After the assignment on line 8, how many X objects are eligible for garbage collection? public class X { public static void main(String [] args) { X x = new X(); X x2 = m1(x); // line 6 X x4 = new X(); x2 = x4; // line 8 doComplexStuff(); } static X m1(X mx) { mx = new X(); return mx; } }

Introduction / Context:
Counting eligible objects requires tracking each allocation and the references that point to them. The twist is the method m1 that returns a newly created object.

Given Data / Assumptions:

• Allocations: one for x in main, one in m1, and one for x4 in main.
• After line 8, x2 is reassigned to refer to x4.

Concept / Approach:
Track objects: A1 (for x), A2 (returned by m1 and held in x2), A3 (held by x4). Reassigning x2 = x4 drops the last reference to A2, making A2 eligible.

Step-by-Step Solution:

Verification / Alternative check:
Printing System.identityHashCode of the three references reveals the handoff: A2 disappears from reachability after line 8.

Why Other Options Are Wrong:
0 ignores A2; 2 or 3 would require additional reference drops; doComplexStuff() executes later and does not affect the count at line 8.

Common Pitfalls:
Forgetting that the parameter reassignment in m1 doesn’t affect the caller’s original x.

Final Answer:
1