public static String concatPaths(String... paths) {
    final StringBuilder builder = new StringBuilder();
    for (String path : paths) {
      if (path.length() == 0) continue;

      final int len = builder.length();
      if (len > 0 && builder.charAt(len - 1) != '/' && builder.charAt(len - 1) != File.separatorChar) {
        builder.append('/');
      }
      builder.append(len != 0 ? trimForwardSlashes(path) : path);
    }
    return builder.toString();
  }
public static String concatPaths(String... paths)