jFairy by Devskiller

Java fake data generator. According to Wikipedia:

Fairyland, in folklore, is the fabulous land or abode of fairies or fays.

Installation

Add the following dependency to your pom.xml:

<dependency>
    <groupId>com.devskiller</groupId>
    <artifactId>jfairy</artifactId>
    <version>0.8.2</version>
</dependency>

Usage

Creating simple objects

Fairy fairy = Fairy.create();
Person person = fairy.person();

System.out.println(person.getFirstName());
// Chloe
System.out.println(person.getLastName());
// Barker
System.out.println(person.getEmail());
// barker@yahoo.com
System.out.println(person.getTelephoneNumber());
// 690-950-802
System.out.println(person.getJobTitle());
// Software Developer

Person adultMale = fairy.person(PersonProperties.male(), PersonProperties.minAge(21));
System.out.println(adultMale.isMale());
// true
System.out.println(adultMale.getDateOfBirth());
// at least 21 years earlier

Creating related objects

Fairy fairy = Fairy.create();
Company company = fairy.company();
System.out.println(company.getName());
// Robuten Associates
System.out.println(company.getUrl());
// http://www.robuteniaassociates.com

Person salesman = fairy.person(PersonProperties.withCompany(company));
System.out.println(salesman.getFullName());
// Juan Camacho
System.out.println(salesman.getCompanyEmail());
// juan.camacho@robuteniaassociates.com

Supported locales

Locale	Language tag
English (default)	en
Polish	pl
German	de
French	fr
Spanish	es
Swedish	sv
Chinese	zh
Georgian	ka
Italian	it
Brazilian Portuguese	br
Slovak	sk
Turkish	tr

Fairy enFairy = Fairy.create();
// Locale.ENGLISH is default
Fairy plFairy = Fairy.create(Locale.forLanguageTag("pl"));
// Polish version
Fairy brFairy = Fairy.create(Locale.forLanguageTag("br"));
// Brazilian version

Unique values

UniqueFairy unique = fairy.unique();
Person p1 = unique.person();  // unique by email
Person p2 = unique.person();  // different email than p1
Company c = unique.company(); // unique by name

For custom uniqueness keys:

UniqueEnforcer<Person> unique = UniqueEnforcer.of(fairy::person, Person::getFullName);
Person p = unique.next();

Thread safety

Fairy objects are not designed for concurrent use by multiple threads. It is recommended to create a separate Fairy instance for each thread.

While some methods might appear safe, the underlying Random implementation can lead to contention and poor performance. Creating dedicated instances ensures both thread safety and optimal execution speed.

JUnit 5 Extension

If you use JUnit 5, check out jfairy-junit-extension — an extension that allows injecting jFairy-generated objects directly into test method parameters.

Building

This project uses Maven and can be built using the provided wrapper:

./mvnw