RFR: 8281631: HashMap.putAll can cause redundant space waste

[XenoAmess]

On Fri, 11 Feb 2022 11:55:13 GMT, stefan-zobel <duke at openjdk.java.net> wrote:

> > I investigated most of the usages. They just give a size, and get a capacity, even not change the 0.75 So maybe we can use some int calculation to replace the 0.75, thus replace Math.ceil for such situations.
> 
> FWIW, `(int) Math.ceil(expected / 0.75)` and `(int) ((expected * 4L + 2L) / 3L)` would be equivalent.

Yes,  and `(int) ((expected * 4L + 2L) / 3L)` actually equals `(expected + (expected + 2) / 3)` IMO, thus even avoid cast to long.

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PR: https://git.openjdk.java.net/jdk/pull/7431