Java wouldn't change a variable
<p>So this is the code I'm working on. Its just a practice and it's something that's bugging me for a while.The problem is that I'm trying to apply the passed parameter(<em>UDPServer server</em>) in the second class to a global variable for the class(<em>myserv</em>) so I could use it in the run method. The thing is that it says that <em>server</em> is not NULL (which is OK it works) but <em>myserv</em> is NULL and it wouldnt change... Its probably some stupid mistake but I cant seem to find it.</p>

<pre><code>package Server;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.io.*;

public class UDPServer{
  JFrame frame;
  JPanel panel;
  JButton button1,button2;
  JTextArea area;
  JScrollPane pane;
  StartThread thread1;
  UDPServer u;

  public static void main(String[] args) {
  UDPServer u = new UDPServer();
  }
  public UDPServer(){
  frame = new JFrame("Text Server");
  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  frame.setUndecorated(true);
  frame.getRootPane()
  .setWindowDecorationStyle(JRootPane.PLAIN_DIALOG);
  panel = new JPanel();
  panel.setLayout(null);
  area = new JTextArea();
  area.setEditable(false);
  button1 = new JButton("Start");
  button1.setBounds(210, 10, 75, 40);
  button1.addActionListener(new ActionListener(){
  public void actionPerformed(ActionEvent ae){
  thread1 = new StartThread(u);
  }
  });
  panel.add(button1);
  button2 = new JButton("Stop");
  button2.setBounds(300, 10, 75, 40);
  button2.addActionListener(new ActionListener(){
  public void actionPerformed (ActionEvent ae){
  thread1.thread.interrupted();
  thread1.socket.close();
  area.append("Server is stopped\n");
  button1.setEnabled(true);
  button2.setEnabled(false);
  }
  });
  button2.setEnabled(false);
  panel.add(button2);
  pane = new JScrollPane(area);
  pane.setBounds(10, 60, 365, 250);
  panel.add(pane);
  frame.add(panel);
  frame.setSize(400, 400);
  frame.setVisible(true);
  }
}
</code></pre>

<p>That was the first class and thats the second one.</p>

<pre><code>package Server;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.UnknownHostException;

public class StartThread implements Runnable{

    DatagramSocket socket;
    private final UDPServer myserv;
    Thread thread;
    StartThread(UDPServer server){
        myserv = server;
        thread = new Thread(this);
        thread.start();
        myserv.button1.setEnabled(false);
        myserv.button2.setEnabled(true);
        }

    public void run(){
        try{
            byte[] buffer = new byte[1024];
            int port = 8080;
            try{
                socket = new DatagramSocket(port);
                while(true){
                    try{
                        myserv.area.append("Server is started\n");
                        //Receive request from client
                        DatagramPacket packet = 
                            new DatagramPacket(buffer, buffer.length );
                        socket.receive(packet);
                        InetAddress client = packet.getAddress();
                            int client_port = packet.getPort();
                            myserv.area.append(" Received "
                                    +new String(buffer)+" from "+client);

                    }
                    catch(UnknownHostException ue){}
                }
            }
            catch(java.net.BindException b){}
        }
        catch (IOException e){
            System.err.println(e);
        }
    }
}
</code></pre>
