code: public OMVRBTreeEntry<K, V> getLowerEntry(final K key) {
      final OMVRBTreeEntry<K, V> p = getEntry(key, true, PartialSearchMode.LOWEST_BOUNDARY);
  
      if (p == null)
        return null;
  
      return previous(p);
    }
docs: Returns the entry for the greatest key less than the specified key; if no such entry exists (i.e., the least key in the Tree is
  greater than the specified key), returns <tt>null</tt>.