Socket Based Server/Client Program Help Needed

Question

Alright,
I am making a Client/Server program.
The idea is that, when I run the 'Server' part, it sits and listens for a connection from the Client.
The Client writes a string to the socket, then the server, interprets the command.
This is what I have so far.
The Server:
public static void main(String[] args) {
         String clientLine = null;
          Socket channel = new Socket();
          try {
               mainWin window = new mainWin();
               window.open();
          } catch (Exception e) {
               e.printStackTrace();
         try{
               ServerSocket server = new ServerSocket(8313);
              BufferedReader reader = new BufferedReader(new InputStreamReader(channel.getInputStream()));
             channel = server.accept();
             clientLine = reader.readLine();
             doCommand(clientLine);
             reader.close();
             channel.close();
             server.close();
         catch(IOException ioe){
              System.out.println("I/O Exception occurred while using the server");
     }The Client:
public void sendCommand(String command){
          PrintStream socketWriter  = null;
          try{
                Socket client = new Socket("127.0.0.1", 8313);
                socketWriter = new PrintStream(client.getOutputStream());
                socketWriter.println(command);
                socketWriter.close();
                client.close();
          }catch(UnknownHostException uhe){
          }catch(IOException ioe){
     }When I press the command button, it lags for a second, then does nothing.
Does anyone see the problem?

Answer 1

public static void main(String[] args) {
         String clientLine = null;
          Socket channel = new Socket(); //<-- This is connecting to where? nowhere, so initiate it to null instead.
          try {
               mainWin window = new mainWin();
               window.open();
          } catch (Exception e) {
               e.printStackTrace();
         try{
               ServerSocket server = new ServerSocket(8313);
              BufferedReader reader = new BufferedReader(new InputStreamReader(channel.getInputStream())); //<-- Getting an input stream from nowhere?
             channel = server.accept(); //<-- Perhaps you want to do this before you try to get the input stream from it?
             clientLine = reader.readLine();
             doCommand(clientLine);
             reader.close();
             channel.close();
             server.close();
         catch(IOException ioe){
              System.out.println("I/O Exception occurred while using the server");
     }