Reading from socket inputstream returns -1

Question

I'm using a socket in order to connect to a chat server. The code is:
Socket socket;
InputStreamReader isr;
OutputStreamWriter osw;
try {
  socket = new Socket(sHost, iPort);
  isr = new InputStreamReader(socket.getInputStream());
  osw = new OutputStreamWriter(socket.getOutputStream());
  int iCharRead;
  char[] buffer = new char[512];
  while((iCharRead=isr.read(buffer, 0, 512))!=-1) {
      // do something
  System.err.println("Error: InputStream has returned -1.");
  System.err.println("\tsocket.isBound()=" + socket.isBound());
  System.err.println("\tsocket.isClosed()=" + socket.isClosed());
  System.err.println("\tsocket.isConnected()=" + socket.isConnected());
  System.err.println("\tsocket.isInputShutdown()=" + socket.isInputShutdown());
  System.err.println("\tsocket.isOutputShutdown()=" + socket.isOutputShutdown());
} catch (Exception e) {
  e.printStackTrace();
} finally {
  try {if (isr!=null) isr.close();} catch (Exception ex) {}
  try {if (osw!=null) osw.close();} catch (Exception ex) {}
  try {if (socket!=null) socket.close();} catch (Exception ex) {}
}Ther server is supposed to be sending data continuously but sometimes, after being connected successfully for a while, the read method returns -1. As you can see in the previous code then I'm checking out some socket information and I get:
Error: InputStream has returned -1.
     socket.isBound()=true
     socket.isClosed()=false
     socket.isConnected()=true
     socket.isInputShutdown()=false
     socket.isOutputShutdown()=falseThe socket seems to be bounded, it is not closed and isConnected also returns true. Besides, input and output streams are not closed. So, why does the read method return -1? What does it really mean? Is it a problem in the server side, that is overloaded or simply malfunctioning? What can I do in order to keep on reading data from the socket connection? Do I have to close the current socket and reconnect again to the server or is there any other way to recover from this situation?
Thanks.

Answer 1

isConnected means was ever connected.
Check whether isr is closed. If so, the server has disconnected/closed the connection.