Here is the code to send an attachment:

import java.util.Properties;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;

public class AttachExample {
public static void main (String args[])
throws Exception {
String host = args[0];
String from = args[1];
String to = args[2];
String fileAttachment = args[3];

// Get system properties
Properties props = System.getProperties();

// Setup mail server
props.put("mail.smtp.host", host);

// Get session
Session session =
Session.getInstance(props, null);

// Define message
MimeMessage message =
new MimeMessage(session);
message.setFrom(
new InternetAddress(from));
message.addRecipient(
Message.RecipientType.TO,
new InternetAddress(to));
message.setSubject(
"Hello JavaMail Attachment");

// create the message part
MimeBodyPart messageBodyPart =
new MimeBodyPart();

//fill message
messageBodyPart.setText("Hi");

Multipart multipart = new MimeMultipart();
multipart.addBodyPart(messageBodyPart);

// Part two is attachment
messageBodyPart = new MimeBodyPart();
DataSource source =
new FileDataSource(fileAttachment);
messageBodyPart.setDataHandler(
new DataHandler(source));
messageBodyPart.setFileName(fileAttachment);
multipart.addBodyPart(messageBodyPart);

// Put parts in message
message.setContent(multipart);

// Send the message
Transport.send( message );
}
}