RFR: 8310837: Use ByteArrayLittleEndian in java.util.zip

[Jaikiran Pai]

On Fri, 23 Jun 2023 20:00:12 GMT, Glavo <duke at openjdk.org> wrote:

> Using `ByteArrayLittleEndian` is simpler and faster.
> 
> `make test TEST="micro:java.util.zip.ZipFileOpen"`:
> 
> 
>   Benchmark                     (size)  Mode  Cnt      Score      Error  Units
> - ZipFileOpen.openCloseZipFile     512  avgt   15  39052.832 ±  107.496  ns/op
> + ZipFileOpen.openCloseZipFile     512  avgt   15  36275.539 ±  663.193  ns/op
> - ZipFileOpen.openCloseZipFile    1024  avgt   15  77106.494 ± 4159.300  ns/op
> + ZipFileOpen.openCloseZipFile    1024  avgt   15  71955.013 ± 2296.050  ns/op

On an existing Java runtime, I had a quick look at the classes loaded at application startup to see if `MethodHandles` already gets loaded before `ZipUtils` (and related jar/zip classes). From what I see in the output, `MethodHandles` indeed is already loaded before `ZipUtils`. So I think this change doesn't bring in any new/unexpected usage of `MethodHandles` that could potentially impact startup performance.

P.S: I just noticed Alan has a similar comment about startup performance, so yes, having some numbers for a startup benchmark would be useful.

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PR Comment: https://git.openjdk.org/jdk/pull/14632#issuecomment-1605275101