Default response charset is set to Shift_JIS from JWS 5.7

Issue

If a host locale is ja_JP.UTF-8 or when calling HttpServletResponse.setLocale(Locale.JAPANESE) from a servlet, the default response charset is set to charset=Shift_JIS from JWS 5.7. This change has caused compatibility issues. Is there any workaround for this issue?

@WebServlet("/echo")
public class EchoServlet extends HttpServlet {
    @Override
    public void doGet(HttpServletRequest req, HttpServletResponse res)
            throws ServletException, IOException {
        res.setContentType("text/plain"); // no ;chatset=<charset> attribute in setContentType
        res.setLocale(Locale.JAPANESE);   // set response locale to ja
        res.getOutputStream().println("echo");
    }
}

JWS 5.6 or earlier:

$ curl -v 127.0.0.1:8080/echo/echo
...
< HTTP/1.1 200 
< Content-Type: text/plain   <<<===
< Content-Language: ja
< Content-Length: 6
< Date: Thu, 24 Nov 2022 09:11:37 GMT
< 
echo

JWS 5.7.0 or later:

$ curl -v 127.0.0.1:8080/echo/echo
...
> 
< HTTP/1.1 200 
< Content-Type: text/plain;charset=Shift_JIS  <<<===
< Content-Language: ja
< Content-Length: 6
< Date: Thu, 24 Nov 2022 09:11:59 GMT
< 
echo