code: public String radio (String name, String value, String defaultValue)
      {
          StringBuilder buf = new StringBuilder();
          buf.append("<input type=\"radio\"");
          buf.append(" name=\"").append(name).append("\"");
          buf.append(" value=\"").append(value).append("\"");
          String selectedValue = getValue(name, defaultValue);
          if (value.equals(selectedValue)) {
              buf.append(_useXHTML ? " checked=\"checked\"" : " checked");
          }
          buf.append(getCloseBrace());
          return buf.toString();
      }
docs: Creates a radio button with the specified name and value.