How to Iterate Over Array in Java: Simple Syntax and Examples

In Java, you can iterate over an array using a for loop with an index or an enhanced for-each loop. The for loop lets you access elements by their position, while the for-each loop simplifies reading each element directly.

Syntax

There are two common ways to iterate over an array in Java:

• For loop: Use an index to access each element by position.
• Enhanced for loop (for-each): Automatically goes through each element without using an index.

java

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

// For loop syntax
for (int i = 0; i < numbers.length; i++) {
    int element = numbers[i];
    // Use element
}

// Enhanced for loop syntax
for (int element : numbers) {
    // Use element
}

Example

This example shows both ways to print all elements of an integer array.

java

public class ArrayIteration {
    public static void main(String[] args) {
        int[] numbers = {10, 20, 30, 40, 50};

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

        System.out.println("Using enhanced for loop:");
        for (int num : numbers) {
            System.out.println(num);
        }
    }
}

Output

Using for loop:
10
20
30
40
50
Using enhanced for loop:
10
20
30
40
50

Common Pitfalls

Common mistakes when iterating arrays include:

• Using i <= array.length instead of i < array.length, which causes an error because array indexes start at 0 and go to length - 1.
• Modifying the array size inside the loop (arrays have fixed size).
• Using enhanced for loop when you need the index (then use regular for loop).

java

int[] arr = {1, 2, 3};

// Wrong: causes ArrayIndexOutOfBoundsException
for (int i = 0; i <= arr.length; i++) {
    System.out.println(arr[i]);
}

// Right:
for (int i = 0; i < arr.length; i++) {
    System.out.println(arr[i]);
}

Quick Reference

Use this quick guide to choose the right loop:

Loop Type	When to Use	Example
For loop	Need index or modify elements	for (int i = 0; i < arr.length; i++)
Enhanced for loop	Just read elements easily	for (int num : arr)

Key Takeaways

Use a for loop with index to access elements by position in an array.

Use an enhanced for loop to read each element simply without index.

Always use i < array.length to avoid errors.

Arrays have fixed size; do not try to change length during iteration.

Choose loop type based on whether you need the index or just the element.