code: private void writeHeader(final String dtd) throws IOException {
      if (forHtml){
        wtr.write("<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
        return;
      }
      
      wtr.write("<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n");
  
      if (dtd == null) {
        return;
      }
  
      wtr.write("<!DOCTYPE properties SYSTEM \"");
      wtr.write(dtd);
      wtr.write("\">\n");
    }
docs: /* Write out the xml header