My JSON payload used to be:

{ "a": "some-value" }

And I mapped it to:

class Item {

  @JsonProperty("a")
  public String value;

}

Now I want to deprecate property a and introduce a new property b in its place. For a grace period, both shall be accepted.

@JsonAlias seems to be the best way to achieve this:

class Item {

  @JsonProperty("b")
  @JsonAlias("a")
  public String value;

}

It works perfect when either a or b are present, and when both are present and b comes after a:

{ "b": "some-value" }

{ "a": "some-value" }

{ "a": "this-is-ignored", "b": "uses-this-value" }

However, the properties are processed in order and Jackson will choose whichever comes last, so if the deprecated property is at the end, it wins:

{ "b": "it-should-use-this-value", "a": "but-uses-this-one-instead" }

Is there a way I can configure Jackson to always prefer the main mapping and ignore the aliases if multiple are present?