아래 코드는 Head first Java의 예제이다.

import java.io.*;
import java.net.*;
import java.util.*;
import javax.swing.*;

import com.sun.corba.se.spi.servicecontext.SendingContextServiceContext;

import java.awt.*;
import java.awt.event.*;

public class SimpleChatclient {
 JTextArea incoming;
 JTextField outgoing;
 BufferedReader reader;
 PrintWriter writer;
 Socket sock;
 
 public static void main(String[] args){
  SimpleChatclient client = new SimpleChatclient();
  client.go();
 }
 
 public void go(){
  JFrame frame = new JFrame("Simple Chat Client");
  JPanel mainPanel = new JPanel();
  incoming = new JTextArea(15,50);
  incoming.setLineWrap(true);
  incoming.setWrapStyleWord(true);
  incoming.setEditable(false);
  JScrollPane qScroller = new JScrollPane(incoming);
  qScroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
  qScroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
  outgoing = new JTextField(20);
  JButton sendButton = new JButton("Send");
  sendButton.addActionListener(new SendButtonListener());
  mainPanel.add(qScroller);
  mainPanel.add(outgoing);
  mainPanel.add(sendButton);
  setUpNetworking();
 
  Thread readerThread = new Thread(new IncomingReader());
  readerThread.start();
 
  frame.getContentPane().add(BorderLayout.CENTER, mainPanel);
  frame.setSize(400, 500);
  frame.setVisible(true);  
 }
 
 private void setUpNetworking(){
  try{
   sock = new Socket("127.0.0.1",5000);
   InputStreamReader streamReader = new InputStreamReader(sock.getInputStream());
   reader = new BufferedReader(streamReader);
   writer = new PrintWriter(sock.getOutputStream());
   System.out.println("networking established");
  }catch(IOException ex){
   ex.printStackTrace();
  }
 }
 
 public class SendButtonListener implements ActionListener{
  public void actionPerformed(ActionEvent ev){
   try{
   writer.println(outgoing.getText());
   writer.flush();
   }catch(Exception ex){
    ex.printStackTrace();
   }
   outgoing.setText("");
   outgoing.requestFocus();
  }
 }
 
 public class IncomingReader implements Runnable{
  public void run(){
   String message;
   try{
    while((message = reader.readLine())!= null){
     System.out.println("read "+ message);
     incoming.append(message+ "\n");
     }
    }catch(Exception ex){
     ex.printStackTrace();
    }
   }
  }
 }