RFR: 8298567: Make field in RandomAccessFile final [v2]

[Chris Hegarty]

On Mon, 12 Dec 2022 14:26:40 GMT, Per Minborg <pminborg at openjdk.org> wrote:

>> This PR proposes making a field in `RandomAccessFile` final. Also, it modernises a switch statement.
>
> Per Minborg has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Make the field rw final

LGTM

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Marked as reviewed by chegar (Reviewer).

PR: https://git.openjdk.org/jdk/pull/11632