Update using PoJo setters result in a "NullPointerException"

Hi
the todo tutorial show an "updateTodo" sample with the following comment:

// You can update the document as a JSON document directly.
// For more complex operations - you could de-serialize the document in
// to a POJO, update the POJO, and then re-serialize the POJO back in to
// a document.

I want to update my pojo using the java object (not the documentdb "Document" setters)
When I do that,

    Document myDoc = getDocumentById(myId);
    // De-serialize the document in to a TodoItem.
    MyObject my = gson.fromJson(myDoc .toString(), MyObject.class);
    LOG.debug("update object {}", my);
    my.setName("IWantToUsePojoPlease");
    Document updDocument = new Document(gson.toJson(my));
    updDocument.setResourceId(myDoc.getResourceId());
    updDocument.setId(myDoc.getId());
    updDocument.set("entityType", ENTITY_TYPE);
    try {
        // Persist/replace the updated document.
        updDocument = getDC().replaceDocument(updDocument, null).getResource();

I got the following error:

java.lang.NullPointerException
at com.microsoft.azure.documentdb.DocumentClient.trimBeginingAndEndingSlashes(DocumentClient.java:2160)
at com.microsoft.azure.documentdb.DocumentClient.joinPath(DocumentClient.java:2148)
at com.microsoft.azure.documentdb.DocumentClient.replaceDocument(DocumentClient.java:503)

I think this is a bug. Maybe the new Document instance loose the "_self"(SELF_LINK) reference and that's why the replace doesn't work. How could we keep this link ? Is it possible to fix this issue and add a second update sample using PoJo ?

If possible, I would like to avoid an update that will use Document.set(FIELD,VALUE) method but use PoJo (business) setters.

Regards

Comece com DocumentClient.replaceDocument e as localizações do stack trace DocumentClient.java:2148 e :2160; em seguida, compare o Document original com o novo Document criado a partir do POJO. Verifique o exemplo updateTodo do tutorial de todo e determine como a substituição baseada em POJO deve preservar a referência de documento necessária. Está concluído quando a atualização não gerar mais a NullPointerException relatada e o exemplo explicar o workflow compatível.