code: private void processMethods() {
      Method[] methods = listenerClass.getDeclaredMethods();
      for (Method method : methods) {
        for (CallbackType callbackType : CallbackType.values()) {
          if (method.isAnnotationPresent(callbackType.getAnnotationClass())) {
            validateMethod(method, callbackType);
            metadata.putListener(callbackType, method);
          }
        }
      }
    }
docs: Processes the methods in the listener class and updates the metadata for any valid methods
  found.