Jackson strips leading underscore - jackson

Question

Our swagger specification defines a property _links.
places-result:
type: object
properties:
_links:
$ref: "#/components/schemas/links-underscore-type"
Using swagger-codegen, we see this name end up in the output class:
#JsonProperty("_links")
private LinksUnderscoreType _links = null;
#Schema(
description = ""
)
#Valid
public LinksUnderscoreType getLinks() {
return this._links;
}
However, Jackson adds a property with and without the leading underscore:
{
"result": {
"links": {
"self": "http://localhost:8083/places?page=181",
"previous": "http://localhost:8083/places?page=180",
"first": "http://localhost:8083/places?page=0"
},
"_links": {
"self": "http://localhost:8083/places?page=181",
"previous": "http://localhost:8083/places?page=180",
"first": "http://localhost:8083/places?page=0"
}
}
As it is a Spring Boot application, we should be able to influence the naming strategy using this property:
spring.jackson.property-naming-strategy: LOWER_CASE
None of the accepted values seems to preserve the specified property name.
How can we preserve the leading underscore?

Answer 1

It turns out the non-underscore property came in because it was matched by the getter method. The solution is to not match the getter methods. This can be achieved in the Spring Boot config:
spring:
jackson:
mapper:
AUTO_DETECT_GETTERS: false
Or in code:
objectMapper.configure(MapperFeature.AUTO_DETECT_GETTERS, false);