First element in unwrapped XML array is ignored during deserialization to base class #567
Description
During Jackson migration, I discovered an issue that looks like a regression in 2.11.1. In this version, the first element in XML array is ignored when I deserialize to the base class.
@JsonSubTypes({ @JsonSubTypes.Type(value = Wrapper.class, name = "wrapper") }) @JsonIgnoreProperties(ignoreUnknown = true) @JsonInclude(JsonInclude.Include.NON_NULL) public class Base { } @JacksonXmlRootElement(localName = "wrapper") public class Wrapper extends Base { @JacksonXmlProperty(localName = "item") @JacksonXmlElementWrapper(useWrapping = false) private List<Item> items = new ArrayList<>(); public Wrapper(List<Item> items) { this.items = items; } public Wrapper() { } public List<Item> getItems() { return items; } public void setItems(List<Item> items) { this.items = items; } @Override public String toString() { return "Wrapper{" + "items=" + items + '}'; } } @JacksonXmlRootElement(localName = "item") @JsonInclude(JsonInclude.Include.NON_NULL) @JsonIgnoreProperties(ignoreUnknown = true) public class Item { private String id; public Item(String id) { this.id = id; } public Item() { } public String getId() { return id; } public void setId(String id) { this.id = id; } @Override public String toString() { return "Item{" + "id='" + id + '\'' + '}'; } } public class Main { public static void main(String[] args) throws JsonProcessingException { String xmlString = """ <?xml version="1.0" encoding="UTF-8"?> <wrapper type="wrapper"> <item><id>1</id></item> <item><id>2</id></item> <item><id>3</id></item> </wrapper> """; Base base = new XmlMapper().readValue(xmlString, Base.class); System.out.println(base); } } Output:
Version 2.11.0
Version 2.11.1+
Workarounds:
- Deserizalize to the concrete Wrapper class instead of Base:
new XmlMapper().readValue(xmlString, Wrapper.class); - Add following setter for the Wrapper class
@JsonSetter public void setItems(Item item) { this.items.add(item); } Unofortunately workarounds doesn't suit my needs as this is library code base that is used in many other projects :(
Link to the code in GitHub:
https://github.com/tetradon/jackson-xml-deserialization-issue