What is the main purpose of an iterator in Java?

• A. To sort data in ascending order
• B. To traverse a collection
• C. To modify items in a collection
• D. To create new collections from existing ones

Answer: (B)

The main purpose of an iterator in Java is to traverse a collection, allowing you to sequentially access each element in that collection without exposing its underlying representation. Iterators provide a uniform way to navigate through different types of collections, such as lists, sets, and maps.

Using an iterator, you can access elements one at a time and also have the capability to remove elements from the collection during the traversal process. This design helps in writing cleaner and more maintainable code by encapsulating the iteration logic so that clients of the collection do not need to know about its structure.

While sorting data, modifying items, or creating new collections may involve iterators, these tasks are not their primary purpose. The iterator's core functionality focuses on traversal, making it a crucial component in Java’s collection framework.