code: public <T extends Object> T findById(Object id, Class<T> clazz) {
          Preconditions.checkNotNull(clazz, "Tryed to find an object by id, but given class is null");
          Preconditions.checkNotNull(id, "Tryed to find an object by id, but given id is null");
  
          return this.datastore.get(clazz, (id instanceof ObjectId) ? id : new ObjectId(String.valueOf(id)));
      }
docs: Retrieves a mapped Morphia object from MongoDB. If the id is not of
  type ObjectId, it will be converted to ObjectId
  
  @param id The id of the object
  @param clazz The mapped Morphia class
  @param <T> JavaDoc requires this - please ignore
  
  @return The requested class from MongoDB or null if none found