Java UDP Multicast problems with sending data

Hey guys,

I'm working on a Pong network game, I have it working using TCP/IP fine, but I can't seem to send data from the client to the server using UDP.

Here is my server I created

package Pong;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.MulticastSocket;
import java.net.Socket;

//This is the actual server
public class PongUDPServerThread extends Thread {
	
	//speed to send data
	private long dataSpeed = 10;
	private int port = 4447;
	private int idPlayer = 0;
	private PongModel model;
	private PongView  view;
	private PongPlayerThread players[] = new PongPlayerThread[2];
	private MulticastSocket socket = null;
	private InetAddress group;
	private int ID = 1;
	
	public PongUDPServerThread() throws IOException 
	{
		super("PongUDPServerThread");
	}
	
	public String rtnInfo()
	{
		String str;
		str = model.getBall().getX() + ":" +
			  model.getBall().getY() + ":" +
			  model.getBats()[0].getX() + ":" +
			  model.getBats()[0].getY() + ":" +
			  model.getBats()[1].getX() + ":" +
			  model.getBats()[1].getY();
		return str;
	}
	
	public void setupPong() throws IOException 
	{
		System.out.println("Pong");
		model = new PongModel();
		view  = new PongView();
		        new PongController( model, view );

		model.addObserver( view );       // Add observer to the model

		//view.setVisible(true);           // Display Screen
		model.makeActiveObject();        // Start play
		//start server
		socket = new MulticastSocket(port);
		InetAddress group = InetAddress.getByName("230.0.0.1");
		socket.joinGroup(group);
		//socket.setReuseAddress(true);
		//Inform server user
		System.out.println("Server is running");
	}
	
	public void run()
	{
		//Server loop
		while(true)
		{
			
			//Receive data
			byte[] recBuf = new byte[256];
			DatagramPacket recData = new DatagramPacket(recBuf, recBuf.length);
			try
			{
			socket.receive(recData);
			}
			catch (IOException e)
			{
				e.printStackTrace();
			}
			try
			{
				byte[] buf = new byte[256];
				
				//Gather data
				buf = rtnInfo().getBytes();
				//System.out.println(buf.toString());
				
				//Send data
				DatagramPacket packet = new DatagramPacket(buf, buf.length, InetAddress.getByName("230.0.0.1"), port);
				socket.send(packet);
				
				//Sleep the server
				try
				{
					sleep((long)dataSpeed);
				}
				catch (InterruptedException e)
				{
					
				}
			}
			catch (IOException e)
			{
				e.printStackTrace();
			}
		}
		
		//socket.close();
		
	}
	
}

And here is my client

package Pong;

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

public class PongUDPClient {
	
	private static int port = 4447;

	public static void main(String[] args) throws IOException
	{
		
		//Setup pong rdy
		PongModel model = new PongModel();
	    PongView  view  = new PongView();
	                      new PongController( model, view );

	    model.addObserver( view );       // Add observer to the model
	    
	    String pos;
	    
	    model.makeActiveObject();        // Start play
	    //model.clientModel();
		
		MulticastSocket socket = new MulticastSocket(port);
		//socket.setReuseAddress(true);
		InetAddress address = InetAddress.getByName("230.0.0.1");
		//Join the UDP list port
		socket.joinGroup(address);
		
		DatagramPacket packet;
		view.setVisible(true);           // Display Screen
		
		System.out.println("Connected");
		//Id is sent here.
		
		while(true)
		{
			
			//Lets try to send some data to the server
			byte[] sendData = new byte[256];
			String data = "Hello";
			sendData = data.getBytes();
			DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, InetAddress.getByName("230.0.0.1"), port);
			socket.send(sendPacket);
			
			byte[] buf = new byte[256];
			packet = new DatagramPacket(buf, buf.length);
			socket.receive(packet);
			//Sending data
			/*byte[] sendBuf = new byte[256];
    		String data = "up";
			sendBuf = data.getBytes();
			DatagramPacket sendPacket = new DatagramPacket(sendBuf, sendBuf.length, InetAddress.getByName("230.0.0.1"), port);
    		socket.send(sendPacket);*/
			
			String  received = new String(packet.getData(), 0, packet.getLength());
			//System.out.println("Server data: " + received);
			
			String[] posValues = received.split(":");

	    	model.getBall().setX(Double.parseDouble(posValues[0]));
	    	model.getBall().setY(Double.parseDouble(posValues[1]));
	    	model.getBats()[0].setX(Double.parseDouble(posValues[2]));
	    	model.getBats()[0].setY(Double.parseDouble(posValues[3]));
	    	model.getBats()[1].setX(Double.parseDouble(posValues[4]));
	    	model.getBats()[1].setY(Double.parseDouble(posValues[5]));
	    	
	    	//Check for keyboard input
	    	
	    	if(PongController.moveUp == true && PongController.moveDown == false)
	    	{
	    		System.out.println("Up");
	    		PongController.moveUp = false;
	    	}
	    	else if(PongController.moveUp == false && PongController.moveDown == true)
	    	{
	    		System.out.println("Down");
	    		PongController.moveDown = false;
	    	}
	    	else
	    	{
	    		//serverOut.println("nothing");
	    	}
			
		}
	}

}

When I start my server, and then connect a client, the client will receive one package from the server then stop and throw this error in console

Exception in thread "main" java.lang.NumberFormatException: For input string: "Hello"
	at sun.misc.FloatingDecimal.readJavaFormatString(Unknown Source)
	at java.lang.Double.parseDouble(Unknown Source)
	at Pong.PongUDPClient.main(PongUDPClient.java:63)

Line 63 is me just trying to use the data from the server I receive.

If anyone could shine some light on this or help me out at all, it would be great :)

Canvas