private void checkMovable(File file, JimfsPath path) throws FileSystemException {
    if (file.isRootDirectory()) {
      throw new FileSystemException(path.toString(), null, "can't move root directory");
    }
  }
Copies or moves the file at the given source path to the given dest path.
jimfs/src/main/java/com/google/common/jimfs/FileSystemView.java