[PATCH] Use StringJoiner where appropriate in java.base

[Martin Buchholz]

On Wed, Jun 19, 2019 at 6:13 AM Сергей Цыпанов <sergei.tsypanov at yandex.ru>
wrote:

>
> Also toString() of AtomicIntegerArray, AtomicLongArray and
> AtomicReferenceArray partially duplicate logic of corresponding method
> available in j.u.Arrays and can be replaced with call to delegate.
>

 This looks incorrect to me - it replaces volatile reads with plain reads,
breaking the happens-before guarantee, (but that's  hard to demonstrate in
a test).