code: public List<String> getChildren(String fqn) {
          final Node n = findNode(fqn);
          if (n == null)
              return null;
          final Set<String> names = n.getChildrenNames();
          return new ArrayList<String>(names);
      }
docs: Returns all children of a given node.
  
  @param fqn The fully qualified name of the node
  @return A list of child names (as Strings)