When does the Float object created on line 3 become eligible for garbage collection? public Object m() { Object o = new Float(3.14F); Object[] oa = new Object[1]; oa[0] = o; // line 5 o = null; // line 6 oa[0] = null; // line 7 return o; // line 8 }

Introduction / Context:
Determining GC eligibility requires tracking every live reference to an object. Arrays are objects too and can keep other objects alive by holding references in their elements.

Given Data / Assumptions:

• A Float is created and referenced by o.
• The reference is stored into oa[0].
• o is later set to null and then oa[0] is set to null.

Concept / Approach:
The Float remains reachable as long as either o or oa[0] holds its reference. It becomes eligible only when both references are removed. Returning o at line 8 returns null (since line 6 set it to null) and thus does not resurrect the object.

Step-by-Step Solution:

Verification / Alternative check:
Swap the order of lines 6 and 7; eligibility would still occur after the second nulling step.

Why Other Options Are Wrong:
Lines 5 and 6 still leave a live reference; line 8 returns null, not the Float.

Common Pitfalls:
Overlooking references held inside arrays; assuming returning o implies returning the object (it returns null in this code).

Final Answer:
just after line 7