How to Check if an Array is Empty or Not in Java?

Last Updated : 09 Dec, 2024

In Java, arrays do not have a built-in method like isEmpty() to check if they are empty. So, we need to use other ways to check if an array is empty in Java.

Example: The simplest way to determine if an array is empty is by evaluating its length or verifying if it is null. This approach ensures our code handles both uninitialized and empty arrays effectively.

Java

// Java program to Check if an Array is Empty
// by checking Array Length 
public class ArrayCheck {
  
    public static void main(String[] args) {
      
        int[] arr = {};    

        // Check if the array is empty
        if (arr == null || arr.length == 0) {
          
            System.out.println("The array is empty.");
        } else {
          
            System.out.println("The array is not empty.");
        }
    }
}

Output

The array is empty.

Explanation: The array == null checks if the array reference is uninitialized or null and the array.length == 0 checks if the array has no elements.

Other Methods to Check Empty Arrays

1. Using Utility Method

If we need to check arrays frequently, we can create a reusable utility method to simplify array emptiness check.

Java

// Java Program to Check if an Array 
// is Empty using a Utility Method
public class ArrayUtils {
  
    public static boolean isArrayEmpty(int[] arr) {
      
        return arr == null || arr.length == 0;
    }

    public static void main(String[] args) {
      
        int[] arr = {};      // Example array
        System.out.println("" + isArrayEmpty(arr));
    }
}

Output

true

Note: This code is reusable and provides a clean, clear way to check if an array is empty in Java.

2. Using Java Optional

Java's Optional class provides a clean and functional approach to check if an array is empty.

Java

// Java Program to Check if an Array 
// is Empty using Optional Class
import java.util.Optional;

public class ArrayCheck {
  
    public static void main(String[] args) {
      
        int[] arr = {};     // Example array

        // Use Optional.ofNullable to 
        // handle null checks gracefully
        boolean isEmpty = Optional.ofNullable(arr)
                                  .map(arr1 -> arr1.length == 0)
                                  .orElse(true);

        System.out.println("" + isEmpty);
    }
}

Output

true

Explanation: Here, we have used Optional.ofNullable to safely handle potential null arrays, avoiding NullPointerException. It checks if the array's length is 0 and prints true if the array is empty or uninitialized.