code: protected void init() {
          FormModel model = createFormModel();
          if(getId() == null)
              formId = model.getId();
          if (model instanceof ValidatingFormModel) {
              ValidatingFormModel validatingFormModel = (ValidatingFormModel) model;
              setFormModel(validatingFormModel);
          } else {
              throw new IllegalArgumentException("Unsupported form model implementation " + formModel);
          }
          getApplicationConfig().applicationObjectConfigurer().configure(this, getId());
  	}
docs: Hook called when constructing the Form.