code: public void cache(String key, Object obj) {
          H.Session sess = session();
          if (null != sess) {
              sess.cache(key, obj);
          } else {
              app().cache().put(key, obj);
          }
      }
docs: Add an object into cache by key. The key will be used in conjunction with session id if
  there is a session instance
  
  @param key
  the key to index the object within the cache
  @param obj
  the object to be cached