Here’s the hierarchical structure of the given interfaces in the Java Collections Framework (JCF):
┌──────────────────────┐
│ Iterable<E> │ (Superinterface of Collection)
└──────────▲───────────┘
│
┌─────────┴──────────┐
│ Collection<E> │ (Root interface for List & Set)
└─────────▲──────────┘
│
┌──────────────┴──────────────┐
│ │
List<E> Set<E>
│ │
│ ├───────────┐
│ │ │
│ SortedSet<E> (Set with ordering)
│ │
│ ▼
│ NavigableSet<E> (Extends SortedSet)
▼
(Implementations: ArrayList, LinkedList, Vector, Stack)
──────────────────────────────────────────────────────────
Map<K, V> (Separate hierarchy)
│
├──────────────┐
│ │
SortedMap<K, V> (Map with ordering)
│
▼
NavigableMap<K, V> (Extends SortedMap)
Explanation of Hierarchy:
Iterable<E>– The topmost interface, allowing iteration over elements.Collection<E>– ExtendsIterable<E>and serves as the root forList<E>andSet<E>.List<E>– Ordered collection (e.g.,ArrayList,LinkedList).Set<E>– Unordered collection, no duplicates (e.g.,HashSet).SortedSet<E>– ASetwith elements stored in sorted order (e.g.,TreeSet).NavigableSet<E>– ExtendsSortedSetwith navigation methods likehigher(),lower().
Map<K, V>– A separate hierarchy that stores key-value pairs.SortedMap<K, V>– AMapwhere keys are stored in sorted order (e.g.,TreeMap).NavigableMap<K, V>– ExtendsSortedMap, providing extra methods for navigation (e.g.,TreeMap).
Key Takeaways:
Collection<E>is the root forList<E>andSet<E>, butMap<K, V>is a separate hierarchy.SortedSet<E>andSortedMap<K, V>enforce natural ordering or a custom comparator.NavigableSet<E>andNavigableMap<K, V>provide enhanced navigation methods.