Java Collections

What is the Collections Framework?

Java's Collections framework provides ready-made, resizable data structures for storing groups of objects, more flexible than fixed-size arrays.

Common Collection Types

• List (e.g., ArrayList): an ordered collection that allows duplicates.
• Set (e.g., HashSet): a collection with no duplicate elements.
• Map (e.g., HashMap): stores key-value pairs for fast lookup by key.

Why Testers Use Collections

Collections are used constantly in test automation — for example, storing a List of expected values, or a Map representing a JSON request payload before sending it via Rest Assured.