code: public String html(String htmlSource) {
          String cleanSource = htmlCleaner.cleanupPreFormatted(htmlSource);
          return "<div>" + StringEscapeUtils.unescapeHtml4(cleanSource) + "</div>";
      }
docs: Unescapes supplied HTML content so it can be rendered inside a wiki page.
  @param htmlSource HTML code to display (possibly surrounded by <pre></pre> tags).
  @return unescaped content, enclosed in <div></div> so wiki will not escape it.