Client/Server hang up?

Question

I'm writing a basic client server program. I created an ArrayList to hold all the sockets of a connection so each client could, hopefully, eventually interact.
Right now my client is a text field with a text area under it. A user types a command up top and then hits enter and sends that along to the server. However when i send in the message it seems to hang up and never sends back a reply. But what's really odd about it, is that if i close my server window and there by shutting it down the client then outputs exactly what i expected it to if it was working right. So im curious why there's this hangup in my code?
Server:
import java.awt.BorderLayout;
import java.awt.Font;
import java.io.IOException;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
public class Server extends JFrame{
          private JTextArea jta = new JTextArea();
          private static ArrayList<Socket> clients = new ArrayList<Socket>();
          public Server(){
               getContentPane().setLayout(new BorderLayout());
               getContentPane().add(new JScrollPane(jta), BorderLayout.CENTER);
               jta.setFont( new Font( "Times", Font.BOLD, 20));
               setSize(500, 300);
               setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
               setVisible(true);
               try{
                    setTitle("Server: " + InetAddress.getLocalHost().getHostName());
                    int clientNo = 1;
                    ServerSocket serverSocket = new ServerSocket(0);
                    jta.append("Port: " + serverSocket.getLocalPort() + "\n");
                    while(true){
                         Socket socket = serverSocket.accept();
                         InetAddress inetAddress = socket.getInetAddress();
                         clients.add(socket);
                         World thread = new World(socket);
                         jta.append("Connected with client :" + clientNo + "\n");
                         thread.start();
                         clientNo++;
               }catch(IOException ex){
                    System.err.println(ex);
          public static void main(String[] args){
               new Server();
          public static ArrayList getClients(){
               return clients;
     }World:
import java.io.IOException;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.util.ArrayList;
import java.util.Scanner;
public class World extends Thread {
     private Socket mySocket;
     private int myPort;
     private InetAddress myInetAddress;
     private String myHostName;
     private ArrayList<Socket> theClients;
     public World(Socket newSocket) {
          mySocket = newSocket;
          myPort = mySocket.getPort();
          myInetAddress = mySocket.getInetAddress();
          myHostName = myInetAddress.getHostName();
     public void run() {
          String test;
          Scanner input = null;
          PrintWriter output = null;
          try {
               String fileName;
               input = new Scanner(mySocket.getInputStream());
               output = new PrintWriter(mySocket.getOutputStream(), true);
          }catch(IOException e){
          output.println("Please Enter Command");
          while((test = input.nextLine()) != null){
               if(test.contains("get clients") ){
                    theClients = Server.getClients();
                    for(int i = 0; i < theClients.size(); i++){
                         output.println(theClients.get(i).getInetAddress().getHostName());
                    output.flush();
               }else{
                    output.println("not sure");
                    output.flush();
}Client:
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
import java.util.Scanner;
import javax.swing.*;
public class Client extends JFrame implements ActionListener{
     private JTextField jtf;
     private JTextArea jta = new JTextArea();
     private PrintWriter output;
     private Scanner input;
     public Client(String host, int port){
          JPanel p1 = new JPanel();
          p1.setLayout(new BorderLayout());
          p1.add(jtf = new JTextField(10), BorderLayout.CENTER);
          jtf.setHorizontalAlignment(JTextField.RIGHT);
          jtf.setFont(new Font("Times", Font.BOLD, 20));
          jta.setFont(new Font("Times", Font.BOLD, 20));
          getContentPane().setLayout(new BorderLayout());
          getContentPane().add(p1, BorderLayout.NORTH);
          getContentPane().add(new JScrollPane(jta), BorderLayout.CENTER);
          jtf.addActionListener(this);
          setSize(500,300);
          setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          setVisible(true);
          try{
               setTitle("Client: " + InetAddress.getLocalHost().getHostName());
               Socket socket = new Socket(host, port);
               input = new Scanner(socket.getInputStream());
               output = new PrintWriter(socket.getOutputStream(), true);
               jta.append(input.nextLine() + "\n");
          }catch(IOException ex){
               jta.append(ex.toString() + "\n");
     public void actionPerformed(ActionEvent e){
          String nextLine;
          String findFile = jtf.getText().trim();
          ((JTextField)(e.getSource())).setEditable(false);
          if ( e.getSource() instanceof JTextField){
                    jta.append("Getting file: \"" + findFile + "\" \n");
                    output.println(findFile);
                    output.flush();
                    while(input.hasNext()){
                         nextLine = input.nextLine();
                         jta.append(nextLine + "\n");
     public static void main(String[] args){
          int portSend;
          if (args.length != 2){
               System.out.println("not Enough arguments");
               System.exit(-1);
          portSend = Integer.parseInt(args[1]);
          new Client(args[0], portSend);
}

Answer 1

Don't run networking code in the constructor. Start a separate thread for the accept loop.