public void mark(int readAheadLimit) throws IOException {
  if (stream != null) {
    stream.mark(readAheadLimit);
  }
 else {
    reader.mark(readAheadLimit);
  }
}

public void mark ( int readAheadLimit ) throws IOException { if ( stream != null ) { stream . mark ( readAheadLimit ) ; } else { reader . mark ( readAheadLimit ) ; } }
set the mark position .
