Error reading entity from input stream on null list - jackson

Question

I'm attempting to call a REST endpoint that returns JSON for a validated civic address. On a successful call, I get back something like this:
{
"success":true,
"results":[
{
"civicnumberid":123456,
"civic_address_as_string":"123 Main Street, My City, My Municipality, My County",
"esri_point":{
"x":12345.678,
"y":54321.012
}
}
],
"error":null
}
However if I send a request in a format that the service can't handle, I back back something like this:
{
"success":false,
"results":null,
"error":{
"code":123,
"message":"Invalid Civic Address. Valid Example: 123 Main St, My City...",
"details":[
"The civic address submitted to the service contained an alphabetic character where a number was expected."
]
}
}
Note the "results": null. While attempting to convert the response using JAX-RS 2.0 and Jackson 2.5.1:
ResponseObject response = client.target(url)
.path(REST_REQUEST_CONTEXT)
.queryParam("search_str", searchAddress)
.request(MediaType.APPLICATION_JSON)
.get(ResponseObject.class);
... it fails with "Error reading entity from input stream." Here's my current ObjectMapper setup:
defaultObjectMapper.configure(SerializationFeature.WRAP_ROOT_VALUE, true)
.configure(DeserializationFeature.UNWRAP_ROOT_VALUE, true)
.configure(DeserializationFeature.UNWRAP_SINGLE_VALUE_ARRAYS, true)
.configure(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true)
.configure(DeserializationFeature.ACCEPT_EMPTY_ARRAY_AS_NULL_OBJECT, true)
.configure(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT, true)
My ResponseObject is a JAXB object:
public class ResponseObject
implements Serializable
{
private final static long serialVersionUID = 1L;
protected Boolean success;
#XmlElement(nillable = true)
protected List<Result> results;
#XmlElement(nillable = true)
protected Error error;
Can "results": null be handled gracefully or should I work with the service provider to return an empty list?

Answer 1

I was wrong in assuming that the null results was the issue. The Error jaxb type was defined using the following schema type:
<xs:complexType name="Error">
<xs:sequence>
<xs:element minOccurs="0" name="code" type="xs:int" />
<xs:element minOccurs="0" name="message" nillable="true" type="xs:string" />
<xs:element minOccurs="0" name="details" nillable="true"
type="q1:ArrayOfstring" xmlns:q1="http://schemas.microsoft.com/2003/10/Serialization/Arrays" />
</xs:sequence>
</xs:complexType>
... which resulted in the following JAXB type:
public class Error {
protected Integer code;
#XmlElement(nillable = true)
protected String message;
#XmlElement(nillable = true)
protected ArrayOfstring details;
But when I changed the schema to this:
<xs:complexType name="Error">
<xs:sequence>
<xs:element minOccurs="0" name="code" type="xs:int" />
<xs:element minOccurs="0" name="message" nillable="true" type="xs:string" />
<!--
<xs:element minOccurs="0" name="details" nillable="true"
type="q1:ArrayOfstring" xmlns:q1="http://schemas.microsoft.com/2003/10/Serialization/Arrays" />
-->
<xs:element minOccurs="0" name="details" maxOccurs="unbounded" nillable="true" type="xs:string" />
</xs:sequence>
</xs:complexType>
... The following JAXB type works:
public class Error {
private final static long serialVersionUID = 1L;
protected Integer code;
#XmlElement(nillable = true)
protected String message;
#XmlElement(nillable = true)
protected List<String> details;