How to Print a Java Array in a Readable Format?

What is the easiest method to output a Java array in a human-readable format?

int[] intArray = new int[] {1, 2, 3, 4, 5};
System.out.println(intArray);

// Desired Output: [1, 2, 3, 4, 5]

Java arrays do not provide a default human-readable format when printed directly due to the lack of a `toString()` override. Instead, they produce a cryptic representation displaying the type and hash code. To print arrays in a user-friendly way, we can utilize the `Arrays.toString()` method from the `java.util.Arrays` class or manual iteration for more flexibility.

import java.util.Arrays;

public class Main {
    public static void main(String[] args) {
        int[] intArray = new int[] {1, 2, 3, 4, 5};
        String[] strArray = new String[] {"John", "Mary", "Bob"};

        System.out.println(Arrays.toString(intArray)); // Output: [1, 2, 3, 4, 5]
        System.out.println(Arrays.toString(strArray)); // Output: [John, Mary, Bob]
    }
}

Causes

• Java arrays inherit the default `toString()` method from `Object`, which does not reflect the array's contents.
• Directly printing an array results in output that includes type and hash code, leading to confusion.

Solutions

• Use `Arrays.toString()` for one-dimensional arrays to easily print array contents.
• For multi-dimensional arrays, use `Arrays.deepToString()` to print nested structures.
• Manually iterate through the array and construct a string if custom formatting is needed.

Mistake: Using `System.out.println()` directly on arrays and expecting readable output.

Solution: Always use `Arrays.toString()` or similar methods to get human-readable output.

Mistake: Not importing the `java.util.Arrays` package.

Solution: Ensure to import `java.util.Arrays` at the start of your Java file.