Simple client host program

Question

I have 3 classes:
- A server
- A client
- A program which start a new server and a new client in seperate threads.
I'm wondering why the client doesn't receive messages like "message", "hello", "knock knock".
I'm also wondering whether the threads correctly terminate and whether my code is safe.
import java.io.IOException;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
public class Server {
     public Server() throws IOException {
          ServerSocket server = new ServerSocket(4321);
          System.out.println("Server created");
          Socket client = server.accept();
          System.out.println("Server: connected to " + client);
          Scanner in =  new Scanner(client.getInputStream());
          PrintWriter out = new PrintWriter(client.getOutputStream());
          while(true) {
               System.out.println("sending messages");
               out.println("message");
               out.println("hello");
               out.println("knock knock");
               out.println("I love you");
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Scanner;
public class TestClient {
     public TestClient() throws IOException {
          Scanner stdIn = new Scanner(System.in);
          Socket socket = new Socket("127.0.0.1", 4321); //
          System.out.println("Client created");
          Scanner in = new Scanner(socket.getInputStream());
          PrintWriter out = new PrintWriter(socket.getOutputStream());
          System.out.println("ready for input:");
          while (true) {
               System.out.println("Enter exit to exit");
               String message = stdIn.next();
               if (message.equals("exit"))
                    break;
               System.out.println("Client receives: " + in.nextLine());
          out.close();
          in.close();
          socket.close();
          System.out.println("Client: is closed");
mport java.io.IOException;
public class Runner {
     public static void main(String[] args) throws IOException{
          (new Thread() {
               @Override
               public void run() {
                    try {
                         new Server();
                    } catch (IOException e) {
                         System.err.println(e);
          }).start();
          (new Thread() {
               @Override
               public void run() {
                    try {
                         new TestClient();;
                    } catch (IOException e) {
                         System.err.println(e);
          }).start();
          System.out.println("Runner is done.");
}It's current output says:
Runner is done.
Client created
java.net.SocketException: Unrecognized Windows Sockets error: 2: JVM_Bind
ready for input:
Exception in thread "Thread-1" java.util.NoSuchElementException
     at java.util.Scanner.throwFor(Unknown Source)
     at java.util.Scanner.next(Unknown Source)
     at TestClient.<init>(TestClient.java:21)
     at Runner$2.run(Runner.java:21)

Answer 1

Somelauw wrote:
tschodt wrote:
Somelauw wrote:
If you want to use a PrintWriter, at least check for errors.I would rather get an exception raised giving me some information then a boolean telling me that there is something wrong.So don't use a PrintWriter.What should I use instead? I do want high-level stuff like println.You could use
BufferedWriter
[write(String)|http://java.sun.com/javase/6/docs/api/java/io/Writer.html#write%28java.lang.String%29]
[newLine()|http://java.sun.com/javase/6/docs/api/java/io/BufferedWriter.html#newLine%28%29]
>>
I guess you think my client needs to rest for 99 milliseconds every cycle.I put that in after testing your code and noticing that the client telling me
"Enter exit to exit"
was scrolling up out of view by the server telling me
"sending messages".If I comment out that line my code works.When using the code I suggested in [reply #1|http://forums.sun.com/thread.jspa?messageID=10891212#10891212] it becomes evident that the server goes though umpteen iterations of sending messages to the client.
>>
With that delay the last text on the screen is the client prompt.
Should my server rest too?What do you think?I don't see a problem, but your question suggests I shouldn't.Was that an answer? If so, can you clarify
as it is not clear what you think.