Help!!, problem with Dan question

[zurial zurial]

Help, I confuse with this question of Dan Chrisholm. Thanks Dan to think up a lot of creative questions .

class B {
  private String name;
  public B(String s) {name = s;}
  public void finalize() {System.out.print(name);}
}
 
class E {
  public static void m() {
    B x1 = new B("X");
    B y1 = new B("Y");
  }
 
  public static void main(String[] args) {
    m();
    System.gc();
  }
}

Which of the following are true statements and which of the following could be a result of attempting to compile and run the program?
a. Prints: XY
b. Prints: YX
c. Prints: XXYY
d. Prints: YYXX
e. Nothing is printed.
f. There is no guarantee that the garbage collector will run.
g. Compiler Error.
h. Run Time Error.
i. None of the above.
The answer is a,b,e,f .
plzzz anybody help me, Why the answer can be also be b,e,f, because I think it only a. What is actually happens in this code??
Thanks a lot.
Edited by Corey McGlone: Added Code Tags
[ March 22, 2003: Message edited by: Corey McGlone ]

[Corey McGlone]

One key thing to remember when dealing with garbage collection is that there are no guarantees about when of even if it will execute.
Therefore, we have no idea if the garbage collector will execute at all, making answers e and f correct.
Also, we have no guarantee as to what order the garbage collector will collect unused objects, therefore, answers a and b are also correct.
Hope that helps,
Corey

[Harry D'Souza]

Hi Corey,
Please correct me if I am wrong. I do not understand how a and b could be the correct answers. I sure do understand that that e and f are correct answers.
As far as my understanding goes, I think any object that has references to it cannot be Garbage collected.
Hence assuming that the

System.gc()  

did succeed to invoke the Garbage collection thread, how could these objects (i.e. x1 and y1) be garbage collected ?
-Harry.
[ March 23, 2003: Message edited by: Harry D'Souza ]

[Dan Chisholm]

When method m returns both objects, x1 and y1, are out of scope and are eligible for garbage collection.