Deserializing an Object in Java

The following DeserializeDemo program deserializes the Employee object created in the SerializeDemo program. Study the program and try to determine its output:

import java.io.*;
public class DeserializeDemo
{
public static void main(String [] args)
{
Employee e = null;
try
{
FileInputStream fileIn =
new FileInputStream("employee.ser");
ObjectInputStream in = new ObjectInputStream(fileIn);
e = (Employee) in.readObject();
in.close();
fileIn.close();
}catch(IOException i)
{
i.printStackTrace();
return;
}catch(ClassNotFoundException c)
{
System.out.println(.Employee class not found.);
c.printStackTrace();
return;
}
System.out.println("Deserialized Employee...");
System.out.println("Name: " + e.name);
System.out.println("Address: " + e.address);
System.out.println("SSN: " + e.SSN);
System.out.println("Number: " + e.number);
}
}

Serializing an Object in Java

The ObjectOutputStream class is used to serialize an Object. The following Serialize Demo program instantiates an Employee object and serializes it to a file. When the program is done executing, a file named employee.ser is created. The program does not generate any output, but study the code and try to determine what the program is doing.

Note: When serializing an object to a file, the standard convention in Java is to give the file a.ser extension.

import java.io.*;
public class SerializeDemo
{
public static void main(String [] args)
{
Employee e = new Employee();
e.name = "Reyan Ali";
e.address = "Phokka Kuan, Ambehta Peer";
e.SSN = 11122333;
e.number = 101;
try
{
FileOutputStream fileOut =
new FileOutputStream("employee.ser");
ObjectOutputStream out =
new ObjectOutputStream(fileOut);
out.writeObject(e);
out.close();
fileOut.close();
}catch(IOException i)
{
i.printStackTrace();
}
}
}

Data Structures (Properties) in Java

Example: Properties
The following program illustrates several of the methods supported by this data structure:

import java.util.*;
public class PropDemo {
public static void main(String args[]) {
Properties capitals = new Properties();
Set states;
String str;
capitals.put("Illinois", "Springfield");
capitals.put("Missouri", "Jefferson City");
capitals.put("Washington", "Olympia");
capitals.put("California", "Sacramento");
capitals.put("Indiana", "Indianapolis");
states = capitals.keySet();
Iterator itr = states.iterator();
while(itr.hasNext()) {
str = (String) itr.next();
System.out.println("The capital of " +
str + " is " + capitals.getProperty(str) + ".");
}
System.out.println();
str = capitals.getProperty("Florida", "Not Found");
System.out.println("The capital of Florida is "
+ str + ".");
}
}