这句话什么意思？

Question

连接SMTP服务器，服务器地址是mail.jltg.com.cn，端口号：25 后面是用户名密码

Answer 1

我想问一下我这段群发代码的类有问题吗？如果有问题在那里？
package mailsend;
import java.io.PrintStream;
import java.util.*;
import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;public class SendMail1
{    public SendMail1()
    {
    }    public boolean Send(String s, Vector vector, String s1, String s2)
    {
        try
        {
            Properties properties = new Properties();
            Session session = Session.getInstance(properties, null);
            properties.put("mail.smtp.host", "mail.thwhgf.com");
            properties.put("mail.smtp.auth", "true");
            MimeMessage mimemessage = new MimeMessage(session);
            mimemessage.setFrom(new InternetAddress(s));
            mimemessage.setSubject(s1);
            mimemessage.setSentDate(new Date());
            mimemessage.setText(s2);
            Transport transport = session.getTransport("smtp");
            transport.connect("mail.thwhgf.com", 25, "gw", "tg");
            for(int i = 0; i < vector.size(); i++)
            {
                String s3 = (String)vector.elementAt(i);
                if(s3 != null && !s3.equals(""))
                {
                    InternetAddress internetaddress = new InternetAddress(s3);
                    mimemessage.setRecipient(javax.mail.Message.RecipientType.TO, internetaddress);
                    transport.sendMessage(mimemessage, mimemessage.getAllRecipients());
                }
            }            transport.close();
            System.out.println("\u53D1\u9001\u6210\u529F");
            return true;
        }
        catch(MessagingException messagingexception)
        {
            System.out.println(messagingexception.toString());
        }
        return false;
    }
}