Develop Reference

File transfer Client to Client in JAVA

I need to implement a program to transfer files. I decided to make it using a chat template I've made about 1 month ago so I would have a chat with file transfer option.
The transfer should follow the following points:
1- Server only keeps a list of all files provided by connected clients (No file are actually located in the server, only their names)
2- Client "1" requests file "A" then:
if file "A" is located ONLY in client "2", then client "2" should send 100% of the file to client "1"
if file "A" is located in client "2" and client "3" also has file "A", then client "2" should send 50% of the file to client "1" and client "3" should send the other 50%.
(if the file is located in 4 clients it should be 25% each....and so it goes...)
I've already managed to make the server find out which client is requesting the file and which clients have it. But now I'm stuck, I don't know how to make the transfer.
Could someone give me an example of how to do it? or point me through the right direction?
[I'm aware my code has some flaws and I will fix it later, right now I need to make the transfer happen before working on fixes, so please, unless it's related, try to focus on that]
Server:
package tor;
import java.util.*;
import java.io.*;
import java.net.*;
public class Server extends Thread {
private String cname;
private Socket client;
public static Vector<PrintStream> clients;
public static Vector<String> clientnames;
public static Vector<String> archives;
public Server(Socket client) {
this.client = client;
}
public static void main(String[] args) {
clients = new Vector<PrintStream>();
clientnames = new Vector<String>();
archives = new Vector<String>();
try {
ServerSocket server = new ServerSocket(2391);
System.out.println("Server Started!!\n");
while (true) {
Socket client = server.accept();
Server s = new Server(client);
s.start();
}
} catch (IOException e) {
System.out.println("Server could not start ");
}
}
#Override
public void run() {
try {
BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
PrintStream out = new PrintStream(client.getOutputStream());
cname = in.readLine();
System.out.println(cname + " Connected --- SERVER!");
if (cname == null) {
System.out.println("Unknown Name");
return;
}
clientnames.add(cname);
clients.add(out);
connected(" ********** [", cname, "] Connected! **********");
String arq;
int size = in.read();
System.out.println(size);
for (int i = 0; i < size; i++) {
arq = in.readLine();
archives.add(arq);
}
String msg = in.readLine();
String selected;
while (true) {
while (!(msg).equals("/exit") && !(msg).equals("/Exit") && !(msg).equals("/EXIT")) {
if ((msg).equals("/list") || (msg).equals("/List") || (msg).equals("/list")) {
out.println("-------- Archives List --------");
for (int i = 0; i < archives.size(); i++) {
out.println(i+"- "+archives.get(i));
}
out.println("-------- ******************* --------");
msg = in.readLine();
} else if (msg.equals("/get") || (msg.equals("/GET")) || (msg.equals("/Get"))){
msg = in.readLine();
int gnum = Integer.parseInt(msg);
selected=archives.get(gnum);
returnAll("[", out, "]: ", "idreq");
out.println("1");
reqAll(selected);
// I BELIVE HERE IS THE RIGHT PLACE TO MAKE DE TRANSFER CODE
msg = in.readLine();
} else {
returnAll("[", out, "]: ", msg);
msg = in.readLine();
}
}
msg = in.readLine();
size = Integer.parseInt(msg);
for (int i = 0; i <= size; i++) {
arq = in.readLine();
for(int j=0;j<archives.size();j++) {
if (archives.get(j).equals(arq)) {
archives.remove(j);
}
}
}
returnAll(" ********** [", out, "] disconnected ", " ********** ");
clients.remove(out);
clientnames.remove(cname);
client.close();
break;
}
} catch (IOException e) {
System.out.println("A Client disconnected ");
}
}
// METHOD TO SEND CONNECTION MESSAGE
public void connected(String msg1, String cname, String msg2) throws IOException {
Enumeration<PrintStream> e = clients.elements();
while (e.hasMoreElements()) {
PrintStream message = (PrintStream) e.nextElement();
message.println(msg1 + cname + msg2);
