Java 21's Sequenced Collections: Enhancing List, Set, and Map Interfaces

Java 21's introduction of Sequenced Collections, revolutionizes handling ordered data structures. These collections maintain a defined sequence of elements, offering both forward and reverse order. Key interfaces include SequencedCollection, SequencedSet, and SequencedMap, enhancing Lists, Sets, and Maps respectively. They support operations like addFirst, addLast, getFirst, getLast, along with the new reversed method for reverse-order views. This feature bridges gaps in the Collections Framework, enabling more intuitive and powerful data manipulation​.

This code showcases the use of SequencedSet, utilizing a LinkedHashSet to create an ordered collection of strings. This demonstrates adding elements and accessing the first and last elements. It also highlights the new reversed() method, which provides a reverse-ordered view of the set. This shows the enhanced capabilities of Sequenced Collections in efficiently managing ordered data structures.