What is ObjectUtils.allNull in Java?
allNull() is a ObjectUtils class that is used to check if all the values in the array point to a null reference.
- The method returns
falseif any value in the array of values is notnull. - The method returns
trueif all the values in the passed array arenullor the array isnullor empty.
How to import ObjectUtils
The definition of ObjectUtils can be found in the Apache Commons Lang package, which we can add to the Maven project by adding 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.
You can import the ObjectUtils class as follows:
import org.apache.commons.lang3.ObjectUtils;
Syntax
public static boolean allNull( Object... values)
Parameters
values: The list of objects to test.
Return value
The allNull() method returns true if all of the objects in the list are null. Otherwise, it returns false.
Code
import org.apache.commons.lang3.ObjectUtils;import java.util.Arrays;public class Main {public static void main(String[] args) {Object[] objects = {"hi", 3, 3.24};System.out.printf("The output of ObjectUtils.allNull() for the string - '%s' is %s", Arrays.toString(objects), ObjectUtils.allNull(objects));System.out.println();objects = null;System.out.printf("The output of ObjectUtils.allNull() for the string - '%s' is %s", Arrays.toString(objects), ObjectUtils.allNull(objects));System.out.println();objects = new Object[]{null, null, null};System.out.printf("The output of ObjectUtils.allNull() for the string - '%s' is %s", Arrays.toString(objects), ObjectUtils.allNull(objects));System.out.println();objects = new Object[]{1.2, null, null};System.out.printf("The output of ObjectUtils.allNull() for the string - '%s' is %s", Arrays.toString(objects), ObjectUtils.allNull(objects));System.out.println();objects = new Object[0];System.out.printf("The output of ObjectUtils.allNull() for the string - '%s' is %s", Arrays.toString(objects), ObjectUtils.allNull(objects));System.out.println();}}
Output
The output of the code is as follows:
The output of ObjectUtils.allNull() for the string - '[hi, 3, 3.24]' is false
The output of ObjectUtils.allNull() for the string - 'null' is true
The output of ObjectUtils.allNull() for the string - '[null, null, null]' is true
The output of ObjectUtils.allNull() for the string - '[1.2, null, null]' is false
The output of ObjectUtils.allNull() for the string - '[]' is true
Explanation
Example 1
objects = ["hi", 3, 3.24]
The method returns false because none of the objects in the list are null.
Example 2
objects = null
The method returns true because the array/list of objects points to null.
Example 3
objects = [null, null, null]
The method returns true because all the values in the array/list of objects point to null.
Example 4
objects = [1.2, null, null]
The method returns false because at least one of the objects in the list is not null.
Example 5
objects = []
The method returns true because the array/list of objects is empty.
