/**
  * Clears the volatile cache attached to a user session.
  *
  * @param sessionInfo the session of a user.
  */
 public static void clearFrom(SessionInfo sessionInfo) {
   VolatileResourceCacheService cache =
       sessionInfo
           .getCache()
           .get(VolatileResourceCacheService.class.getName(), VolatileResourceCacheService.class);
   if (cache != null) {
     cache.clear();
   }
 }
 /** Clears all the resources referenced into this instance of volatile cache. */
 public void clear() {
   final VolatileResourceCacheService current = this;
   try {
     ManagedThreadPool.invoke(
         () -> {
           try {
             current.deleteAllAttachments();
           } catch (RuntimeException e) {
             // This treatment must not disturb the server in any case, so nothing is thrown here.
             SilverLogger.getLogger(this)
                 .error("The clear of volatile cache did not end successfully...", e);
           }
         });
   } catch (RuntimeException e) {
     // This treatment must not disturb the server in any case, so nothing is thrown here.
     SilverLogger.getLogger(this)
         .error("The clear of volatile cache did not end successfully...", e);
   }
 }