I can't send mail to the site that required Authenticator

Question

How can I send mail to the smtp site that required Authenticator,If th smtp site doesn't require Authenticator ,I can send mail.
My program:
Properties props=new Properties();
props.put("smtp","smtp.163.com");
props.put("auth","true");
MailUser mu=new MailUser("username","password");
javax.mail.Session session=javax.mail.Session.getDefaultInstance(props,mu);
public class MailUser extends Authenticator
String username;
String password;
public MailUser(String us,String ps)
this.username=us;
this.password=ps;
}

Answer 1

Properties props = System.getProperties();
props.put("mail.smtp.host", "hiart.co.kr");
props.put("mail.smtp.auth","true");//auth module....
session = Session.getDefaultInstance(props,null);
          Date date = new Date();
msg = new MimeMessage(session);
          System.out.println(from);
msg.setFrom(new InternetAddress(from+"@hiart.co.kr"));