I managed to setup a server which will accept & manage multiple socket clients.
but now when I try to send a message, the server just doesn't receive anything, yet I do flush the message.
This is the method that's managing the clients:
public void run() {
while(true) {
for (Client c : this.clients) {
try {
if (c.getStream().read() != -1) {
if (c.getInputStream() != null) {
System.out.println("He sent message");
c.sendMessage("hey client");
}
}
} catch (IOException e) {
c.destruct();
this.clients.remove(c); break;
}
}
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
Client list:
public ArrayList<Client> clients = new ArrayList<Client>(); // client list
And Client object:
public class Client {
private Socket socket;
private int clientId;
private BufferedReader inStream;
private PrintWriter outStream;
private boolean socketAlive = true;
public Client(Socket sock) {
this.socket = sock;
}
public void setup() {
setInputOutputStream();
System.out.println("New connection: " + this.getIpAddress());
this.sendMessage("Successfully connected!");
}
public BufferedReader getStream() {
return this.inStream;
}
public String getInputStream() {
String toReturn = "";
try {
toReturn = this.inStream.readLine();
} catch (IOException e) {
e.printStackTrace();
}
return toReturn;
}
public void destruct() {
try {
this.inStream.close();
this.inStream = null;
this.outStream.close();
this.outStream = null;
System.out.println("Client destruct: " + this.socket.getLocalSocketAddress());
this.socket.close();
this.socket = null;
} catch (IOException e) {
e.printStackTrace();
}
}
public Socket getConnection() {
return this.socket;
}
private void setInputOutputStream() {
try {
inStream = new BufferedReader(new InputStreamReader(this.socket.getInputStream()));
outStream = new PrintWriter(this.socket.getOutputStream());
} catch (IOException e) {
e.printStackTrace();
}
}
public void sendMessage(String s) {
this.outStream.println(s);
this.outStream.flush();
}
public String getIpAddress() {
return this.socket.getRemoteSocketAddress().toString();
}
}
And the client side (sender) :
public static void main(String[] args) {
try {
System.out.println("Client started");
Socket sock = new Socket("localhost", 43594);
Scanner scanner = new Scanner(System.in);
String input;
PrintWriter out = new PrintWriter(sock.getOutputStream());
BufferedReader reader = new BufferedReader(new InputStreamReader(sock.getInputStream()));
while (true) {
input = scanner.nextLine();
if (input != null) {
out.print(input);
out.flush();
}
}
} catch (IOException e) {
System.out.println("Client error");
}
}
Why is my server not receiving anything?
One thing:
If I send message + disconnect, this what the server will log (It looks like it only sends the message upon disconnect or something, well no, it enters the if block only upon it):
Server is successfully running on port 43594
New connection: /127.0.0.1:57102
He sent message
java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at sun.nio.cs.StreamDecoder.readBytes(Unknown Source)
at sun.nio.cs.StreamDecoder.implRead(Unknown Source)
at sun.nio.cs.StreamDecoder.read(Unknown Source)
at java.io.InputStreamReader.read(Unknown Source)
at java.io.BufferedReader.fill(Unknown Source)
at java.io.BufferedReader.readLine(Unknown Source)
at java.io.BufferedReader.readLine(Unknown Source)
at Client.getInputStream(Client.java:32)
at ClientHandler.run(ClientHandler.java:21)
Client destruct: 0.0.0.0/0.0.0.0:43594
What did I do wrong? how can I fix that
Server (main class)
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.*;
import java.util.ArrayList;
public class Server {
private int port = 43594;
public void listen() {
System.out.println("Trying to listen...");
try {
final ServerSocket server = new ServerSocket(port);
// Create new thread to handle clients I/O
ClientHandler handler = new ClientHandler(server);
// START it
handler.start();
System.out.println("Server is successfully running on port " + port);
while (true) {
// New connection found create a new Client object
Client cl = new Client(server.accept());
cl.setup();
// add it to clietns list in the I/O handler
handler.clients.add(cl);
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
// start up
System.out.println("Starting up..");
// server instance
final Server server = new Server();
// create a new thread for server
new Thread(new Runnable() {
#Override
public void run() {
// listen for new connections
server.listen();
}
}).start();
}
}
The client is sending data and the servers is reading.
