If you don't want to have a setter in your bean and only use fields and getters, you can use the visibility checker of ObjectMapper
to allow field visibility.
Something like following:
ObjectMapper mapper = new ObjectMapper();
mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
mapper.setVisibility(VisibilityChecker.Std.defaultInstance().withFieldVisibility(JsonAutoDetect.Visibility.ANY));