code: protected void startHtml(PrintWriter out) {
          logger.entering(out);
          try {
  
              Template t = ve.getTemplate("/templates/header.part.html");
              VelocityContext context = new VelocityContext();
              StringBuilder output = new StringBuilder();
              for (Entry<String, String> temp : ConfigSummaryData.getConfigSummary().entrySet()) {
                  Entry<String, String> formattedTemp = ReporterDateFormatter.formatReportDataForBrowsableReports(temp);
                  output.append(formattedTemp.getKey()).append(" : <b>").append(formattedTemp.getValue()).append("</b><br>");
              }
  
              context.put("configSummary", output.toString());
              StringWriter writer = new StringWriter();
              t.merge(context, writer);
              out.write(writer.toString());
  
          } catch (Exception e) {
              logger.log(Level.SEVERE, e.getMessage(), e);
          }
          logger.exiting();
  
      }
docs: Starts HTML stream