Add translation of Validation Messages for Japanese language

Description

I wrote ValidationMessage_ja.properties for Japanese language.
This translation has been reviewed by members of the Java community in Japan.
The log of the review is below. (Japanese)

https://qiita.com/aoetk/items/415978ee083cff9a3bcb

Environment

None

Assignee

Takashi Aoe

Reporter

Takashi Aoe

Labels

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Feedback Requested

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Feedback Requested By

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backPortable

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Suitable for new contributors

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backportDecision

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backportReEvaluate

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Components

Fix versions

Priority

Minor
Configure