Question 1

Which of the following statements about a callback is NOT true?

Accepted Answer

A)  A callback can allow you to implement a new method for a class that is not under your control. 
B)  A callback can be implemented using an interface. 
C)  A callback is a mechanism for specifying code to be executed later. 
D)  A callback method declared in an interface must specify the class of objects that it will manipulate. 
A)  A callback can allow you to implement a new method for a class that is not under your control. 
B)  A callback can be implemented using an interface. 
C)  A callback is a mechanism for specifying code to be executed later. 
D)  A callback method declared in an interface must specify the class of objects that it will manipulate.

Question 2

A/an ____ is used to capture mouse events.

Accepted Answer

A)  action listener 
B)  event listener 
C)  mouse listener 
D)  component listener 
A)  action listener 
B)  event listener 
C)  mouse listener 
D)  component listener

Question 3

What role does an interface play when using a mock class?

Accepted Answer

A)  The mock class should be an interface that will be implemented by the real class. 
B)  The real class should be an interface that will be implemented by the mock class. 
C)  Interfaces are not involved when using mock classes. 
D)  An interface should be implemented by both the real class and the mock class to guarantee that the mock class accurately simulates the real class when used in a program. 
A)  The mock class should be an interface that will be implemented by the real class. 
B)  The real class should be an interface that will be implemented by the mock class. 
C)  Interfaces are not involved when using mock classes. 
D)  An interface should be implemented by both the real class and the mock class to guarantee that the mock class accurately simulates the real class when used in a program.

Question 4

Which of the following is an event source?

Accepted Answer

A)  A JButton object. 
B)  An event listener. 
C)  An inner class. 
D)  An event adapter. 
A)  A JButton object. 
B)  An event listener. 
C)  An inner class. 
D)  An event adapter.

Question 5

Which of the following statements about a mock class is true?

Accepted Answer

A)  A mock class does not provide an implementation of the services of the actual class. 
B)  A mock class provides a complete implementation of the services of the actual class. 
C)  A mock class provides a simplified implementation of the services of the actual class. 
D)  A mock class must be an interface. 
A)  A mock class does not provide an implementation of the services of the actual class. 
B)  A mock class provides a complete implementation of the services of the actual class. 
C)  A mock class provides a simplified implementation of the services of the actual class. 
D)  A mock class must be an interface.

Question 6

Consider the following code snippet: public class MyMouseListener
{
Public void mousePressed(MouseEvent event)
{
Double x;
Double y;
_______
System.out.println("x: " + x + ", y: " + y);
}
}
Which of the following statements should be in the indicated position to print out where the mouse was pressed?

Accepted Answer

A)  x = event.getXposition(); y = event.getYposition(); 
B)  x = (MouseEvent) getX(); y = (MouseEvent) getY(); 
C)  x = event.printX(); y = event.printY(); 
D)  x = event.getX(); y = event.getY(); 
A)  x = event.getXposition(); y = event.getYposition(); 
B)  x = (MouseEvent) getX(); y = (MouseEvent) getY(); 
C)  x = event.printX(); y = event.printY(); 
D)  x = event.getX(); y = event.getY();

Question 7

Consider the following declarations: public interface Encryptable
{
Void encrypt(String key);
}
Public class SecretText implements Encryptable
{
Private String text;
_____________________________
{
// code to encrypt the text using encryption key goes here
}
}
Which of the following method headers should be used to complete the SecretText class?

Accepted Answer

A)  public void encrypt() 
B)  public void encrypt(String aKey) 
C)  public String encrypt(String aKey) 
D)  void encrypt(String aKey) 
A)  public void encrypt() 
B)  public void encrypt(String aKey) 
C)  public String encrypt(String aKey) 
D)  void encrypt(String aKey)

Question 8

Which of the following statements about an interface is true?

Accepted Answer

A)  An interface has methods and instance variables. 
B)  An interface has methods but no instance variables. 
C)  An interface has neither methods nor instance variables. 
D)  An interface has both public and private methods. 
A)  An interface has methods and instance variables. 
B)  An interface has methods but no instance variables. 
C)  An interface has neither methods nor instance variables. 
D)  An interface has both public and private methods.

Question 9

Consider the following code snippet: public class ClickListener implements ActionListener
{
Public void actionPerformed(ActionEvent event)
{
System.out.println("I was clicked.");
}
}
Public class ButtonTester
{
Public static void main(String[] args)
{
JFrame frame = new JFrame();
JButton button = new JButton("Click me!");
Frame.add(button);
ActionListener listener = new ClickListener();
Button.addActionListener(listener);
)..
}
}
Which of the following statements is correct?

