BufferedReader readLine() blocks

Question

When receiving data using readLine(), even though I put a \"\\n\" at the end of the message using the .flush when sending the message, the while loop that reads my message s

Answer 1

It'd be better avoid using readline(). This method is dangerous for network communications because some servers don't return LF/CR symbols and your code will be stuck. When you read from a file it isn't critical because you will reach end of the file anyway and stream will be closed.

public String readResponse(InputStream inStreamFromServer, int timeout) throws Exception {
    BufferedReader reader = new BufferedReader(new InputStreamReader(inStreamFromServer, Charsets.UTF_8));
    char[] buffer = new char[8092];
    boolean timeoutNotExceeded;
    StringBuilder result = new StringBuilder();
    final long startTime = System.nanoTime();
    while ((timeoutNotExceeded = (TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startTime) < timeout))) {
        if (reader.ready()) {
            int charsRead = reader.read(buffer);
            if (charsRead == -1) {
                break;
            }
            result.append(buffer, 0, charsRead);
        } else {
            try {
                Thread.sleep(timeout / 200);
            } catch (InterruptedException ex) {
                LOG.error("InterruptedException ex=", ex);
            }
        }
    }
    if (!timeoutNotExceeded) throw new SocketTimeoutException("Command timeout limit was exceeded: " + timeout);

    return result.toString();
}

It has a timeout and you can interrupt communication if it take a lot of time