I am using Morphia, the Pojo mapper for MongoDB, and I find difficult a task that in my view should be very simple: getting an object by id. I am able to find all the objects in a collection but I cannot figure out the simple task of querying using an id I got from the list. I am actually talking about the ObjectId. If I try to render it in JSON I see
Answer
This question seems incomplete.
It also seems like the answer to you question is on the Morphia QuickStart page. Seems to be as simple as follows.
Datastore ds = morphia.createDatastore("testDB");
String hotelId = ...; // the ID of the hotel we want to load
// and then map it to our Hotel object
Hotel hotel = ds.get(Hotel.class, hotelId);
So you'll definitely need more details.