*/
          toJoin = Arrays.copyOf(toJoin, expandedCapacity(toJoin.length, toJoin.length + 1));
        }
        toJoin[i++] = toString(part);
      }
      // We might not have seen the expected number of elements, as discussed above.
      if (i != toJoin.length) {
        toJoin = Arrays.copyOf(toJoin, i);
      }
      return String.join(separator, toJoin);
    }
    return join(parts.iterator());

      }
    }
  }

  /** Invokes {@code toJoin.}{@link Thread#join() join()} uninterruptibly. */
  @J2ktIncompatible
  @GwtIncompatible // concurrency
  public static void joinUninterruptibly(Thread toJoin) {
    boolean interrupted = false;
    try {
      while (true) {
        try {
          toJoin.join();
          return;
        } catch (InterruptedException e) {