code: public void setLineSeparator(String newline) {
  
      if (!LINE_SEPARATOR_CRLF.equals(newline) && !LINE_SEPARATOR_LF.equals(newline) && !LINE_SEPARATOR_LFCR.equals(newline)
          && !LINE_SEPARATOR_CR.equals(newline)) {
        throw new IllegalArgumentException(newline);
      }
      this.lineSeparator = newline;
    }
docs: This method sets the {@link #getLineSeparator() line-separator}.
  
  @param newline is the new line-separator.