Thread: Read Mail From A Folder

Hello to all in this forum. I'm new in Java and try to learn through the programs that I create.
So I try to create a programm tha reads e-mails from a local folder. My problem is that I can't open that folder.
I don't know what I'm doing wrong. Βelow is the code of my programm.

import java.io.*;
import java.util.*;
import javax.mail.*;
 
public class MailREad {  
 
	public static void main(String args[]) throws Exception {  
 
		String path = "C:\\Users\\Desktop\\mail folder";
			Folder folder =null;
 
		folder.open(path); //this is the problem
 
		Message[] message = folder.getMessages(); 
 
		//mail
 
        for (int i = 0; i < message.length; i++) {
 
            System.out.println("------------ Message " + (i + 1) + " ------------");
 
            System.out.println("SentDate : " + message[i].getSentDate());
            System.out.println("From : " + message[i].getFrom()[0]);
            System.out.println("Subject : " + message[i].getSubject());
            System.out.print("Message : ");
 
            InputStream stream = message[i].getInputStream();
            while (stream.available() != 0) {
                System.out.print((char) stream.read());
            }
            System.out.println();
        }
	}

Thank you in advance for your answers.