Complex remote operations typically allow you to specify a callback function. The callback function is called after the operation has completed, either successfully or unsuccessfully. This allows you to postpone subsequent steps until a remote resource is in a defined state again.

Callback functions often receive an OperationResult argument. Such objects indicate in their success attribute whether the attempted operation was successful. In the case of errors, the attribute error points to a RemoteError object further detailing the problems. Individual operations may return richer result objects. For example, the previous section already mentioned the FlushResult, which also references the modified bean in the remoteBean property.