code: public synchronized void close() throws IOException {
          if (in == null)
              return;
          in.close();
          in = null;
          buf = null;
      }
docs: Closes this input stream and releases any system resources
  associated with the stream.
  Once the stream has been closed, further read(), unread(),
  available(), reset(), or skip() invocations will throw an IOException.
  Closing a previously closed stream has no effect.
  
  @exception  IOException  if an I/O error occurs.