Arrays in Java

📚 Arrays in Java

Arrays in Java are one of the most basic yet powerful data structures. They allow you to store multiple values of the same type in a single container, making it easier to organize and manipulate related data efficiently.

Whether you're working with numbers, strings, or objects, mastering Arrays in Java is a must-have skill for any Java developer.

🛠️ Declaring and Initializing Arrays

Declaring an array in Java is straightforward. You specify the type followed by square brackets [], then the array name. Initializing can be done either at the time of declaration or later.

// Declaring an array of integers
int[] numbers;

// Initializing with size
numbers = new int[5];

// Declaring and initializing at once
String[] fruits = {"Apple", "Banana", "Cherry"};

🔄 Accessing and Modifying Array Elements

Arrays are zero-indexed, meaning the first element is at index 0. You can access or update elements by their index.

int firstNumber = numbers[0]; // Access first element
numbers[1] = 10;              // Update second element

🔁 Looping Through Arrays

One of the most common operations is iterating over an array.

Java provides multiple ways to do this:

// Using a traditional for loop
for (int i = 0; i < numbers.length; i++) {
    System.out.println(numbers[i]);
}

// Using enhanced for loop (for-each)
for (String fruit : fruits) {
    System.out.println(fruit);
}

🧩 Multi-Dimensional Arrays

Java supports multi-dimensional arrays, often used to represent tables or matrices.

// Declaring a 2D array
int[][] matrix = {
    {1, 2, 3},
    {4, 5, 6}
};

// Accessing an element
int val = matrix[1][2];  // Output: 6

📏 Array Length and Limits

Every array has a fixed length, accessible via the length property. Note that array sizes cannot be changed once created.

System.out.println("Array length: " + fruits.length);

⚠️ Common Pitfalls

• IndexOutOfBoundsException: Accessing indexes outside the array range causes runtime errors.
• Fixed Size: Arrays can't grow dynamically; consider using collections like ArrayList if you need resizable structures.

🚀 Conclusion

Arrays in Java offer a simple yet efficient way to group related data of the same type. By understanding declaration, initialization, traversal, and common use cases like multi-dimensional arrays, you build a solid foundation for working with data in Java applications.