RFR 8206123 : ArrayDeque created with default constructor can only hold 15 elements

[joe darcy]

Hello,

Note that another approach would be to change the spec to match the 
long-standing implementation. That is the the default resolution patch 
in situations like this, but in this case I don't think it matters very 
much how the matter is resolved.

Cheers,

-Joe


On 6/29/2018 7:21 PM, Ivan Gerasimov wrote:
> Hello!
>
> The spec states that an ArrayDeque created with the default 
> constructor should be able to hold 16 elements.
>
> https://docs.oracle.com/javase/10/docs/api/java/util/ArrayDeque.html#%3Cinit%3E() 
>
> """
> Constructs an empty array deque with an initial capacity sufficient to 
> hold 16 elements.
> """
>
> In the constructor an array of size 16 is created:
>         elements = new Object[16];
>
> However, one element must always be null:
>     /**
>      * The array in which the elements of the deque are stored.
>      * All array cells not holding deque elements are always null.
>      * The array always has at least one null slot (at tail).
>      */
>     transient Object[] elements;
>
> which leaves us space for only 15 elements, contrarily to what the 
> spec promises.
>
>
> Would you please help review a trivial fix?
>
> BUGURL: https://bugs.openjdk.java.net/browse/JDK-8206123
> WEBREV: http://cr.openjdk.java.net/~igerasim/8206123/00/webrev/
>
> Thanks in advance!
>