Deck 7: Object-Oriented Design

Question 1

Java does not support multiple inheritance, but some of the abilities of multiple inheritance are available by

A) importing classes
B) implementing interfaces
C) overriding parent class methods
D) creating aliases
E) using public rather than protected or private modifiers

Answer 1

B
Explanation: B) Since a class can implement any number of interfaces, that class is in essence using the interface classes as if those interfaces were defined in this class. So, this class is inheriting the methods and constants of the interfaces. Further, the class could extend another class and thus inherit directly and indirectly from multiple classes. This is not the exact same as multiple inheritance, but it is as close as Java comes to that concept.

Question 2

In general, spending more time in development to ensure better software will

A) shorten testing time
B) slightly reduce maintenance efforts
C) slightly increase maintenance efforts
D) greatly reduce maintenance efforts
E) not alter the time it takes for any other stage whatsoever

Answer 2

D
Explanation: D) Spending more time in development promises better software, which in turn leads to less maintenance effort.

Question 3

Which of the following is not a method of the Object class?

A) clone
B) compareTo
C) equals
D) toString
E) all of the above are methods of the Object class

Answer 3

B
Explanation: B) The Object class defines clone to create a copy of any object, equals to determine if two objects are the same object, and toString to translate an Object into a String. However, compareTo is not implement by Object and must be explicitly implemented in any class that wants to implement the Comparable interface.

Question 4

An example of an aggregation relationship is

A) parent and child
B) animal and dog
C) teacher and computer
D) phone and fax machine
E) all of the above

Question 5

During program development, software requirements specify

A) how the program will accomplish the task
B) what the task is that the program must perform
C) how to divide the task into subtasks
D) how to test the program when it is done
E) all of the above

Question 6

The activities of the development cycle are generally thought to

A) be strictly linear
B) be rigidly ordered
C) overlap
D) have optional steps
E) both A and B are True

Question 7

Inheritance through an extended (derived) class supports which of the following concepts?

A) interfaces
B) modulary
C) information hiding
D) code reuse
E) correctness

Question 8

The idea of having programmers and developers meet in order to critique a software design or implementation is known as

A) an interview
B) a walkthrough
C) prototyping
D) aggregation
E) evolutionary development

Question 9

Static methods cannot

A) reference instance data
B) reference non-static instance data
C) reference other objects
D) invoke other static methods
E) invoke non-static methods

Question 10

Abstract methods are used when defining

A) interface classes
B) derived classes
C) classes that have no constructor
D) arrays
E) classes that have no methods

Question 11

It is easier to correct errors found in a program if

A) they are identified early in the development cycle
B) they are identified during testing
C) they are identified during program use
D) they are identified during maintenance
E) all of the above are equally True, errors are easily corrected in any of these stages

Question 12

Which of the following methods is a static method? The class in which the method is defined is given in parentheses following the method name.

A) equals (String)
B) toUpperCase (String)
C) sqrt (Math)
D) format (DecimalFormat)
E) paint (Applet)

Question 13

The idea that an object can exist separate from the executing program that creates it is called

A) transience
B) static
C) persistence
D) serialization
E) finality

Question 14

Which of the following interfaces would be used to implement a class that represents a group (or collection) of objects?

A) Iterator
B) Speaker
C) Comparable
D) MouseListener
E) KeyListener

Question 15

An object that refers to part of itself within its own methods can use which of the following reserved words to denote this relationship?

A) inner
B) i
C) private
D) this
E) static

Question 16

A bad programming habit is to build an initial program and then spend a great deal of time modifying the code until it is acceptable. This is known as

A) the prototyping approach
B) the waterfall model
C) iterative development
D) the recursive approach
E) the build-and-fix approach

Question 17

Modifying a program in order to eliminate deficiencies is done in the ________ phase of the development cycle.

A) design
B) implementation
C) testing
D) use
E) maintenance

Question 18

Of the various phases in software development, which of the following is usually the lengthiest?

