code: public static String child(String node) {
          final int index = node.lastIndexOf('/');
          if (index < 0 || index == node.length() - 1)
              return null;
          return node.substring(index + 1, node.length());
      }
docs: Returns the last component of a node's full path (i.e. its child name in its parent).
  @param node A tree node's full path.
  @return The last component of a node's full path.