I resolved implementing in this way:
1) adding the Runnable implementation
@ManagedBean(eager= true, name="dashboardbean")
@ApplicationScoped
public class DashboardBean implements Serializable, Runnable {
2) adding implementation method "run"
@Override
public void run() {
    System.out.println("##########populateData#############");
    allServerCount = numbersServer.get("serverCount");
    System.out.println("###########server "+allServerCount+"#############");
    System.out.println("###########end populateData#############");
}
3) implemented the init method of the bean
@PostConstruct
public void init() {
    System.out.println("##########init#############");
    scheduler = Executors.newSingleThreadScheduledExecutor();
    scheduler.scheduleAtFixedRate(this, 0, 2, TimeUnit.MINUTES);
    System.out.println("##########end#############");
}
4) adding part for destroing scheduler
private ScheduledExecutorService scheduler; 
@PreDestroy
public void destroy() {
    scheduler.shutdownNow();
}
and this is the output generated every 2 minutes on the logs
##########populateData#############
###########server 339#############
###########end populateData#############
##########populateData#############
###########server 340#############
###########end populateData#############
##########populateData#############
###########server 340#############
###########end populateData#############