Problem from a networking newbie

[Sven Thor]

I have problems when I try to run this simple textbook-like example.
The server starts ok. Writing data from the client to the server is ok. The server receives string and is supposed to write a string back to the stream connected to the client. However, the client hangs when it tries to read the result from the stream. I do not see why ?

I would think this would work without multithreading the server or using callbacks.

br,
Sven

//THE SERVER
import java.io.*;
import java.net.*;
 
public class CalcServer{
 
public static void main(String[] arg){
try{
ServerSocket server  = new ServerSocket(1313);
Socket connection = null;
while(true){
try{
System.out.println("Server is listening...");
connection = server.accept();
System.out.println("Client connected...");
 
//Read input
InputStream in = connection.getInputStream();
StringBuffer sb = new StringBuffer();
int c = 0;
while((c=in.read()) != -1)
sb.append((char)c);
System.out.println("Received from client: " + sb.toString());
 
//Write output
Writer out = new OutputStreamWriter(connection.getOutputStream());
out.write("String to client");
out.flush();
}
catch(IOException ex){}
finally{
try{
if(connection != null) connection.close();
}catch(IOException ex){}
}
}
}
catch(IOException ex){
ex.printStackTrace();
}
}
}
 
//THE CLIENT
import java.io.*;
import java.net.*;
 
class CalcClient{
 
public static void main(String[] arg){
Socket connection = null;
System.out.println("Enter q to quit");
while(true){
String input = "";
 
try{
BufferedReader inUser = new BufferedReader(
new InputStreamReader(System.in));
System.out.println("---------------");
System.out.print("Enter string; ");
input = inUser.readLine();
if (input.equals("q")) break;
 
connection = new Socket("localhost", 1313);
 
//Write output
Writer out = new OutputStreamWriter(
new BufferedOutputStream(connection.getOutputStream()));
out.write(input);
out.flush();
 
//Read input
InputStream in = connection.getInputStream();
StringBuffer sb2 = new StringBuffer();
int c = 0;
while((c=in.read()) != -1)
sb2.append((char)c);
System.out.println(sb2.toString());
}
catch(IOException  ex){
ex.printStackTrace();
}
finally{
try{
if(connection != null) connection.close();
}catch(IOException ex){}
}
}
}
}
 
  

[Joe Ess]

You are reading until the end-of-stream:

  
while((c=in.read()) != -1)

But you aren't terminating the output stream on the client or the server. You can do that by invoking close() on the output stream or shutdownOutput() on the socket.