Can not deserialize empty content within tags when newline met

Have following 2 classes:<br>

@Data
@AllArgsConstructor
@NoArgsConstructor
@JsonIgnoreProperties(ignoreUnknown = true)
public class Structure {
    @JacksonXmlProperty
    private Info info;


@Data
@JsonIgnoreProperties(ignoreUnknown = true)
@NoArgsConstructor
@AllArgsConstructor
public class Info{
    private Subinfo subinfo;
}

doing deserialization like:

 private static final XmlMapper XML_MAPPER = new XmlMapper();
 Structure structure = XML_MAPPER.readValue(input, Structure.class);

where input is my XML(see below)

got exception:

com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `com.test.models.Info` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('

    ')

this Jackson feature did not help:

XML_MAPPER.enable(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT);

my XML that failed:

<?xml version='1.0' encoding='UTF-8' ?>
  <Structure>
    <Info>

    </Info>
  </Structure>

for this XML deserialization works OK:

<?xml version='1.0' encoding='UTF-8' ?>
  <Structure>
    <Info/>
  </Structure>

The problem is with tag closing approach:
<Info/> VS <Info></Info>

<Info/> works OK
while

<Info>

 </Info>

causes Exception when line terminators occurred

As others already mentioned in their comments, <code>DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT</code> converts only empty strings to null, but you have spaces and line separators within your Info element.

Others cannot reproduce your problem since you either missed to mention that you also use <code>XML_MAPPER.configure(MapperFeature.ACCEPT_CASE_INSENSITIVE_PROPERTIES, true)</code> in your code or Info in your example XML should actually be info, otherwise the element is ignored.

To handle empty strings and strings that only contain spaces and/or line separators you can add the following code before you parse the XML:

XML_MAPPER.addHandler(new DeserializationProblemHandler() {
    
    @Override
    public Object handleMissingInstantiator(DeserializationContext ctxt, Class<?> instClass,
            ValueInstantiator valueInsta, JsonParser p, String msg) throws IOException {
    
	  String value = p.getValueAsString();
	
	  // ignore "empty" Info elements
	  if (instClass.isAssignableFrom(Info.class) && (value.isEmpty() || value.matches("[\n\s]+"))) {
	    return null;
	  }
	  return super.handleMissingInstantiator(ctxt, instClass, valueInsta, p, msg);
    }
   
});

If you want to do this for all elements you can simply ignore <code>instClass</code>