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
Other than that, there is RandomAccess interface.