code: public static @Nullable String get(@NotNull ServletRequest request, @NotNull String param) {
      return get(request, param, null);
    }
docs: Returns a request parameter.<br>
  In addition the method fixes problems with incorrect UTF-8 characters returned by the servlet engine.
  All character data is converted from ISO-8859-1 to UTF-8 if not '_charset_' parameter is provided.
  @param request Request.
  @param param Parameter name.
  @return Parameter value or null if it is not set.