Qustion about Garbage Collection

[Aiglee Castillo]

Hi!
I just did a practice test of the Whizlabs SCJP 5.0 Exam Simulator and I'm not sure about this question:

How many objects are eligible for garbage collection when the System.gc() method is invoked?

  class MyClass {
public void finalize() {System.out.print ("finalize");}
}
class Test {
private static void f(MyClass[] array) {
array[0] = null;
array[1] = array[0];
array[2] = array[1];
array = null;
}
public static void main (String[] args) {
MyClass[] array = new MyClass[4];
for (int i=0; i<array.length; i++)
   array[i] = new MyClass();
f(array);
System.gc();
}
}  

A) 3
B) 4
C) 5
D) Code does not compile
E) None of the above

It says the answer is A, because the array, but what about the variable i of the loop??

Thanks in advance!!

[Zip Ped]

Variable i is a local vaiable in the for block. The variable becomes inaccessible once the block is over.

[Aiglee Castillo]

exactly, would not be garbage collected too?

[Rachil Chandran]

'i' is a primitive and disappears after the the stack for the block is erased

[Neelesh Bodas]

Originally posted by Aiglee Castillo:
It says the answer is A, because the array, but what about the variable i of the loop??

Only "Objects" are Garbage-collected. Not the variables. (Variables hold either references to objects or values of primitives)

to put in other words, only those things are GC'ed which are created by using "new" operator. (Lets keep String literals aside) In your code, did you create "i" by saying something line new i() ?

[ramesh subramani]

After making array=null all its elements hold null, so the answer should be 4??
[ August 22, 2006: Message edited by: ramesh subramani ]

[Barry Gaunt]

Originally posted by ramesh subramani:
After making array=null all its elements hold null, so the answer should be 4??

[ August 22, 2006: Message edited by: ramesh subramani ]

No, because the variable array being set to null is the local variable in method m.
The varable array in method main still holds a reference to the array.
[ August 22, 2006: Message edited by: Barry Gaunt ]

[Aiglee Castillo]

Ohh!

Thank you!!!