Arrays in Java – Introduction

In Java, an array is a collection of elements of the same data type that are stored in a contiguous block of memory. Each element in an array can be accessed by an index, which represents its position in the array. The index of the first element in the array is 0, and the index of the last element in the array is the length of the array minus one.

Here’s an example of how to declare and initialize an array of integers in Java:

int[] numbers = { 1, 2, 3, 4, 5 };

In this example, the numbers array contains five elements, each of which is an integer. The elements are initialized with the values 1, 2, 3, 4, and 5.

You can also declare an array without initializing it, and then initialize it later:

int[] numbers = new int[5];
numbers[0] = 1;
numbers[1] = 2;
numbers[2] = 3;
numbers[3] = 4;
numbers[4] = 5;

In this example, the numbers array is declared with a length of 5, but the elements are not initialized. The elements are then initialized one by one using the index notation.

Arrays can be used in a variety of ways in Java. For example, you can use arrays to store the results of a computation, to represent a matrix or a grid, or to implement a stack or a queue.

It’s important to note that arrays in Java have a fixed length, which is determined when the array is created. Once an array is created, its length cannot be changed. If you need a collection of elements that can grow or shrink dynamically, you should use a collection instead of an array.