Garbage collection dan's question

[Shiva Mohan]

    void m1() {
  Q q1 = null;
  for (int i = 0; i < 10; i++) {
    q1 = new Q();   // 1
    m2(q1);         // 2
  }
  System.out.print("All done"); // 3
  }

/*When the processing of line 3 begins, how many objects of type Q that were created at line 1 are eligible for garbage collection?

a. 0
b. 1
c. 9
d. 10
e. Indeterminate.
f. Compile-time error
g. Run-time error
h. None of the above
**/
The given explanation is
If method m2 causes a reference to be saved for each object that is passed in as an argument, then none of the objects are eligible for garbage collection when line 3 begins. Since we don't know what method m2 might be doing, we can not know if the objects are eligible for garbage collection.

But i am thinking,the compiler error will occur a line 2 since we didn't have the method m2(q1);.

[Barry Gaunt]

You are meant to assume that method m2(Q q) exists but you do not know what it does.

[Shaan Shar]

Originally posted by Shiva Mohan:

    void m1() {
  Q q1 = null;
  for (int i = 0; i < 10; i++) {
    q1 = new Q();   // 1
    m2(q1);         // 2
  }
  System.out.print("All done"); // 3
  }

/*When the processing of line 3 begins, how many objects of type Q that were created at line 1 are eligible for garbage collection?

a. 0
b. 1
c. 9
d. 10
e. Indeterminate.
f. Compile-time error
g. Run-time error
h. None of the above
**/
The given explanation is
If method m2 causes a reference to be saved for each object that is passed in as an argument, then none of the objects are eligible for garbage collection when line 3 begins. Since we don't know what method m2 might be doing, we can not know if the objects are eligible for garbage collection.

But i am thinking,the compiler error will occur a line 2 since we didn't have the method m2(q1);.

Dear Shiva,

This is the most innocent answer I have seen ever in my life.


Well dear, it's not a whole question given in the paper, you must assume that there is a method m2();. And if you are looking at compile error then why didn't you point out the main method missing and no class definations block is there.

Well, I think now you got the point, you have to assume about the method m2(Q q1);.

[Shiva Mohan]

Ok�......

If method m2 causes a reference to be saved for each object that is passed in as an argument, then none of the objects are eligible for garbage collection when line 3 begins.

    
class Q{
    public static void main (String args[]) {
      new Objective3().m1();
  }
}
 
class Objective3{
void m1() {
  Q q1 = null;
  for (int i = 0; i < 10; i++) {
    q1 = new Q();   // 1
    m2(q1);         // 2
    
  }
  
  System.out.print("All done"); // 3
}
  void m2(Q q2){
     q2=new Q(); //am i writting this statement correctly as reference to be saved for each each object that is passed in as an argument (?)
  }
}

If method m2 causes a reference to be saved for each object that is passed in as an argument, then none of the objects are eligible for garbage collection when line 3 begins

Is true.Can anyone please explain the above sentence for me.
[ September 29, 2006: Message edited by: Shiva Mohan ]