langtools/src/jdk.jshell/share/classes/jdk/internal/jshell/tool/resources/l10n_ja.properties

This line in startup.feedback didn't get translated:
/set format normal display '{pre}{action} variable {name}, reset to null{post}' replaced-vardecl,varinit-ok-update

The word of "variable" and "reset to null" should be translated.