Javamail Configuration clarification - jakarta-mail

Question

Through my application using Javamail API if I want to send email between any two external email addresses say gmail->yahoo or yahoo->gmail or any other email account without using authentication mechanism how should I configure mail.smtp.host property?
What is the correct way of configuring javamail properties for sending emails between any two external email addresses ?
Sample code to send mail is given below:
Session session = Session.getDefaultInstance(new Properties(),null);
MimeMessage message = new MimeMessage(session);
message.setFrom(new InternetAddress("test#gmail.com"));
InternetAddress[] toAddress = {new InternetAddress("test#yahoo.com")};
message.setRecipients(Message.RecipientType.TO, toAddress);
message.setSubject("test mail"); message.setText("test body");
Transport.send(message);

Answer 1

Most public mail servers require authentication. If you want to do it without authentication, you'll need to run your own mail server.

Answer 2

This is for gmail, try it. You need mail.jar
public static void main(String[] args) {
final String username = "yourId#gmail.com";
final String password = "your-pwd";
Properties props = new Properties();
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.starttls.enable", "true");
props.put("mail.smtp.host", "smtp.gmail.com");
props.put("mail.smtp.port", "587");
Session session = Session.getInstance(props,
new javax.mail.Authenticator() {
protected PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication(username, password);
}
});
try {
Message message = new MimeMessage(session);
message.setFrom(new InternetAddress("yourId#gmail.com"));
message.setRecipients(Message.RecipientType.TO,
InternetAddress.parse("some-mail#gmail.com"));
message.setSubject("A Mail Subject");
message.setText("Hey I'm sending mail using java api");
Transport.send(message);
System.out.println("Done");
} catch (MessagingException e) {
throw new RuntimeException(e);
}
}
Edit :
Link to download Java mail Api along with mail.jar