List

01What is a List?

List is an interface in the Collection Framework that represents an ordered group of elements, where duplicate values are allowed, and each element has a specific position (index), just like an array.

02Why is it used?

List is used whenever the order of elements matters, and duplicates are acceptable — like maintaining a list of items in a shopping cart, where the same item could appear more than once.

03Real-Life Example

Think of a to-do list written on paper. Items are in a specific order, and you could accidentally write the same task twice — both are perfectly fine for a List.

java
List<DataType> listName = new ArrayList<>(); // or LinkedList, Vector, etc.

java
import java.util.List;
import java.util.ArrayList;

public class ListDemo {
    public static void main(String[] args) {
        List<String> tasks = new ArrayList<>();
        tasks.add("Read");
        tasks.add("Write");
        tasks.add("Read"); // duplicate allowed
        System.out.println(tasks);
    }
}

[Read, Write, Read]