garbage collectiion

[sakthi karthik]

can anyone explain me about "isolating a refernce"

[Ismael Upright]

Probably you mean the little part of chapter 3 of Kathy Sierra's book named "Isolating a Reference". You need to have good understanding of the terms "reference" and "garbage collector".



As far as I understand it, you can't do such thing as "isolating the reference". You can only isolate a group of objects.

Let's say that you have two objects, a and b. Object a has the reference to object b. Object b has reference to object a. There is no other references to object a and there is no other references to object b.

In such situation we call object a and b together as island of isolation. It is named like that because there is no way to get there, as there is no reference from the outside.

Usually garbage collector detects such islands and removes them.


Do you understand?

If no, please try to point the parts of the explanation above which you don't understand and describe what should be clarified.

[Dinesh Tahiliani]

Let's say that you have two objects, a and b. Object a has the reference to object b. Object b has reference to object a. There is no other references to object a and there is no other references to object b.

I didn't get this. You are telling a has reference of ba nd b has rference of a tht means a=b and b=a . Correct me if i am wrong.
What means to other refrence in your quote, can you explain in detail little

[Ivan Ivanic]

public class Isolated{
  public Isolated isol; //has-a relationship
}
 
class Testing123{
  public static void main(String[]args){
    Isolated i1 = new Isolated();
    Isolated i2 = new Isolated();
 
    i1.isol = i2;
    i2.isol = i1;//lets assume that this is all part of larger code
                 //and i1 & i2 are not referenced anywhere else,
                 //at this point i1 & i2 are creating island of isolation
  }
}

-----------------------
here i1 has-a ref to i2, and i2 has-a ref to i1. Assumption is that there is no other objects that have has-a relationship regarding this two objects, so in that situation they are "island of isolation", and thus eligible for gc.

regards,
Ivan Ivanic
[ April 22, 2008: Message edited by: ivan ivanic ]

[sakthi karthik]

thank you Ismael Upright & ivan ivanic
i understand now clearly
if two or more objects has references with each other and when there is no other reference from outside then they are isolated references.

is that right?

thank you once again

regards
sakthi

[Ismael Upright]

That is right

And islands of isolation can be removed by garbage collector from the memory.