Java : Using Javamail to read email

Question

I've been working on a program, that's suppose to use javamail, to read through an inbox, and if an email contains a specific String, it should be opened.

First off, this is my first time trying to use this javamail api - I'm pretty sure that my properties are all messed up - Can anyone give me at tip on correctly setting up properties for javamail?

Secondly, it seems like i can connect via the API, but if I try to search for subjects AND the subject is null, I get a null pointer exception - If I however don't try to match the subject with "Ordretest", I get no nullpointer - Any tips would be a great help :)

package vildereMail;

import java.util.Properties;

import javax.mail.Address;
import javax.mail.BodyPart;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.internet.InternetAddress;
import javax.mail.search.FromTerm;
import javax.mail.search.SearchTerm;
import javax.mail.search.SubjectTerm;

public class vildereMail {


    public boolean match(Message message) {
        try {
            if (message.getSubject().contains("Ordretest")) {
                System.out.println("match found");
                return true;
            }
        } catch (MessagingException ex) {
            ex.printStackTrace();
        }
        return false;
    };
        public static void main(String[] args) {
            Properties props = System.getProperties();
        props.setProperty("mail.store.protocol", "imaps");
            props.put("mail.imap-mail.outlook.com.ssl.enable", "true");
            props.put("mail.pop3.host", "outlook.com");
            props.put("mail.pop3.port", "995");
            props.put("mail.pop3.starttls.enable", "true");
            try {
                Session session = Session.getInstance(props, null);
                Store store = session.getStore();
                store.connect("imap-mail.outlook.com", "myEmail@live.dk", "MyPassword");
                session.setDebug(true);
                Folder inbox = store.getFolder("INBOX");
                inbox.open(Folder.READ_ONLY);


                SearchTerm sender = new FromTerm(new InternetAddress("myMail@live.dk"));

                Message[] messages = inbox.search(sender);
                System.out.println(messages);

                for (int i = 0 ; i < messages.length ; i++) {

                    System.out.println(messages[i].getSubject());
                    if (messages[i].getSubject().equals(null)) {
                        System.out.println("null in subject");
                        break;
                    }
                    else if (messages[i].getSubject().contains("Ordretest")){
                        System.out.println("1 match found");
                    }
                    else {
                    System.out.println("no match");
                    }
                }
                System.out.println("no more messages");
                store.close();

            } catch (Exception mex) {
                mex.printStackTrace();
            }
        }
    }

Answer 1

Without knowing on which line you get the NPE (Null Pointer Exception) I guess it occurs here:

if (messages[i].getSubject().equals(null)) 

If getSubject() returns null and you try to do .equals() it will throw a NPE (because you try to invoke a method). So try to rewrite it to (assuming your message object can't be null):

if (messages[i].getSubject() == null) 

Answer 2

Where to start...

Have you found the JavaMail FAQ ?

You can get rid of all the property settings because they're doing nothing since you're using the "imaps" protocol, not the "pop3" protocol.

As others have explained, the getSubject method might return null, so you need to check for that.