private @Nullable JimfsPath checkPath(Path other) {
    if (checkNotNull(other) instanceof JimfsPath && other.getFileSystem().equals(getFileSystem())) {
      return (JimfsPath) other;
    }
    return null;
  }
Resolves the given name against this path. The name is assumed not to be a root name.
jimfs/src/main/java/com/google/common/jimfs/JimfsPath.java