A) specification
B) design
C) implementation
D) testing
E) maintenance

Question 19

In order to create a constant, you would use which of the following Java reserved words?

A) private
B) static
C) int
D) final
E) class

Question 20

Once we have implemented the solution, we are not done with the problem because

A) the solution may not be the best (most efficient)
B) the solution may have errors and need testing and fixing before we are done
C) the solution may, at a later date, need revising to handle new specifications
D) the solution may, at a later date, need revising because of new programming language features
E) all of the above

Question 21

Which of the following is considered a top-level container?

A) Panel
B) Frame
C) Box
D) Layout Manager
E) A, B, and C

Question 22

In using the BoxLayout, adding space between components in a container can be accomplished by

A) including TabbedPanes
B) including JButtons that have no names and thus will appear invisible
C) adding invisible components
D) inserting IconImages of blank images
E) any of the above

Question 23

The JFrame below has a JBorder created using which of the following BorderFactory formats?

A) TitledBorder
B) MatteBorder
C) EtchedBorder
D) RaisedBevelBorder
E) LoweredBevelBorder

Question 24

Which Layout Manager type would you use if you want GUI components to be placed at the North, South, East, West and Center of the container?

A) FlowLayout
B) BorderLayout
C) BoxLayout
D) GridLayout
E) TabbedPane

Question 25

What is wrong with the following message to create a BoxLayout for the JPanel jp?
Jp)setLayout(new BoxLayout(BoxLayout.X_AXIS));

A) X_AXIS is not a valid constant for BoxLayout, it should instead be HORIZONTAL
B) Aside from X_AXIS, the constructor also requires a Dimension to determine the size of the Box
C) Aside from X_AXIS, the constructor also needs a command regarding horizontal glue as in createHorizontalGlue( )
D) The BoxLayout constructor is lacking a reference to the container that the BoxLayout manager will govern
E) There is nothing wrong with it at all

Question 26

The goal of testing is to

A) ensure that the software has no errors
B) find syntax errors
C) find logical and run-time errors
D) evaluate how well the software meets the original requirements
E) give out-of-work programmers something to do

Question 27

To take 2 borders and use one as an outer border and the other as an inner border, you would create a

A) compound border
B) nested border
C) split border
D) border factory
E) matte border

Question 28

Having multiple class methods of the same name where each method has a different number of or type of parameters is known as

A) encapsulation
B) information hiding
C) tokenizing
D) importing
E) method overloading

Question 29

Arranging components in a GUI container is accomplished by using which of the following?

A) Layout manager
B) Listener interface
C) String array
D) Event generator
E) JComboBox

Question 30

In which phase of program development would you expect the programmer(s) to determine the classes and objects needed?

A) software requirements
B) software design
C) software implementation
D) software testing
E) could occur in any of the above

Question 31

Which Layout Manager type would you use if you want GUI components to be placed in 2 columns over 5 rows?

A) FlowLayout
B) BorderLayout
C) BoxLayout
D) GridLayout
E) TabbedPane

Question 32

In which phase of program development would you expect the programmer(s) to create the pseudocode?

A) Software requirements
B) Software design
C) Software implementation
D) Software testing
E) Could occur in any of the above

Question 33

It is important to dissect a problem into manageable pieces before trying to solve the problem because

A) most problems are too complex to be solved as a single, large activity
B) most problems are solved by multiple people and it is easy to assign each piece to a separate person
C) it is easier to integrate small pieces of a program into one program than it is to integrate one big chunk of code into one program
D) our first solution may not solve the problem correctly
E) all of the above

Question 34

For the questions below, consider a class called ChessPiece. This class has two instance data, String type and int player. The variable type will store "King", "Queen", "Bishop", etc and the int player will store 0 or 1 depending on whose piece it is. We wish to implement Comparable for the ChessPiece class. Assume that, the current ChessPiece is compared to a ChessPiece passed as a parameter. Pieces are ordered as follows: "Pawn" is a lesser piece to a "Knight" and a "Bishop", "Knight" and "Bishop" are equivalent for this example, both are lesser pieces to a "Rook" which is a lesser piece to a "Queen" which is a lesser piece to a "King."
Which of the following would not be considered an algorithm?

