Thread: Applet Error

I'm making this simple chatserver/chatclient gui in java using an applet instead of JFrame. The problem I'm having is that I set the correct run configuration but error comes up when client coonects and when i got to that line the error is on iI don't know what to do. Any help is much appriciated.

ChatClient:

public class ChatClient extends Applet {
	private Socket socket = null;
	private DataInputStream console = null;
	private DataOutputStream streamOut = null;
	private ChatClientThread client = null;
	private TextArea display = new TextArea();
	private TextField input = new TextField();
	private Button send = new Button("Send"), connect = new Button("Connect"), quit = new Button("Bye");
	private String serverName = "localhost";
	private int serverPort = 8080;
 
	public void init() {
		Panel keys = new Panel();
		keys.setLayout(new GridLayout(1, 2));
		keys.add(quit);
		keys.add(connect);
		Panel south = new Panel();
		south.setLayout(new BorderLayout());
		south.add("West", keys);
		south.add("Center", input);
		south.add("East", send);
		Label title = new Label("Simple Chat Client Applet", Label.CENTER);
		title.setFont(new Font("Helvetica", Font.BOLD, 14));
		setLayout(new BorderLayout());
		add("North", title);
		add("Center", display);
		add("South", south);
		quit.disable();
		send.disable();
		getParameters();
		display.append(str.toString());
	}
 
	public boolean action(Event e, Object o) {
		if (e.target == quit) {
			input.setText(".bye");
			send();
			quit.disable();
			send.disable();
			connect.enable();
		} else if (e.target == connect) {
			connect(serverName, serverPort);
		} else if (e.target == send) {
			send();
			input.requestFocus();
		}
		return true;
	}
 
	public void connect(String serverName, int serverPort) {
		println("Establishing connection. Please wait ...");
		try {
			socket = new Socket(serverName, serverPort);
			println("Connected: " + socket);
			open();
			send.enable();
			connect.disable();
			quit.enable();
		} catch (UnknownHostException uhe) {
			println("Host unknown: " + uhe.getMessage());
		} catch (IOException ioe) {
			println("Unexpected exception: " + ioe.getMessage());
		}
	}
 
	private void send() {
		try {
			streamOut.writeUTF(input.getText());
			streamOut.flush();
			input.setText("");
		} catch (IOException ioe) {
			println("Sending error: " + ioe.getMessage());
			close();
		}
	}
 
	public void handle(String msg) {
		if (msg.equals(".bye")) {
			println("Good bye. Press RETURN to exit ...");
			close();
		} else
			println(msg);
	}
 
	public void open() {
		try {
			streamOut = new DataOutputStream(socket.getOutputStream());
			client = new ChatClientThread(this, socket);
		} catch (IOException ioe) {
			println("Error opening output stream: " + ioe);
		}
	}
 
	public void close() {
		try {
			if (streamOut != null)
				streamOut.close();
			if (socket != null)
				socket.close();
		} catch (IOException ioe) {
			println("Error closing ...");
		}
		client.close();
		client.stop();
	}
 
	private void println(String msg) {
		display.appendText(msg + "\n");
	}
 
	public void getParameters() {
		serverName = getParameter("host");
		serverPort = Integer.parseInt(getParameter("port"));
	}
}

ChatClientThread:

public class ChatClientThread extends Thread {
	private Socket socket = null;
	private ChatClient client = null;
	private DataInputStream streamIn = null;
 
	public ChatClientThread(ChatClient _client, Socket _socket) {
		client = _client;
		socket = _socket;
		open();
		start();
	}
 
	public void open() {
		try {
			streamIn = new DataInputStream(socket.getInputStream());
		} catch (IOException ioe) {
			System.out.println("Error getting input stream: " + ioe);
			client.stop();
		}
	}
 
	public void close() {
		try {
			if (streamIn != null)
				streamIn.close();
		} catch (IOException ioe) {
			System.out.println("Error closing input stream: " + ioe);
		}
	}
 
	public void run() {
		while (true) {
			try {
				client.handle(streamIn.readUTF());
			} catch (IOException ioe) {
				System.out.println("Listening error: " + ioe.getMessage());
				client.stop();
			}
		}
	}
}

