Given: 1. Iterator iter = List.of(1,2,3).iterator(); 2. while (iter.hasNext()) { 3. foo(iter.next()); 4. } 5. Iterator iter2 = List.of(1,2,3).iterator(); 6. while (iter.hasNext()) { 7…

Question

Options

• AThe loop starting line 11
• BThe loop starting line 7
• CThe loop starting line 14
• DThe loop starting line 3

• A
  74% (35)
• B
  6% (3)
• C
  4% (2)
• D
  15% (7)

Explanation

Option A is correct because the for loop on line 10 declares Iterator iter in its initializer - but iter was already declared on line 1 in the same enclosing scope. Java does not allow a local variable to be re-declared in the same scope (or a nested scope within the same method), so this is a duplicate variable compile-time error.

Why the distractors are wrong:

• D (line 3) and B (line 7): The while loops use iter and iter2 that were previously declared - they reference existing variables rather than declaring new ones, so no compile error occurs. (The loop at line 7 won't execute since iter is already exhausted, but that's a runtime behavior issue, not a compile error.)
• C (line 14): The for loop on line 13 declares Iterator iter2, but the condition iter.hasNext() still refers to the iter from line 1, which remains in scope - no variable conflict.

Memory tip: Think of it as the "for-init is not a free pass" rule - declaring a variable in a for initializer (for (Type x = ...;)) follows the exact same scoping rules as any other local variable declaration. If that name already exists in the enclosing method scope, it's a duplicate declaration error, just as if you'd written Type x = ...; as a regular statement.

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