About Question enthuware.ocajp.i.v7.2.919 :

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shambhavi
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Re: About Question enthuware.ocajp.i.v7.2.919 :

Post by shambhavi »

public int getObject(Object a) //0
{
Object b = new Object(); //XXX
Object c, d = new Object(); //1
c = b; //2
b = a = null; //3
return 0; //4
} // 5

in this code, when is XXX eligible for garbage collection ? after line 5 ?
can you also tell me , once control is abruptly returned back after line 4 back to the caller, when actually is the scope of this method over ?

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Re: About Question enthuware.ocajp.i.v7.2.919 :

Post by admin »

Scope of a method is always from opening bracket to closing bracket.
Object will be eligible to be GCed after line //4 itself. The difference between //4 and //5 is not important for the purpose of the exam.
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shambhavi
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Re: About Question enthuware.ocajp.i.v7.2.919 :

Post by shambhavi »

after line 4 anyways the control is transferred back to the caller, which means that we are out of the scope of the method after line 4 ,

and hence we say as long as we are in/within the method , the object is never eligible for GC .
Am I right ? :)

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Re: About Question enthuware.ocajp.i.v7.2.919 :

Post by admin »

That is correct.
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shambhavi
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Re: About Question enthuware.ocajp.i.v7.2.919 :

Post by shambhavi »

thank you !

and one more clarification .
if instead of return c, if we had return (c=null);

then on this line itself the object would become eligible for garbage collection right ? i.e. after the expression (c=null ) is evaluated . since before the full statement return (c=null); is complete, when (c=null ) is evaluated itself its eligible for GC.

Am I right ?

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Re: About Question enthuware.ocajp.i.v7.2.919 :

Post by admin »

yes, right.
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shambhavi
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Re: About Question enthuware.ocajp.i.v7.2.919 :

Post by shambhavi »

thanks ! :joy:

Sergey
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Re: About Question enthuware.ocajp.i.v7.2.919 :

Post by Sergey »

Once a method returns all the variables that it created are gone. The stack space (where all the automatic variables are kept) is cleared up and reclaimed. So there is no question of a variable hanging on to an object after the method returns.
based on this explanation (from another question 7.2.921) i should think that object can be garbage collected after "return" statement i.e. after line 4.
Where am i wrong?

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Re: About Question enthuware.ocajp.i.v7.2.919 :

Post by admin »

The variables of this method are indeed gone after the method returns. But in this case the return statement returns the reference to the object to the caller.
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Re: About Question enthuware.ocajp.i.v7.2.919 :

Post by flex567 »

Why is answer nr. 5 not a correct option?

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Re: About Question enthuware.ocajp.i.v7.2.919 :

Post by admin »

Because it can be determined the object can never be garbage collected in this method. Option 4 and 5 are contradictory. So, if 4 is correct, 5 cannot be correct.
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Re: About Question enthuware.ocajp.i.v7.2.919 :

Post by flex567 »

Had there been no Option 4, The Option 5 would be correct ?

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Re: About Question enthuware.ocajp.i.v7.2.919 :

Post by admin »

In that case, yes.
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Re: About Question enthuware.ocajp.i.v7.2.919 :

Post by ethanaidenies »

Hi,I get your point @inaelrodrigues. Honestly,
I chose the same answer.
For me, after line 3, the references a, b and c point to null, so the object itself is eligible for garbage collection from that point (line 3) and not later.

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