code: public static PTBTokenizer<CoreLabel> newPTBTokenizer(Reader r, boolean tokenizeNLs, boolean invertible) {
      return new PTBTokenizer<CoreLabel>(r, tokenizeNLs, invertible, false, new CoreLabelTokenFactory());
    }
docs: Constructs a new PTBTokenizer that makes CoreLabel tokens.
  It optionally returns carriage returns
  as their own token. CRs come back as Words whose text is
  the value of <code>PTBLexer.NEWLINE_TOKEN</code>.
  
  @param r The Reader to read tokens from
  @param tokenizeNLs Whether to return newlines as separate tokens
  (otherwise they normally disappear as whitespace)
  @param invertible if set to true, then will produce CoreLabels which
  will have fields for the string before and after, and the
  character offsets
  @return A PTBTokenizer which returns CoreLabel objects