GC

[Srinivas Katta]

Hi,

I have executed the below program for K&B Book Chapter 3 and attached the Diagram of my understanding

class Beta { }
 class Alpha {
 static Beta b1;
 Beta b2;
 }
 public class Tester {
 public static void main(String[] args) {
 Beta b1 = new Beta(); Beta b2 = new Beta();
 Alpha a1 = new Alpha(); Alpha a2 = new Alpha();
 a1.b1 = b1;
 a1.b2 = b1;
 a2.b2 = b2;
 a1 = null; b1 = null; b2 = null;
// do stuff
}
}

Could you Please explain how many objects will be eligible for garbage collection when line marked as //dostuff is reached?

Thanks
Srinivas

[Ankit Garg]

This question has been discussed a lot of times before (search for "alpha beta"). See these threads

https://coderanch.com/t/481398/Programmer-Certification-SCJP/certification/many-eligible-gc
https://coderanch.com/t/474980/Programmer-Certification-SCJP/certification/Garbage-Collection-Clarification
https://coderanch.com/t/469606/Programmer-Certification-SCJP/certification/Garbage-Collection

[Harshit Sethi]

Only one object is eligible and that is object that was referred by a1 before it was set to null.

[Harshit Sethi]

This is the proper diagram,i used paint so its not that tidy,but still you can get what you want from this diagram.

link to image

[Harshit Sethi]

Someone tell me how to upload image here?

[Mahmoud Hossam]

Harshit Sethi wrote:Someone tell me how to upload image here?

click on "attachments" button below the text pane,then select the file(s) you want to upload

The files cannot be larger than 1024KB,and you can't upload more than 3 files per post

[Harshit Sethi]

Here it is finally....