}
}
// METHOD TO RETURN MESSAGE TO ALL CLIENTS
public void returnAll(String msg1, PrintStream saida, String ac, String msg2) throws IOException {
Enumeration<PrintStream> e = clients.elements();
while (e.hasMoreElements()) {
PrintStream message = (PrintStream) e.nextElement();
message.println(msg1 + cname + ac + msg2);
}
}
public void reqAll(String req) throws IOException {
Enumeration<PrintStream> e = clients.elements();
while (e.hasMoreElements()) {
PrintStream message = (PrintStream) e.nextElement();
message.println(req);
}
}
}
Client:
package tor;
import java.io.*;
import java.net.*;
import java.util.ArrayList;
import java.util.Scanner;
public class Client extends Thread {
private Socket con;
private static boolean done = false;
static ArrayList<String> localArq = new ArrayList<String>();
static int c=0;
public Client(Socket s) {
con = s;
}
public static void main(String[] args) {
try {
String ip;
Scanner s = new Scanner(System.in);
System.out.print("Enter Server's IP: ");
ip =s.next();
Socket con = new Socket(ip, 2391);
PrintStream out = new PrintStream(con.getOutputStream());
System.out.println("Connected to Server!");
System.out.print("Enter your Nickname: ");
BufferedReader scan = new BufferedReader(new InputStreamReader(System.in));
String cname = scan.readLine();
out.println(cname);
String dir="C:\\javator\\"+cname;
Thread t = new Client(con);
t.start();
File folder = new File(dir);
folder.mkdir();
File[] listOfFiles = folder.listFiles();
for (int i = 0; i < listOfFiles.length; i++) {
if (listOfFiles[i].isFile()) {
localArq.add(listOfFiles[i].getName());
}
}
int size=localArq.size();
out.write(size);
for(int i=0;i<size;i++) {
out.println(localArq.get(i));
}
String msg;
while (true) {
System.out.print("");
msg = scan.readLine();
if(msg.equals("/ll")) {
System.out.println("-------- LOCAL LIST --------");
for (int i = 0; i < localArq.size(); i++) {
System.out.println(localArq.get(i));
}
System.out.println("-------- ******************* --------");
msg = scan.readLine();
}else if(msg.equals("/exit") || (msg.equals("/Exit")) || (msg.equals("/EXIT"))) {
out.println(msg);
size=localArq.size();
out.println(size);
for(int i=0;i<size;i++) {
out.println(localArq.get(i));
}
}
else if(msg.equals("/get") || (msg.equals("/GET")) || (msg.equals("/Get"))) {
System.out.println("Chose file's number to /get: ");
c++;
}
if (done == true) {
break;
}
out.println(msg);
}
} catch (UnknownHostException e) {
System.out.println(e.getMessage());
} catch (IOException e) {
System.err.println(e.getMessage());
}
}
#Override
public void run() {
try {
BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
String rmsg;
String req;
while (true) {
rmsg = in.readLine();
if (rmsg == null) {
System.out.println("Connection Terminated");
break;
}else if(rmsg.substring(rmsg.length() - 5).equals("idreq")) {
req = in.readLine();
for(int i=0;i<localArq.size();i++) { //IDENTIFIES WHO OWNS THE REQUESTED FILE
if(localArq.get(i).equals(req)) {
System.out.println("Owns requested file");
Socket requester = new Socket("192.168.3.114", 2007);
ObjectOutputStream outputr = new ObjectOutputStream(requester.getOutputStream());
ObjectInputStream inputr = new ObjectInputStream(requester.getInputStream());
Object mens= inputr.readObject();
System.out.println(mens);
outputr.writeObject("OWNER FOUND");
}
}
if(c==1) { //IDENTIFIES WHO WANTS THE FILE
rmsg = in.readLine();
c= Integer.parseInt(rmsg);
System.out.println("file: "+req);
ServerSocket peer = new ServerSocket(2007);
System.out.println("OPEN FOR CONNECTIONS\n");
Socket client = peer.accept();
System.out.println("Client connected: " + client.getInetAddress().getHostAddress());
ObjectOutputStream outputo = new ObjectOutputStream(client.getOutputStream());
ObjectInputStream inputo = new ObjectInputStream(client.getInputStream());
outputo.flush();
outputo.writeObject("Connected to requester");
Object mens= inputo.readObject();
System.out.println(mens);
}
}
else {
System.out.println(rmsg);
}
}
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
done = true;
}
}

