ArrayList Size in Java

We can get the size of an ArrayList using the .size() method:

List<Integer> ourArray = new ArrayList<>(List.of(50, 40, 30));

// Printing the size:
System.out.println(ourArray.size()); // Output: 3

// Changing the ArrayList:
ourArray.remove(2);

// Printing the new size:
System.out.println(ourArray.size()); // Output: 2

Using the size

We can use the size to access items from the end of an ArrayList.

Because ArrayLists are 0-indexed, the index of the last item is size - 1:

List<Integer> ourArray = new ArrayList<>(List.of(50, 40, 30));

int size = ourArray.size();

// Printing the last item:
System.out.println(ourArray.get(size - 1)); // Output: 30

// Printing the second to last item:
System.out.println(ourArray.get(size - 2)); // Output: 40

Assignment
Follow the Coding Tutorial and let's play with some arrays.

Hint
Look at the examples above if you get stuck.