code: private void transferLinks(LinkedHashMapEntry<K,V> src,
                                 LinkedHashMapEntry<K,V> dst) {
          LinkedHashMapEntry<K,V> b = dst.before = src.before;
          LinkedHashMapEntry<K,V> a = dst.after = src.after;
          if (b == null)
              head = dst;
          else
              b.after = dst;
          if (a == null)
              tail = dst;
          else
              a.before = dst;
      }
docs: apply src's links to dst