j.l.String.join(java.lang.CharSequence, java.lang.Iterable) sample doesn't compile and is incorrect

JDK8 b104:

http://download.java.net/jdk8/docs/api/java/lang/String.html#join%28java.lang.CharSequence,%20java.lang.Iterable%29

Normative part of the spec contains usage sample:

     Set<String> strings = new HashSet<>();
     Strings.add("Java"); strings.add("is");
     strings.add("very"); strings.add("cool");
     String message = String.join("-", strings);
     //message returned is: "Java-is-very-cool"

1) It doesn't compile
2) HashSet doesn't guarantee order of iteration