Java — Which collection class allows resizing, provides indexed access, but is not synchronized?

Introduction / Context:
This checks understanding of ArrayList vs other collections in terms of resizing, indexing, and synchronization.

Concept / Approach:

• ArrayList → resizable array, indexed access, not synchronized.
• Vector → synchronized, older alternative.
• HashSet/LinkedHashSet → no indexing, store unique elements.
• List → interface, not a class.

Final Answer:
java.util.ArrayList