public void close() throws IOException {
  unlock();
  _fileChannel=null;
  InputStream is=_is;
  _is=null;
  if (is != null)   is.close();
}

public void close ( ) throws IOException { unlock ( ) ; _fileChannel = null ; InputStream is = _is ; _is = null ; if ( is != null ) is . close ( ) ; }
closes the underlying stream .
