Garbage Collection Question from Devaka's Exam Labs for SCJP6 - diagnostic exam question number 70.

[Anbarasu Aladiyan]

Question: How many objects are eligible for garbage collection after executing statement “c.aob=null”

class A{
     A aob;
     public static void main(String args[]){
          A a=new A();
          A b=new A();
          A c=new A();
          a.aob=b;
          b.aob=a;
          c.aob=a.aob;
          A d=new A().aob=new A();
          c=b;
          c.aob=null;
          System.gc();
     }
}

I thought only one object is eligible for garbage collections ( ie created at line 6).
But the correct answer is two objects are eligible for garbage collection. But how?

[Ankit Garg]

This question has been asked in the past like here and here. Checkout the explanation in those topics...

[Anbarasu Aladiyan]

Thanks Ankit

[Devaka Cooray]

anbarasu aladiyan wrote:Question from Devika's Exam Labs

Who is that?

[Ankit Garg]

Oh my god Devaka, you had a sex change operation??

[Anbarasu Aladiyan]

Do not worry Devaka (I think i am correct at this time...) i changed it. And Ankit

[Devaka Cooray]

anbarasu aladiyan wrote:And Ankit

Cool down anbarasu, Ankit was joking here as usual .
And, having such a sex change operation is a violation of the JavaRanch naming policy

[Ankit Garg]

anbarasu aladiyan wrote:And Ankit

, that was just a joke mate, don't get pissed

[Anbarasu Aladiyan]

@Ankit Garg ,
@Devaka Cooray
i was just kidding.

[Shailesh Phatak]