Arrays and Lists.

import java.util.ArrayList;

public class Main {

    public static void main(String[] args) {

        ArrayList<Integer> ints1 = new ArrayList<Integer>();
        ArrayList<Integer> ints2 = new ArrayList<Integer>();

        ints2.add(0, -1);
        ints2.add(0, -2);
        ints2.add(0, -3);
        ints2.add(0, -4);
        ints2.add(0, -5);

        // Add an item:
        System.out.println("Add an item:");
        System.out.println(ints1);
        ints1.add(0, 1);
        System.out.println(ints1);
        System.out.println("");

        // Add items from another list:
        System.out.println("Add items from another list:");
        System.out.println(ints1);
        ints1.addAll(0, ints2);
        System.out.println(ints1);
        System.out.println("");

        // Get size of array:
        System.out.println("Get size of array:");
        System.out.println(ints1.size());
        System.out.println("");

        // This method is used to remove all the elements in the list:
        System.out.println("This method is used to remove all the elements in the list");
        System.out.println(ints1);
        ints1.clear();
        System.out.println(ints1);
        System.out.println("");

        ints1.add(0, 1);
        ints1.add(0, 2);
        ints1.add(0, 3);
        ints1.add(0, 4);
        ints1.add(0, 5);

        // This method removes an element from the specified index:
        System.out.println("This method removes an element from the specified index:");
        System.out.println(ints1);
        ints1.remove(1);
        System.out.println(ints1);
        System.out.println("");

        // This method is used to remove the first occurrence of the given element in the list
        System.out.println("This method removes an element from the specified index:");
        System.out.println(ints1);
        ints1.remove(0);
        System.out.println(ints1);
        System.out.println("");

    }

}

Main.main(null);

Add an item:
[]
[1]

Add items from another list:
[1]
[-5, -4, -3, -2, -1, 1]

Get size of array:
6

This method is used to remove all the elements in the list
[-5, -4, -3, -2, -1, 1]
[]

This method removes an element from the specified index:
[5, 4, 3, 2, 1]
[5, 3, 2, 1]

This method removes an element from the specified index:
[5, 3, 2, 1]
[3, 2, 1]