@Nullable
  private static String getJVMClassName(File outputRoot, String className) {
    while (true) {
      final File candidateClass = new File(outputRoot, className + ".class");
      if (candidateClass.exists()) {
        return className;
      }
      final int position = className.lastIndexOf('/');
      if (position < 0) {
        return null;
      }
      className = className.substring(0, position) + '$' + className.substring(position + 1);
    }
  }
@Nullable
  private static String getJVMClassName(File outputRoot, String className)