What is StringUtils.firstNonEmpty in Java?

How to import `StringUtils`

StringUtils is defined in the Apache Commons Lang package. Apache Commons Lang can be added 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 StringUtils class as follows.

import org.apache.commons.lang3.StringUtils;

Syntax

public static <T extends CharSequence> T firstNonEmpty(final T... values)

Parameters

final T... values: list of values to test

To understand what ... is, refer to What are the three dots in Java?

Return value

The function returns the first non-empty value

import org.apache.commons.lang3.StringUtils;
public class Main {
    public static void main(String[] args) {
        String[] strings = {null, ""};
        System.out.println("First Non-Empty for the strings - " + StringUtils.firstNonEmpty(strings));
        strings = new String[]{null, "", "   ", "educative.io", null, "  "};
        System.out.println("First Non-Empty for the strings - " + StringUtils.firstNonEmpty(strings));
        strings = new String[]{null, "", "educative.io", null, "  "};
        System.out.println("First Non-Empty for the strings - " + StringUtils.firstNonEmpty(strings));
    }
}

Explanation

string list: [null, ""]

The output of the method when the string list above is passed is null, as there are no non-null and non-empty elements in the list.

string list: [null, "", " ", "educative.io", null, " "]

The output of the method when this string list is passed is " " i.e. the first string that is not empty, null or whitespace only. Here, whitespace is considered a non-empty string having a whitespace character.