runtime error
B) contain an unknown value
C) be automatically initialized to 0
D) cause a compiler error

Question 32

A constructor

A) always accepts two arguments
B) has the same name as the class
C) has the return type of void
D) always has a private access specifier

Question 33

Which of the following is not involved in identifying the classes to be used when developing an object-oriented application?

A) Describe the problem domain.
B) Write the code.
C) Refine the list of nouns to include only those relevant to the problem.
D) Identify all the nouns.

Question 34

The key word new

A) creates a new class
B) creates a new Java byte code file
C) creates an object in memory
D) creates a new variable in memory

Question 35

After the header, the body of the method appears inside a set of

A) braces, { }
B) parentheses, ( )
C) brackets, [ ]
D) double quotes, " "

Question 36

What is the following statement an example of?
import java.util.*;

A) an explicit import statement
B) an unconditional import statement
C) a wildcard import statement
D) a conditional import statement

Question 37

A method

A) may have zero or more parameters
B) never has parameter variables
C) must have at least two parameter variables
D) may not have only one parameter variable

Question 38

It is common practice in object-oriented programming to make all of a class's

A) fields private
B) methods private
C) fields public
D) fields and methods public

Question 39

The scope of a local variable is

A) inside the parentheses of a method header
B) the method in which it is defined
C) inside the class but not inside any method
D) the entire class

Question 40

What is the following statement an example of?
import java.util.Scanner;

A) an explicit import statement
B) an unconditional import statement
C) a wildcard import statement
D) a conditional import statement