Which interfaces does ArrayList.iterator() implement? Evaluate the instanceof results. import java.util.*; class I { public static void main (String[] args) { Object i = new ArrayList().iterator(); System.out.print((i instanceof List) + ","); System.out.print((i instanceof Iterator) + ","); System.out.print(i instanceof ListIterator); } }

Introduction / Context: This question distinguishes between Iterator, ListIterator, and collection types. The object returned by new ArrayList().iterator() is an Iterator but not a List and not a ListIterator.

Given Data / Assumptions:

• i holds the iterator returned from an empty ArrayList.
• Three instanceof checks are printed as booleans.

Concept / Approach: An Iterator is produced by iterator(). A ListIterator—which supports bidirectional traversal and index operations—is produced by listIterator(), not iterator(). Also, an iterator is not a collection, so it is not a List.

Step-by-Step Solution: i instanceof List → false. i instanceof Iterator → true. i instanceof ListIterator → false. Output is false, true, false.

Verification / Alternative check: Replace iterator() with listIterator() and the third check becomes true for many list implementations.

Why Other Options Are Wrong: Any claim that List is true confuses data structures with iterators; claiming ListIterator is true ignores the specific method used.

Common Pitfalls: Assuming all list iterators are bidirectional; forgetting distinct factory methods in the collections API.

Final Answer: Prints: false, true, false