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Multithreading echo server

Hello it is my first topic here.
I wrote some code to making connection client-server by sockets. As a client I mean opening terminal window and connection to this server by telnet. Application works as a server listening for requests from client on specified port. Every single connection is treat as a new thread. Once the connection is bound the client can send a message and gets an answer back as an echo.
The problem is I want to be informed when the client closes the terminal window (finish thread). I want to know id of this closed thread.
This is full code:
public class MultithreadEchoServer
{
public static void main(String[] args) throws IOException
{
int count=0;
long[] ids = new long[10];
try (ServerSocket ss = new ServerSocket(1234))
{
System.out.println("Listening...");
while(true)
{
count++;
Socket s = ss.accept();
Runnable r = new MyThread(s, count);
Thread t = new Thread(r);
t.start();
ids[count-1] = t.getId();
if(Thread.activeCount() != count+1)
{
count = Thread.activeCount();
System.out.println("Client "+/*??thread's id??*/" left the session. Now connected: "+count);
}
System.out.println("Clients connected: "+count);
System.out.println(ids[count-1]);
}
}
}
}
class MyThread implements Runnable
{
private Socket s;
private int count;
private long id;
InputStream io;
OutputStream os;
private PrintWriter pw;
MyThread(Socket s, int count)
{
this.s = s;
this.count = count;
}
public long getId()
{
id = Thread.currentThread().getId();
return id;
}
#Override
public void run()
{
try
{
io = s.getInputStream();
os = s.getOutputStream();
}
catch (IOException e) {System.err.println(e);}
try (Scanner sc = new Scanner(io))
{
pw = new PrintWriter(os, true);
pw.println("Connected");
while(sc.hasNextLine())
{
String line = sc.nextLine();
System.out.println("Client "+count+": "+line);
pw.println("Echo: "+line);
}
}
}
}

Why you donn't print Thread ID inside Thread execution with a finally statement after your try with resource statement :
try (Scanner sc = new Scanner(io))
{
pw = new PrintWriter(os, true);
pw.println("Connected");
while(sc.hasNextLine())
{
String line = sc.nextLine();
System.out.println("Client "+count+": "+line);
pw.println("Echo: "+line);
}
}
finally {
System.out.println("Client " + this.id + " left the session."");
}
MultithreadEchoServer
public class MultithreadEchoServer
{
public static void main(String[] args) throws IOException
{
int count=0;
long[] ids = new long[10];
try (ServerSocket ss = new ServerSocket(1234))
{
System.out.println("Listening...");
while(true)
{
count++;
Socket s = ss.accept();
Runnable r = new MyThread(s, count);
Thread t = new Thread(r);
t.start();
ids[count-1] = t.getId();
if(Thread.activeCount() != count+1)
{
count = Thread.activeCount();
System.out.println("Now connected: "+count);
}
System.out.println("Clients connected: "+count);
System.out.println(ids[count-1]);
}
}
}
}
MyThread
class MyThread implements Runnable
{
private Socket s;
private int count;
private long id;
InputStream io;
OutputStream os;
private PrintWriter pw;
MyThread(Socket s, int count)
{
this.s = s;
this.count = count;
}
public long getId()
{
id = Thread.currentThread().getId();
return id;
}
#Override
public void run()
{
try
{
io = s.getInputStream();
os = s.getOutputStream();
}
catch (IOException e) {System.err.println(e);}
try (Scanner sc = new Scanner(io))
{
pw = new PrintWriter(os, true);
pw.println("Connected");
while(sc.hasNextLine())
{
String line = sc.nextLine();
System.out.println("Client "+count+": "+line);
pw.println("Echo: "+line);
}
}
finally {
System.out.println("Client " + this.id + " left the session."");
}
}
}

