Garbage collection?

[RAGU KANNAN]

Hello,

The answer is given by K & B is C and E. My answer is A and B
Because the two objects references X3 and X4 references the object in line 12.
I am making null for those references for garbage collection. So what is wrong with my answer pls explain to me to understand the concept.

Thanks, Raghu.K



14. Given the following,
12. X3 x2 = new X3();
13. X3 x3 = new X3();
14. X3 x5 = x3;
15. x3 = x2;
16. X3 x4 = x3;
452 Chapter 7: Objects and Collections
17. x2 = null;
18. // insert code

What two lines of code, inserted independently at line 18, will make an object eligible for
Garbage collection? (Choose two.)

A. x3 = null;
B. x4 = null;
C. x5 = null;
D. x3 = x4;
E. x5 = x4;

[Keith Lynn]

Notice what happens after each line executes.

X3 x2 = new X3();

x2 -> O1, an object

13. X3 x3 = new X3();

x3 -> O2, an object

14. X3 x5 = x3;

x2 -> O1, x3,x5 -> O2

15. x3 = x2;

x2,x3 -> O1, x5 -> O2

16. X3 x4 = x3;

x2,x3,x4 -> O1, x5 -> O2

17. x2 = null;

x3,x4 -> O1, x5 -> O2

Now if we look at the options.

A. x3 = null, x4 still points to O1 and x5 still points to O2
B. x4 = null, x3 still points to O1 and x5 still points to O2
C. x5 = null, x3 and x4 point to O1, but O2 is eligible for collection
D. X3 = x4, x3 and x4 still point to O1, and x5 still points to O2
E. x5 = x4, x3,x4, and x5 point to O1, but O2 is eligible for collection

[RAGU KANNAN]

Awesome Keith, I got it.

Thanks, Raghu.K