Cannot send and read objects through sockets

Question

I have these 4 classes to send objects through sockets. Message and Respond classes are just for
trials. I use their objects to send ıver the network. I do not get any compile time error or runtime error but
the code just does not send the objects. I used object input and output streams to send and read objects
in server (SOTServer) and in the client (SOTC) classes. When I execevute the server and client I can see
that the clients can connect to the server but they cannot send any objects allthough I wrote them inside the main method of client class. This code stops in the run() method but I could not find out why it
does do that. Run the program by creating 4 four classes.
Message.java
Respond.java
SOTC.java
SOTServer.java
Then execute server and then one or more clients to see what is going on.
Any ideas will be appreciated
thanks.
ASAP pls
//***********************************Message class**********************
import java.io.Serializable;
public class Message implements Serializable
private String chat;
private int client;
public Message(String s,int c)
client=c;
chat=s;
public Message()
client=0;
chat="aaaaa";
public int getClient()
return client;
public String getChat()
return chat;
//*******************************respond class*****************************
import java.io.Serializable;
public class Respond implements Serializable
private int toClient;
private String s;
public Respond()
public Respond(String s)
this.s=s;
public int gettoClient()
return toClient;
public String getMessage()
return s;
//***********************************SOTServer*********************
import java.io.*;
import java.net.*;
import java.util.Vector;
//private class
class ClientWorker extends Thread
private Socket client;
private ObjectInputStream objectinputstream;
private ObjectOutputStream objectoutputstream;
private SOTServer server;
ClientWorker(Socket socket, SOTServer ser)
client = socket;
server = ser;
System.out.println ("new client connected");
try
objectinputstream=new ObjectInputStream(client.getInputStream());
objectoutputstream=new ObjectOutputStream(client.getOutputStream());
catch(Exception e){}
public void sendToClient(Respond s)
try
objectoutputstream.writeObject(s);
objectoutputstream.flush();
catch(IOException e)
e.printStackTrace();
public void run()
do
Message fromClient;
try
fromClient =(Message) objectinputstream.readObject();
System.out.println (fromClient.getChat());
Respond r=new Respond();
server.sendMessageToAllClients(r);
System.out.println ("send all completed");
catch(ClassNotFoundException e){e.printStackTrace();}
catch(IOException ioexception1)
ioexception1.printStackTrace();
break;
Respond k=new Respond();
sendToClient(k);
}while(true);
public class SOTServer
ServerSocket server;
Vector clients;
public static void main(String args[]) throws IOException
SOTServer sotserver = new SOTServer();
sotserver.listenSocket();
SOTServer()
clients = new Vector();
System.out.println ("Server created");
public void sendMessageToAllClients(Respond str)
System.out.println ("sendToallclient");
ClientWorker client;
for (int i = 0; i < clients.size(); i++)
client = (ClientWorker) (clients.elementAt(i));
client.sendToClient(str);
public void listenSocket()
try
System.out.println ("listening socket");
server = new ServerSocket(4444, 6);
catch(IOException ioexception)
ioexception.printStackTrace();
do
try
ClientWorker clientworker=new ClientWorker(server.accept(), this);
clients.add(clientworker);
clientworker.start();
catch(IOException ioexception1)
ioexception1.printStackTrace();
while(true);
protected void finalize()
try
server.close();
catch(IOException ioexception)
ioexception.printStackTrace();
//*************************SOTC***(client class)*********************
import java.io.*;
import java.net.Socket;
import java.net.UnknownHostException;
class SOTC implements Runnable
private Socket socket;
private ObjectOutputStream output;
private ObjectInputStream input;
public void start()
try
socket= new Socket("127.0.0.1",4444);
input= new ObjectInputStream(socket.getInputStream());
output= new ObjectOutputStream(socket.getOutputStream());
catch(IOException e){e.printStackTrace();}
Thread outputThread= new Thread(this);
outputThread.start();
public void run()
try
do
Message m=new Message("sadfsa",0);
output.writeObject(m);
Respond fromServer=null;
fromServer=(Respond)input.readObject();
}while(true);
catch(NullPointerException e){run();}
catch(Exception e){e.printStackTrace();}
public SOTC()
start();
public void sendMessage(Message re)
try
Message k=new Message("sdasd",0);
output.writeObject(k);
output.flush();
catch(Exception ioexception)
ioexception.printStackTrace();
System.exit(-1);
public static void main(String args[])
SOTC sotclient = new SOTC();
try
System.out.println("client obje sonrasi main");
Message re=new Message("client &#305;m ben mesaj bu da iste",0);
sotclient.sendMessage(re);
System.out.println ("client gonderdi mesaji");
catch(Exception e) {e.printStackTrace();}

Answer 1

ObjectStreams send a few bytes at construct time. The OutputStream writes a header and the InputStram reads them. The InputStream constrcutor will not return until oit reads that header. Your code is probably hanging in the InputStream constrcutor. (try and verify that by getting a thread dump)
If that is your problem, tolution is easy, construct the OutputStreams first.