java chat application not working on other machines

I have made a basic chat application which runs fine on the same PC but I want it to work on different machines as well.
For the sake of simplicity, I have omitted the GUI code. I receive the IP, name, and port from a separate application which passes it to the client's constructor. I have entered the IP and port of the machine on which the server is running.
Client
public class ClientGui extends JFrame implements Runnable, KeyListener, ActionListener
{
private JPanel contentPane;
private Socket socket;
private String name , ip;
private int port;
private JTextField input;
private JTextArea console;
private JButton send;
private String message;
private DateFormat format;
private BufferedReader in;
private PrintWriter out;
private String reply;
public ClientGui(String name, String ip, int port)
{
format = DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.SHORT);
this.name = name;
this.ip = ip;
this.port = port;
new Thread(this).start();
}
public void run()
{
try {
socket = new Socket(ip, port);
in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
out = new PrintWriter(socket.getOutputStream(), true);
while (true) {
out.println(name);
reply = in.readLine();
if (reply.equals("NAME")) {
name = JOptionPane.showInputDialog("Name taken , Enter another");
} else {
input.setEditable(true);
setTitle(name);
break;
}
}
while (true) {
reply = in.readLine();
if (reply.startsWith("MESSAGE")) {
log(reply.substring(7));
}
}
} catch (Exception e) {
try {
out.close();
in.close();
socket.close();
} catch (Exception e2) {
dispose();
System.exit(0);
}
dispose();
System.exit(0);
}
}
}
Server
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.HashSet;
public class Server implements Runnable
{
private static ArrayList<PrintWriter> writers;
private static HashSet<String> names;
private Socket socket;
private String name;
private String message;
public Server(Socket socket)
{
this.socket = socket;
}
public void run()
{
PrintWriter temp = null;
try (BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()))) {
try (PrintWriter out = new PrintWriter(socket.getOutputStream(), true)) {
while (true) {
name = in.readLine();
if (names.contains(name)) {
out.println("NAME");
} else {
out.println("NAMEACCEPTED");
names.add(name);
break;
}
}
writers.add(out);
temp = out;
while(true) {
message = in.readLine();
for (PrintWriter writer : writers) {
writer.println("MESSAGE" + name + " : " + message);
}
}
}
} catch (Exception e) {
try {
names.remove(name);
writers.remove(temp);
socket.close();
} catch (Exception ignored) {
}
}
}
public static void main(String[] args)
{
writers = new ArrayList<>();
names = new HashSet<>();
ServerSocket server = null;
try {
int port = Integer.parseInt(args[0]);
server = new ServerSocket(port);
} catch (Exception e) {
System.out.println("Enter a valid port");
System.exit(0);
}
while (true) {
try {
System.out.println("Waiting for clients....");
new Thread(new Server(server.accept())).start();
System.out.println("Client Received");
} catch (Exception e) {
System.out.println("Server can't accept clients");
break;
}
}
}
}

I think it could be, because
1) you haven't installed the rigth jre-Version on both devices
2) you aren't in the same Network or you haven't forwarded you'r Ip
have you tried to use this in a Virtual box?
(client1 == vbox1, Server == Computer, client2 == vbox2)
hopefully, this helped

Sorry about the inconvenience to all
the problem was with the port i was using when i switched it , it worked on different machines
thanks for all your help

Multiple threads dont seem to be working

I have 2 classes, a server and a client. The server uses multiple threads to accept many clients. So x clients can join the same server. However in an attempt to identify the threads from the client method, I seem to have found that its not making multiple threads as the ID are the same for all clients. The code I have is as follows:
SERVER:
public class Server
{
ServerSocket serverSocket;
int portNumber;
public static volatile String userInput;
public volatile int noOfClients = 0;
public static void main(String[] args)
{
Server s = new Server();
s.startup();
}
/**
* Start the server on the user picked port
*/
public void startup()
{
try
{
System.out.println("Enter a port");
Scanner dif = new Scanner(System.in);
portNumber = Integer.parseInt(dif.nextLine());
dif.close();
serverSocket = new ServerSocket(portNumber);
newThread();
}
catch (IOException e) {
System.out.println("Error");
System.exit(0);
}
}
public void newThread()
{
Thread thread =new Thread()
{
public void run()
{
while(true) {
try {
accept();
} catch (Exception e) {
System.out.println("Error");
}
}
}
};
thread.start();
}
public void accept()
{
try
{
Socket clientSocket = serverSocket.accept();
new Thread(new ClientSocket(clientSocket)).start();
System.out.println("A new client has just connected.");
noOfClients++;
} catch(IOException e)
{
System.out.println("Error");
System.exit(0);
}
}
class ClientSocket implements Runnable {
Socket clientSocket;
public ClientSocket(Socket clientSocket) {
this.clientSocket = clientSocket;
}
public void run() {
{
try
{
PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
while (true)
{
userInput = in.readLine();
}
} catch (IOException e)
{
System.out.println("Error");
}
}
}
}
}
CLIENT:
public class Client
{
Socket clientSocket;
public static int threadName;
public static void main(String[] args) throws IOException {
String hostName = args[0];
int portNumber = Integer.parseInt(args[1]);
try {
Socket serverSocket = new Socket(hostName, portNumber);
PrintWriter out = new PrintWriter(serverSocket.getOutputStream(), true);
BufferedReader in = new BufferedReader(new InputStreamReader(serverSocket.getInputStream()));
BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
Thread thread = Thread.currentThread();
System.out.println("RunnableJob is being run by " + thread.getName() + " (" + thread.getId() + ")");
String userInput;
while ((userInput = stdIn.readLine()) != null)
{
out.println(userInput);
System.out.println("Server: " + userInput);
}
} catch(UnknownHostException e) {
System.out.println("error in host");
} catch(IOException e) {
System.out.println("error in IO");
}
}
}
When running two separate clients, the
System.out.println("RunnableJob is being run by " + thread.getName() + " (" + thread.getId() + ")");
line of code prints out the same. How can i fix it so that each new client connection is started within is own UNIQUE thread. so 2 clients will have 2 threads in total? Thanks :)

