MappingJackson2HttpMessageConverter default character set issue

[kyucumber]

Version: Spring Framework 5.2.7

MappingJackson2HttpMessageConverter

 * <p>By default, this converter supports {@code application/json} and {@code application/*+json}
 * with {@code UTF-8} character set. This can be overridden by setting the
 * {@link #setSupportedMediaTypes supportedMediaTypes} property.

The above comment says that MappingJackson2HttpMessageConverter's default charater set is UTF-8.

But my MappingJackson2HttpMessageConverter's default characterSet is null.

Is the comment wrong? Or am I doing somethig wrong?

Is the default character set deprecated?

If the default character set is deprecated, I think it would be better to delete the content from the comment.

[bclozel]

I'm not sure I understand the issue. JSON encoding is UTF-8 by default (see #22788).
This defaultCharset attribute is inherited from its class hierarchy - being null might be perfectly acceptable since it's marked as @Nullable.

Do you have a sample application that shows an incorrect behavior? If so, could you share it with us?

[kyucumber]

@bclozel

I saw the document (#22788)
Thank you.

It works well in spring applications.
However, some tests using mockMvc do not work normally.

The defaultCharacterSet is UTF-8 in the comment of the MappingJackson2HttpMessageConverter class.
However, the defaultCaracterSet value of the parent class value was null.
So I was confused.

I'll close because I'm sure there's no problem with that content.
Thank you.