I think the problem is in Client.getInputStream
this.inStream.readLine(), it reads a line of text.
From documentation:
"Reads a line of text. A line is considered to be terminated by any one of a line feed ('\n'), a carriage return ('\r'), or a carriage return followed immediately by a linefeed."
http://docs.oracle.com/javase/7/docs/api/java/io/BufferedReader.html
If you use read instead, maybe it is going to work. Just use a kind of protocol like sending first 1 or 2 bytes with the length of the message. Or you may send a '\n' from the client.
BTW, the reason for the exception in the server when you send and disconnect in the client side may be due to a TCP fact. The client closed the connection and it probably received a TCP ACK from the server. Then TCP in the client sends a RESET segment. Not so sure though. The server was at this.inStream.readLine() and then it received an exception. Didn't you also received "Connection closed by peer"?
I am not sure why, but I needed to use out.println(input) out.flush() instead of .print() or .write()
I don't have an explanation of why do I need to do that. but it worked.
I think the problem comes from the fact that you've got a list of clients and are trying to manage them with that. I looked up java.net.SocketException: Connection reset, and found this question: What's causing my java.net.SocketException: Connection reset?
The answer to this question comes up with this:
In your case it seems that the connection has been closed by the
server end of the connection. This could be an issue with the request
you are sending or an issue at their end.
This made me think that you aren't holding the connection to the client every time. You store it, and then you lose it, so the message isn't sent. To handle more clients, you might rather want to have a list of IPs, rather than clients, and then you connect when you want to send a message. You can't store the Socket connection. It has to be active. Java (The JVM) has it's own "Garbage Collection" system that'll just kill it.
Related
I created 2 Java programs with sockets in it. I want the client to send continuous data to the server. But after the message sent to the server, the client keeps sending 'null' value to the server (it happens when I close the socket in client program).
Here is my codes:
import ...
public class MainClient {
private Socket serverSock;
private PrintStream clientOutput;
public static void main(String[] args) {
MainClient client = new MainClient();
client.runClient();
}
public void runClient() {
try {
serverSock = new Socket("127.0.0.1",8282);
clientOutput = new PrintStream(serverSock.getOutputStream());
clientOutput.println("Hello, I'm Connected.");
for (int i=0;i<5;i++) {
clientOutput.println(i + "");
clientOutput.flush();
}
} catch (IOException e) {
e.printStackTrace();
}finally {
// try {
// serverSock.close(); It will keeps sending 'null' data to the server if I use this line.
// } catch (IOException e) {
// e.printStackTrace();
// }
}
}
}
The Server Side:
public class MainServer {
private ServerSocket serverSocket;
private int listenPort = 8282;
private InputStream inps;
private Socket clientSocket;
private BufferedReader clientInput;
private MainServer() {
String clientMsg = "";
try {
serverSocket = new ServerSocket(listenPort);
System.out.println("Server is Listening on " + listenPort);
clientSocket = serverSocket.accept();
clientInput = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
while(clientSocket.isConnected()) {
clientMsg = clientInput.readLine();
System.out.println("Client : " + clientMsg);
}
}catch(IOException ex) {
ex.printStackTrace();
}finally {
try {
clientSocket.close();
} catch (IOException e) {}
}
}
public static void main(String[] args) {
new MainServer();
}
}
I tried to close the OutputStream on the Client side with clientOutput.close(); but it sends nulls to the server after it sends the 0-4 loop.
To make it stop and avoid the client sends null data, i should not insert the serverSock.close(); on the Client, but it will returns SocketException. I wanted the client to send 'Closed' message after its done.
Summary, the output on the server is:
Client: 0
Client: 1
Client: 2
Client: 3
Client: 4
Client: null
Client: null
//And so on..
I think there is something missing on the Client Program, i guess?
Thank you for the help :)
As the comment noted, the client is not sending a null value.
