Difference between Array and ArrayList

1) A regular array has to be declared its size upon creation. But for ArrayList, just need to make an object of type ArrayList. You can actually give initial size to ArrayList too.

int[] myList = new int[];
ArrayList<Integer> myArrayList = new ArrayList<>();

2) To put an object in a regular array, you must assign it to a specific location. With ArrayList, you can specify an index using the add(anInt, anObject) method, or you can just keep saying add(anObject) and the ArrayList will keep growing to make room for the new thing.

myList[1] = 7;
myArrayList.add(3);

3) Arrays use array syntax that’s not used anywhere else in Java. 4) ArrayLists are parameterised. They use parameterised types in <> syntax.