code: public static List<File> getFilesInDir(final File inputPath) {
      final List<File> fileList = new ArrayList<File>();
      for (final File aFile : Files.fileTreeTraverser().preOrderTraversal(
          inputPath)) {
        if (aFile.isFile()) {
          fileList.add(aFile);
        }
      }
      return fileList;
    }
docs: Recursively get every file in a directory and add them to a list.
  
  @param inputPath
  the input directory
  @return the list containing all the files