MailSession session = MailSession.getDefaultInstance();
session.put(MailSession.SMTP_HOST, new Properties.Str("smtp.sample.com")); // SMTP host address
session.put(MailSession.SMTP_PORT, new Properties.Int(25)); // unless noticed otherwise by the server, SMTP uses port 25
session.put(MailSession.SMTP_USER, new Properties.Str("foo@bar.com")); // usually the full e-mail address
session.put(MailSession.SMTP_PASS, new Properties.Str("VerySecurePassword")); // e-mail account password

Message myMessage = new Message(); // our new message
myMessage.from = new Address("foo@bar.com", "Mr. Foo"); // the e-mail address I wan't to be visible to the recipient and a personal name.
myMessage.addRecipient(RecipientType.TO, new Address("someone@somewhere.com", null)); // the recipient of the e-mail
myMessage.subject = "Testing SMTP with authentication"; // e-mail subject
myMessage.setText("This is just a test message"); // simple e-mail with plain text
Transport.send(myMessage); // sends our message using the propert Transport for this Message, and the properties defined on the default MailSession.

 
// text part
Part textPart = new Part();
textPart.setText("Plain text");
// image part
Part imagePart = new Part();
File image = new File("/myImage.png", File.READ_WRITE); // keep file open!
imagePart.setContent(image, "image/png");
imagePart.fileName = "myImage.png";
// create the multiparts
Multipart multipart = new Multipart();
multipart.addPart(textPart);
multipart.addPart(imagePart);
// create the message
Message myMessage = new Message();
myMessage.setContent(multipart);
myMessage.subject = "E-mail with attachment";
myMessage.from = new Address("from@someone.com", "Someone name");
myMessage.addRecipient(Message.RecipientType.TO, new Address("to@url.com", "ToMe"));
// send the message
Transport.send(myMessage);
// close the image file AFTER the message is sent
image.close();

MailSession session = MailSession.getDefaultInstance();
session.put(MailSession.POP3_HOST, new Properties.Str("pop3.sample.com"));
session.put(MailSession.POP3_PORT, new Properties.Int(110));
session.put(MailSession.POP3_USER, new Properties.Str("foo@bar.com"));
session.put(MailSession.POP3_PASS, new Properties.Str("VerySecurePassword"));

Store store = MailSession.getDefaultInstance().getStore("pop3");
store.connect();
Folder folder = store.getFolder("INBOX");
folder.open();
int messageCount = folder.getMessageCount();
if (messageCount > 0)
{
   Message msg = folder.getMessage(1);
   String msgContent = (String) msg.getContent();
   if (msgContent != null)
      new MessageBox(msg.from.address, msgContent).popup();
}
folder.close(true);
store.close();