The isConnected() method does not do what you think it does, namely it does not tell you if the socket is currently "connected" to its peer, at least in the way you think it should. isConnected() becomes true as soon as the socket transitions into the connected state, and stays true thereafter, even after the socket is shutdown. See this discussion and others on stackoverflow.
The correct way to determine if the peer has shutdown the connection is to attempt to read from the socket and then examine the result for evidence of closure. Please read the Javadocs for the method you are using, they will tell you what the various return values mean. For the BufferedReader.readLine() method, it says:
Returns:
A String containing the contents of the line, not including
any line-termination characters, or null if the end of the stream has
been reached
Throws:
IOException - If an I/O error occurs
Thus you need to check for a null return value to detect a normal socket closure, and if you receive an IOException that indicates some kind of network anomaly.
Your MainClient() have no problem.
clientSocket.isConnected() function in MainServer() always check the status of the client and which results an infinite loop, so after the message 'client:4', clientInput.readLine() should return 'null'.
So instead of checking the client socket is connected or not you can check the client socket is closed or not using function 'clientSocket.isClosed()'.
replace the while loop in MainServer() with below code,
while(!clientSocket.isClosed()) {
clientMsg = clientInput.readLine();
System.out.println("Client : " + clientMsg);
if(clientMsg.equals("Closed")){
clientSocket.close();
// serverSocket.close();
}
}
this will help you to close the client socket at the time of receiving 'Closed' message from server and this avoid the infinite execution of while loop as well as null statement printing.
The code "serverSocket.close()" help you to close the server socket and you can use this at 'MainServer()' if you need to stop the port listening.
typically the code should be something similar
private MainServer() {
String clientMsg = "";
try {
serverSocket = new ServerSocket(listenPort);
System.out.println("Server is Listening on " + listenPort);
clientSocket = serverSocket.accept();
clientInput = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
while ((clientMsg = clientInput.readLine()) != null) {
if(isTerminationString(clientMsg)) {
break;
}
System.out.println("Client : " + clientMsg);
}
} catch (IOException ex) {
ex.printStackTrace();
} finally {
try {
clientSocket.close();
} catch (IOException e) {
}
}
}
boolean isTerminationString(String msg) {
return msg.equals("DONE!");
}
where in isTerminationString you check if the msg is a termination msg, the communication protocol should be shared between the client and the server . i gave the example of sending
a DONE message, but it could more complex than that .
as closing the close method on the socket does not guarantee that the socket on the other part gets closed as well, using the isClosed method might not be effective and results in the same problem you have .
I am trying to open a socket inside a bukkit plugin so i could send data to it using php or node but instead of socket remaining open after one use it just closes and also server does not load before this happens what should i do i am out of ideas.
Main:
public class Main extends JavaPlugin {
public void onEnable() {
saveDefaultConfig();
getConfig().options().copyDefaults(true);
System.out.println("[INFO] Main class loaded.");
start();
}
public void start() {
SocketServer server = new SocketServer();
try {
server.start(getConfig().getInt("port"), getConfig().getString("socket-password"));
System.out.println("[INFO] Main successfully called start.");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Socket server class:
When called this should read information convert it into array check the first item in array and use it as auth code then array should be converted into string and used in Command executor class. This works fine but after one use this just closes
public class SocketServer {
private ServerSocket serverSocket;
private Socket clientSocket;
private PrintWriter out;
private BufferedReader in;
public void start(int port, String socketpwd) throws IOException {
System.out.println("[INFO] Socket server listening on: " + port);
serverSocket = new ServerSocket(port);
clientSocket = serverSocket.accept();
out = new PrintWriter(clientSocket.getOutputStream(), true);
in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
Boolean enabled = true;
try {
// Socket authentication
String message = in.readLine();
String suffix[] = message.split(" ");
System.out.println("Socket auth code used: "+ suffix[0]);
System.out.println("Socket pwd is: " + socketpwd);
if (socketpwd.equals(suffix[0])) {
out.println("Auth sucessfull!");
// do the following command from args here
String command = suffix[1];
int suffixL = suffix.length;
// add arguments to command
for (int i = 2; i < suffixL; i++) {
command = command + " " + suffix[i];
}
// call req exec
System.out.println("[INFO] Socket server contacted Request executor with: " + command);
RequestExecutor.executor(command);
enabled = false;
}
else {
out.println("Unrecognised auth code!");
}
} catch (NullPointerException e) {
System.out.println("Exception prevented!");
}
}
public void stop() throws IOException {
in.close();
out.close();
clientSocket.close();
serverSocket.close();
}
}
Other problem as i mentioned is that bukkit server does not fully load before one request has been made to this socket.
