Arrays and ArrayLists have each their own uses.

First, I’ll talk how good ArrayLists are. I think the similar datapart for arrayLists from C++ is Vector… and not sure about other languages. There are also other List types, such as LinkedList, Vector, Stack

ArrayList is first great because it can be dynamically sized. When making arrays, we should define the size of the array and the size is not mutable. But for arrayLists, we can just initialize it and then add as many elements as we want. For Java, another thing to note is that in arrayList, we cannot store primitive datatypes, but arrays can have primitive datatypes as well as objects.

Also, we can change arrays into arraylists and arraylists into arrays also. This uses java.util.Arrays library, so we have to import either java.util.Arrays or java.util.*.

    String[] strArr = {"jim", "mo"};
	
	List al = Arrays.asList(strArr);
	System.out.println(al);

Also, we can switch arrayList to an array like

        List<Integer> al = new ArrayList<Integer>();
        al.add(10);
        al.add(20);
        al.add(30);
        al.add(40);
 
        Integer[] arr = new Integer[al.size()];
        arr = al.toArray(arr);
 
        for (Integer x : arr)
        System.out.print(x + " ");

Note that the initial arraylist was holding the integer object so the transformed array also holds the Integer object.