code: protected BeanDesc getNestedBeanDesc(Field field, Class<?> beanType) {
          try {
              return BeanDescFactory.getBeanDesc(beanType);
          } catch (RuntimeException e) { // may be setAccessible(true) failure
              throwExecuteMethodFieldNestedBeanDescFailureException(field, beanType, e);
              return null; // unreachable
          }
      }
docs: ---------