Object Death without a Reference

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Here is a simple one for you guys (well not so simple for me!):

If an class is instantiated in a method within another class but that method does not return a reference, does the object die? In other words, is the object submitted for garbage collection at the close of the loop?

I appreciate the help, as always.

Posted 24-May-11 7:19am

Isaiah83

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Abhinav S · Accepted Answer · 2011-05-24T07:22:00

Solution 1

It would not really be submitted to garbage collection right at this time.
It would be viable for garbage collection whenever the collector runs the next time.

Posted 24-May-11 7:22am

Abhinav S

Comments

Isaiah83 24-May-11 13:30pm

Let me further this question then for my understanding. What if another class (Foo), which is instantiated elsewhere holds a global (field) reference to this object I am referring to - the object that is viable for garbage collection? Would it still be up for termination? And thanks for the response.

Abhinav S 24-May-11 13:36pm

AFAIK, No it wont.

Sergey Alexandrovich Kryukov 24-May-11 13:55pm

This is correct, my 5. This is not so trivial but absolutely transparent to the developer.
I explained in more detail, please see.
--SA

Abhinav S 24-May-11 13:57pm

Thank you SA.

Isaiah83 24-May-11 14:07pm

So if in one class(Foo1) I instantiate an ArrayList (ArrayList myArray1 = new ArrayList();)
and in another class(Foo2) I maintain an ArrayList reference (ArrayList myArray1), The ArrayList object of Foo1 won't be eligible for GC, correct?

My big and final question here is: Should the reference that maintains the object of Foo1 should keep the same name (e.g. myArray1).

yesotaso 24-May-11 16:34pm

Checkout http://en.wikipedia.org/wiki/Variable_scope

Sergey Alexandrovich Kryukov · Accepted Answer · 2011-05-24T07:55:00

The idea of GC is this: not to allow the program to reference a destucted object, ever.

When all the object references accessible to the program are lost, this object is a subject to Garbage Collection. However, it does not happen immediately. It is "decided" by GC according to its own strategy. That's why the code cannot rely on the order of constructor calls. Even writing constructors should be quite rare.

The mechanism is more cunning that one may think. For example, the problem of "islands" is resolved. For example, object A references object B, object B references object C and object C references A. References are not lost, but if no code running in the given Application Domain can get reference to any of A, B or C, they are destructed and collected anyway.

—SA