In java, implement a simple email messaging system. a message has a recipient, a sender, and a message text. a mailbox can store messages. supply a number of mailboxes for different users and a user interface for the user to login, send messages to other users, read their own messages, and log out. Given the code I have so far, what needs to be added? class Message {     private String sender;     private String recipient;     private String messageText;       public Message(String sender, String recipient) {         this.sender = sender;         this.recipient = recipient;         this.messageText = " ";     }       public void append(String text) {         this.messageText += text;     }       public String toString() {         return "From: " + sender + "  To: " + recipient + "\n" + this.messageText;       } }   class Mailbox {     private ArrayList email;       public Mailbox() {         this.email = new ArrayList();     }       public Message getMessage(int i) {         return this.email.get(i);     }       public void addMessage(Message m) {         this.email.add(m);     }       public void removeMessage(int i) {         this.email.remove(i);     }       public int mailBoxSize() {         return this.email.size();     } }

In java, implement a simple email messaging system. a message has a recipient, a sender, and a message text. a mailbox can store messages. supply a number of mailboxes for different users and a user interface for the user to login, send messages to other users, read their own messages, and log out.

Given the code I have so far, what needs to be added?

class Message {

    private String sender;

    private String recipient;

    private String messageText;

    public Message(String sender, String recipient) {

        this.sender = sender;

        this.recipient = recipient;

        this.messageText = " ";

    }

    public void append(String text) {

        this.messageText += text;

    }

    public String toString() {

        return "From: " + sender + "  To: " + recipient + "\n" + this.messageText;

    }

}

class Mailbox {

    private ArrayList<Message> email;

    public Mailbox() {

        this.email = new ArrayList<Message>();

    }

    public Message getMessage(int i) {

        return this.email.get(i);

    }

    public void addMessage(Message m) {

        this.email.add(m);

    }

    public void removeMessage(int i) {

        this.email.remove(i);

    }

    public int mailBoxSize() {

        return this.email.size();

    }

}