Sockets: Why a Connection reset exception on Windows but not on Linux
when a client disconnects from a server
I'm curious why I get a Connection reset exception when I run this
code on Windows but not on Linux.
It's a client and a server communicating through a socket. The
exception occurs on the server when the client terminates suddenly.
It's ordinary client-server code, but I'll include it for
illustration.
It make sense that the exception occurs - the server is waiting for
the client to send a command, but the client suddenly terminates.
What's odd is that the exception occurs on Windows but not on Linux.
Here are the results on the server side, when run on Windows Vista:
Accepting clients now
Client acquired on port #7777, reading from socket
Hi
java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source)
at sun.nio.cs.StreamDecoder.readBytes(Unknown Source)
at sun.nio.cs.StreamDecoder.implRead(Unknown Source)
at sun.nio.cs.StreamDecoder.read(Unknown Source)
at java.io.InputStreamReader.read(Unknown Source)
at java.io.BufferedReader.fill(Unknown Source)
at java.io.BufferedReader.readLine(Unknown Source)
at java.io.BufferedReader.readLine(Unknown Source)
at Server.serviceClient(Server.java:31)
at Server.main(Server.java:51)
Here are the results when run on Linux:
Accepting clients now
Client acquired on port #7777, reading from socket
Hi
Client serviced
Here's the code for the Server and the Client.
Server.java:
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
public class Server {
private ServerSocket serverSocket;
private BufferedReader bufferedReader;
public Server(int port) throws java.io.IOException {
serverSocket = new ServerSocket(port);
}
/**
* serviceClient accepts a client connection and reads lines from
the socket.
* Each line is handed to executeCommand for parsing and
execution.
*/
public void serviceClient() throws java.io.IOException {
System.out.println("Accepting clients now");
Socket clientConnection = serverSocket.accept();
// Arrange to read input from the Socket
InputStream inputStream = clientConnection.getInputStream();
bufferedReader = new BufferedReader(new InputStreamReader
(inputStream));
// Arrange to write result across Socket back to client
OutputStream outputStream = clientConnection.getOutputStream
();
PrintStream printStream = new PrintStream(outputStream);
System.out.println("Client acquired on port #" +
serverSocket.getLocalPort() + ", reading from socket");
String commandLine;
while ((commandLine = bufferedReader.readLine()) != null) {
try {
System.out.println(commandLine);
} catch (Exception ex) {
System.out.println("ERROR: " + ex);
}
}
}
public static void main(String argv[]) {
int port = 1099;
if (argv.length > 0) {
try {
port = Integer.parseInt(argv[0]);
} catch (Exception e) {
}
}
try {
Server server = new Server(port);
server.serviceClient();
System.out.println("Client serviced");
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
Client.java:
public class Client {
public static void main(String[] args) {
try {
// parse command line arguments
String host = args[0];
int port = Integer.parseInt(args[1]);
SocketWriter sw = new SocketWriter(host, port);
sw.sayHi();
} catch (Exception ae) {
System.out.println("An exception occurred");
ae.printStackTrace();
}
}
}
SocketWriter.java:
import java.io.*;
import java.net.Socket;
class SocketWriter {
private Socket socket;
private PrintStream printStream;
private BufferedReader inputReader;
SocketWriter(String host, int port) throws java.io.IOException {
socket = new Socket(host, port);
OutputStream outputStream = socket.getOutputStream();
printStream = new PrintStream(outputStream);
InputStream inputStream = socket.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader
(inputStream);
inputReader = new BufferedReader(inputStreamReader);
}
void sayHi() {
printStream.println("Hi");
}
}
---
Paul