A mechanism is provided for efficiently serializing complex objects. When a server application returns a complex object, the server application creates a string object. String objects are already defined as serializable. The string object may simply be a hash key in a hash table for the server application, which stores the complex object. Thus, the complex object does not have to be inefficiently serialized, because the string is returned rather than the complex object. The client may then use the complex object to call another server application without knowing the structure of the complex object.