(SOLVED) Java Code Exam

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  • May 8, 2024

Java Code Exam

QUESTION 1

  1. A/an ____ object contains methods that describe the actions to be taken when a user clicks a user-interface graphical object.
    Event listener
    Event source
    Action listener
    Action method

2 points   

QUESTION 2

  1. Which statement should be added to this code fragment to ensure that the frame is shown?

    JFrame frame = new JFrame();

    frame.setVisible(true);
    frame.visible = true;
    JFrame.setVisible();
    frame.setVisible();

2 points   

QUESTION 3

  1. Consider the following code snippet:

    import ____________________
    import awt.event.ActionListener;

    /**
    An action listener that prints.
    */
    public class ClickListener implements ActionListener
    {
    public void actionPerformed(ActionEvent event)
    {
    System.out.println(“I was clicked.”);
    }
    }

    Which of the following statements will complete this code?

    java.swing.event.ActionEvent;.
    javax.swing.event.ActionEvent;
    javax.awt.event.ActionEvent;
    java.awt.event.ActionEvent;

2 points   

QUESTION 4

  1. When drawing complex shapes, provide a(n) ____ to set the position of the shape.
    constructor
    viewer
    component
    frame

2 points   

QUESTION 5

  1. Which statement will add a dollar sign and the value of the double variable balance to a JTextArea component called results?
    results.addText(“$” + balance);
    results.append(“$” + balance);
    results.addText(“$” + Double.parseDouble(balance));
    results.append(“$ + (String) balance”);

2 points   

QUESTION 6

  1. Which java package must be imported if a program wishes to respond to button events?
    javax.swing.event.ActionListener
    java.awt.event.ActionListener
    javax.swing.JButton
    java.awt.JButton

2 points   

QUESTION 7

  1. When drawing complex shapes, make a separate class for each part and provide a(n) ___ method that draws the shape.
    draw
    add
    sketch
    outline

2 points   

QUESTION 8

  1. Which of the following statements will compile without error?
    public interface AccountListener()
{
void actionPerformed(AccountEvent event);
}
    public interface AccountListener()
{
void actionPerformed(AccountEvent);
}
    public interface AccountListener
{
void actionPerformed(AccountEvent event);
}
    public abstract AccountListener
{
void actionPerformed(AccountEvent event);
}

2 points   

QUESTION 9

  1. To respond to a button event, a listener must supply instructions for the ____ method of the ActionListener interface.
    actionEvent
    actionPerformed
    eventAction
    eventResponse

2 points   

QUESTION 10

  1. Consider the following code snippet:

    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)
    {
    . . .
    }
    }
    }

    Which of the local variables can be accessed within the actionPerformed method?

    Only button can be accessed..
    All of the local variables can be accessed.
    label and myOrder can be accessed.
    Only myOrder can be accessed.

2 points   

QUESTION 11

  1. Use the ____ method to specify the height and width of a graphical component when you add it to a panel.
    setPreferredDimensions.
    setInitialDimensions.
    setPreferredSize.
    setInitialSize.

2 points   

QUESTION 12

  1. Which of the following statements about events and graphical user interface programs is true?
    Your program must indicate the specific types of events to which it wishes to respond.
    Your program will automatically receive notifications about all events that have occurred.
    Your program must respond to notifications of all types of events that are sent to it while it is running.
    Your program must override the default methods to handle events.

11)____ are generated when the user presses a key, clicks a button, or selects a menu item.
a) Listeners
b) Interfaces.
*c) Events.
d) Errors.

2 points   

QUESTION 13

  1. Which of the following statements creates a button with “Calculate” as its label?
    Button JButton = new Button(“Calculate”)
    button = new Button(JButton, “Calculate”)
    Button = new JButton(“Calculate”)
    JButton button = new JButton(“Calculate”)

2 points   

QUESTION 14

  1. The methods of a/an ____ describe the actions to be taken when an event occurs.
    event source
    event listener
    event interface
    action source

2 points   

QUESTION 15

  1. Insert the missing statement(s) in the following code fragment. The code is intended to display a message “Your cost is: ” in a text area and display the cost on the next line.

    double cost = 500.99;
    String message = “Your cost is:”;
    JTextArea result = new JTextArea(10, 30);

    __________________________________________
    setEditable(false);

    result.setText(message);
result.append(cost);
    result.addText(message + “\n” + cost);
    result.append(message + cost);
    result.setText(message + “\n”);
result.append(cost);

2 points   

QUESTION 16

  1. Which of the following statements is correct?
    Methods of an inner class can access instance variables from the surrounding scope.
    If an interface variable refers to an object, then the object need not belong to a class.
    It is illegal to have variables whose type is an interface.
    Methods of an inner class cannot access final variables from the surrounding scope.

2 points   

QUESTION 17

  1. Which of the following statements should be added to this code fragment to set the frame size to a width of 400 and a height of 200?

    final int FRAME_WIDTH = 400;
    final int FRAME_HEIGHT = 200;
    JFrame frame = new JFrame();

    frame.size = (FRAME_WIDTH, FRAME_HEIGHT);
    frame.addSize(FRAME_WIDTH, FRAME_HEIGHT);
    frame.setSize(FRAME_WIDTH, FRAME_HEIGHT);
    frame.setSize(FRAME_HEIGHT, FRAME_WIDTH);

2 points   

QUESTION 18

  1. Consider the following code snippet:

    JPanel panel = new JPanel();
    JFrame frame = new JFrame();
    JLabel label = new JLabel(“Show the answer”);
    JTextField field = new JTextField(5);
    add(label);
    frame.add(field);
    panel.add(frame);

    Which of the following statements is true?

    This code will correctly show all components.
    The label and field should be added to the panel first, and then the panel should be added to the frame.
    The frame should be added to the panel before adding the label and field to the frame.
    The panel should be added to the frame first, and then the label and field should be added to the panel.

2 points   

QUESTION 19

  1. What happens if a text field’s width is set to 10 characters and the user types more characters into it?
    The user interface automatically widens the field’s width.
    An InputMismatchException is thrown.
    The earlier characters are deleted and only the last ten are shown and entered.
    The characters are entered but only those that fit into the width are shown.

2 points   

QUESTION 20

  1. Consider the following code snippet:

    JPanel panel = new JPanel();
    JFrame frame = new JFrame();
    JButton button = new JButton(“Click me”);
    JLabel label = new JLabel(“Show the answer”);
    add(label);
    frame.add(button);
    panel.add(frame);

    Which of the following statements is true?

    This code will correctly build the user interface.
    The button and label should be added to the panel first, and then the panel should be added to the frame.
    The frame should be added to the panel before adding the button and label to the frame.
    The panel should be added to the frame first, and then the button and label should be added to the panel.

 

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