Java Store a Fixed-Size Sequence

Understand the idea

Array positions start at zero and stop before length. An array’s length is a field, unlike a collection’s size method or a String’s length method. An enhanced for loop visits values without exposing an index; use an indexed loop when the position is part of the task or when replacing elements. An array is an object, and copying its reference shares the same storage.

Run it locally

Use a local JDK 21 or newer. Save the complete example as Main.java in a separate lab folder, then compile and run it with the commands below. Java examples do not run in Bhylu’s browser playground. The -ea option enables assertion checks used by some lessons.

JDK and terminal setup

javac --release 21 -encoding UTF-8 -d out Main.java
java -ea -cp out Main

A worked example

public class Main {
    public static void main(String[] args) {
        int[] booked = {4, 7, 2};
        int total = 0;
        for (int seats : booked) total += seats;
        booked[1] = 6;
        System.out.println(total);
        System.out.println(booked.length);
        System.out.println(booked[1]);
    }
}

Expected output

13
3
6

The total is computed before the second element is changed, so it remains thirteen. Updating an array element does not automatically recalculate a separate local variable. The array still has three positions. If the number of records must grow as bookings arrive, a collection such as ArrayList is a more natural starting point.