Arrays.toString() Method in Java

The Arrays.toString() method returns a string representation of a one-dimensional array in Java: the elements are listed comma-separated and enclosed in square brackets. It is the shortest way to print an array to the console — one call instead of looping over the elements with a for loop. The method is static and lives in the java.util.Arrays class, so you need the import java.util.Arrays; at the top of the file.

How Arrays.toString() works

Pass a one-dimensional array to the method — and you get a ready-to-use string:

import java.util.Arrays;

public class ArraysToStringExample {
    public static void main(String[] args) {
        int[] array = {1, 4, 6, 3, 8};
        System.out.println(Arrays.toString(array));
    }
}

Console output:

[1, 4, 6, 3, 8]

The method works with arrays of any type. For a String[] array each element goes into the result as is, without quotes:

String[] names = {"Anna", "Boris", "Clara"};
System.out.println(Arrays.toString(names)); // [Anna, Boris, Clara]

A full description of all overloads is available in the official Oracle documentation for the Arrays class.

Why an array prints as [I@1b6d3586

If you pass an array directly to System.out.println(), instead of the elements you will see something like [I@1b6d3586 on the console:

int[] array = {1, 4, 6, 3, 8};
System.out.println(array);                  // [I@1b6d3586
System.out.println(Arrays.toString(array)); // [1, 4, 6, 3, 8]

The reason is that an array in Java is an object, but it does not override the toString() method. The default implementation from the Object class kicks in: the type name ([I — a one-dimensional int array), the @ character, and the hash code in hexadecimal. Such a string carries no information about the elements — which is exactly why Arrays.toString() exists. With a two-dimensional array the same problem repeats at every nesting level:

int[][] twoDArray = {{1, 2}, {3, 4}};
System.out.println(twoDArray);                  // [[I@4554617c
System.out.println(Arrays.toString(twoDArray)); // [[I@74a14482, [I@1540e19d]

For such cases there is a dedicated method Arrays.deepToString(), covered in detail in the lesson «Arrays.deepToString() method».

Comparing ways to print an array

How to convert an array to a string without brackets

Arrays.toString() always adds square brackets and commas. If you need to convert an array to a string in your own format — for example, to write it to a file or build a message — use String.join() for a string array:

String[] names = {"Anna", "Boris", "Clara"};
String result = String.join(", ", names);
System.out.println(result); // Anna, Boris, Clara

For an array of primitives, the Stream API with Collectors.joining() does the job:

int[] array = {1, 4, 6, 3, 8};
String result = Arrays.stream(array)
        .mapToObj(String::valueOf)
        .collect(Collectors.joining(", "));
System.out.println(result); // 1, 4, 6, 3, 8

The separator can be anything in both cases: a hyphen, a line break, a semicolon.

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