code: public static <T> boolean isValidConfigInterface(Class<T> configClass)
      {
          checkNotNull(configClass);
          if (!configClass.isInterface()) {
              log.warn("Class {} is not a valid config interface; it is not an interface.", configClass.getName());
              return false;
          }
  
          if (Arrays.stream(configClass.getMethods()).noneMatch(m -> !m.isDefault())) {
              log.warn("Class {} is not a valid config interface; it has no non-default methods defined.", configClass.getName());
              return false;
          }
          return true;
      }
docs: Validates that a given config interface is valid. NOTE that this does not validate the methods, which needs
  to be done with separate calls to {@link #isValidConfigInterfaceMethod(java.lang.reflect.Method) }.
  
  @param <T>         the config interface class
  @param configClass a reference to the config interface class
  @return true if the config interface has passed validations