RFR: 8312089: Simplify and modernize equals, hashCode, and compareTo in java.nio and implementation code

[Pavel Rappo]

On Fri, 14 Jul 2023 12:06:29 GMT, Pavel Rappo <prappo at openjdk.org> wrote:

> Please review this PR to use modern APIs and language features to simplify equals, hashCode, and compareTo for in java.nio and implementation code.
> 
> Please note, test results are pending.
> 
> Additional notes:
> 
> * This PR saves a volatile read in java.nio.file.attribute.AclEntry.hashCode. Not that it's too important, but worth noting because of rearrangements.
> 
> * java.nio.charset.Charset#compareTo seems **inconsistent** with equals. If so, I cannot see where that inconsistency is specified.
> 
> * Is this a **bug** in sun.nio.ch.FileKey#hashCode? Tell me if not, I'll revert it.
> 
> * This PR simplifies the tail of java.nio.file.attribute.FileTime.compareTo. Unless I'm missing something, that comment in source above the affected lines **seems** not to prohibit such a simplification.
> 
> * sun.nio.fs.UnixFileStore#hashCode does not include entry.name(). While it's not wrong, I wonder if it was on purpose.
> 
> * Despite its title, this PR also and opportunistically refactors sun.nio.fs.UnixPath.endsWith.

src/java.base/share/classes/java/nio/charset/Charset.java line 963:

> 961: 
> 962:     /**
> 963:      * {@return Computes a hashcode for this charset}

Oops. Should be this instead:

    {@return a hashcode for this charset}

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PR Review Comment: https://git.openjdk.org/jdk/pull/14886#discussion_r1263662782