Accepted Answer

A)  Class ButtonTester is an interface type. 
B)  A ClickListener object can be added as a listener for the action events that buttons generate. 
C)  Class ClickListener is an interface type. 
D)  Class ButtonTester implements an interface type. 
A)  Class ButtonTester is an interface type. 
B)  A ClickListener object can be added as a listener for the action events that buttons generate. 
C)  Class ClickListener is an interface type. 
D)  Class ButtonTester implements an interface type.

Question 10

A method that has no implementation is called a/an ____ method.

Accepted Answer

A)  interface 
B)  implementation 
C)  overloaded 
D)  abstract 
A)  interface 
B)  implementation 
C)  overloaded 
D)  abstract

Question 11

Which of the following is a good use for an anonymous class?

Accepted Answer

A)  Use an anonymous class to implement polymorphism. 
B)  Use an anonymous class to implement a callback. 
C)  Use an anonymous class when all methods of the class will be static methods. 
D)  Use an anonymous class when the program will only need one object of the class. 
A)  Use an anonymous class to implement polymorphism. 
B)  Use an anonymous class to implement a callback. 
C)  Use an anonymous class when all methods of the class will be static methods. 
D)  Use an anonymous class when the program will only need one object of the class.

Question 12

Suppose you are writing an interface called Resizable, which includes one void method called resize. public interface Resizable
{
_________________________
}
Which of the following can be used to complete the interface declaration correctly?

Accepted Answer

A)  private void resize(); 
B)  protected void resize(); 
C)  void resize(); 
D)  public void resize() { System.out.println("resizing ..."); } 
A)  private void resize(); 
B)  protected void resize(); 
C)  void resize(); 
D)  public void resize() { System.out.println("resizing ..."); }

Question 13

The methods of a/an ____ describe the actions to be taken when an event occurs.

Accepted Answer

A)  event source 
B)  event listener 
C)  event interface 
D)  action source 
A)  event source 
B)  event listener 
C)  event interface 
D)  action source

Question 14

Consider the following code snippet: class MouseClickedListener implements ActionListener
{
Public void mouseClicked(MouseEvent event)
{
Int x = event.getX();
Int y = event.getY();
Component.moveTo(x,y);
}
}
What is wrong with this code?

Accepted Answer

A)  The mouseClicked method cannot access the x and y coordinates of the mouse. 
B)  repaint() method was not called. 
C)  The class has implemented the wrong interface. 
D)  There is nothing wrong with this code. 
A)  The mouseClicked method cannot access the x and y coordinates of the mouse. 
B)  repaint() method was not called. 
C)  The class has implemented the wrong interface. 
D)  There is nothing wrong with this code.

Question 15

Which of the following statements about converting between types is true?

Accepted Answer

A)  When you cast number types, you take a risk that an exception will occur. 
B)  When you cast number types, you will not lose information. 
C)  When you cast object types, you take a risk of losing information. 
D)  When you cast object types, you take a risk that an exception will occur. 
A)  When you cast number types, you take a risk that an exception will occur. 
B)  When you cast number types, you will not lose information. 
C)  When you cast object types, you take a risk of losing information. 
D)  When you cast object types, you take a risk that an exception will occur.

Question 16

Assume that the TimerListener class implements the ActionListener interface. If the actionPerformed method in TimerListener needs to be executed every second, what statement should be used to complete the following code segment? ActionListener listener = new TimerListener();
_________________________________ // missing statement
Timer.start();

Accepted Answer

A)  Timer timer = new Timer(listener); 
B)  Timer timer = new Timer(1, listener); 
C)  Timer timer = new Timer(100, listener); 
D)  Timer timer = new Timer(1000, listener); 
A)  Timer timer = new Timer(listener); 
B)  Timer timer = new Timer(1, listener); 
C)  Timer timer = new Timer(100, listener); 
D)  Timer timer = new Timer(1000, listener);

Question 17

____ are generated when the user presses a key, clicks a button, or selects a menu item.

Accepted Answer

A)  Listeners 
B)  Interfaces. 
C)  Events. 
D)  Errors. 
A)  Listeners 
B)  Interfaces. 
C)  Events. 
D)  Errors.

Question 18

Consider the following class: public class ClickListener implements ActionListener
{
__________________________________________
{
System.out.println("mouse event ...");
}
}
Which of the following method headers should be used to complete the ClickListener class?

