What is the main function of the ArrayList collection in Java?

The main function of the ArrayList collection in Java is to store elements in a dynamically resizable array with quick access by index. ArrayList allows adding, removing, and modifying elements, automatically increasing the size of the internal array when necessary. It is a convenient data structure when fast access to elements and their insertion order are important.

Example of usage:

import java.util.ArrayList;

public class Example {
    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<>();
        list.add("First");
        list.add("Second");
        System.out.println(list.get(0)); // Will output "First"
    }
}