javamail api to access gmail inbox messages - gmail

Question

I have been trying to use the javamail api to read gmail inbox messages. I found the following code on the internet. I'm trying to run this on Eclipse, but it is failing with an "Invalid credentials exception". I have mail.jar, activation.jar, imap.jar and other jar files in the lib directory of the web-app.
Any ideas as to why I am receiving this exception ? Thanks.
javax.mail.AuthenticationFailedException: Invalid credentials n67if632335wep.219
at com.sun.mail.imap.IMAPStore.protocolConnect(IMAPStore.java:665)
at javax.mail.Service.connect(Service.java:295)
at javax.mail.Service.connect(Service.java:176)
at org.mb.mail.MailReader.main(MailReader.java:23)
package org.mb.mail;
import java.util.Properties;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.NoSuchProviderException;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.*;
public class MailReader {
public static void main(String args[]) {
Properties props = System.getProperties();
props.setProperty("mail.store.protocol", "imaps");
try {
Session session = Session.getDefaultInstance(props, null);
Store store = session.getStore("imaps");
store.connect("imap.gmail.com", "<username>", "password");
System.out.println(store);
Folder inbox = store.getFolder("Inbox");
inbox.open(Folder.READ_ONLY);
Message messages[] = inbox.getMessages();
for(Message message:messages) {
System.out.println(message);
}
} catch (NoSuchProviderException e) {
e.printStackTrace();
System.exit(1);
} catch (MessagingException e) {
e.printStackTrace();
System.exit(2);
}
}
}

Answer 1

Throw away that code and use this code from the JavaMail FAQ, where you'll also find lots of other helpful tips, including debugging tips.

Answer 2

If you see this exception you are in correct path, just you need to change the mail id or create a new gmail id which will have less security.(for example a primary gmail account is much configured in smartphones and its highly secured with google with Oauth2.0, so that gmail account connection will be blocked by google but when you tried with alternate gmail id or gmail id which not configured in mobile can be easily get connected)
Previously this issue broke my head finally got fixed. Thanks