What is ArrayUtils.nullToEmpty in Java?

nullToEmpty is a static method of the ArrayUtils class that returns an empty arrayan array of length zero if the passed array reference points to null.

The method returns the same array reference if the passed array reference doesn’t point to null.

Add apache commons-lang package

ArrayUtils is defined in the Apache Commons Lang package. To add Apache Commons Lang to the Maven Project, add the following dependency to the pom.xml file.

<dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.12.0</version>
</dependency>

For other versions of the commons-lang package, refer to the Maven Repository.

How to import ArrayUtils

You can import the ArrayUtils class as follows.

import org.apache.commons.lang3.ArrayUtils;

Syntax

public static int[] nullToEmpty(final int[] array)

Parameters

  • final int[] array: the array reference to check for null.

Return value

This method returns an empty array if the input array is null. Otherwise, it returns the passed array if the input array is not null.

Code

Example 1

  • array = null

Application of the nullToEmpty function will result in the following empty array: [].

Example 2

  • array = [1,2]

Application of the nullToEmpty function will result in the same array reference: [1,2].

import org.apache.commons.lang3.ArrayUtils;
public class Main {
    public static void main(String[] args) {
        int[] array = null;
        int[] result = ArrayUtils.nullToEmpty(array);
        System.out.println("Length of the result array is " + result.length);
        array = new int[]{1};
        result = ArrayUtils.nullToEmpty(array);
        System.out.println("Length of the result array is " + result.length);
    }
}

Output

Length of the result array is 0
Length of the result array is 1

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