Question

Please see code below:

s = new Socket(nextHopIP, 3434);

            fileIn = new FileInputStream(fileName);
            fileOut = s.getOutputStream();
            buffer = new byte[bufferSize];
            pw = new PrintWriter(s.getOutputStream());
            br = new BufferedReader(new InputStreamReader(s.getInputStream()));

            pw.println(fromIP);
            pw.println(toIP);
            pw.println(fileName.split("\\\\")[fileName.split("\\\\").length - 1]);
            pw.flush();

            //Send file
            fileTransferTime = System.currentTimeMillis();
            while((readFile = fileIn.read(buffer)) != -1) {
                fileOut.write(buffer, 0, readFile);
            }
            pw.println("");
            pw.flush();
            fileIn.close();
            fileOut.close();
            br.readLine(); //error here
            fileTransferTime = System.currentTimeMillis() - fileTransferTime;
            System.out.println("File transfer time: " + fileTransferTime);
            pw.close();
            br.close();
            s.close();

By the time it reaches br.readLine(), socket closed exception is raised. I’ve only closed the outputstream so far. Does closing the outputstream also closes the inputstream in this case?

Thanks!

Answer 1

From the API docs of java.net.Socket.getOutputStream

Closing the returned OutputStream will close the associated socket.

br is closed because it decorates the input stream associated with the socket. Strange, but true. It is possible to half-close a socket.

Also note that resource handling should be done as:

Resource resource = acquire();
try {
    Decorator decorated = decorate(resource);
    use(decorated);
    decorated.flush();
} finally {
    resource.release();
}

(Possibly using the Execute Around idiom.)