[BUG][JAVA] Deserialization of array with uniqueItems=true doesn't preserve order

After https://github.com/OpenAPITools/openapi-generator/issues/5254 was fixed and merged, when using Jackson, arrays with uniqueItems=true gets deserialized to HashSet rather than LinkedHashSet, thus not preserving order as expected.

Even though the field (myProp) is initialized to an empty LinkedHashSet, it is promptly overwritten with a regular HashSet given that there is no deserialization-hint (@JsonDeserialize(as = LinkedHashSet.class)) on the setMyProp-method. The method invoked looks like this:

  @JsonProperty(JSON_PROPERTY_MY_PROP)
  @JsonInclude(value = JsonInclude.Include.ALWAYS)
  public void setMyProp(Set<SomeEnum> myProp) {
    this.myProp = myProp;
  }

and thus there is no way for Jackson to understand that order needs to be preserved.

This issue is present in version 5.2.1

Start at the generated Java model's setMyProp method, which currently accepts a Set and replaces the initialized LinkedHashSet during Jackson deserialization. Trace how uniqueItems=true produces this setter and verify the generated model's deserialized collection preserves input order; the issue provides no specific file or test path.