ecco l'attuale codice:

codice:
import java.io.*;
import java.util.*;
import java.net.*;

public class InviaMsg
{
int port;
String host;

public static final String CRLF = "\r\n";

public static void main(String[] args) throws Exception
  {
    Socket s = new Socket("nome_host", 25);
    OutputStreamWriter out = new OutputStreamWriter(s.getOutputStream());
    BufferedReader in = new BufferedReader(new InputStreamReader(s.getInputStream()));
    String line;

    line = in.readLine();
    System.out.println(line);
     if(!line.startsWith("220"))
       {
         throw new Exception(line);
       }

// saluto server       
    line = "HELO nome_host.dominio";
    out.write(line+CRLF); out.flush();
    System.out.println(line);

// risposta server
    line = in.readLine();
    System.out.println(line);
     if(!line.startsWith("250"))
       {
         throw new Exception(line);
       }

// Sender
     line = "MAIL FROM: <user@nome_host>";
     out.write(line+CRLF); out.flush();
     System.out.println(line);

     line = in.readLine();
     System.out.println(line);
       if(!line.startsWith("250"))
         {
            throw new Exception(line);
         }

// destinatario
        line = "RCPT TO: <user@nome_host>";
        out.write(line+CRLF); out.flush();
        System.out.println(line);

        line = in.readLine();
        System.out.println(line);
          if(!line.startsWith("250"))
	    {
              throw new Exception(line);
            }
	    
// Subject
        line = "Subject: ";
        out.write(line); out.flush();
        System.out.println(line);

        line = in.readLine();
        System.out.println(line);
          if(!line.startsWith("250"))
	    {
              throw new Exception(line);
            }
	    
// scrittura testo
        line = "DATA";
        out.write(line+CRLF); out.flush();
        System.out.println(line);

        line = in.readLine();
        System.out.println(line);
          if(!line.startsWith("354"))
	    {
              throw new Exception(line);
            }


// comando chiusura
        line = "QUIT";
        out.write(line+CRLF); out.flush();
        System.out.println(line);

        line = in.readLine();
        System.out.println(line);
          if(!line.startsWith("221"))
	    {
              throw new Exception(line);
            }
        
        s.close();
    }
}