Accepted Answer

A)  public void actionPerformed(ActionEvent event) 
B)  public void actionPerformed(ClickListener event) 
C)  public void actionPerformed() 
D)  public void actionPerformed(ActionListener event) 
A)  public void actionPerformed(ActionEvent event) 
B)  public void actionPerformed(ClickListener event) 
C)  public void actionPerformed() 
D)  public void actionPerformed(ActionListener event)

Question 19

Which container is used to group multiple user-interface components together?

Accepted Answer

A)  text area 
B)  table 
C)  panel 
D)  rectangle 
A)  text area 
B)  table 
C)  panel 
D)  rectangle

Question 20

Consider the following code snippet which is supposed to show the total order amount when the button is clicked: public static void main(String[] args)
{
Final Order myOrder = new Order();
JButton button = new JButton("Calculate");
Final JLabel label = new JLabel("Total amount due");
) . .
Class MyListener implements ActionListener
{
Public void actionPerformed(ActionEvent event)
{
Label.setText("Total amount due " + myOrder.getAmountDue());
}
}
ActionListener listener = new MyListener();
}
What is wrong with this code?

Accepted Answer

A)  button should be declared as final 
B)  The listener has not been attached to the button. 
C)  The listener cannot access the methods of the myOrder object. 
D)  This code will display the total order amount. 
A)  button should be declared as final 
B)  The listener has not been attached to the button. 
C)  The listener cannot access the methods of the myOrder object. 
D)  This code will display the total order amount.

Which of the following statements about a callback is NOT true?

A/an ____ is used to capture mouse events.

What role does an interface play when using a mock class?

Which of the following is an event source?

Which of the following statements about a mock class is true?

Which of the following statements about an interface is true?

A method that has no implementation is called a/an ____ method.

Which of the following is a good use for an anonymous class?

Suppose you are writing an interface called Resizable, which includes one void method called resize. public interface Resizable { _________________________ } Which of the following can be used to complete the interface declaration correctly?

The methods of a/an ____ describe the actions to be taken when an event occurs.

Consider the following code snippet: class MouseClickedListener implements ActionListener { Public void mouseClicked(MouseEvent event) { Int x = event.getX(); Int y = event.getY(); Component.moveTo(x,y); } } What is wrong with this code?

Which of the following statements about converting between types is true?

____ are generated when the user presses a key, clicks a button, or selects a menu item.

Consider the following class: public class ClickListener implements ActionListener { __________________________________________ { System.out.println("mouse event ..."); } } Which of the following method headers should be used to complete the ClickListener class?

Which container is used to group multiple user-interface components together?

Introduction

Using Objects

Implementing Classes

Fundamental Data Types

Decisions

Loops

Arrays and Array Lists

Designing Classes

Inheritance

Inputoutput and Exception Handling

Object-Oriented Design

Recursion

Sorting and Searching

The Java Collections Framework

Basic Data Structures

Tree Structures

Generic Classes

Graphical User Interfaces

Streams and Binary Inputoutput

Multithreading

Internet Networking

Relational Databases

XML

Web Applications

Filters

Exam 10: Interfaces

Which of the following statements about a callback is NOT true?

A/an ____ is used to capture mouse events.

What role does an interface play when using a mock class?

Which of the following is an event source?

Which of the following statements about a mock class is true?

Which of the following statements about an interface is true?

A method that has no implementation is called a/an ____ method.

Which of the following is a good use for an anonymous class?

Suppose you are writing an interface called Resizable, which includes one void method called resize. public interface Resizable { _________________________ } Which of the following can be used to complete the interface declaration correctly?

The methods of a/an ____ describe the actions to be taken when an event occurs.

Consider the following code snippet: class MouseClickedListener implements ActionListener { Public void mouseClicked(MouseEvent event) { Int x = event.getX(); Int y = event.getY(); Component.moveTo(x,y); } } What is wrong with this code?

Which of the following statements about converting between types is true?

____ are generated when the user presses a key, clicks a button, or selects a menu item.

Consider the following class: public class ClickListener implements ActionListener { __________________________________________ { System.out.println("mouse event ..."); } } Which of the following method headers should be used to complete the ClickListener class?

Which container is used to group multiple user-interface components together?

Introduction

Using Objects

Implementing Classes

Fundamental Data Types

Decisions

Loops

Arrays and Array Lists

Designing Classes

Inheritance

Inputoutput and Exception Handling

Object-Oriented Design

Recursion

Sorting and Searching

The Java Collections Framework

Basic Data Structures

Tree Structures

Generic Classes

Graphical User Interfaces

Streams and Binary Inputoutput

Multithreading

Internet Networking

Relational Databases

XML

Web Applications

Filters