First, you are checking the thread ids for the clients, which are separate from each other, so that won't work.
However using a thread id is not a very good way to identify clients. Instead why don'y you keep a count of the number of clients, then when a new one joins, increment the number and give the client object that number as an id.

Multiple clients will connect at different port no with server. You can use that port no to distinguish between clients.
You can store ClientSocket some where to retrieve other information of each client in future if needed as shown in below code.
Here is the code:
private static HashMap<Integer, ClientSocket> clientInfo = new HashMap<Integer, ClientSocket>();
class ClientSocket implements Runnable {
Socket clientSocket;
public ClientSocket(Socket clientSocket) {
this.clientSocket = clientSocket;
System.out.println(clientSocket.getPort());
clientInfo.put(clientSocket.getPort(), this);
}
...
Read more about Java Server with Multiclient communication.

Java Socket Programing

Problem:
I have written one java socket server which send response when I send first message from the client to it. But I want to send one more message based on the first response. After the first response i am not getting any other response?
Here is the Server code:
public class SendSmsServerSocket {
private final static CxpsLogger logger = CxpsLogger.getLogger(SendSmsServerSocket.class);
SendSmsServerSocket(){
try {
new SeverSocketForSms(new ServerSocket(4330));
} catch (IOException e) {
e.printStackTrace();
}
}
}
private static class SeverSocketForSms extends Thread {
private Socket socket;
private ServerSocket serversocket;
private volatile static boolean running = true;
public SeverSocketForSms(ServerSocket ssocket) throws IOException {
this.serversocket = ssocket;
start();
}
public void run() {
try{
while(running) {
this.socket = serversocket.accept();
InputStreamReader ir = new InputStreamReader(socket.getInputStream());
BufferedReader br = new BufferedReader(ir);
String msg = br.readLine();
PrintStream ps = new PrintStream(socket.getOutputStream());
ps.println("inside SeverSocketForSms: msg received is : "+msg);
}
}
catch(Exception e){
e.printStackTrace();
}
catch(Throwable t) {
System.out.println("Caught " + t + "xmlServerThread - closing thread");
}
}
public static void shutdown() {
System.out.println("Stopping socket connection and thread");
try{
socket.close();
}catch (Exception e) {
e.printStackTrace();
}
running = false;
}
public static void main (String [] args){
try {
System.out.println("Starting sms server ----- Please press Enter Key to stop the server after receiving one message");
SendSmsServerSocket s=new SendSmsServerSocket();
new Scanner(System.in).nextLine();
SeverSocketForSms.shutdown();
} catch (Exception e) {
e.printStackTrace();
}
}
}

Once you have an incoming connection, you should delgate the responsibility for handling that incoming connection to another Thread, otherwise you will block your "accept" thread until the current connection is closed...
while (running) {
this.socket = serversocket.accept();
Thread thread = new Thread(new Handler(socket));
thread.start();
}
And the Handler
public class Handler implements Runnable {
private Socket socket;
public Handler(Socket socket){
this.socket = socket;
}
public void run() {
// You may need to add a repeat and exit clause here...
InputStreamReader ir = new InputStreamReader(socket.getInputStream());
BufferedReader br = new BufferedReader(ir);
String msg = br.readLine();
PrintStream ps = new PrintStream(socket.getOutputStream());
ps.println("inside SeverSocketForSms: msg received is : " + msg);
}
}

Java Server Sockets: My Server Socket only allows client connections running on the same internet connection?

