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Java Collections - Interfaces


There are number of data structures. To handle varies kind of collections, Collection framework has different interfaces.

  • Collection - fundamental interface for most of the collections
  • Set  - no duplicates. no order.
  • List - ordered collection. contain duplicates. can access using position.
  • Queue - typically has first-in-first-out structure.
  • Deque - double-ended queue. can behave both as first-in-first-out and last-in-last-out. can insert and remove from both ends.
  • SortedSet - maintain sort order
  • Map - contains key-value pairs. no duplicates allowed.
  • SortedMap - maintain sorted key order

Collection Interface

Map Interface


Other than that, there is RandomAccess interface.