What is Validate.notEmpty() in Java?

How to import `Validate`

The definition of Validate 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 Validate class as follows.

import org.apache.commons.lang3.Validate;

Syntax

public static <T> T[] notEmpty(final T[] array, final String message, final Object... values)

Parameters

final T[] array: The array to check.
final String message: The exception message.
final Object... values: The optional values for the formatted exception message.

Return value

This method returns the validated array.

Overloaded methods

public static <T> T[] notEmpty(final T[] array)
public static <T extends Collection<?>> T notEmpty(final T collection, final String message, final Object... values)
public static <T extends Collection<?>> T notEmpty(final T collection)
public static <T extends Map<?, ?>> T notEmpty(final T map, final String message, final Object... values)
public static <T extends Map<?, ?>> T notEmpty(final T map)

import org.apache.commons.lang3.Validate;
import java.util.Arrays;
public class Main{
    public static void main(String[] args){
        // Example 1
        Integer[] ints = new Integer[]{1, 2, 3};
        System.out.printf("Validate.notEmpty(%s) = %s", Arrays.toString(ints), Arrays.toString(Validate.notEmpty(ints)));
        System.out.println();
        // Example 2
        ints = new Integer[0];
        String exceptionMessage = "The array must not be null or empty";
        System.out.printf("Validate.notEmpty(%s) = %s", Arrays.toString(ints), Arrays.toString(Validate.notEmpty(ints, exceptionMessage)));
        System.out.println();
    }
}

Output

The output of the code will be as follows:

Validate.notEmpty([1, 2, 3]) = [1, 2, 3]
Exception in thread "main" java.lang.IllegalArgumentException: The array must not be null or empty
	at org.apache.commons.lang3.Validate.notEmpty(Validate.java:249)
	at Main.main(Main.java:16)