Thank you for your help.
First of all you shouldn't be running a socket like that on the main thread, typically you should be running this on an async task using the Bukkit scheduler.
Then once you open the socket you should create a while loop to continuously poll for a connection and handle the incoming data. Instead what you are doing is opening the socket, reading a line and then dropping the connection.
You want to be doing something similar to
while(true){
Socket socket = serverSocket.accept();
}
See this webpage for some more info.
I am currently coding a simple TCP chat client-server application which works with sockets. A client connects to the server and as soon as it gets accepted, a new worker thread is created to listen for client input. Connecting to the sever (localhost at port 8818) works fine, but as soon as the worker thread starts listening for more client input after the login a java.net.SocketException: Connection reset is thrown (see stack trace below). I am aware that one possible source of this exception can be a socket that hasn't been closed properly or forcefully by either the server or the client. Therefore, my assumption is that I am not handling the closing of my client socket properly which causes the connection to reset.
What I would like to achieve:
The worker listens for client input, as long as this is not null, requests (e.g. a simple login) are processed, otherwise, the socket is closed (see code excerpts below). My client receives a 'Login Successful' message from the server indicating that my handleLogin() function works, but instead of closing the socket after receiving no more input from the client, the server seems to just reset, even though clientSocket.close() is issued after the while loop.
Server.java
#Override
public void run() {
try {
ServerSocket serverSocket = new ServerSocket(serverPort);
while (true) {
// Accept connection(s) from new chat client(s)
System.out.println("SERVER: WAITING TO ACCEPT CLIENT CONNECTIONS ...");
Socket clientSocket = serverSocket.accept();
System.out.println("SERVER: CONNECTION ACCEPTED FROM: " + clientSocket);
// Process client request in separate Thread
WorkerThread worker = new WorkerThread(this, clientSocket);
workerList.add(worker);
worker.start();
}
} catch (IOException e) {
e.printStackTrace();
}
}
WorkerThread.java
#Override
public void run() {
try {
handleClientSocket();
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
private void handleLogin(OutputStream outputStream, String[] tokens) throws IOException {
if (tokens.length != 3) {
outputStream.write("LOGIN FAILED!\n".getBytes());
return;
}
// Extract username and password from user input
String username = tokens[1];
String password = tokens[2];
if (username.equals("anna") && password.equals("anna")) {
outputStream.write("Login successful!\n".getBytes());
} else {
outputStream.write("Error logging in!\n".getBytes());
}
}
private void handleClientSocket() throws IOException, InterruptedException {
InputStream inputStream = clientSocket.getInputStream();
this.outputStream = clientSocket.getOutputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
String line;
// THIS IS WHERE THE EXCEPTION OCCURS AFTER CLIENT HAS LOGGED IN SUCCESSFULLY
while ((line = bufferedReader.readLine()) != null) {
String[] tokens = StringUtils.split(line);
if (tokens.length > 0 && tokens != null) {
String command = tokens[0];
// Evaluate the entered command and handle the request accordingly
if ("login".equalsIgnoreCase(command)) {
handleLogin(outputStream, tokens);
}
// process other commands ...
}
}
clientSocket.close(); // POSSIBLY WORNG WAY OF CLOSING THE CLIENT SOCKET?
