Learning Java Program

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

class MulticastSender implements Runnable
{
    static int port;
    static MulticastSocket ms;
    static String group;
    static int status = 0 ;
    MulticastSender() throws Exception
    {
        port = 5000;
        group = "225.4.5.6";
        ms = new MulticastSocket(4000);
    }
    public void run()
    {
        while(true)
        {
            try
            {
                BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
                byte sbuf[] = new byte[2000];
                sbuf = br.readLine().getBytes();
                DatagramPacket spack = new DatagramPacket(sbuf, sbuf.length,
                                                 InetAddress.getByName(group), port);
                ms.send(spack);                                                
               
            }catch(Exception e){ System.out.println(e);}
        }
    }
    public static void main(String args[]) throws Exception
    {
        MulticastSender sender = new MulticastSender();
        Thread t = new Thread(sender);
               
        ms.joinGroup(InetAddress.getByName(group));
        t.start();
       
        int count =0;
        byte rbuf[] = new byte[1000];
        while(true)
        {
            DatagramPacket rpack =new DatagramPacket(rbuf,rbuf.length);
            ms.receive(rpack);
            String str = new String(rpack.getData(),0,rpack.getLength());
            if(str.equalsIgnoreCase("join"))
            {
                count++;
                System.out.println("Client joined the group");
                System.out.println("\ncurrently " + count + " client/clients is/are in the group");
               
            }
            else if(str.equalsIgnoreCase("leave"))
            {
                count--;
                System.out.println("Client left the group");
                System.out.println("\ncurrently " + count + " client/clients is/are in the group");
                if(count == 0)
                {
                    ms.leaveGroup(InetAddress.getByName(group));
                    ms.close();
                    break;
                }
            }
        }
    }
}

import java.io.*;
import java.net.*;
class MulticastReceiver implements Runnable
{
    static MulticastSocket ms;
    static int port;
    static int status = 0;
    MulticastReceiver() throws Exception
    {
        port = 5000;
        ms= new MulticastSocket(port);
    }
    public void run()
    {
        while(true)
        {
            try
            {
                byte rbuf[] = new byte[2000];
                DatagramPacket  rpack = new DatagramPacket(rbuf,rbuf.length);
                if (status == 1)
                {
                    ms.close();
                    break;
                }
                ms.receive(rpack);
                System.out.println(new String(rpack.getData(),0,rpack.getLength()));
            }catch(Exception e){System.out.println(e);}
        }
    }
   
    public static void main(String args[]) throws Exception
    {
        MulticastReceiver mr =new MulticastReceiver();
        Thread t = new Thread(mr);
       
        String group = "225.4.5.6";
      
        System.out.println("Do you wish to join the group?");
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        if(br.readLine().equalsIgnoreCase("yes"))
        {
            ms.joinGroup(InetAddress.getByName(group));
           
            byte sbuf[] = new byte[2000];
            sbuf = "join".getBytes();
            DatagramPacket spack = new DatagramPacket(sbuf, sbuf.length,InetAddress.getByName("localhost"),4000);
            ms.send(spack);
          
            System.out.println("Joined the group");
            t.start();
            while(true)
            {
                if(br.readLine().equalsIgnoreCase("leave"))
                {
                    status = 1;
                    byte sbuf2[] = new byte[2000];
                    sbuf2 = "leave".getBytes();
                    DatagramPacket spack2 = new DatagramPacket(sbuf2,sbuf2.length,InetAddress.getByName("localhost"),4000);
                    ms.send(spack2);
                    ms.leaveGroup(InetAddress.getByName(group));
                    break;
                }
            }
        }
    }
}

Do you wish to join the group?
yes
Joined the group
hi

Client joined the group

currently 1 client/clients is/are in the group
hi