Arrays — Java Tutorial

Creating and Using Arrays

Arrays store multiple values of the same type in a fixed-size container.

Example

// Declare and initialize
int[] numbers = {10, 20, 30, 40, 50};
String[] names = new String[3]; // empty array of size 3

// Access elements (0-indexed)
System.out.println(numbers[0]); // 10
numbers[2] = 99;                // modify element

// Array length
System.out.println(numbers.length); // 5

// Loop through array
for (int i = 0; i < numbers.length; i++) {
    System.out.println(numbers[i]);
}

// For-each loop
for (int num : numbers) {
    System.out.println(num);
}

Multi-dimensional Arrays and Arrays Class

Java supports multi-dimensional arrays and provides the Arrays utility class for common operations.

Example

import java.util.Arrays;

// 2D array
int[][] matrix = {
    {1, 2, 3},
    {4, 5, 6},
    {7, 8, 9}
};
System.out.println(matrix[1][2]); // 6

// Arrays utility methods
int[] arr = {5, 3, 1, 4, 2};
Arrays.sort(arr);                    // [1, 2, 3, 4, 5]
String str = Arrays.toString(arr);   // "[1, 2, 3, 4, 5]"
int idx = Arrays.binarySearch(arr, 3); // 2
int[] copy = Arrays.copyOf(arr, 3);  // [1, 2, 3]
Arrays.fill(arr, 0);                // [0, 0, 0, 0, 0]