I was able to make a transfer between two clients easily with the information provided and a little research on stackOverflow to understand more about out/inputStreams!
This post also helped me a lot: Sending a file with Java Sockets, losing data
next step is the shared transfer

json file not arriving complete when using sockets

I have a stream of video. And every frame I need to send a small json file with data from that frame, speed it´s crucial. Whats the best way to do this?
My Server is something like this. Waits for a json file and then has to send that json file to a python application.
public class ServerClass {
public static void main(String[] args) {
Marcoserver mimarco=new Marcoserver();
}
}
class Marcoserver implements Runnable {
public Marcoserver(){
Thread miHilo = new Thread(this);
miHilo.start();
}
public void run() {
try {
ServerSocket server = new ServerSocket(7777);
while (true) {
Socket miSocket = server.accept();
BufferedReader entrada = new BufferedReader(new InputStreamReader(miSocket.getInputStream(), "UTF8"));
String mensaje = entrada.readLine();
JSONObject obj;
obj = new JSONObject(mensaje);
System.out.println(obj);
ConectorSocket cntor = new ConectorSocket("localhost", 6363);
cntor.Conectar();
cntor.Send(mensaje);
cntor.Close();
miSocket.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
public class ConectorSocket{
private String host;
private int port;
Socket sockSend;
public ConnectClass(String hst, int prt ) {
this.host = hst;
this.port = prt;
}
public void Conectar() {
this.sockSend = new Socket(this.host, this.port);
}
public void Send(String mensaje) {
DataOutputStream flujo_salida = new DataOutputStream(sockSend.getOutputStream());
flujo_salida.writeBytes(mensaje);
flujo_salida.close();
}
public boolean Close() {
this.sockSend.close();
}
}
This is the python app simplified:
serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
serversocket.bind(('localhost', 6666))
serversocket.listen()
while True:
connection, address = serversocket.accept()
buf = connection.recv(2048)
if len(buf) > 0:
print(buf.decode())
My problem is that the python app prints incomplete information such as:
{"keyword"
{"keyword": [[14, 1, -1]]}
{"keyword": [[14,
instead of:
{"keyword":[]}
{"keyword":[[14,1,-1]]}
{"keyword":[[14,2,-1]]}

There's nothing wrong with your Java code, but your Python code is not good:
while True:
connection, address = serversocket.accept()
buf = connection.recv(2048)
if len(buf) > 0:
print(buf.decode())
That will print just the first received TCP packet for each connection.
You need to continue calling recv until it returns 0:
while True:
connection, address = serversocket.accept()
msg = []
while True:
buf = connection.recv(65536)
if (len(buf) == 0):
break
msg.append(buf)
print(''.join(msg))
connection.close()
You also need to close each connection.

Why don't the two equal strings match?

I want to compare the response from the server with a string, but I get a false result when testing the two strings. Why?
I found this but didn't help: How do I compare strings in Java?
I tried two ways:
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF8"));
String code;
if(Objects.equals((code = in.readLine()), "S")) { //Input string: "S"
//code
}
 
