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.

Sorry, but saying "this is the problem" or "I can't open that folder" is as useful for us as us saying "then fix the problem" or "then open that folder differently" is useful to you.

What do you mean by each of those things? Are you getting an Exception? Unexpected behavior? Something else? Be specific.

But just glancing at it, you never declare your folder variable. For that matter, what is Folder? I don't see that class in the standard API.

PS- When posting code, make sure you use the code tags.

Hello qwert678,

Welcome to the Java Programming Forums.

I have added the highlight tags around your code. For future posts, please use: [highlight=Java] code [/highlight]

I'm not sure if you are aware but you have a missing } at the end of your code. Looking at your path, that is correct.

I will need to import javax.mail before I can look into this any further..

OK i've imported javax.mail and the problem is:

The method open(int) in the type Folder is not applicable for the arguments (String)

Check these links:

Folder (JavaMail API documentation)

Java Mail POP3Client Example

Another problem is that the folder variable is null. Even if the open() method is given the correct argument, it's still going to cause an NPE.

What type of files are in this local folder? What extension?

I found this example online. See if this helps you move forward. Take note of folder.open(Folder.READ_ONLY);

    public static void main(String[] args) throws Exception {
 
        URLName server = new URLName("protocol://username:password@host/foldername");
 
        Session session = Session.getDefaultInstance(new Properties(), null);
 
        Folder folder = session.getFolder(server);
 
        if (folder == null) {
          System.out.println("Folder " + server.getFile() + " not found.");
          System.exit(1);
        }
        folder.open(Folder.READ_ONLY);
 
        // Get the messages from the server
        Message[] messages = folder.getMessages();
        for (int i = 0; i < messages.length; i++) {
          System.out.println("------------ Message " + (i + 1) + " ------------");
          messages[i].writeTo(System.out);
        }
 
        folder.close(false);
      }