Weiqi Gao's Observations - quiz tag

Friday Java Quiz: Know Your JDK

Fri, 11 May 2012 12:48:36 GMT

Haven't had one of these for a while. I was busy doing other things.

Since it's been so long, I'll pose an easy quiz today:

Q: What does the following command print?

weiqi@gao /opt/jdk1.7.0_04/bin$ ls | wc -l

(/opt/jdk1.7.0_04 is where I installed my JDK, your JDK installation locations may vary.)

Strict rules apply today: You have twenty minutes to think about it and you must write down your answer before you go to your JAVA_HOME and run the command.

Friday Java Quiz: Know Your Properties Files

Fri, 24 Sep 2010 16:02:00 GMT

Here's a little Java quiz to cheer everyone up:

Given the following foo.properties file:

Start Time: Fri Sep 24 11\:02\:45 CDT 2010

Q: After loading this file into a java.util.Properties object, what is the value of the Start Time property in the object?

Strict rules apply today: No compiling, googling, or reading any documentations before you write down your answer.

Friday Java Quiz: What Will The GUI Show?

Fri, 02 Jul 2010 12:12:55 GMT


1    import javax.swing.*; 
2    import java.awt.*; 
3    import java.awt.event.*; 
4     
5    public class Foo { 
6        public static void main(final String[] args) { 
7            EventQueue.invokeLater(new Runnable() { 
8                public void run() { 
9                    swingMain(); 
10               } 
11           }); 
12       } 
13    
14       private static void swingMain() { 
15           JFrame frame = new JFrame("Demo"); 
16           frame.setLayout(new FlowLayout()); 
17    
18           JTextField tf1 = new JTextField(20); 
19           final JTextField tf2 = new JTextField(20); 
20           JButton b = new JButton("Click Me"); 
21    
22           tf1.addFocusListener(new FocusAdapter() { 
23               @Override 
24               public void focusLost(FocusEvent e) { 
25                   tf2.setText("Lost Focus!"); 
26               } 
27           }); 
28    
29           b.addActionListener(new ActionListener() { 
30               public void actionPerformed(ActionEvent e) { 
31                   tf2.setText("Clicked!"); 
32               } 
33           }); 
34    
35           frame.add(tf1); 
36           frame.add(tf2); 
37           frame.add(b); 
38           frame.pack(); 
39           frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); 
40           frame.setVisible(true); 
41       } 
42   }

Q: If, after starting the above Swing program, you click on the JButton b, what will the JTextField jt2 show?
Lost Focus!
or
Clicked!

Strict rule apply: no compiling and running, no Googling, and your first answer is the final answer. You are allowed to read the Javadoc of the relevant classes though.