메일이 가지지 않는데요 . 소스코드에서 문제가 있는거 같습니다.

고수님들 좀 바로 잡아 주세여...

부탁들립니다 ㅜㅜ
NMailSender.java

package com.android.mailsend;

import java.io.ByteArrayInputStream; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.OutputStream; 
import java.security.Security; 
import java.util.Properties; 
 
import javax.activation.DataHandler; 
import javax.activation.DataSource; 
import javax.mail.Message; 
import javax.mail.PasswordAuthentication; 
import javax.mail.Session; 
import javax.mail.Transport; 
import javax.mail.internet.InternetAddress; 
import javax.mail.internet.MimeMessage; 
 
public class NMailSender extends javax.mail.Authenticator { 
    private String mailhost = "smtp.naver.com"; 
    private String user; 
    private String password; 
    private Session session; 
 
    public NMailSender(String user, String password) { 
        this.user = user; 
        this.password = password; 
 
        Properties props = new Properties(); 
        props.setProperty("mail.transport.protocol", "smtp"); 
        props.setProperty("mail.host", mailhost); 
        props.put("mail.smtp.auth", "true"); 
        props.put("mail.smtp.port", "587"); 
        props.put("mail.smtp.socketFactory.port", "587"); 
        props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory"); 
        props.put("mail.smtp.socketFactory.fallback", "false"); 
        props.setProperty("mail.smtp.quitwait", "false"); 
 
        session = Session.getDefaultInstance(props, this); 
    } 
    /* (non-Javadoc)
     * @see javax.mail.Authenticator#getPasswordAuthentication()
     */
    protected PasswordAuthentication getPasswordAuthentication() { 
        return new PasswordAuthentication(user, password); 
    } 
 
    public synchronized void sendMail(String subject, String body, String sender, String recipients) throws Exception
    { 
        MimeMessage message = new MimeMessage(session); 
        DataHandler handler = new DataHandler(new ByteArrayDataSource(body.getBytes(), "text/plain")); 
        message.setSender(new InternetAddress(sender)); 
        message.setSubject(subject); 
        message.setDataHandler(handler); 
       
        if (recipients.indexOf(',') > 0) 
            message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(recipients)); 
        else 
            message.setRecipient(Message.RecipientType.TO, new InternetAddress(recipients)); 
        Transport.send(message); 
    } 
 
    public class ByteArrayDataSource implements DataSource { 
        private byte[] data; 
        private String type; 
 
        public ByteArrayDataSource(byte[] data, String type) { 
            super(); 
            this.data = data; 
            this.type = type; 
        } 
 
        public ByteArrayDataSource(byte[] data) { 
            super(); 
            this.data = data; 
        } 
 
        public void setType(String type) { 
            this.type = type; 
        } 
 
        public String getContentType() { 
            if (type == null) 
                return "application/octet-stream"; 
            else 
                return type; 
        } 
 
        public InputStream getInputStream() throws IOException { 
            return new ByteArrayInputStream(data); 
        } 
 
        public String getName() { 
            return "ByteArrayDataSource"; 
        } 
 
        public OutputStream getOutputStream() throws IOException { 
            throw new IOException("Not Supported"); 
        } 
    } 
}



 MailSend .java

package com.android.mailsend;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

public class MailSend extends Activity{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
       
        final Button send = (Button)this.findViewById(R.id.send);
       
        send.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v)
   {
    NMailSender sender = new NMailSender("pyun0270@naver.com","편본좌");
    
    try{
     sender.sendMail("안녕하세요","메일본문입니다.","pyun0270@naver.com","pyun0270@naver.com");
    }
    catch (Exception e)
    {
     // TODO: handle exception
     Log.e("SendMail",e.getMessage());
    }
   }
  });  
      }
}