To run each example use: java --enable-preview --source 20 <FileName.java>

JEPs proposed to target:

• 431 - Sequenced Collections

• Sequenced Collections
  • new interfaces to define a common way to iterate throught sequenced collections (list, sets and maps)
  • collections type hierarchy with new interfaces
  • sequenced collection:
    • a sequenced collection is a collection whose elements have a defined encounter order
    • sequenced collection has a first and last elements, and the elements between them have successors and predecessors
    • it supports common operations at the beginning and the end of the collection, also allow iterate it forward or backward
    • methods from SequencedCollection<E> interface:
      • reversed
      • addFirst
      • addLast
      • getFirst
      • getLast
      • removeFirst
      • removeLast
  • sequenced set:
    • sequenced set is a set that is sequenced collcetion that do not allow duplicate elements
    • methods from SequencedSet<E> interface:
      • reversed
  • sequenced map:
    • sequenced map is a map whose entries have a defined encounter order
    • methods from SequencedMap<K,V> interface:
      • reversed
      • sequencedKeySet
      • sequencedValues
      • sequencedEntrySet
      • putFirst
      • putLast
      • firstEntry
      • lastEntry
      • pollFirstEntry
      • pollLastEntry
  • new methods in Collections:
    • unmodifiableSequencedCollection
    • unmodifiableSequencedSet
    • unmodifiableSequencedMap

• JDK 21 Jeps