True/False
Indicate whether the
statement is true or false.
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1.
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When a Java program is executing, the computer's memory must hold all class
templates in their compiled form, variables that refer to objects, and objects as needed.
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2.
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The identity of an object is simply the variable that references the
object.
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3.
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A class's implementation details can be changed radically without affecting
any of its clients provided its interface remains the same.
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4.
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In Java it is illegal to have two variables referencing the same object.
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5.
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The keyword public indicates that the class is accessible to all potential
clients.
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6.
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Constructors do not have return types, but all other methods do.
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7.
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A class can include only one constructor.
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8.
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A method can only have one return statement.
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9.
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Variables declared within any compound statement enclosed in braces are said to
have local scope.
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10.
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Global variables can be reused within several different methods without causing
a conflict.
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11.
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A good way to provide temporary storage is to use global variables.
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12.
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When using turtle graphics, the color of a pen cannot be changed.
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Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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13.
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The process of creating a new object is called:
a. | encapsulation | c. | instantiation | b. | class | d. | new |
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14.
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Java deletes objects from memory in a process called:
a. | deletion | c. | memory allocation | b. | garbage collection | d. | memory dumping |
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15.
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Which characteristic of an object says that at any moment its instance variables
have particular values.
a. | state | c. | identity | b. | behavior | d. | instantiation |
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16.
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What is the list of the methods supported by the server referred to as?
a. | encapsulation | c. | behavior | b. | state | d. | interface |
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17.
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Messages that change an object's state are called:
a. | accessors | c. | mutators | b. | constructors | d. | methods |
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18.
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What is the name of a method that indicates how to initialize a new
object?
a. | initializer | c. | mutator | b. | constructor | d. | accessor |
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19.
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If class A extends class B, class B is the _________ of class A.
a. | parent | c. | nephew | b. | child | d. | subclass |
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20.
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If a class A omits the extends <some class> clause, which class is
assumed to be the superclass of class A.
a. | Object | c. | System | b. | KeyboardReader | d. | Math |
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21.
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What are activated when the keyword new is used and at no other time.
a. | accessors | c. | constructors | b. | mutators | d. | methods |
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22.
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A method whose implementing code is omitted is called a:
a. | accessor | c. | helper | b. | mutator | d. | stub |
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23.
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Values passed to a method when it is invoked are called:
a. | actual parameters | c. | constructors | b. | formal parameters | d. | initial values |
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24.
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To provide temporary working storage for data in a method a programmer can
declare:
a. | global variables | c. | instance variables | b. | local variables | d. | classes |
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25.
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The ________ of a variable is that region of the program within which it can
validly appear in lines of code.
a. | lifetime | c. | value | b. | type | d. | scope |
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26.
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Variables defined as instance variables of a class are referred to as:
a. | local | c. | temporary | b. | global | d. | public |
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27.
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The _________ of a variable is the period during which it can be used.
a. | time period | c. | lifetime | b. | scope | d. | type |
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Completion
Complete each
statement.
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28.
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An object has _________ as defined by the methods of its class.
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29.
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If a reference variable of an object is set to _______, and no other variable
points to that object, the computer reclaims the object's memory during garbage
collection.
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30.
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Using the visibility modifier __________ for instance variables is an important
aspect of information hiding.
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31.
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Constructors with empty parameter lists are called ___________
constructors.
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32.
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Parameters listed in a method's definition are called ________
parameters.
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33.
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Methods that are usually private that help break down tasks to reduce complexity
are called _________ methods.
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34.
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A programmer uses the symbol ______ to refer to the current instance of a class
within that class's definition.
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35.
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The default width of a pen in turtle graphics is two ________, or picture
elements.
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Short Answer
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36.
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When messages are sent, which two objects are involved?
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