A live demo is running at https://ff4j-demo.herokuapp.com/ (it can take up to 30s to start, heroku start the demo only on-demand). The following steps will help you build this sample.

1.a - Using DOCKER
If you already have Docker install on your machine you can simply run the demo with the command below, it should start at http://localhost:8080. 🤘

docker run -p 8080:8080 ff4j/ff4j-sample-springboot2x:1.8.5

1.b - Using MAVEN
The source code of this demo is available on youtube at https://github.com/ff4j/ff4j-samples/tree/master/spring-boot-2x/ff4j-sample-springboot2x let's clone and run the sample. It should (also) start at http://localhost:8080. You can now start to copy paste or retro engineering, sometime the fastest way right.

git clone https://github.com/ff4j/ff4j-samples.git

cd spring-boot-2x/ff4j-sample-springboot2x

mvn spring-boot:run

This is what it look likes

Unzip, import the project in your favorite IDE, open your pom.xml file and add the following dependencies.

<dependency>
 <groupId>org.ff4j</groupId>
 <artifactId>ff4j-spring-boot-starter</artifactId>
 <version>${ff4j.version}</version>
</dependency>
<dependency>
 <groupId>org.ff4j</groupId>
 <artifactId>ff4j-web</artifactId>
 <scope>test</scope>
 <version>${ff4j.version}</version>
</dependency>	  

You will define the property ff4j.version to match the current version   --

<properties>
  <ff4j.version>...</ff4j.version>
</properties>

import org.ff4j.FF4j;
import org.ff4j.audit.repository.InMemoryEventRepository;
import org.ff4j.property.store.InMemoryPropertyStore;
import org.ff4j.store.InMemoryFeatureStore;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class FF4jConfig {
    
    @Bean
    public FF4j getFF4j() {
        FF4j ff4j = new FF4j();
        
        /* 
         * Implementation of each store. Here this is boiler plate as if nothing 
         * is specified the inmemory is used. Those are really the one that will
         * change depending on your technology.
         */
        ff4j.setFeatureStore(new InMemoryFeatureStore());
        ff4j.setPropertiesStore(new InMemoryPropertyStore());
        ff4j.setEventRepository(new InMemoryEventRepository());

        // Enabling audit and monitoring, default value is false
        ff4j.audit(true);

        // When evaluting not existing features, ff4j will create then but disabled 
        ff4j.autoCreate(true);

        // To define RBAC access, the application must have a logged user
        //ff4j.setAuthManager(...);

        // To define a cacher layer to relax the DB, multiple implementations
        //ff4j.cache([a cache Manager]);
        
        return ff4j;
    }
}

@Configuration
// Enable the REST API documentation
@EnableFF4jSwagger
// The class should be on classpath : FF4jDispatcherServlet
@ConditionalOnClass({FF4jDispatcherServlet.class})
// Setup FF4j first, not is required
@AutoConfigureAfter(FF4jConfig.class)
public class FF4jWebConsoleConfiguration extends SpringBootServletInitializer {
    @Bean
    @ConditionalOnMissingBean
    public FF4jDispatcherServlet defineFF4jServlet(FF4j ff4j) {
        FF4jDispatcherServlet ff4jConsoleServlet = new FF4jDispatcherServlet();
        ff4jConsoleServlet.setFf4j(ff4j);
        return ff4jConsoleServlet;
    }
    @Bean
    @SuppressWarnings({"rawtypes","unchecked"})
    public ServletRegistrationBean registerFF4jServlet(FF4jDispatcherServlet ff4jDispatcherServlet) {
        return new ServletRegistrationBean(ff4jDispatcherServlet, "/ff4j-web-console/*");
    }
}

@RestController
@RequestMapping("/")
public class HomeController {
    
    private static final Logger LOGGER = LoggerFactory.getLogger(HomeController.class);
    private static final String FEATURE_SHOW_WEBCONSOLE = "showWebConsoleURL";
    private static final String FEATURE_SHOW_REST_API   = "showRestApiURL";
    private static final String FEATURE_SHOW_USERNAME   = "showUserName";
    private static final String PROPERTY_USERNAME       = "username";
    
    @Autowired
    public FF4j ff4j;
    
    @PostConstruct
    public void populateDummyFeatureForMySample() {
        if (!ff4j.exist(FEATURE_SHOW_WEBCONSOLE)) {
            ff4j.createFeature(new Feature(FEATURE_SHOW_WEBCONSOLE, true));
        }
        if (!ff4j.exist(FEATURE_SHOW_REST_API)) {
            ff4j.createFeature(new Feature(FEATURE_SHOW_REST_API, true));
        }
        if (!ff4j.exist(FEATURE_SHOW_USERNAME)) {
            ff4j.createFeature(new Feature(FEATURE_SHOW_USERNAME, true));
        }
        if (!ff4j.getPropertiesStore().existProperty(PROPERTY_USERNAME)) {
            ff4j.createProperty(new PropertyString(PROPERTY_USERNAME, "cedrick"));
        }
        LOGGER.info(" + Features and properties have been created for the sample.");
    }

@RequestMapping(value = "/", method = RequestMethod.GET, produces = "text/html")
    public String get() {
        LOGGER.info(" + Rendering home page...");
        StringBuilder htmlPage = new StringBuilder("<html><body><ul>");
        htmlPage.append("<h2>This is home page.</h2>");
        htmlPage.append("<p>Displaying the links below is driven by features in FF4j."
                + "If you disable the feature "
                + "the link will disapear (but the servlet will still response, "
                + "this is just a trick to illustrate "
                + "response in the UI)</p>");
        htmlPage.append("<p><b>List of resources for you :"
                + "</b><br/><ul>");
        if (ff4j.check(FEATURE_SHOW_WEBCONSOLE)) {
            htmlPage.append("<li> To access the  To access the <b>REST API</b> "
                    + "please go to <a href=\"./api/ff4j\" target=\"_blank\">ff4j-rest-api </a>");
        }
        if (ff4j.check(FEATURE_SHOW_USERNAME)) {
            if (ff4j.getPropertiesStore().existProperty(PROPERTY_USERNAME)) {
                htmlPage.append("<li> " + PROPERTY_USERNAME + " value is ");
                htmlPage.append("<span style=\"color:blue;font-weight:bold\">");
                htmlPage.append(ff4j.getPropertiesStore().readProperty(PROPERTY_USERNAME).asString());
                htmlPage.append("</span>");
            } else {
                htmlPage.append("<li> " + PROPERTY_USERNAME + " does not exist.");
            }
        }
        htmlPage.append("</ul></body></html>");
        return htmlPage.toString();
}