This TypeReference<T> implements Comparable<TypeReference<T>> is part of jackon library. And this is part of com.fasterxml.jackson.core.type. From the API documentation:

This generic abstract class is used for obtaining full generics type information by sub-classing; it must be converted to ResolvedType implementation (implemented by JavaType from "databind" bundle) to be used. Class is based on ideas from http://gafter.blogspot.com/2006/12/super-type-tokens.html, Additional idea (from a suggestion made in comments of the article) is to require bogus implementation of Comparable (any such generic interface would do, as long as it forces a method with generic type to be implemented). to ensure that a Type argument is indeed given. Usage is by sub-classing: here is one way to instantiate reference to generic type List:

TypeReference ref = new TypeReference<List>() { }; which can be passed to methods that accept TypeReference, or resolved using TypeFactory to obtain ResolvedType.

This is basically used to de-serialize the Generic type of JSON objects, for example the JAVA Collection objects as below:

public List<Double> getDoubleList() {

  return getObjectFromJson(new TypeReference<List<Double>>() {
  });
}


public <T> T getObjectFromJson(String jsonString, final TypeReference<T> typeReference) {
  try {
    return new ObjectMapper().readValue(jsonString, typeReference);
  } catch (JsonProcessingException e) {
    // TODO
  }
}

'JavaType' works !! I was trying to unmarshall (deserialize) a List in json String to ArrayList java Objects and was struggling to find a solution since days.
Below is the code that finally gave me solution. Code:

JsonMarshallerUnmarshaller<T> {
    T targetClass;

    public ArrayList<T> unmarshal(String jsonString) {
        ObjectMapper mapper = new ObjectMapper();

        AnnotationIntrospector introspector = new JacksonAnnotationIntrospector();
        mapper.getDeserializationConfig()
            .withAnnotationIntrospector(introspector);

        mapper.getSerializationConfig()
            .withAnnotationIntrospector(introspector);
        JavaType type = mapper.getTypeFactory().
            constructCollectionType(
                ArrayList.class, 
                targetclass.getClass());

        try {
            Class c1 = this.targetclass.getClass();
            Class c2 = this.targetclass1.getClass();
            ArrayList<T> temp = (ArrayList<T>) 
                mapper.readValue(jsonString,  type);
            return temp ;
        } catch (JsonParseException e) {
            e.printStackTrace();
        } catch (JsonMappingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return null ;
    }  
}