What data structures exist in Java?

In Java, there are several core data structures implemented in the standard Collections Framework:

• List — an ordered list of elements allowing duplicates. For example, ArrayList, LinkedList.
• Set — a collection of unique elements without a specific order (or with ordering). For example, HashSet, TreeSet.
• Map — a key-value mapping where keys are unique. For example, HashMap, TreeMap.
• Queue — a data structure with FIFO access. For example, LinkedList as a queue, PriorityQueue.
• Stack — a data structure with LIFO access. In Java, Deque can be used as a stack.

Each data structure is suitable for different tasks depending on requirements for access speed, insertion, and deletion of elements.