code: public static Class<?>[] getDeclaredClasses(Class<?> clazz) {
          assertReflectionAccessor();
          try {
              return accessor.getDeclaredClasses(clazz);
          } catch (Exception e) {
              throw SneakyException.sneakyThrow(e);
          }
      }
docs: Get all inner classes and interfaces declared by the given class.
  
  @param clazz Class to reflect inner classes from.
  @return An {@code Array} of inner classes and interfaces declared by the given class.
  @throws RuntimeException If any error occurs.