Nested object de-serialization in JsonRepresentation not working

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Nested object de-serialization in JsonRepresentation not working

rameshsr
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I have an Order class and OrderDetail model as described below.  

class Order {
   long id;
   String description;
   Collection<OrderDetail> details;

   public Collection<OrderDetail> getDetails() {
         return details;
   }
  .... other methods
}

class OrderDetail {
    long id;
    String productId;
    String qty;

   ... methods here...
}

And I have a JSON string of one Order with nested collection of OrderDetail. And I am trying to de-serialize this json string into Order object and expecting that the Order object will now contain the OrderDetail collection also as expected. But it is not working as expected.

Here is the code snippet I have:

JacksonRepresentation<Order> jsonRepresentation = new JacksonRepresentation<Order>(representation, Order.class);
System.out.println(jsonRepresentation.getText()); // HERE IS THE CULPRIT
Order order = jsonRepresentation.getObject();  
Collection<OrderDetail> details = order.getDetails();

1) When I do jsonRepresentation.getObject(), it is throwing an exception.

 (java.io.EOFException) java.io.EOFException: No content to map to Object due to end of input

Why is that jsonRepresentation.getText(), causing the subsequent getObject to fail?

2) I have an extended Collection class called ForeignCollection, which is simply a subclass of Collection. In order to use ForeignCollection instead of Collection, what do I have to do in Restlet? I am getting the following error when I change Collection to ForeignCollection in the above two classes - Order and OrderDetail:

 (org.codehaus.jackson.map.JsonMappingException) org.codehaus.jackson.map.JsonMappingException: Can not find a deserializer for non-concrete Collection type [collection type; ForeignCollection, contains [simple type, class Order]

I am using Restlet 2.1.2.