String to = "abc@example.com";
  String user = "sp@example.com";
  String pass = "1234";
    Properties props = new Properties();
    props.put("mail.smtp.host", "smtp.example.com");
    props.put("mail.smtp.port", "587");
    props.put("mail.smtp.auth", "true");
    props.put("mail.smtp.starttls.enable", "true");
Session session = Session.getInstance(props,new javax.mail.Authenticator()
{
  protected PasswordAuthentication getPasswordAuthentication()
  {
     return new PasswordAuthentication(user,pass);
  }

session.setDebug(true);