Is Jackson really unable to deserialize json into a generic type?

I tried using the same approach but I haven't annotated my model class. It worked fine for me.

This is my model class

public class BasicMessage<T extends Serializable> implements Message<T> {
    private MessageHeader messageHeader = new MessageHeader();
    private T payload;
    public MessageHeader getHeaders() {
        return messageHeader;
    }

    public Object getHeader(String key) {
        return messageHeader.get(key);
    }

    public Object addHeader(String key, Object header) {
        return messageHeader.put(key, header);
    }

    public T getPayload() {
        return payload;
    }

    public void setPayload(T messageBody) {
        this.payload = messageBody;
    }
}

And I used the following method for deserializing the payload

public static <T extends Serializable> BasicMessage<T> getConcreteMessageType(String jsonString, Class<T> classType) {
        try {
            ObjectMapper mapper = new ObjectMapper();
            JavaType javaType = mapper.getTypeFactory().constructParametricType(BasicMessage.class, classType);
            return mapper.readValue(jsonString, javaType);
        } catch (IOException e) {

        }
 }

where jsonString contains the BasicMessageObject in a string.

If you programmatically pick up the java.lang.reflect.Type from for instance a method return type or a field, then it is easiest to use

Type type = obj.getClass().getDeclaredField( "aKnownFieldName" ).getGenericType(); 
// or
Type type = obj.getClass().getDeclaredMethod( "aKnownMethod" ).getGenericReturnType(); 


ObjectMapper mapper = new ObjectMapper();
JavaType javaType = mapper.getTypeFactory().constructType( type );
Object value = mapper.readValue( json, javaType );

A fully nested JavaType is created, so Controller<PID<Temperature,Double>>> will be deserialzed correctly.

You need to add some annotations on the constructor to tell Jackson how to build the object. The following worked for me:

public class AgentResponse<T> {

    private T result;

    @JsonCreator
    public AgentResponse(@JsonProperty("result") T result) {
        this.result = result;
    }
    public T getResult() {
        return result;
    }
}

Without the @JsonCreator annotation, Jackson cannot know to call this constructor. And without the @JsonProperty annotation, Jackson does not know that the first argument of the constructor maps to the result property.