code: @Override
      public T get(final long _id)
      {
          if (!hasEntries()) {
              initialize(AbstractAutomaticCache.class);
          }
          return getCache4Id().get(new Long(_id));
      }
docs: Returns for given key id the cached object from the cache4Id cache. If
  the cache is NOT initialized <code>null</code> is returned.
  
  @param _id   id of searched cached object
  @return cached object