Ok so I have constructed a working example of a client and server which can accept multiple client connections. My problem is is that I cannot connect a client which is not running the same internet connection as the one the server is being hosted on. Is this possible using server sockets?
Here is the code for my server:
import java.io.IOException;
import java.net.*;
public class MultipleSocketServer {
public static Socket connection;
public static String name = "Tyler's Server";
public static int limit = 2;
public static Thread[] clients = new Thread[limit];
public static int current = 0;
public static int port = 25565;
public static String[] connected = new String[limit];
public static ServerSocket socket;
public static void main(String[] args) {
System.out.println("Server starting...");
for(int i = 0; i < limit; i++) {
connected[i] = "";
}
try {
ServerSocket socket = new ServerSocket(port);
while(true) {
Socket connection = socket.accept();
String ip = connection.getRemoteSocketAddress().toString().substring(1, 13);
loop:
for(int i = 0; i < connected.length; i++) {
if(connected[0].equals(ip) || connected[1].equals(ip)) {
break loop;
}else if(!connected[i].equals(ip)) {
connected[i] = ip;
MultiServer_Client client = new MultiServer_Client(connection, i);
Thread run = new Thread(client);
run.start();
break loop;
}
}
}
} catch (IOException e1) {
System.out.println("Could not bind server on: " + port);
System.exit(-1);
}
}
}
And here is the rest:
import java.io.*;
import java.net.Socket;
public class MultiServer_Client implements Runnable {
public String time;
public Socket client;
public StringBuffer process = new StringBuffer();
public BufferedInputStream inputStream;
public InputStreamReader reader;
public BufferedOutputStream outputStream;
public OutputStreamWriter writer;
public StringVis check = new StringVis("");
public StringChangeListener checkListener = new StringChangeListener() {
public void textChanged(StringChangeEvent e) {
System.out.println("Changed");
write("Server recieved message...");
}
};
public boolean connected = true;
public int ID;
public MultiServer_Client(Socket connection, int i) {
client = connection;
ID = i;
try {
//declare text input/output
inputStream = new BufferedInputStream(client.getInputStream());
reader = new InputStreamReader(inputStream);
outputStream = new BufferedOutputStream(client.getOutputStream());
writer = new OutputStreamWriter(outputStream, "US-ASCII");
} catch (IOException e) {
System.out.println("IOException: " + e);
}
System.out.println(MultipleSocketServer.connected[ID] + " connected...");
write("Connected to " + MultipleSocketServer.name);
}
public void run() {
while(connected) {
read();
}
System.out.println("Disconnecting client...");
}
public void write(String authen) {
try {
time = new java.util.Date().toString();
String message = time + ": " + authen + (char) 13;
writer.write(message);
writer.flush();
} catch (IOException e) {
connected = false;
MultipleSocketServer.connected[ID] = "";
}
}
public void read() {
//read from client
int character;
process = new StringBuffer();
try {
while ((character = reader.read()) != 13) {
process.append((char) character);
}
check.setText(process.toString());
process.delete(0, process.length());
} catch (IOException e) {
connected = false;
MultipleSocketServer.connected[ID] = "";
}
}
}
Here's the client code:
import java.net.*;
import java.util.Scanner;
import java.io.*;
public class SocketClient {
public static String host = "69.182.134.79";
public static int port = 25565;
public static void main(String [] args) {
StringBuffer imports = new StringBuffer();
String time;
System.out.println("Client starting...");
try {
//establish client
InetAddress address = InetAddress.getByName(host);
Socket connection = new Socket(address, port);
BufferedOutputStream bos = new BufferedOutputStream(connection.getOutputStream());
OutputStreamWriter osw = new OutputStreamWriter(bos, "US-ASCII");
BufferedInputStream bis = new BufferedInputStream(connection.getInputStream());
InputStreamReader isr = new InputStreamReader(bis, "US-ASCII");
while(true) {
Scanner scan = new Scanner(System.in);
String message = scan.nextLine();
//write to server
time = new java.util.Date().toString();
String process = host + ":" + port + " sent data at " + time + ": " + message + (char) 13;
osw.write(process);
osw.flush();
//read from server
int c;
while ((c = isr.read()) != 13) {
imports.append((char) c);
}
System.out.println(imports);
imports.replace(0, imports.length(), "");
if(message.equals("--EXIT")) {
connection.close();
}
}
} catch (UnknownHostException e) {
System.out.println("UnknownHostException: " + e);
} catch (IOException e) {
System.out.println("IOExcepion: " + e);
}
}
}

Change
MultiServer_Client client = new MultiServer_Client(connection, i);
to
MultiServer_Client client = new MultiServer_Client(new Socket([Server IP], port), i);
This should work.