Illegal reflective access operation warning when using `java.lang.Void` as value type

I’m using Jackson (2.9.7) through Spring’s RestTemplate:

ResponseEntity<Void> response = getRestTemplate().exchange(
		requestUrl,
		HttpMethod.PATCH,
		new HttpEntity<>(dto, authHeaders),
		Void.class
);

When Void is used to indicate that the ResponseEntity has no body, the following warning appears in the console:

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.fasterxml.jackson.databind.util.ClassUtil (file:/<snip>repository/com/fasterxml/jackson/core/jackson-databind/2.9.7/jackson-databind-2.9.7.jar) to constructor java.lang.Void()
WARNING: Please consider reporting this to the maintainers of com.fasterxml.jackson.databind.util.ClassUtil
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

The problem disappears if String is used as generic type.

[cowtowncoder]

It probably also makes sense to add explicit handling for (nominal) type Void. Not much point in introspecting it as POJO. I’ll actually re-open this to have a look.

[cowtowncoder]

Ok: as an orthogonal thing, I added handling for Void as special type to avoid handling of type as POJO; this should prevent warning. There are already handlers for “always read/write asnull”, as it happens, so not much additional work.