Stream, spliterator, supplier and size

[Brian Goetz]

>> But I don't think we've exposed them to the users!  The stream()
>> methods are not for users, they are for library writers to implement
>> stream-producing methods.  If users are using them then that means
>> we've forgotten to provide something else.  (Writing Iterators is a
>> pain the neck, much more so.  But again, most users don't write
>> iterators.)
>
> Library writers are users. Everything, we will expose will be used.

What we're exposing to library writers is easy!  Here's the 
implementation in ArrayList:

     @Override
     public Stream<E> stream() {
         return Streams.stream(() -> Arrays.spliterator((E[]) 
elementData, 0, size),
                               StreamOpFlag.IS_ORDERED | 
StreamOpFlag.IS_SIZED);
     }

Before, it was much harder for ArrayList.