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF8"));
String code;
if((code = in.readLine()).equals("S")) { //Input string: "S"
//code
}
The code does not run in either case because the value of the test is false.
Full code
Server side - C# (Windows)
class ManagePhoneClients
{
public void managePhoneClients(object obj)
{
Boolean socketalive = true;
TcpClient tcpClient = (TcpClient)obj;
StreamReader sr = new StreamReader(tcpClient.GetStream(), Encoding.UTF8);
StreamWriter sw = new StreamWriter(tcpClient.GetStream(), Encoding.UTF8);
Boolean isPhoneClientConnected = false;
String user;
String answer;
String tl;
List<string> LC = new List<string>();
Boolean qss = false;
Program program = new Program();
Int32 points = 0;
ConsoleMethods.writeLine("Thread started for the phone client.", "Info", ConsoleColor.Cyan);
sw.WriteLine("S");
sw.Flush();
while (socketalive == true)
{
try
{
if (Program.isMainClientConnected != true || Program.isPowerPointConnected != true)
{
ConsoleMethods.writeLine("Connection refused because the necessary clients are not connected!", "Error", ConsoleColor.Red);
sw.WriteLine("NS");
sw.Flush();
tcpClient.Close();
socketalive = false;
}
else
{
sw.WriteLine("LC");
sw.Flush();
}
if (isPhoneClientConnected != true & sr.Peek() != -1)
{
String rLC = sr.ReadLine();
LC.AddRange(rLC.Split('|'));
if (LC[1].ToString() == Program.passPhoneClient)
{
user = LC[0];
Program.userNames.Add(user);
ConsoleMethods.writeLine("Phone connected from: " + tcpClient.Client.RemoteEndPoint, "Info", ConsoleColor.Cyan);
sw.WriteLine("S");
sw.Flush();
Program.utnr = rLC;
isPhoneClientConnected = true;
}
else
{
sw.WriteLine("NS");
sw.Flush();
socketalive = false;
ConsoleMethods.writeLine("Phone client disconnected because the password was invalid!", "Error", ConsoleColor.Red);
}
}
switch (sr.ReadLine())
{
case "CLIENT-EXCEPTION":
ConsoleMethods.writeLine("Exception in phone client from: " + tcpClient.Client.RemoteEndPoint + "\n" + sr.ReadLine(), "Client-Error", ConsoleColor.DarkRed);
break;
case "RECEIVED_POINTS":
int point = int.Parse(sr.ReadLine());
points += point;
ConsoleMethods.writeLine("Phone client succesfully completed a task from: " + tcpClient.Client.RemoteEndPoint + " Point: " + point, "Client-Received Points", ConsoleColor.DarkRed);
ConsoleMethods.writeLine("Phone client collected points from: " + tcpClient.Client.RemoteEndPoint + " Points: " + points, "Client-Collected Points", ConsoleColor.DarkRed);
break;
}
}
catch (Exception e)
{
tcpClient.Close();
socketalive = false;
ConsoleMethods.writeLine(e.Message + e.StackTrace + e.StackTrace, "Error", ConsoleColor.Red);
}
}
}
}
(This is not yet complete!)
Client side - Java (Android)
public void login(View v) {
final Context context = this;
new Thread(new Runnable() {
public void run() {
try {
final Socket socket = new Socket("192.168.0.104", 90);
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF8"));
PrintWriter out = new PrintWriter(socket.getOutputStream());
out.print("P" + "\r\n");
out.flush();
String code;
code = in.readLine();
if(code.equals("S")) {
if (Objects.equals((code = in.readLine()), "LC")) {
out.print(((EditText)findViewById(R.id.username)).getText().toString() + "|" + ((EditText)findViewById(R.id.password)).getText().toString() + "\r\n");
out.flush();
if(Objects.equals((code = in.readLine()), "S")) {
new ServerContact(context).Listener(socket);
startActivity(new Intent(Login.this, Waiting.class));
} else {
throw new Exception("Login failed because the server refused the login request. Server responded with status code: '" + code + "'.");
}
} else {
throw new Exception("Login failed because the server refused the login request. Server responded with status code: '" + code + "'.");
}
} else {
throw new Exception("Login failed because the server refused the login request. Server responded with status code: '" + code + "'.");
}
} catch (Exception e) {
new ExceptionWriter(e);
}
}
}).start();
}
(This is not yet complete!)

I managed to solve it. On the server side I have to disable the BOM.
No BOM:
StreamWriter sw = new StreamWriter(tcpClient.GetStream(), new UTF8Encoding(false));
With BOM:
StreamWriter sw = new StreamWriter(tcpClient.GetStream(), Encoding.UTF8);

It works for me (using your first case). I think we've all concluded that code is not in fact equal to "S", sorry about that.
public class EqualsTest {
public static void main( String[] args ) throws IOException {
MyStream socket = new MyStream( new ByteArrayInputStream( "S\n".getBytes() ));
BufferedReader in = new BufferedReader( new InputStreamReader( socket.getInputStream(), "UTF8" ) );
String code;
if( Objects.equals( (code = in.readLine()), "S" ) ) {
System.out.println( "true" );
} else {
System.out.println( "false" );
}
}
static class MyStream {
private final InputStream ins;
public MyStream( InputStream ins ) {
this.ins = ins;
}
public InputStream getInputStream() {
return ins;
}
}
}
Output:
run:
true
BUILD SUCCESSFUL (total time: 0 seconds)
I'll add some ideas for testing code for debugging:
// how to debug
System.err.println( "code="+code+" length="+code.length() );
System.err.println( "code bytes="+Arrays.toString( code.getBytes() ) );

