Garbage Collection question

[Shiva Mohan]

At what point is the object CREATED AT LINE 05 available for garbage collection.

    
  01:  public class Base{
  02:
  03:   private void test() {
  04:
  05:      String anObj = new String("sample");
  06:
  07:      anObj.trim(); 
  08:     
  09:      anObj = anObj.toUpperCase(); 
  10:     
  11:      anObj = null; 
  12:    }
  13:         
  14:    static public void main(String[] a) {
  15:       new Base().test();
  16:   }   
  17:  
  18:  }

Select most appropriate answer
a) At line 5
b) At line 7
c) At line 8
d) At line 10
e) At line 9
f) At line 12

My doubt is the answer option d or e is correct. Kindly help.
When the control comes to execute line 09,the anObj object reference started to point to new object SAMPLE.So I am asking is the answer e is correct.
[ September 27, 2006: Message edited by: Shiva Mohan ]

[Chris Goad]

E looks good to me. At that point, your variable would be referring to a new object since Strings are immutable.

Chris

[Pedro Lobato Sena]

"E" appears to be the right answer for me too.

[Anvi Dixit]

since the strings are immutable thats why a new object is created by this line
anObj = anObj.UpperString();

but my question is control cannot go back ...
only when the obj is assigned null then only it is valid entry for the GC..

please can anyone explain me..

thnx
Anvi

[Sireesha Mullapudi]

Hi,

if the object has no references from any live thread,then it is eligible for the garbage collection.

when
anObj = anObj.toUpperCase();
is executed a new string object will be created and the reference anObj is pointing to it.But the old string doesn't have any references assigned to it. so it is eligible for garbage collection.