Deck 6: A Second Look at Classes and Objects

Question 1

When an object is passed as an argument, it is actually a reference to the object that is passed.

Answer 1

True

Question 2

The only limitation that static methods have is

A) they must be declared outside of the class
B) they cannot refer to nonstatic members of the class
C) they can only be called from static members of the class
D) they can refer only to nonstatic members of the class

Answer 2

B

Question 3

You can declare an enumerated data type inside a method.

Answer 3

False

Question 4

The JVM periodically performs the __________ process to remove unreferenced objects from memory.

A) memory shuffling
B) system restore
C) garbage collection
D) memory sweeping

Question 5

An instance of a class does not have to exist in order for values to be stored in a class's static fields.

Question 6

A class's static methods do not operate on the fields that belong to any instance of the class.

Question 7

The "has a" relationship is sometimes called a(n) __________ because one object is part of a greater whole.

A) enterprise
B) possession
C) mutual relationship
D) whole-part relationship

Question 8

If a class has a method named finalize, it is called automatically just before an instance of the class is destroyed by the garbage collector.

Question 9

If you write a toString method for a class, Java will automatically call the method any time you concatenate an object of the class with a string.

Question 10

CRC stands for

A) Class, Recyclability, Collaborations
B) Class, Redundancy, Collections
C) Class, Responsibilities, Collaborations
D) Code, Reuse, Constancy

Question 11

enum constants have a toString method.

Question 12

When you write an enumerated type declaration, you

A) are actually creating a special kind of class
B) do not enclose the enum constants in quotation marks
C) should use the standard convention of writing the enum constants in uppercase
D) All of these

Question 13

A method's signature consists of

A) the method name and the parameter list
B) the return type, the method name, and the parameter list
C) the size of the method in memory
D) the return type and the method name

Question 14

__________ is the term for the relationship created by object aggregation.

A) "Has a"
B) Inner class
C) "Is a"
D) One-to-many

Question 15

When you make a copy of the aggregate object and of the objects that it references,

A) you are performing a shallow copy
B) you are performing a nested copy
C) you are performing a deep copy
D) a compiler error will occur

Question 16

An enumerated data type is actually a special type of class.

Question 17

Overloading is

A) writing a method that does too much processing
B) writing a program that is too large to fit in memory
C) having two or more methods with the same name but different signatures
D) having two or more methods with the same signature

Question 18

A class that is defined inside another class is called a(n)

A) nested class
B) enumerated class
C) inner class
D) helper class

Question 19

The key word this is the name of a reference variable that an object can use to refer to itself.

Question 20

The names of the enum constants in an enumerated data type must be enclosed in quotation marks.

Question 21

Of the following, which would be considered the no-arg constructor for the Rectangle class?

A) public Rectangle(int len, int width)
B) public Rectangle(double len, double width)
C) public Rectangle()
D) public Rectangle(length, width)

Question 22

When a method's type is an object, what is actually returned by the calling program?

A) a reference to an object of that class
B) only the values in the object that the method accessed
C) an object of that class
D) a null reference

Question 23

If object1 and object2 are objects of the same class, to make object2 a copy of object1

A) write a method for the class that will make a field by field copy of object1 data members into object2 data members
B) use the copy method that is a part of the Java API
C) use the default constructor to create object2 with object1 data members
D) use an assignment statement to make object2 a copy of object1

Question 24

To get the name of a calling enum constant

A) simply use the enum constant in the statement
B) use the ordinal method
C) use the displayName method
D) use the toString method

Question 25

If you have defined a class, SavingsAccount, with a public static method, getNumberOfAccounts, and created a SavingsAccount object referenced by the variable account20, which of the following will call the getNumberOfAccounts method?

A) account20.getNumberOfAccounts();
B) SavingsAccount.getNumberOfAccounts();
C) getNumberOfAccounts();
D) SavingsAccount.account20.getNumberOfAccounts();

Question 26

When the this variable is used to call a constructor

A) it must be the first statement in the constructor making the call
B) it can be anywhere in the constructor making the call
C) it must be the last statement in the constructor making the call
D) None of these. You cannot use the this variable in a constructor call.

Question 27

When a field is declared static there will be

A) a copy of the field for each method in the class
B) a copy of the field in each class object
C) only one copy of the field in memory
D) two reference copies of the field for each method in the class

Question 28

You cannot use the fully-qualified name of an enum constant for

A) a case expression
B) an argument to a method
C) a boolean expression
D) Any of these

Question 29

Which of the following can you use to compare two enum data values?

A) the ordinal method
B) the ==, >, and < operators
C) the equals and compareTo methods
D) the moreThan, lessThan, and equalsTo methods

Question 30

Enumerated types have the __________ method which returns the position of an enum constant in the declaration list.

A) position
B) location
C) ordinal
D) index

Question 31

When a method in the __________ class returns a reference to a field object, it should return a reference to a copy of the field object to prevent security holes.

A) aggregate
B) inner
C) String
D) nested

Question 32

If the following is from the method section of a UML diagram, which of the statements shown is true? + equals(object2:Stock) : boolean

A) This is a public method that accepts a Stock object as its argument and returns a boolean value.
B) This is a public method that returns a reference to a String object.
C) This is a private method that receives two objects from the Stock class and returns a boolean value.
D) This is a private method that returns a boolean value.

Question 33

A declaration for an enumerated type begins with the __________ key word.

A) enumerated
B) enum type
C) ENUM
D) enum

Question 34

Given the following method header, what will be returned from the method? public Rectangle getRectangle()

A) the address of an object of the Rectangle class
B) the values stored in the data members of the Rectangle object
C) a null value
D) an object that is contained in the class Rectangle

Question 35

Given the following declaration: enum Tree ( OAK, MAPLE, PINE )
What is the fully-qualified name of the PINE enum constant?

A) enum.PINE
B) PINE
C) Tree.PINE
D) enum.Tree.PINE

Question 36

Assume the following declaration exists: enum Tree ( OAK, MAPLE, PINE )
What will the following code display?
System.out.println(Tree.OAK);

A) OAK
B) Tree.OAK
C) 0
D) 1

Question 37

You can use the enum key word to

A) create your own data type
B) specify the values that belong to the type
C) Both of these
D) Neither of these

Question 38

Assume the class BankAccount has been created and the following statement correctly creates an instance of the class. BankAccount account = new BankAccount(5000.00);
What is true about the following statement?
System.out.println(account);

A) A runtime error will occur.
B) The method will display unreadable binary data on the screen.
C) The account object's toString method will be implicity called.
D) A compiler error will occur.

Question 39

A static field is created by placing the key word static

A) after the access specifier and the field's data type
B) after the access specifier and before the field's data type
C) after the field name
D) in brackets, before the field's data type

Question 40

By default, a reference variable that is an instance field is initialized to the value

A) null
B) 0
C) static
D) void