How to find vCD inventory object through vCO REST java sdk?

For example, I'd like to a find a InventoryItem which is a reference of vCD catalog by the catalog's name.

Refer to vCO REST java SDK example, I use the session.getRestTemplate().getForObject(URI, InventoryItem.class), but I ran into an exception message "browseInventory()".

But I send rest request to the same URI via Firefox RESTclient, it is successful. So weird.

If the way I used to get InventoryItem is wrong please correct me. Or could you share some solution to me?

Another question is what is the best choice for vCO web service client, Java REST SDK or directly using HttpClient + XML?

Many thanks.

Redbrick