Password authentication socket programming

I have 3 classes (Client, Server, and Protocol) that allow a user to login and send a message to another user. I'm trying to add a password feature to the program but nothing I've tried has worked so far. I've added my code below, I want to prompt the user to put the password in after the error checking on the username has been done. The password should be compared and checked that it is a match, and only then should the user be able to view their messages and send messages.
Any tips would really be appreciated, thanks!
Client.java
import java.io.*;
import java.net.*;
public class Client {
public static void main(String[] args) {
String messages = "";
// Makes sure there are only two arguments entered
if(args.length != 2) {
System.err.println("Usage: java Client <host name> <port number>");
System.exit(1);
}
// Stores the command line arguments for readability further in the program
String host = args[0];
int port = Integer.parseInt(args[1]);
try (
// Creates the socket to be used
Socket s = new Socket(host, port);
// Reader and Writer to talk with Server
PrintWriter pw =
new PrintWriter(s.getOutputStream(), true);
BufferedReader bf = new BufferedReader(
new InputStreamReader(s.getInputStream()));
) {
// Reader to read from standard input (keyboard)
BufferedReader keyboard =
new BufferedReader(new InputStreamReader(System.in));
// User interface
while (true) {
System.out.println("Please enter your username: ");
String username = keyboard.readLine();
// Check that the login is valid
if (username == null) {
System.out.println("No username entered");
}
else if (username.contains(" ")) {
System.out.println("Username cannot contain spaces");
}
// Send username to server and return number of messages
else {
pw.println(username);
messages = bf.readLine();
System.out.println("You have " + Integer.parseInt(messages) + " messages");
break;
}
}
// Enable the user to continue reading and composing messages until
// they choose to exit
while (true) {
System.out.println("Would you like to READ, COMPOSE or EXIT?");
String choice = keyboard.readLine();
// Shows the messages left for the user
if (choice.equals("READ")) {
pw.println("READ");
messages = bf.readLine();
if (messages == "0") {
System.out.println("NO MESSAGES");
}
else {
String incoming = bf.readLine();
System.out.println(incoming);
incoming = bf.readLine();
System.out.println(incoming);
}
}
// Allows user to write a message to another user
else if (choice.equals("COMPOSE")) {
pw.println("COMPOSE");
System.out.println("Enter message recipient");
String recipient = keyboard.readLine();
if (recipient == null) {
System.out.println("No recipient username entered");
}
else if (recipient.contains(" ")) {
System.out.println("Recipient username cannot contain spaces");
}
else {
pw.println(recipient);
System.out.println("Enter message to be sent");
String im = keyboard.readLine();
pw.println(im);
System.out.println(bf.readLine());
}
}
else if (choice.equals("EXIT")) {
pw.println("EXIT");
System.exit(1);
}
else {
System.out.println("Error: you must either READ, COMPOSE or EXIT");
}
}
}
// Catches the exception in which the server cannot be found
catch(IOException e) {
System.out.println("Error, could not connect to Server");
System.exit(1);
}
}
}
Server.java
import java.io.*;
import java.net.*;
public class Server {
public static void main(String[] args) {
String request;
// Makes sure that the user has specified the correct number of command line arguments
if(args.length != 1) {
System.err.println("Usage: java Server <port number>");
System.exit(1);
}
int port = Integer.parseInt(args[0]);
try (
// Creates a server socket and waits for a connection
ServerSocket ss = new ServerSocket(port);
// A socket to communicate with the client
Socket cs = ss.accept();
// Reader and Writer to talk with Client
PrintWriter pw =
new PrintWriter(cs.getOutputStream(), true);
BufferedReader bf = new BufferedReader(
new InputStreamReader(cs.getInputStream()));
)
// Links the server to the protocol
{
Protocol protocol = new Protocol();
protocol.storeUsername(bf.readLine());
pw.println(protocol.messagesNumber());
// Loop through user input until EXIT is entered
while (true) {
request = bf.readLine();
// Controls output if user inputs READ
if (request.equals("READ")) {
pw.println(protocol.messagesNumber());
pw.println(protocol.readSender());
pw.println(protocol.readMessage());
}
// Controls input if user inputs COMPOSE
else if (request.equals("COMPOSE")) {
String sender = bf.readLine();
String message = bf.readLine();
if (protocol.append(sender, message)) {
pw.println("MESSAGE SENT");
}
else {
pw.println("MESSAGE FAILED");
}
}
// Exits the server
else {
System.exit(1);
}
}
}
// Catches the exception in which the server cannot find a client
catch(IOException e) {
System.out.println("Failed to find a client");
System.exit(1);
}
}
}
Protocol.java
import java.net.*;
import java.io.*;
import java.util.*;
public class Protocol {
private String username;
private String recipient;
private String sender;
private HashMap<String, ArrayList<String>> senderMap = new HashMap<String, ArrayList<String>>();
private HashMap<String, ArrayList<String>> messageMap = new HashMap<String, ArrayList<String>>();
// Stores the username for the logged in user
public void storeUsername(String user) {
username = user;
}
// Stores the recipient name
public void storeRecipient(String name) {
recipient = name;
}
// Returns how many messages the logged in user has
public int messagesNumber() {
if(messageMap.containsKey(username))
return messageMap.get(username).size();
else
return 0;
}
public boolean append(String recipient, String message) {
boolean success = false;
// If there is an entry for that name, just add the message to the end
if(messageMap.containsKey(recipient)) {
senderMap.get(recipient).add(username);
messageMap.get(recipient).add(message);
success = true;
}
// If there is no entry for that name, create a new entry with a list of messages and add the first message
else {
senderMap.put(recipient, new ArrayList<String>());
senderMap.get(recipient).add(username);
messageMap.put(recipient, new ArrayList<String>());
messageMap.get(recipient).add(message);
success = true;
}
return success;
}
public String readSender() {
// If the user has an entry and has at least 1 sender, return the least recent sender and then remove it (the sender first in the list)
if(senderMap.containsKey(username)) {
if(senderMap.get(username).size() > 0) {
String temp = senderMap.get(username).get(0);
senderMap.get(username).remove(0);
return temp;
}
else
// If there are no messages left to read
return "NO MESSAGES";
}
else
// If the login hasn't been created yet
return "NO MESSAGES";
}
public String readMessage() {
// If the user has an entry and has at least 1 unread message, return the least recent unread message and then remove it (the first message in the list)
if(messageMap.containsKey(username)) {
if(messageMap.get(username).size() > 0) {
String temp = messageMap.get(username).get(0);
messageMap.get(username).remove(0);
return temp;
}
else
// If there are no messages left to read
return "NO MESSAGES";
}
else
// If the login hasn't been created yet
return "NO MESSAGES";
}
}

