Tengo un problema al compilar un ejemplo GET de bloqueo simple del HttpRequest JavaDoc:

package org.example;

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

import static java.net.http.HttpRequest.noBody;
import static java.net.http.HttpResponse.asString;

public class Http2 {
    public static void main(String[] args) throws URISyntaxException, IOException, InterruptedException {
        HttpResponse response = HttpRequest
                .create(new URI("http://www.infoq.com"))
                .body(noBody())
                .GET().response();
        int responseCode = response.statusCode();
        String responseBody = response.body(asString());

        System.out.println(responseBody);
    }
}

Me estoy poniendopackage java.net.http does not exist error al compilar utilizando JDK 9:

{ jdk9 }  » /cygdrive/c/Program\ Files/Java/jdk-9/bin/javac -d out/production -modulesourcepath org.example.module1/src/ -m org.example.module1

org.example.module1\src\org.example.module1\org\example\Http2.java:6: error: package java.net.http does not exist
import java.net.http.HttpRequest;
                    ^
org.example.module1\src\org.example.module1\org\example\Http2.java:7: error: package java.net.http does not exist
import java.net.http.HttpResponse;
                    ^
org.example.module1\src\org.example.module1\org\example\Http2.java:9: error: package java.net.http does not exist
import static java.net.http.HttpRequest.noBody;
                           ^
org.example.module1\src\org.example.module1\org\example\Http2.java:9: error: static import only from classes and interfaces
import static java.net.http.HttpRequest.noBody;
^
org.example.module1\src\org.example.module1\org\example\Http2.java:10: error: package java.net.http does not exist
import static java.net.http.HttpResponse.asString;
                           ^
org.example.module1\src\org.example.module1\org\example\Http2.java:10: error: static import only from classes and interfaces
import static java.net.http.HttpResponse.asString;
^
org.example.module1\src\org.example.module1\org\example\Http2.java:14: error: cannot find symbol
        HttpResponse response = HttpRequest
        ^
  symbol:   class HttpResponse
  location: class Http2
org.example.module1\src\org.example.module1\org\example\Http2.java:14: error: cannot find symbol
        HttpResponse response = HttpRequest
                                ^
  symbol:   variable HttpRequest
  location: class Http2
org.example.module1\src\org.example.module1\org\example\Http2.java:16: error: cannot find symbol
                .body(noBody())
                      ^
  symbol:   method noBody()
  location: class Http2
org.example.module1\src\org.example.module1\org\example\Http2.java:19: error: cannot find symbol
        String responseBody = response.body(asString());
                                            ^
  symbol:   method asString()
  location: class Http2
10 errors

El mismo error ocurre usando la línea de comando e IntelliJ.

No es un problema con mi módulo porque las clases sin java.net.http compilan y se ejecutan sin ningún problema.

¿Alguna idea de lo que está pasando?