Problem when client closes

Question

Here is my server side:
import java.net.*;
import java.io.*;
public class server {
     private static ServerSocket serversocket = null;
     public static void main(String[] args) {
          //ServerSocket serversocket = null;
         try {
              serversocket = new ServerSocket(11116);
         } catch (IOException e) {
              System.out.println(e);
         while(true) {
              ClientWorker clientworker;
              try {
                   clientworker = new ClientWorker(serversocket.accept());
                   Thread thread = new Thread(clientworker);
                   thread.start();
              } catch(IOException e){
                   System.out.println(e);
                   System.exit(-1);
     protected void finalize(){
          try{
              serversocket.close();
          } catch (IOException e) {
              System.out.println("Could not close socket");
              System.exit(-1);
class ClientWorker implements Runnable {
     private Socket socket;
     public ClientWorker(Socket socket) {
          this.socket = socket;
     public void run(){
          String strLine;
          BufferedReader input = null;
          PrintWriter output = null;
          try{
               input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
               output = new PrintWriter(socket.getOutputStream(), true);
         } catch (IOException e) {
              System.out.println(e);
         while(true){
              try{
                   strLine = input.readLine();
                   output.println(strLine);
                   System.out.println(strLine);
              } catch (IOException e) {
                    System.out.println(e);
                    System.exit(-1);
and my client side
import java.net.*;
import java.io.*;
public class client {
     public static void main(String[] args) {
          Socket socket = null;
          BufferedReader input = null;
          PrintWriter output = null;
          String strServer = "192.168.0.3";
          String strLine = "";
          try {
               socket = new Socket(strServer, 11116);
               input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
               output = new PrintWriter(socket.getOutputStream(),true);
          } catch(UnknownHostException e) {
               System.out.println("Couldn't get I/O for the connection to: " + strServer);
          } catch(IOException e) {
               System.out.println(e);
          BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
          if(socket!=null && input!=null && output!=null) {
               while(!strLine.equals("quit")) {
                    try {
                         System.out.print("Output: ");
                         strLine = stdIn.readLine();
                         output.println(strLine);
                         System.out.println("Server: " + input.readLine());
                    } catch(UnknownHostException e) {
                         System.out.println("Couldn't get I/O for the connection to: " + strServer);
                    } catch(IOException e) {
                         System.out.println(e);
          try {
               output.close();
               input.close();
               socket.close();
          } catch(UnknownHostException e) {
               System.out.println("Couldn't get I/O for the connection to: " + strServer);
          } catch(IOException e) {
               System.out.println(e);
     } //end main method
}Seems like everytime I close my client, the server crashes which is "java.net.SocketException: Connection reset"
A little info about the program, it's just a multi-threaded server where clients can connect to it.
How do i fix it?
Thanks

Answer 1

Really? :)
strLine = stdIn.readLine(); // user
output.println(strLine); // send to serverYes, really. That 'strLine' is null if the client has closed. The OP is not checking for this condition so he is writing the null after the client has already closed, and this happens in a hard loop from which there is no escape until the exception.
So this happens because you are reading from the client after the client has closed its socket.That would cause readLine() to return a null. It wouldn't cause an IOException.
Message was edited by:
ejp