Demonstration of the transient keyword

[Java Tip]

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Date;

public class Logon implements Serializable {
  private Date date = new Date();

  private String username;

  private transient String password;

  public Logon(String name, String pwd) {
    username = name;
    password = pwd;
  }

  public String toString() {
    String pwd = (password == null) ? "(n/a)" : password;
    return "logon info: \n   username: " + username + "\n   date: " + date
        + "\n   password: " + pwd;
  }

  public static void main(String[] args) throws Exception {
    Logon a = new Logon("Hulk", "myLittlePony");
    System.out.println("logon a = " + a);
    ObjectOutputStream o = new ObjectOutputStream(new FileOutputStream(
        "Logon.out"));
    o.writeObject(a);
    o.close();
    Thread.sleep(1000); // Delay for 1 second
    // Now get them back:
    ObjectInputStream in = new ObjectInputStream(new FileInputStream(
        "Logon.out"));
    System.out.println("Recovering object at " + new Date());
    a = (Logon) in.readObject();
    System.out.println("logon a = " + a);
  }
}