}
Client.java
import java.io.*;
import java.net.Socket;
public class Client {
private final String serverName;
private final int serverPort;
private Socket mySocket;
private OutputStream serverOut;
private InputStream serverIn;
public Client(String serverName, int serverPort) {
this.serverName = serverName;
this.serverPort = serverPort;
}
private boolean connect() {
try {
mySocket = new Socket(serverName, serverPort);
serverOut = mySocket.getOutputStream();
serverIn = mySocket.getInputStream();
return true;
} catch (IOException e) {
e.printStackTrace();
}
return false;
}
private void login(String username, String password) throws IOException {
String command = "login " + username + " " + password + "\n";
serverOut.write(command.getBytes());
}
public static void main(String[] args) throws IOException {
Client client = new Client("localhost", 8818);
if (client.connect()) {
System.out.println("Connection successful!");
client.login("anna", "anna");
} else {
System.err.println("Connection failed ...");
}
}
}
Stack Trace
java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(SocketInputStream.java:189)
at java.net.SocketInputStream.read(SocketInputStream.java:121)
at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:284)
at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:326)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
at java.io.InputStreamReader.read(InputStreamReader.java:184)
at java.io.BufferedReader.fill(BufferedReader.java:161)
at java.io.BufferedReader.readLine(BufferedReader.java:324)
at java.io.BufferedReader.readLine(BufferedReader.java:389)
at WorkerThread.handleClientSocket(WorkerThread.java:70)
at WorkerThread.run(WorkerThread.java:45)
When I test my server with PUTTY (i.e. by connecting to localhost and then issuing commands in PUTTY's terminal), everything works just fine.
I am still fairly new to socket programming, so I also might have a logic flaw here. Any help will be much appreciated as I really would like to continue this project.
Thanks in advance!
The reason of this exception is that you terminated the client once you connected the server, but the server still read something from the stream. The exception occurs. Here is the code I tested:
while (inputStream.available() != 0) {
line = bufferedReader.readLine();
String[] tokens = StringUtils.split(line);
if (tokens.length > 0 && tokens != null) {
String command = tokens[0];
// Evaluate the entered command and handle the request accordingly
if ("login".equalsIgnoreCase(command)) {
handleLogin(outputStream, tokens);
}
// process other commands ...
}
}
change the condition in while loop to check if the inputstream is still available to read.
If I have a server and a client and I opened a socket between the two:
1.Is it possible that the client will have a printWriter stream, in order to write things to the socket, but the server won't have in the mean time a bufferReader?
If the answer of 1 is yes, if that client will send a message to the server (who currently doesn't have a reading stream), what will happend to this message until te server will create a reading stream and read the message?
thank you
This is not at all specific to Java, but TCP/IP. There are buffers to keep the data received, so it's not possible that some data would be lost because one end isn't "ready" yet. This is because TCP will retransmit data that hasn't been acknowledged as received, guaranteeing that all the bytes that are written are received on the other (barring obvious cases).
in addition to #Kayaman's answer:
consider this Compile-able simple Java implemented example:
Server Side:
import java.io.*;
import java.net.*;
public class SimpleServer implements Runnable{
int serverPort = 45000;
ServerSocket serverSocket = null;
boolean isStopped = false;
public SimpleServer(int port){
this.serverPort = port;
}
public void run(){
try {
serverSocket = new ServerSocket(serverPort);
} catch (IOException e) {
System.err.println("Cannot listen on this port.\n" + e.getMessage());
System.exit(1);
}
while(!isStopped){
try {
Socket clientSocket = serverSocket.accept();
} catch (IOException e) {
// do nothing
}
}
}
public static void main(String[] args) throws IOException {
SimpleServer server = new SimpleServer(45000);
new Thread(server).start();
System.out.println("Server is waiting to connect");
}
}
Client Side:
import java.io.*;
import java.net.*;
public class SimpleClient {
public static void main(String[] args) throws IOException {
Socket socket = null;
PrintWriter out = null;
try {
socket = new Socket("127.0.0.1", 45000);
out = new PrintWriter(socket.getOutputStream(), true);
System.out.println("output stream created");
out.write(9);
System.out.println("message was sent to output with no listener");
} catch (UnknownHostException e) {
// do nothing
} catch (IOException e) {
// do nothing
}
}
}
the example is an implementation of a very basic client server connection in which a socket is created and a stream is defined only on the client side, followed by a write to the stream that will eventually be read by the server (if at all).
therefore, to answer you questions:
1) yes, it's possible to open a one-way connection stream without a "listener"
2) edit: according to #EJP: It will be saved within the socket's buffer until it is read or the socket is closed.
