RFR: 8221723: Avoid storing zero to String.hash

[Aleksey Shipilev]

On 4/1/19 10:08 PM, Brian Goetz wrote:
> There's another reason to avoid these writes, besides CDS optimizations: do-nothing writes generate
> useless card mark activity.

Not for primitive stores, like hash code. But you can construct a funny workload where storing zero
hash code would false-share with something important. I think CDS is the major use case here, and it
is a legit one.

-Aleksey