Socket OutputStream

Question

Hi,
I've been working on something with a friend of mine, which includes server-client communications, and I've encountered something that I can't understand. What's happening, is, well, I'll just show you an SSCCE and then make it simple under that.
SSCEE:
public class Main {
     private static Connection connection;
     private static Connection connectionTwo = new Connection("0.0.0.0", 5555);
     public static void main(String[] args) {
          connection = new Connection("0.0.0.0", 5555);
          System.out.println("connection: " + connection.getOutStream());
          System.out.println("connectionTwo: " + connectionTwo.getOutStream());
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.net.UnknownHostException;
public class Connection extends Thread {
     private Socket socket;
     private OutputStream outStream;
     private InputStream inStream;
     public Connection(String ip, int port) {
          try {
               socket = new Socket(ip, port);
               outStream = socket.getOutputStream();
               inStream = socket.getInputStream();
          } catch (UnknownHostException e) {
               e.printStackTrace();
          } catch (IOException e) {
               e.printStackTrace();
     public Socket getSocket() {
          return socket;
     public InputStream getInStream() {
          return inStream;
     public OutputStream getOutStream() {
          return outStream;
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import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = null;
        try {
            serverSocket = new ServerSocket(5555);
            System.out.println("Server listening on *:5555");
        } catch (IOException e) {
            System.err.println("Could not listen on port: 5555.");
            System.exit(1);
        Socket clientSocket = null;
        try {
            clientSocket = serverSocket.accept();
        } catch (IOException e) {
            System.err.println("Accept failed.");
            System.exit(1);
        PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
        BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        out.close();
        in.close();
        clientSocket.close();
        serverSocket.close();
}What happens, is, when setting connection via the main method, and then grabbing it below it, i receive 'null' as the variables value, yet if I set connectionTwo via the method declaration it will grab it fine and dandy.
I'm not using that same exact example, but it's relatively similar, and I'm using xSocket for networking, and as far as I know, SSCCE's don't call of included libraries. In my example if I set the connection variable via the declaration, all is well, yet if I set it inside of a method and then call it, it doesn't go too well.
I hope I explained this well enough, thanks for any help in advance.

Answer 1

The Connection refused exception that your example code throws means that there is not a server listening on the designated host/port combination.
The problem is that your server code sample does not contain a loop, so it will only accept the first client connection it sees. In this case, the static object connectionTwo is instantiated when the class is loaded - before the main method executes and attempts to create the object connection.
Typically I would expect to see some type of loop around serverSocket.accept( ) and then passing the client connection off to a separate worker thread to actually process the request.