garbage collection

[Puja Sinha]

Hi,

Please refer to the following code and let me know how may objects are created and how many objects are eligible for garbage collection:

class Dozens {
 int[] dz = {1,2,3,4,5,6,7,8,9,10,11,12};
 }
 public class Eggs {
 public static void main(String[] args) {
 Dozens [] da = new Dozens[3];
 da[0] = new Dozens();
 Dozens d = new Dozens();
 da[1] = d;
 d = null;
 da[1] = null;
 // do stuff
 }
 }

Which two are true about the objects created within main(), and eligible for garbage collection
when line 12 is reached?

Regards,
Puja

[Pranav Raulkar]

Hi Puja, I think it goes like this

Line 6 creates 3 objects as "new" keyword is used. (Total objects = 3, available for GC = 0)
Line 7 creates a new object (again "new" keyword used), but since assigned to d[0], object previously held by d[0] is now "available" for GC (Total objects = 3, available for GC = 1)
Line 8 creates a new object (Total objects = 4)
Line 9 assigns object created at line 8 to d[1], so again previous object at d[1] is available for GC (Total objects = 3, available for GC = 2)
Line 10 d is assigned null, so its available for GC too (Total objects = 2, available for GC = 3)
Line 11 d[1] = d but d is already null (Total objects = 2, available for GC = 3)

Whats say you?

[Faraz Kadri]

This question has been asked and discussed many times. Please see this link for one such discussion.

[Puja Sinha]

Thanks Faraz! That was a good thread. I got the answer

[Mohamed Sanaulla]

Just a general tip- lot of times the SCJP related doubts would have been raised and solved before. You might get faster results when you will SearchFirst