code: public VirtualFile getChild(String path) {
          if (path == null) {
              throw VFSMessages.MESSAGES.nullArgument("path");
          }
          final List<String> pathParts = PathTokenizer.getTokens(path);
          VirtualFile current = this;
          for (String part : pathParts) {
              if (PathTokenizer.isReverseToken(part)) {
                  final VirtualFile parent = current.parent;
                  current = parent == null ? current : parent;
              } else if (PathTokenizer.isCurrentToken(part) == false) {
                  current = new VirtualFile(part, current);
              }
          }
          return current;
      }
docs: Get a child virtual file.  The child may or may not exist in the virtual filesystem.
  
  @param path the path
  @return the child
  @throws IllegalArgumentException if the path is null