public void close() throws IOException {
  flush();
  if (os != null && os != System.out && os != System.err)   os.close();
  buffer=null;
}

public void close ( ) throws IOException { flush ( ) ; if ( os != null && os != System . out && os != System . err ) os . close ( ) ; buffer = null ; }
closes the bit stream . all resources associated to the stream are released .