I am creating a multi client chat server and i am pretty confident that it will work (Correct me if i'm wrong), I have the issue that on the socket that the client connects to is null so the connections can't be created because i use if(Socket != null) so i don't get errors but i will explain my layout real fast. The server starts with a starter class called (LaunchServer) that uses the class object ClientConnector as Minecraft and then starts the method runServer(). Here is the code for this class:
public class LaunchServer
{
public static void main(String[] args)
{
System.out.println("[Info] Running");
ClientConnector Minecraft = new ClientConnector();
Minecraft.runServer();
}
}
It's fairly simple. This brings us to the ClientConnector class. Here we start at the method runServer(). Right away we have a try catch block. in that block we print a message that the server is trying to connect to the port 1337. we then create a new ServerSocket called serversocket. We then send a message to the console saying that we have bound to port and that we are awaiting a connection. While true, we create a new Socket socket that equals ServerSocket.accept(); OMG fuck it. Heres the code. you know what it does...
import java.util.ArrayList;
import java.net.*;
import java.io.*;
public class ClientConnector
{
public static ArrayList<Socket> Connections = new ArrayList<Socket>();
public static void runServer()
{
try
{
System.out.println("[Info] Attempting to bind to port 1337.");
#SuppressWarnings("resource")
ServerSocket serversocket = new ServerSocket(1337);
System.out.println("[Info] Bound to port 1337.");
System.out.println("[Info] Waiting for client connections...");
while(true)
{
Socket socket = serversocket.accept();
new ClientHandler(socket).start();
Connections.add(socket);
}
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
This takes us to the handler class:
import java.io.*;
import java.net.*;
public class ClientHandler extends Thread
{
Socket Socket;
public ClientHandler(Socket socket)
{
socket = Socket;
System.out.println("[Info] Client connected on port 1337.");
}
public void run()
{
while(true)
{
for(int i = 0; i < ClientConnector.Connections.size(); i++)
{
try
{
if(Socket != null)//This stays null...
{
ObjectOutputStream Output = new //These can't be created...
ObjectOutputStream(Socket.getOutputStream());
ObjectInputStream Input = new ObjectInputStream(Socket.getInputStream());
whileChatting(Input, Output);
}
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
}
public static void sendMessage(String message, String returnedMessage, ObjectOutputStream out)
{
try
{
if(!message.isEmpty())
{
out.writeObject("\247c[Server]\247d " + message);
out.flush();
System.out.println("[Chat] Sent: " + message);
}
else
{
out.writeObject(returnedMessage);
System.out.println("[Chat] Sent: " + returnedMessage);
}
out.flush();
System.out.println("[Info] Fluching remaining data to stream.");
System.out.println("\n[Server] " + message);
}
catch(IOException ioException)
{
System.out.println("[Warning] Error: ioException # sendMessage line 76.");
}
}
public static void whileChatting(ObjectInputStream input, ObjectOutputStream output) throws IOException
{
String message = "";
do
{
try
{
message = (String) input.readObject();
System.out.println("\n" + message);
sendMessage("", message, output);
}
catch(ClassNotFoundException classNotFoundException)
{
System.out.println("[Warning] Error: ClassNotFoundException # whileChatting line 1-7.");
System.out.println("\n idk wtf that user sent!");
}
}while(!message.equals("/stop"));
}
}
Read the run method. There you will see the null problem
Would the connection get accepted then passed to the hander class? How can a null connection get accepted? My question is how can i fix this problem?
The problem is you've got a logic error due to un-recommended naming conventions. You shouldn't name variables with keywords, like your Socket variable, and each variable should have a distinguishable name. e.g. not socket1, socket2 but serverSocket, clientSocket because that will make it easier for you and anyone else to read and fix your code.
Change
Socket Socket;
to
Socket connectedSocket;
and in your constructor
socket = Socket;
to
connectedSocket = socket;
then finally, in your run() method change
if(Socket != null)
to
if(connectedSocket != null)