Question

I have a package which just includes and xsd file to generate (via JAXB) shared classes which are relevant for our server and client applications. So these classes contain XML annotations.

One client is an Android App. I also want to use these classes here for JSON deserialization because I communicate with a REST service which delivers JSON (with Jersey/Jackson).

I try to use Jackson (version 1.7.2) on the Android like this:

ObjectMapper mapper = new ObjectMapper();
mapper = mapper.configure(DeserializationConfig.Feature.USE_ANNOTATIONS,
                false);
mapper = mapper.configure(SerializationConfig.Feature.USE_ANNOTATIONS,
                false);
FooBar someObject = (FooBar) mapper.readValue(jsonString, FooBar.class);

I though configure the MAPPER should avoid using annotations but I still get

02-07 09:30:18.631: ERROR/AndroidRuntime(447): java.lang.NoClassDefFoundError: javax.xml.bind.annotation.XmlAccessorType
02-07 09:30:18.631: ERROR/AndroidRuntime(447):     at java.lang.Class.getDeclaredAnnotations(Native Method)
02-07 09:30:18.631: ERROR/AndroidRuntime(447):     at org.codehaus.jackson.map.introspect.AnnotatedClass.resolveClassAnnotations(AnnotatedClass.java:292)
02-07 09:30:18.631: ERROR/AndroidRuntime(447):     at org.codehaus.jackson.map.introspect.AnnotatedClass.construct(AnnotatedClass.java:139)

Who knows the trick to stop Jackson from resolving annotations.

Thanks
Klaus

Answer 1

My current investigations lead to these results:

The usage of the DeserializationConfig.Feature.USE_ANNOTATIONS property (set to false) will cause the JACKSON DeserializerConfig class to use a NopAnnotationIntrospector. Annotations of a class will then be resolved using this NopAnnotationIntrospector. The NopAnnotationIntrospector will return false on each isHandled request for any annotation on a class – and in fact will not use this annotation in further processing.

So – the system still “inspects” the annotations – which have to be on the Classpath in this case. As Android does not provide any jaxb-api annotations this leads to the NoClassDefFoundError.

I expected USE_ANNOTATIONS = false would bring JACKSON to totally ignore any annotations – but unfortunately it does not. I will now use the Jackson Streaming API to parse the JSON string instead of using JACKSON Data Binding capabilities.