JavaMail : Folder.hasNewMessages() and .getMessageCount() don't seem to work properly

I have this simple code to perdiodically access a pop3 server and check if there are new messages in the inbox folder
public static void main(String[] args) {
try {
String storeType = "pop3";
String host = "...";
int port = ...;
String user = "...";
String psw = "...";
//
int delay = 1;
long mins = 200 * 60 * delay;
firstAccess = true;
Properties properties = new Properties();
properties.put("mail.pop3.host", host);
properties.put("mail.pop3.user", user);
properties.put("mail.pop3.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
properties.put("mail.pop3.port", port);
RomasAuthenticator r = new RomasAuthenticator(user, psw);
Session session = Session.getDefaultInstance(properties, r);
POP3Store emailStore = (POP3Store) session.getStore(storeType);
emailStore.connect(host, port, user, psw);
Folder emailFolder = emailStore.getFolder("INBOX");
emailFolder.open(Folder.READ_ONLY);
while (true) {
if (checkInbox(emailFolder)) {
//prepara la notifica per il voice_service
System.out.println("mes!");
}
firstAccess = false;
Thread.sleep(mins);
}
} catch (Exception ex) {
//return null;
}
}
private static boolean checkInbox(Folder inbox_folder) throws MessagingException, IOException {
System.out.println("checking");
boolean res = false;
try {
int email_actual_count = inbox_folder.getMessageCount();
if (email_actual_count > email_prev_count /*or hasNewMessages()*/) {
if (!firstAccess) {
res = true;
}
}
//bisogna aggiornare comunque email_count in caso siano stati cancellati messaggi
email_prev_count = email_actual_count;
}
catch (Exception e) {
e.printStackTrace();
}
return res;
}
Both getMessageCount() and hasNewMessages() do not work, because the first always returns the same number of messages, and the second always returns false. What's that I'm doing wrong?
I don't want to use a messagelistener because this code will run on a robot with really low performances..
thanks everyone

The JavaMail FAQ explains why these features don't work with the POP3 protocol.