Server does not create ois ?

Question

Hi folks !
At first I wanted to send some Strings via the Client to the Server and print them onto the screen. On a specific String "antwort" I would like to send an Object k from the Server to the Client and prove on the Client the correctness of the object by reading the attribute set on the serverside before sending.
But somehow the server does not create the ObjectInputStreams and I don�t know why.
That�s the code:
// Server:
public class Server {
public Server() {
try{
String input = new String();
ServerSocket sock = new ServerSocket(16348);
Socket socket = sock.accept();
System.out.println("socket"); // this line is printed on connection
ObjectInputStream sockin = new ObjectInputStream(socket.getInputStream());
System.out.println("objectinputstream"); // but this one never appears
ObjectOutputStream sockout = new ObjectOutputStream(socket.getOutputStream());
Kunde k = new Kunde();
k.setNummer(13);
while(!input.equals("Ende")){
input = sockin.readObject().toString();
if(input.equals("antwort")){
sockout.writeObject(k);
sockout.flush();
sockout.reset();
System.out.println(input);
socket.close();
catch(Exception e){
public static void main(String[] args) {
// TODO code application logic here
new Server();
// The Client
public class Client {
public Client() {
try{
Socket sock = new Socket("localhost",16348);
// System.out.println(sock.isOutputShutdown());
sock.setSoTimeout(5000);
System.out.println("socket hergestellt");
ObjectInputStream sockin = new ObjectInputStream(sock.getInputStream());
System.out.println("sockin");
ObjectOutputStream sockout = new ObjectOutputStream(sock.getOutputStream());
System.out.println("sockout");
String eing = "";
System.out.println("vor while");
while(!eing.equals("close")){
eing = erwarteEingabe();
System.out.println("Sende:"+eing);
if(eing.equals("antwort")){
sockout.writeObject(eing);
Kunde k = (Kunde)sockin.readObject();
System.out.println("Nummer des Kunden: "+k.getNr());
else{
sockout.writeObject(eing);
sockout.flush();
sockout.reset();
catch(Exception e){
System.out.println(e);
public static void main(String[] args) {
// TODO code application logic here
new Client();
private String erwarteEingabe(){
String eing = "";
System.out.println("nehme Eing entgegen");
try{
BufferedReader b = new BufferedReader(new InputStreamReader(System.in));
return b.readLine();
catch(Exception e){
System.out.println(e);
return "";
}

Answer 1

When you create an ObjectInputStream it tries to read the object stream header from the underlaying stream. In this case both your server and client are waiting for the other one to send the header before they can continue. This problem can be avoided by simply creating the object output streams first:ObjectOutputStream sockout = new ObjectOutputStream(socket.getOutputStream());
ObjectInputStream sockin = new ObjectInputStream(socket.getInputStream());