How to rewrite iterator code to for/in code ?

Question

I am trying to change my iterator code to code using the for/in construct from Java 1.5
in the howManyMessages() method I am trying to convert:
Iterator it = messages.iterator();
        while(it.hasNext()) {
            MailItem mess = (MailItem) it.next();
            if(mess.getTo().equals(who)) {
                count++;
        Should this become:
for(Object mess: message)
  if(get(mess).getTo().equals(who)
      count++;  and how about the getNextMailItem() method ? it has a it.remove() statement. Is it impossible to use the for/in construct
where there is a remove() method ?
Thank you in advance. Below is the coding
import java.util.Vector;
import java.util.Iterator;
/* A simple model of a mail server. The server is able to receive
* messages for storage, and deliver them to clients on demand.
* @author David J. Barnes and Michael Kolling @version 2001.05.30 */
public class MailServer
    // Storage for the arbitrary number of messages to be stored on the server.
    private Vector messages;
     // Construct a mail server.
         public MailServer()
            messages = new Vector();
     /* @return How many messages are waiting for the given user.
     * @param who The user to check for. */
    public int howManyMessages(String who)
        int count = 0;
        Iterator it = messages.iterator();
        while(it.hasNext()) {
            MailItem mess = (MailItem) it.next();
            if(mess.getTo().equals(who)) {
                count++;
        return count;
     /* Return the next message for who. Return null if there
     * are none.
     * @param who The user requesting their next message.*/
         public MailItem getNextMailItem(String who)
           Iterator it = messages.iterator();
            while(it.hasNext())
               MailItem mess = (MailItem) it.next();
               if(mess.getTo().equals(who))
                   it.remove();
                   return mess;
         return null;
         /* Add the given message to the message list.
          * @param item The mail item to be stored on the server.*/
            public void post(MailItem item)
                 messages.add(item);
/* A class to model a simple mail item. The item has sender and recipient
* addresses and a message string.
* @author David J. Barnes and Michael Kolling
* @version 2001.05.30 */
public class MailItem
    // The sender of the item.
    private String from;
    // The intended recipient.
    private String to;
    // The text of the message.
    private String message;
     /* Create a mail item from sender to the given recipient,
     * containing the given message.
     * @param from The sender of this item.
     * @param to The intended recipient of this item.
     * @param message The text of the message to be sent. */
    public MailItem(String from, String to, String message)
        this.from = from;
        this.to = to;
        this.message = message;
      //Return The sender of this message.
         public String getFrom()
        return from;
     // Return The intended recipient of this message.
         public String getTo()
            return to;
     //Return The text of the message.
         public String getMessage()
        return message;
         // Print this mail message to the text terminal.
         public void print()
            System.out.println("From: " + from);
            System.out.println("To: " + to);
            System.out.println();
            System.out.println("Message:     " + message);
* A class to model a simple email client. The client is run by a
* particular user, and sends and retrieves mail via a particular server.
* @author David J. Barnes and Michael Kolling
* @version 2001.05.30
public class MailClient
    // The server used for sending and receiving.
    private MailServer server;
    // The user running this client.
    private String user;
     * Create a mail client run by user and attached to the given server.
    public MailClient(MailServer server, String user)
     this.server = server;
     this.user = user;
     * Return the next mail item (if any) for this user.
    public MailItem getNextMailItem()
     return server.getNextMailItem(user);
     * Print the next mail item (if any) for this user to the text
     * terminal.
    public void printNextMailItem()
     MailItem item = server.getNextMailItem(user);
     if(item == null) {
         System.out.println("No new mail.");
     else {
         item.print();
     * Send the given message to the given recipient via
     * the attached mail server.
     * @param to The intended recipient.
     * @param mess A fully prepared message to be sent.
    public void sendMessage(String to, String message)
     MailItem mess = new MailItem(user, to, message);
     server.post(mess);
//In this program we learn about the Vector class and the iterator()
//we step into the printNewMailItem() method of the MailClient class with bluej
//we observe the debugger and watch a messege appear.
public class Try_e_mail
  public static void main(String[] args)
      MailServer myMailServer = new MailServer();
      MailClient Julie = new MailClient(myMailServer, "Julie");
      MailClient Sam = new MailClient(myMailServer, "Sam");
      MailItem messageMonday = new MailItem("Sam", "Julie", "I really enjoy studying Java !");
      MailItem messageTuesday = new MailItem("Julie", "Sam", "Computer Science is an important challenge !");
      MailItem messageWednesday = new MailItem("Sam", "Julie", "It is alot more rewarding than watching TV !");
      System.out.println();
      messageMonday.print();
      System.out.println();
      messageTuesday.print();
      System.out.println();
      messageWednesday.print();
//The output I received is:
//From: Sam
//To: Julie
//Message:     I really enjoy studying Java !
//From: Julie
//To: Sam
//Message:     Computer Science is an important challenge !
//From: Sam
//To: Julie
//Message:     It is alot more rewarding than watching TV !

Answer 1

The for/in coding that worked was for a non-generic collection.
So I guess that means that a Vector is a non-generic collection.
What does non-generic mean ?
Thank you in advance
//for non-generic collections
       for(Object obj : messages)
          MailItem mess = (MailItem)obj;
          if ( mess.getTo().equals(who))
            count++;
  //for Generic collections                     
         /*  for(MailItem mess: messages)
             if(mess.getTo().equals(who))
               count++; */