@Throws NullPointerException need to add HttpRequest.Builder as null checks are available for most of the implementation.

Ex:-

public HttpRequest.Builder timeout(TimeUnit timeunit, long timeval) {
    Objects.requireNonNull(timeunit);
.....


JavaDoc :-


    timeout

    public abstract HttpRequest.Builder timeout(TimeUnit unit,
                                                long timeval)

    Sets a timeout for this request. If the response is not received within the specified timeout then a HttpTimeoutException is thrown from HttpRequest.response() or HttpRequest.responseAsync()completes exceptionally with a HttpTimeoutException.

    Parameters:
        unit - the timeout units
        timeval - the number of units to wait for
    Returns:
        this request builder