Answers by Sentry

Print an array in Java

David Y.

The Problem

What is the simplest way to print an array in Java? Passing an array directly to System.out.println produces an object reference rather than a printed representation of the array contents.

class Main {
    public static void main(String[] args) {
        String[] products = new String[]{"Coffee", "Tea", "Chocolate Bar"};

        System.out.println(products); // will print something like [Ljava.lang.String;@49476842
    }
}

How can I get the output ["Coffee", "Tea", "Chocolate Bar"] instead?

The Solution

We can print simple arrays in Java using the method Arrays.toString():

import java.util.Arrays;

class Main {
    public static void main(String[] args) {
        String[] products = new String[]{"Coffee", "Tea", "Chocolate Bar"};

        System.out.println(Arrays.toString(products)); // will print ["Coffee", "Tea", "Chocolate Bar"]
    }
}

This will also work for arrays containing non-String types, such as ints or doubles.

If we have an array containing other arrays, or complex custom objects, we will need to use Arrays.deepToString() to print out an accurate representation:

import java.util.Arrays;

class Main {
    public static void main(String[] args) {
        String[][] productRanges = new String[][]{{"Coffee", "Tea"}, {"Granola Bar", "Chocolate Bar"}};

        System.out.println(Arrays.toString(productRanges)); // will print [[Ljava.lang.String;@49476842, [Ljava.lang.String;@78308db1]
        System.out.println(Arrays.deepToString(productRanges)); // will print [[Coffee, Tea], [Granola Bar, Chocolate Bar]]
    }
}

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