Iterator vs Enumeration in Java: Key Differences & When to Use
Iterator is a modern Java interface for forward-only traversal; Enumeration is its legacy counterpart, supporting only older collections like Vector.
Both let you loop, so new coders often grab Enumeration out of habit. It’s like reaching for a cassette in a Spotify world—works, but feels ancient and soon breaks on newer APIs.
Key Differences
Iterator adds remove(), generics, and fail-fast safety; Enumeration is read-only, raw-type, and absent from modern collections. Iterator lives in java.util; Enumeration is tied to legacy APIs.
Which One Should You Choose?
Use Iterator for all new code; it’s safer, cleaner, and supported everywhere. Reserve Enumeration only when forced by legacy APIs—like reading old serialised data or ancient libraries.
Examples and Daily Life
Iterator: `for (String s : list) s.trim();` Enumeration: `while (enum.hasMoreElements()) enum.nextElement();` The first feels like scrolling Instagram; the second like winding a pager.
Can Enumeration be used with ArrayList?
No—ArrayList doesn’t expose an Enumeration; stick with Iterator or enhanced for-loop.
Does Iterator remove elements safely?
Yes, its remove() is fail-fast and updates the underlying collection instantly.
Is Enumeration deprecated?
Not officially, but it’s effectively obsolete; no new APIs adopt it.