Reference no: EM131060292
Question 1
The method __________ sets the background color to yellow in JFrame frame.
setBackground(Color.YELLOW)
frame.setBackGround(Color.yellow)
setBackground(Color.yellow)
frame.setBackground(Color.YELLOW)
Question 2
What layout manager should you use so that every component occupies the same size in the container?
FlowLayout
any layout
BorderLayout
GridLayout
Question 3
Which of the following statements is for terminating the program when closing the frame?
frame.setDefaultCloseOperation(null)
frame.setDefaultCloseOperation(JFrame.TERMINATE_ON_CLOSE)
frame.setDefaultCloseOperation(JFrame.STOP_ON_CLOSE)
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)
Question 4
Which of the following statements about containers is correct?
Both frames and panels can be placed inside a panel
A panel can be placed inside a panel
A frame can be placed inside a panel
A frame can be placed inside a frame
Question 5
Which method call puts the string "Result" into the TextField named result?
result.findText()
result.text("Result")
result.newText("Result")
result.setText("Result")
Question 6
How many items can be added into a JComboBox object?
0
1
Unlimited
2
Question 7
What kind of object is used group radio buttons?
Group
ButtonGroup
JButtonGroup
ContainerGroup
Question 8
Which of the following method calls is used to prevent the user from modifying a text field tf?
tf.setUneditable()
tf.setEditable(false);
tf.preventMdification()
tf.setChangable(false);
Question 9
When you want to allow the user to select only one of several choices, which you use?
Text fields
Ordinary buttons
Radio buttons
Check boxes
Question 10
What is the benefit of using layout managers?
It reduces the amount of code needed
It defines how components of a window should be arranged when it is resized
It makes the program run much faster
It reduces the amount of memory necessary to store the window components
Question 11
Which of the following true about source and listener objects?
Both objects must be of the same type
The objects must always be of different types
They must always be different objects
They can be the same object
Question 12
Which of the following statements is incorrect?
A listener may listen for multiple sources
The listener object's class must implement the corresponding event-listener interface
A source object can only have one listener object
The listener object must be registered by the source object
Question 13
Given the code below, indicate which statement describes its behavior.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Quiz3A extends JFrame implements ActionListener
{
public Quiz3A()
{
JButton okButton = new JButton("OK");
add(okButton);
}
public void actionPerformed(ActionEvent e)
{
System.out.println("The OK button is clicked");
}
public static void main(String[] args)
{
JFrame frame = new Quiz3A();
frame.setSize(300, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
The actionPerformed method is not executed when you click the OK button, because no instance of Quiz3A is registered with okButton
The program has a compilation error because no listeners are registered for okButton
The message The OK button is clicked is displayed when you click the OK button
The program has a runtime error because no listeners are registered with okButton
Question 14
The listener for an button event is an instance of ________.
KeyListener
ActionListener
MouseListener
ItemListener
Question 15
Which of the following statements registers a panel object aPanel as a listener for a button variable aButton?
aButton.addActionEventListener(aPanel);
addActionListener(aPanel);
aPanel.addEventListener(aPanel);
aButton.addActionListener(aPanel);
Question 16
In the program below, which object is listening for the events of okButton?
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Quiz3B extends JFrame implements ActionListener
{
private JButton okButton = new JButton("OK");
public Quiz3B()
{
add(okButton);
okButton.addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{
System.out.println("The OK button is clicked");
}
public static void main(String[] args)
{
JFrame frame = new Quiz3B();
frame.setSize(300, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
okButton
An anonymous object
frame
JButton
Question 17
What is the benefit of using adapter classes rather than listeners interfaces?
Question 17 options:
It enables multiple inheritance of classes
It makes it unnecessary to implement unused event handling methods
It makes the response time for responding to events much quicker
It makes it possible to respond to several events at the same time
Question 18
In the program below, which object is listening for the events of okButton?
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Quiz3C extends JFrame
{
private JButton okButton = new JButton("OK");
public Quiz3C()
{
add(okButton);
okButton.addActionListener(
new ActionListener()
{
@Override
public void actionPerformed(ActionEvent ae)
{
System.out.println("The OK button is clicked");
}
});
}
public static void main(String[] args)
{
JFrame frame = new Quiz3C();
frame.setSize(300, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
An anonymous object
frame
JButton
okButton
Question 19
Which of the following will occur if you fail to register an object as a listener for the click events of a button?
The containing frame will be considered as the default listener
A compilation error will occur
Nothing will happen when the button is clicked
A class cast exception will be thrown at run-time
Question 20
When a mouse event is generated how is the location of the click point determined?
The event handler must generate a secondary event to obtain the location
It is automatically saved as an instance variable in the object of which the mouse was clicked
It is obtained by calling a method of the mouse object
It is extracted from the mouse event that is passed to the event handler.