A) a recipe
B) a computer program
C) pseudocode
D) a shopping list
E) travel directions

Question 35

In order to implement Comparable in a class, what method(s) must be defined in that class?

A) equals
B) compares
C) both lessThan and greaterThan
D) compareTo
E) both compares and equals

Question 36

For the questions below, consider a class called ChessPiece. This class has two instance data, String type and int player. The variable type will store "King", "Queen", "Bishop", etc and the int player will store 0 or 1 depending on whose piece it is. We wish to implement Comparable for the ChessPiece class. Assume that, the current ChessPiece is compared to a ChessPiece passed as a parameter. Pieces are ordered as follows: "Pawn" is a lesser piece to a "Knight" and a "Bishop", "Knight" and "Bishop" are equivalent for this example, both are lesser pieces to a "Rook" which is a lesser piece to a "Queen" which is a lesser piece to a "King."
Which of the following method headers would properly define the method needed to make this class Comparable?

A) public boolean comparable(Object cp)
B) public int comparable(Object cp)
C) public int compareTo(Object cp)
D) public int compareTo( )
E) public boolean compareTo(Object cp)

Question 37

Which Layout Manager is used by default if you do not specify a Layout Manager for your GUI container?

A) FlowLayout
B) BorderLayout
C) BoxLayout
D) GridLayout
E) TabbedPane

Question 38

Which of the following GUI classes requires that it have a LayoutManager before any GUI components are added to it?

A) JButton
B) JSlider
C) JPanel
D) JFrame
E) both C and D but not A or B

Question 39

In order to display three components vertically in a container, you could use all but which of the following layout managers?

A) FlowLayout
B) BoxLayout
C) GridLayout
D) BorderLayout
E) you could use any of the above

Question 40

For the questions below, consider a class called ChessPiece. This class has two instance data, String type and int player. The variable type will store "King", "Queen", "Bishop", etc and the int player will store 0 or 1 depending on whose piece it is. We wish to implement Comparable for the ChessPiece class. Assume that, the current ChessPiece is compared to a ChessPiece passed as a parameter. Pieces are ordered as follows: "Pawn" is a lesser piece to a "Knight" and a "Bishop", "Knight" and "Bishop" are equivalent for this example, both are lesser pieces to a "Rook" which is a lesser piece to a "Queen" which is a lesser piece to a "King."
Which of the following pieces of logic could be used in the method that implements Comparable? Assume that the method is passed Object a, which is really a ChessPiece. Also assume that ChessPiece has a method called returnType which returns the type of the given piece. Only one of these answers has correct logic.

A) if (this.type < a.returnType( )) return -1;
B) if (this.type = = a.returnType( )) return 0;
C) if (this.type.equals(a.returnType( )) return 0;
D) if (a.returnType( ).equals("King")) return -1;
E) if (a.returnType( ).equals("Pawn")) return 1;

Question 41

All objects implement Comparable.

Question 42

If a GUI container is resized by the user, all components of the GUI are automatically increased or decreased by the same fraction to fit in the newly sized container.

Question 43

The most important decisions regarding the development of a system are made during the implementation phase while code is actively being written.

Question 44

Defining formal parameters requires including each parameters type.

Question 45

In black-box testing, the tester should already know something about how the program is implemented so that he/she can more carefully identify what portion(s) of the software are leading to errors.

Question 46

The size and shape of a GUI container is based on the layout manager selected and the type and number of items added to the container.