ChatServerThread:

public class ChatServerThread extends Thread {
	private ChatServer server = null;
	private Socket socket = null;
	private int ID = -1;
	private DataInputStream streamIn = null;
	private DataOutputStream streamOut = null;
 
	public ChatServerThread(ChatServer _server, Socket _socket) {
		super();
		server = _server;
		socket = _socket;
		ID = socket.getPort();
	}
 
	public void send(String msg) {
		try {
			streamOut.writeUTF(msg);
			streamOut.flush();
		} catch (IOException ioe) {
			System.out.println(ID + " ERROR sending: " + ioe.getMessage());
			server.remove(ID);
			stop();
		}
	}
 
	public int getID() {
		return ID;
	}
 
	public void run() {
		System.out.println("Server Thread " + ID + " running.");
		while (true) {
			try {
				server.handle(ID, streamIn.readUTF());
			} catch (IOException ioe) {
				System.out.println(ID + " ERROR reading: " + ioe.getMessage());
				server.remove(ID);
				stop();
			}
		}
	}
 
	public void open() throws IOException {
		streamIn = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
		streamOut = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));
	}
 
	public void close() throws IOException {
		if (socket != null)
			socket.close();
		if (streamIn != null)
			streamIn.close();
		if (streamOut != null)
			streamOut.close();
	}
}

ChatServer:

public class ChatServer implements Runnable {
	private ChatServerThread clients[] = new ChatServerThread[50];
	private ServerSocket server = null;
	private Thread thread = null;
	private int clientCount = 0;
 
	public ChatServer(int port) {
		try {
			System.out.println("Binding to port " + port + ", please wait  ...");
			server = new ServerSocket(port);
			System.out.println("Server started: " + server);
			start();
		} catch (IOException ioe) {
			System.out.println("Can not bind to port " + port + ": " + ioe.getMessage());
		}
	}
 
	public void run() {
		while (thread != null) {
			try {
				System.out.println("Waiting for a client ...");
				addThread(server.accept());
			} catch (IOException ioe) {
				System.out.println("Server accept error: " + ioe);
				stop();
			}
		}
	}
 
	public void start() {
		if (thread == null) {
			thread = new Thread(this);
			thread.start();
		}
	}
 
	public void stop() {
		if (thread != null) {
			thread.stop();
			thread = null;
		}
	}
 
	private int findClient(int ID) {
		for (int i = 0; i < clientCount; i++)
			if (clients[i].getID() == ID)
				return i;
		return -1;
	}
 
	public synchronized void handle(int ID, String input) {
		if (input.equals(".bye")) {
			clients[findClient(ID)].send(".bye");
			remove(ID);
		} else
			for (int i = 0; i < clientCount; i++)
				clients[i].send(ID + ": " + input);
	}
 
	public synchronized void remove(int ID) {
		int pos = findClient(ID);
		if (pos >= 0) {
			ChatServerThread toTerminate = clients[pos];
			System.out.println("Removing client thread " + ID + " at " + pos);
			if (pos < clientCount - 1)
				for (int i = pos + 1; i < clientCount; i++)
					clients[i - 1] = clients[i];
			clientCount--;
			try {
				toTerminate.close();
			} catch (IOException ioe) {
				System.out.println("Error closing thread: " + ioe);
			}
			toTerminate.stop();
		}
	}
 
	private void addThread(Socket socket) {
		if (clientCount < clients.length) {
			System.out.println("Client accepted: " + socket);
			clients[clientCount] = new ChatServerThread(this, socket);
			try {
				clients[clientCount].open();
				clients[clientCount].start();
				clientCount++;
			} catch (IOException ioe) {
				System.out.println("Error opening thread: " + ioe);
			}
		} else
			System.out.println("Client refused: maximum " + clients.length + " reached.");
	}
 
	public static void main(String args[]) {
		ChatServer server = null;
		if (args.length != 1)
			System.out.println("Usage: java ChatServer port");
		else
			server = new ChatServer(Integer.parseInt(args[0]));
	}
}

eror.JPG

The errors are in the image or here:

java.lang.NumberFormatException: null
at java.lang.Integer.parseInt(Integer.java:542)
at java.lang.Integer.parseInt(Integer.java:615)
at chat.ChatClient.getParameters(ChatClient.java:129)
at chat.ChatClient.init(ChatClient.java:42)
at sun.applet.AppletPanel.run(AppletPanel.java:434)
at java.lang.Thread.run(Thread.java:748)

The imports are:

import java.net.*;
import java.io.*;
import java.applet.*;
import java.awt.*;