I can't help feeling that you're barking up the wrong tree here. If  
you have references to some object then by definition it will not get  
garbage collected. Once there are no more references, then *poof* away  
it goes.

Why are you worrying about objects getting 'deleted'? The only thing  
you seem to have said that seems to offer us any useful info here is a  
mention of a graph of objects; and the same rule applies - as long as  
there are references it must continue to exist. Now you might be  
thinking that references within the graph will stop it getting GC'd  
but in fact there must be references that trace back to a set of root  
objects. If you, for example, made a global and had it be a reference  
to one object in a circular linked list then the list would stay  
alive. As soon as you set the global to point to some other object  
(outside the circle) then the circle would be dead, barring any  
contexts on your execution stack having a reference still alive. The  
fact that objects in the circle reference one another would not  
prevent the garbage collector doing its work.

More explanations of what is worrying you would probably help us to  
explain things to you.

tim
--
tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
The best packed information most resembles random noise.