Storing Many Values

Sometimes you need to keep track of lots of data—like scores, names, or objects. Arrays and ArrayLists are perfect for this.

Arrays

Arrays store a fixed number of elements of the same type.

int[] scores = {90, 85, 72, 100};
String[] names = new String[3];

• Access elements with an index: scores[0] is 90.

ArrayLists

ArrayLists are flexible—they can grow and shrink as needed.

ArrayList<String> friends = new ArrayList<String>();
friends.add("Sam");
friends.add("Alex");

• Use .get(index) to access elements: friends.get(0).

Choosing Between Them

• Use arrays when the number of items is fixed.
• Use ArrayLists for dynamic lists.

Real-Life Example

Arrays are like a row of lockers; ArrayLists are more like a backpack where you can add or remove things.