private static List<String> getJsonFiles (File file) {
    List<String> files = new ArrayList<>();
    if (file.isFile()) {
      if (file.getName().endsWith(".json")) {
        files.add(file.getAbsolutePath());
      }
    } else {
      for (File subFile : file.listFiles()) {
        files.addAll(getJsonFiles(subFile));
      }
    }
    return files;
  }
main method.

@param args relative or absolute path of the configuration file.
KITE-Engine/src/main/java/org/webrtc/kite/Engine.java