Problem in server program: HELP!!!!

Question

I just tried to introduce methods in my server program (TCPServer.java). the methods are
run_server() : for creating server socket object
[b[accept() [/b]: for Listening to a connection, made to the socket and accepting it.
getstreams() : initializing the streams
b]recieve_n_process() : receiving client input and processing it
send_response(): sending response back to client.
But now I am getting runtime exception
C:\Program Files\j2sdk_nb\j2sdk1.4.2\bin\abc>javac TCPServer.java
C:\Program Files\j2sdk_nb\j2sdk1.4.2\bin\abc>java TCPServer
Exception in thread "main" java.lang.NullPointerException
at TCPServer.accept(TCPServer.java:19)
at TCPServer.main(TCPServer.java:58)
C:\Program Files\j2sdk_nb\j2sdk1.4.2\bin\abc>
I know I might have made some silly mistake somewhere, please help me to detect it.
here is my code TCPServer.java
import java.io.*;
import java.net.*;
class TCPServer {
     private ServerSocket welcomeSocket;
     private Socket connectionSocket;
     private ObjectInputStream Client_input;
     private ObjectOutputStream  Client_output;
     private     String clientSentence;
     private String capitalizedSentence;
     private void run_server() throws Exception
      ServerSocket welcomeSocket = new ServerSocket(80);
     private void accept() throws Exception
     {connectionSocket = welcomeSocket.accept(); }
     private void getstreams() throws IOException
     Client_output = new ObjectOutputStream(connectionSocket.getOutputStream());
     Client_output.flush();
         Client_input =  new ObjectInputStream(connectionSocket.getInputStream());
     private void recieve_n_process() throws Exception
     clientSentence = (String ) Client_input.readObject();
     capitalizedSentence = clientSentence.toUpperCase() + '\n';
     private void send_response() throws IOException
     Client_output.writeObject(capitalizedSentence);
  public static void main(String argv[]) throws Exception
     TCPServer server = new TCPServer();
     try{
     server.run_server();
      while(true) {
          server.accept();
            server.getstreams() ;
          server.recieve_n_process();
          server.send_response();
     } catch(EOFException eofException) {}
       catch (IOException ioException) {}     
    }It was working fine before I introduced these methods. Earlier it was like this
import java.io.*;
import java.net.*;
class TCPServer {
  public static void main(String argv[]) throws Exception
      String clientSentence;
      String capitalizedSentence;
      ServerSocket welcomeSocket = new ServerSocket(80);
      while(true) {
                   Socket connectionSocket = welcomeSocket.accept();
           ObjectInputStream inFromClient =  new ObjectInputStream(connectionSocket.getInputStream());
           ObjectOutputStream  outToClient =
             new ObjectOutputStream(connectionSocket.getOutputStream());
           clientSentence = (String ) inFromClient.readObject();
           capitalizedSentence = clientSentence.toUpperCase() + '\n';
           outToClient.writeObject(capitalizedSentence);

Answer 1

hello every one,
i got it where is the problem. I had declared the object of ServerSocket class locally in run_server(). It had to be declared globally though.
private void run_server() throws Exception
     ServerSocket welcomeSocket = new ServerSocket(80);
this one works out
private void run_server() throws Exception
     welcomeSocket = new ServerSocket(80);
     }