code: @Override
      public void clear() {
          final Segment<K,V>[] segments = this.segments;
          for (int j = 0; j < segments.length; ++j) {
              Segment<K,V> s = segmentAt(segments, j);
              if (s != null) {
                s.clear();
              }
          }
      }
docs: Removes all of the mappings from this map.