Client.java

import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Client extends JFrame{
	private JTextField userText;
	private JTextArea chatWindow;
	private ObjectOutputStream output;
	private ObjectInputStream input;
	private String message = "";
	private String serverIP;
	private Socket connection;
	
	public Client(String host){
		super("Client");
		serverIP = host;
		
		userText = new JTextField();
		userText.setEditable(false);
		userText.addActionListener(
				new ActionListener(){
					public void actionPerformed(ActionEvent event){
						sendMessage(event.getActionCommand());
						userText.setText("");
						
						}
					
					}
				);
		add(userText, BorderLayout.NORTH);
		chatWindow = new JTextArea();
		add(new JScrollPane(chatWindow), BorderLayout.CENTER);
		setSize(300,150);
		setVisible(true);		
	}
	
	//connect to server
	public void startRunning(){
		
		try{
			
			connectToServer();
			setupStreams();
			//Ask for files
			////Receive IP/Port of file holder
			//message File holder asking for password
			whileChatting();	
		}catch(EOFException oefException){
			showMessage("\n Client Terminated the connection");
		}catch(IOException ioException){
			ioException.printStackTrace();
			
		}finally{
			closeCrap();
			
		}
	}
	
	//connect to server
	private void connectToServer() throws IOException{
		showMessage("Attempting Connection..\n");
		connection = new Socket(InetAddress.getByName(serverIP),6789);
		showMessage("Connected to: " + connection.getInetAddress().getHostName() );
	}
	// setup streams
	private void setupStreams() throws IOException{
		output = new ObjectOutputStream(connection.getOutputStream());
		output.flush();
		input = new ObjectInputStream(connection.getInputStream());
		showMessage("\n Your streams are now good to go \n");
	}
	// while chatting with server
	private void whileChatting() throws IOException{
		ableToType(true);
		do{
			try{
				message = (String) input.readObject();
				
				showMessage("\n" + message);
				
			}catch(ClassNotFoundException classNotFoundException){
				
				showMessage("\n I dont know that object");
				
			}
			
		}while(!message.equals("SERVER - END"));	
	}
	private void closeCrap(){
		showMessage("\n Closing stuff down");
		ableToType(false);
		try{
			output.close();
			input.close();
			connection.close();
			
			
		}catch(IOException ioException){
			ioException.printStackTrace();
		}
	}
	//send message to server
	private void sendMessage(String message){
		try{
			output.writeObject("CLIENT - " + message);
			output.flush();
			showMessage("\nCLIENT - " + message);
			
		}catch(IOException ioException){
			
			chatWindow.append("\n Something messed up sending message");
			
		}
	}
	// show message
	private void showMessage(final String m){
		SwingUtilities.invokeLater(
				new Runnable(){
					public void run(){
						chatWindow.append(m);
						
				}
					
			}
				
		);
	}
	//gives user permission to type
	private void ableToType(final boolean tof){
		SwingUtilities.invokeLater(
				new Runnable(){
					public void run(){
						userText.setEditable(tof);
						
				}
					
			}
				
		);		
		
	}
}

ClientTest

import javax.swing.JFrame;


public class ClientTest {
	public static void main(String[] args){
		Client client;
		client = new Client("127.0.0.1");
		client.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		client.startRunning();
		
	}
}

Server.java

import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Server extends JFrame{

	private JTextField userText;
	private JTextArea chatWindow;
	private ObjectOutputStream output;
	private ObjectInputStream input;
	private ServerSocket server;
	private Socket connection;
	
	
	//constructor
	public Server(){
		super("Instant Messenger");
		userText = new JTextField();
		userText.setEditable(false);
		userText.addActionListener(
				new ActionListener(){
					public void actionPerformed(ActionEvent event){
						 sendMessage(event.getActionCommand());
						 userText.setText("");
						 
					}
					
				}
				);
		add(userText, BorderLayout.NORTH);
		chatWindow = new JTextArea();
		add(new JScrollPane(chatWindow));
		setSize(300,150);
		setVisible(true);	
	}
	
	//set up and run the server
	public void startRunning(){
		try{
			server = new ServerSocket(6789);
			while(true){
				try{
					
					waitForConnection();
					setupStreams();
					//Receive Request for file
					//check which client has file
					//send ip of client with file
					whileChatting();
					
				}catch(EOFException eofException){
					showMessage("\n Server ended the connection!");
					
				}finally{
					
					closeCrap();
				}
				
			}
			
		}catch(IOException ioException){
			ioException.printStackTrace();
			
		}
		
	}
	
	//wait for connection, then display connection information
	
	private void waitForConnection() throws IOException{
		showMessage("Waiting for someone to connect...\n");
		connection = server.accept();
		showMessage("Now connected to" + connection.getInetAddress().getHostName());
		
	}
	//get stream to send and receive data
	
	private void setupStreams() throws IOException{
		output = new ObjectOutputStream(connection.getOutputStream());
		output.flush();
		input = new ObjectInputStream(connection.getInputStream());
		showMessage("\n Streams are now setup! \n");
		
	}
	// during the chat
	private void whileChatting() throws IOException{
		String message = "You are now connected! ";
		sendMessage(message);
		ableToType(true);
		do{
			//have a conversation
			try{
				message = (String) input.readObject();
				showMessage("\n" + message);
			}catch(ClassNotFoundException classNotFoundException){
				showMessage("\n I dont  know that user sent");
				
			}
			
		}while(!message.equals("CLIENT - END"));
		
	}
	//close streams and sockets after you are done chatting
	private void closeCrap(){
		showMessage("\n Closing connection...\n");
		ableToType(false);
		try{
			output.close();
			input.close();
			connection.close();
			
			
		}catch(IOException ioException){
			ioException.printStackTrace();
		}
		
	}
	//send message to client
	private void sendMessage(String message){
		try{
			output.writeObject("Server - " + message);
			output.flush();
			showMessage("\n SERVER - " + message);
			
		}catch(IOException ioException){
			chatWindow.append("\n ERROR");
			
		}
		
	}
	
	//updates chatWindow
	private void showMessage(final String text){
		SwingUtilities.invokeLater(
					new Runnable(){
						public void run(){
							chatWindow.append(text);
							
							
						}
						
					}
				);
	}
	
	//let the user type stuff into the box
	private void ableToType(final boolean tof){
		SwingUtilities.invokeLater(
				new Runnable(){
					public void run(){
						userText.setEditable(tof);
						
						
					}
					
				}
			);		
		
	}
	
}

ServerTest

import javax.swing.JFrame;

public class ServerTest {
	public static void main(String[] args){
		Server iM = new Server();
		iM.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		iM.startRunning();
		
	}
}