 Secondly, releasing resources during object destruction means that an object must have a "finalizer" (in deterministic memory management known as a "destructor") – the object cannot simply be deallocated – which significantly complicates and slows garbage collection.When multiple objects rely on a single resource, resource management can be complicated.A fundamental question is whether a "has a" relationship is one of "owning" another object (object composition), or "viewing" another object (object aggregation).