code: public V getQuietly(Object key) {
          final Node node = data.get(key);
          return (node == null) ? null : node.getValue();
      }
docs: Returns the value to which the specified key is mapped, or {@code null}
  if this map contains no mapping for the key. This method differs from
  {@link #get(Object)} in that it does not record the operation with the
  page replacement policy.
  
  @param key the key whose associated value is to be returned
  @return the value to which the specified key is mapped, or {@code null}
  if this map contains no mapping for the key
  @throws NullPointerException if the specified key is null