Can you name the main data collections used in Java?

In Java, the main data collections are presented in the java.util package and are divided into several groups:

• List — an ordered list of elements, allows duplicates.

  • Implementations: ArrayList, LinkedList, Vector.

• Set — a collection of unique elements, without order or with a specific order.

  • Implementations: HashSet, LinkedHashSet, TreeSet.

• Queue — a queue, elements are processed according to a certain rule (e.g., FIFO).

  • Implementations: LinkedList, PriorityQueue.

• Map — a key-value mapping, keys are unique.

  • Implementations: HashMap, LinkedHashMap, TreeMap, Hashtable.

Example of using ArrayList:

import java.util.ArrayList;

ArrayList<String> list = new ArrayList<>();
list.add("apple");
list.add("banana");
for (String fruit : list) {
    System.out.println(fruit);
}

These collections are widely used for storing and processing data in Java applications.