In this post, we’ll explore Java arrays and collections - essential data structures that allow you to store and manipulate multiple values efficiently.

Java Arrays

Arrays are used to store multiple values in a single variable, instead of declaring separate variables for each value.

Declaring and Initializing Arrays

To declare an array, define the variable type with square brackets [ ]:

String[] cars;

You can initialize arrays in several ways:

// Method 1: Initialize with values
String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};

// Method 2: Declare size first, then assign values
String[] cars = new String[4];
cars[0] = "Volvo";
cars[1] = "BMW";
cars[2] = "Ford";
cars[3] = "Mazda";

// Method 3: For numeric arrays
int[] students = new int[4];

Accessing Array Elements

public class Main {
    public static void main(String[] args) {
        String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};

        System.out.println(cars[0]); // Outputs: Volvo
        System.out.println(cars.length); // Outputs: 4

        // Modify an element
        cars[0] = "Tesla";
        System.out.println(cars[0]); // Outputs: Tesla
    }
}

Looping Through Arrays

Traditional For Loop:

public class Main {
    public static void main(String[] args) {
        String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};

        for (int i = 0; i < cars.length; i++) {
            System.out.println(cars[i]);
        }
    }
}

Enhanced For Loop (For-Each):

public class Main {
    public static void main(String[] args) {
        String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};

        for (String car : cars) {
            System.out.println(car);
        }
    }
}

The colon (:) is read as “in”. So you can read the loop as: “for each car in cars”.

In the next post, we’ll dive into Object-Oriented Programming concepts in Java!

Happy coding!