URGENT!! - Bug on read (readLine) method?

Question

Hello to all, I have need of a large aid.
I need to know if There is the possibility that the method read() or readLine(), than I use for reading data from a socket from a PLC, has a Bug.
This why, with the socket opened and of the data in arrival from the PLC (than does not give to errors), the method read() raises the "Connection exception reset by peer."
The Technicians of the PLC say not to have errors but and I am surest of the correct operation of the server socket, also why it has been tested with telnet, hyperterminaly and others client without problems.
I do not know that what to say and what to try.
Thanks for every eventual aid.

Answer 1

I don't think there is a bug with BufferedReader. But instead of using buffered reader, you can try using the socket input stream directly for reading to see if it makes any difference:
try {
  // if the PLC is a client:
  ServerSocket serverSocket = new ServerSocket(...);
  Socket socket = serverSocket.accept();
  // or if the PLC is a server:
  Socket socket = new Socket(...);
  // and the rest of the code to test with
  InputStream in = socket.getInputStream();
  byte[] buffer = new byte[1024];
  int length;
  while ((length = in.read(buffer)) != -1) {
    System.out.println("Read "+length+" bytes");
  System.out.println("Connection closed");
} catch (Exception e) {
  e.printStackTrace();
}See if that little example works.
Is the PLC i client or server? Is the PLC the first to write something to your java program or do you have to write something to it first (maybe it doesn't understand what you write to it).
If you use reader/writer classes, there could be problems with the character encoding you use. If you don't specify any with InputStreamReader/OutputStreamWriter, then you will use the default platform encoding. I don't know which character encoding the PLC use, but if the characters are between 0 and 255, and you really want to use reader and writer classes, then use the ISO 8859-1 encoding.