code: public static boolean hasElements(final JsonObject aJsonObject,
            final String... aElementIds) {
      for (final String elementId : aElementIds) {
        if (!aJsonObject.has(elementId) || aJsonObject.get(elementId).isJsonNull()) {
          return false;
        }
      }
  
      return true;
    }
docs: Checks if the {@link JsonObject} has all given elements and if no element
  is null.
  
  @param aJsonObject The object to check.
  @param aElementIds The elements which it should has.
  @return true when the object has all given elements and if no element is
  null.