Question 47

If classes C1 and C2 both implement an interface Cint, which has a method whichIsIt, and if C1 c = new C1( ); is performed at one point of the program, then a later instruction c.whichIsIt( ); will invoke the whichIsIt method defined in C1.

Question 48

A JPanel can itself contain JPanels.

Question 49

Interface classes cannot be extended but classes that implement interfaces can be extended.

Question 50

Provide a reason why a method would be declared static.

Question 51

A border can be put around any Swing component with the exception of a JButton and JScrollPane component.

Question 52

Provide a reason why an instance data would be declared static.

Question 53

It is not possible to test out any single method or class of a system until the entire system has been developed, and so all testing is postponed until after the implementation phase.

Question 54

Assume that the class Bird has a static method fly( ). If b is a Bird, then to invoke fly, you could do Bird.fly( );.

Question 55

Formal parameters are those that appear in the method call and actual parameters are those that appear in the method header.

Question 56

The term "test case" is used to express a set of inputs (or user actions) and the expected outputs to be used in testing out software.

Question 57

All parts of a container in BorderLayout must be used.

Question 58

Any class can implement an interface, but no classes can implement more than a single interface.

Question 59

If a programmer follows the four phases of program development as intended, which of the four phases should require the least amount of creativity?

A) software requirements
B) software design
C) software implementation
D) software testing
E) none of the above, all four levels would require equal creativity

Question 60

Unlike the String class where you must pass a message to an object (instance) of the class, as in x.length( ), in order to use the Math class, you pass messages directly to the class name, as in Math.abs( ) or Math.sqrt( ).

Question 61

Draw the JFrame as you think it would appear given the following set of code:
JButton jb1 = new JButton("A");
JButton jb2 = new JButton("B");
JButton jb3 = new JButton("C");
JButton jb4 = new JButton("D");
JButton jb5 = new JButton("E");
JButton jb6 = new JButton("F");
JButton jb7 = new JButton("G");
JButton jb8 = new JButton("H");
JButton jb9 = new JButton("I");
JPanel jp1 = new JPanel(new BorderLayout( ));
jp1.add(jb1, BorderLayout.NORTH);
jp1.add(jb2, BorderLayout.WEST);
jp1.add(jb3, BorderLayout.EAST);
JPanel jp2 = new JPanel(new BorderLayout( ));
jp2.add(jb4, BorderLayout.WEST);
jp2.add(jb5, BorderLayout.SOUTH);
jp2.add(jb6, BorderLayout.EAST);
JPanel jp3 = new JPanel(new BorderLayout( ));
jp3.add(jb7, BorderLayout.WEST);
jp3.add(jb8, BorderLayout.NORTH);
jp3.add(jb9, BorderLayout.EAST);
JPanel jp4 = new JPanel(new BorderLayout( ));
jp4.add(jp1, BorderLayout.NORTH);
jp4.add(jp2, BorderLayout.EAST);
jp4.add(jp3, BorderLayout.SOUTH);
JFrame jf = new JFrame( );
jf.getContentPane( ).add(jp4);
jf.pack( );
jf.setVisible(True );

Question 62

To implement Comparable for the ChessPiece class, the current ChessPiece's type is compared to a ChessPiece passed as a parameter. The method should return 0 if the types are equal, -1 if this piece's type is a lesser piece than the parameter's type, and 1 if this piece's type is a greater piece than the parameter's type. Pieces are ordered as follows: "Pawn" is a lesser piece to a "Knight" and a "Bishop", "Knight" and "Bishop" are equivalent for this example, both are lesser pieces to a "Rook" which is a lesser piece to a "Queen" which is a lesser piece to a "King." Write the proper method to implement Comparable for this class.

Question 63

Write a static method that is passed two ChessPieces and determines if the two pieces are owned by the same player. It should return True or false.

Question 64

Assume a class Foo implements Comparable. Without knowing anything else about the Foo class, write an equal method that returns True if the Foo parameter passed to this Foo is equal to this Foo as determined by using the implementation of Comparable.

