private void notifyAboutUnlockedAchievement(AchievementDefinition achievementDefinition) {
   notificationService.addNotification(
       new TransientNotification(
           i18n.get("achievement.unlockedTitle"),
           achievementDefinition.getName(),
           new Image(achievementDefinition.getUnlockedIconUrl())));
 }
 @Override
 @Cacheable(CacheNames.ACHIEVEMENTS)
 public Image getUnlockedIcon(AchievementDefinition achievementDefinition) {
   if (Strings.isNullOrEmpty(achievementDefinition.getUnlockedIconUrl())) {
     return new Image(themeService.getThemeFile(ThemeService.DEFAULT_ACHIEVEMENT_IMAGE), true);
   }
   return new Image(achievementDefinition.getUnlockedIconUrl(), true);
 }