public static @NotNull String collapseWhiteSpace(@NotNull CharSequence s) {
    StringBuilder result = new StringBuilder();
    boolean space = false;
    for (int i = 0, length = s.length(); i < length; i++) {
      char ch = s.charAt(i);
      if (isWhiteSpace(ch)) {
        if (!space) space = true;
      }
      else {
        if (space && result.length() > 0) result.append(' ');
        result.append(ch);
        space = false;
      }
    }
    return result.toString();
  }
public static @NotNull String collapseWhiteSpace(@NotNull CharSequence s)