— Scott McNealy, Sun Microsystems Chairman, President and ceo

True or False
D
exercise: 
True or False

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serialization 
and
file I/O
you are here
4
467
This one’s tricky, so we promoted it from an Exercise to full Puzzle status. 
Reconstruct the code snippets to make a working Java program that 
produces the output listed below? (You might not need all of the magnets, 
and you may reuse a magnet more than once.)
public static void main(String [] args) {
DungeonGame d = new DungeonGame();
int getX() {
return x;
public int x = 3;
transient long y = 4;
private short z = 5;
File Edit Window Help Torture
% java DungeonTest
12
8
class DungeonTest {
Code Magnets
long getY() {
return y;
short getZ() {
return z;
d = (DungeonGame) ois.readObject();
} catch (Exception e) {
ois.close();
class DungeonGame implements Serializable {
e.printStackTrace();
FileOutputStream fos = new
FileOutputStream(“dg.ser”);
oos.close();
fos.writeObject(d);
ObjectOutputStream oos = new
ObjectOutputStream(fos);
ObjectInputStream ois = new
ObjectInputStream(fi s);
oos.writeObject(d);
try {
System.out.println(d.getX()+d.getY()+d.getZ());
FileInputStream fi s = new
FileInputStream(“dg.ser”);
import java.io.*;

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468
 
chapter 14
Exercise Solutions
1. Serialization is appropriate when saving data for non-Java programs to use.
2. Object state can be saved only by using serialization.
3. ObjectOutputStream is a class used to save serialized objects. 
4. Chain streams can be usedon their own or with connection streams. 
5. A single call to writeObject() can cause many objects to be saved.
6. All classes are serializable by default. 
7. The transient modifier allows you to make instance variables serializable.
8. If a superclass is not serializable then the subclass can’t be serializable.
9. When objects are deserialized they are read back in last-in, first out sequence. 
10. When an object is deserialized, its constructor does not run. 
11. Both serialization and saving to a text file can throw exceptions.
12. BufferedWriters can be chained to FileWriters.
13. File objects represent files, but not directories.
14. You can’t force a buffer to send its data before it’s full.
15. Both file readers and file writers can optionally be buffered. 
16. The String split() method includes separators as tokens in the result array.
17. Any change to a class breaks previously serialized objects of that class.