Unexpected socket read timeout

Question

Hi everybody.
I am having problems with socket communication. I have a client application which connects to a server, sends a request over a socket and waits for a response. This procedure actually works unless the server doesn?t reply fast enough. I found out that the maximum time for the server to reply is exactly 4 minutes. The weird part is that I do not set any timeouts.
I was able to isolate the problem and it turned out that the unexpected 4 minute timeout only occurs if I use the socket?s shutdownOutput method prior to reading from the input stream.
Does anyone know of this problem and how one can solve it? Or is this a (known) bug in the JDK?
Regards,
Kai

Answer 1

This is a simple server that listens for a one-line message ("HI") which will receive no response, and will then close the connection.
// don't forget to import
import java.io.*;
import java.net.*;
public class Server {
ServerSocket server;
Socket socket;
BufferedReader in;
PrintWriter out;
public Server() {
try {
// Note: No timeouts or linger options were set on THIS machine.
server = new ServerSocket(110); // We will use port 110 for our example
socket = server.accept();
in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
out = new PrintWriter(socket.getOutputStream());
String request = in.readLine(); // this method blocks (unless Java 1.4 is used and the Non-blocking option is set)
System.out.println(request);
in.close();
out.close();
socket.close();
server.close();
} catch(Exception e) {
e.printStackTrace(); // show the error
// add this is you want this to run as a stand-alone application
public static void main(String[] args) {
new Server();
The server starts, listens for connections, prints the 'request' to the console, and then closes the connection and the server is shutdown. There will be no problems since I DO NOT USE socket.shutdownInput()
Use my model code here to by-pass the issue you are having.