Question 65

Why was the Y2K problem a problem of software maintenance and not a problem of software testing?

Question 66

Provide code to generate the following JFrame. Each lettered item is a JButton. Hint: Create several JPanels, each one having two or more JButtons and taken up a portion of the JFrame.

Question 67

Provide code to generate the following JFrame. Each lettered item is a JButton. Hint: Create several JPanels, each one having two or more JButtons and taken up a portion of the JFrame.

Question 68

Why should the add( ), subtract( ), multiply( ), divide( ) methods in the RationalNumber class in the textbook be declared to be public, while the gcd( ) method is declared to be private?

Question 69

Draw the JFrame as you think it would appear given the following set of code:
JButton jb1 = new JButton("A");
JButton jb2 = new JButton("B");
JButton jb3 = new JButton("C");
JButton jb4 = new JButton("D");
JButton jb5 = new JButton("E");
JButton jb6 = new JButton("F");
JButton jb7 = new JButton("G");
JPanel jp1 = new JPanel(new GridLayout(3, 3));
jp1.add(jb1);
jp1.add(jb2);
jp1.add(jb3);
jp1.add(jb4);
jp1.add(jb5);
jp1.add(jb6);
jp1.add(jb7);
JFrame jf = new JFrame( );
jf.getContentPane( ).add(jp1);
jf.pack( );
jf.setVisible(True);

Question 70

Explain the difference between implementing an interface and a derived class.

Question 71

Draw the JFrame as you think it would appear given the following set of code:
JButton jb1 = new JButton("A");
JButton jb2 = new JButton("B");
JButton jb3 = new JButton("C");
JButton jb4 = new JButton("D");
JButton jb5 = new JButton("E");
JButton jb6 = new JButton("F");
JButton jb7 = new JButton("G");
JButton jb8 = new JButton("H");
JButton jb9 = new JButton("I");
JButton jb10 = new JButton("J");
JButton jb11 = new JButton("K");
JButton jb12 = new JButton("L");
JPanel jp1 = new JPanel( );
jp1.add(jb1);
jp1.add(jb2);
jp1.add(jb3);
jp1.add(jb4);
JPanel jp2 = new JPanel(new GridLayout(4, 1));
jp2.add(jb5);
jp2.add(jb6);
jp2.add(jb7);
jp2.add(jb8);
JPanel jp3 = new JPanel(new GridLayout(2, 2));
jp3.add(jb9);
jp3.add(jb10);
jp3.add(jb11);
jp3.add(jb12);
JPanel jp4 = new JPanel(new BorderLayout( ));
jp4.add(jp1, BorderLayout.NORTH);
jp4.add(jp2, BorderLayout.EAST);
jp4.add(jp3, BorderLayout.WEST);
JFrame jf = new JFrame( );
jf.getContentPane( ).add(jp4);
jf.pack( );
jf.setVisible(True);

Question 72

Define an interface class that contains two int constants, X = 5 and Y = 10 and one int method called useXY which receives no parameters. Call your interface class XYClass

Question 73

Write a set of code that will allow a user to select an input image and then place this image in a JLabel lab1 and add lab1 to a JPanel as the northern component in a JFrame using BorderLayout. The JFrame has already been instantiated as jf and the BorderLayout already established. Hint: a JFileChooser returns a File and JLabel requires the String name of a file as an argument. A File can return its name using File class' method getAbsolutePath( )

Question 74

In what way is black-box testing better than glass-box testing?
In what way is glass-box testing better than black-box testing?

Question 75

Write code to create a JPanel with 4 JCheckBox GUI components and two JLabels for output, one that says "Current cost is" and the other that outputs the computed cost based on which of the food items has been selected.

Question 76

Provide code to generate the following JFrame. Each lettered item is a JButton. Hint: Create several JPanels, each one having two or more JButtons and taken up a portion of the JFrame.