Spring Boot request header return null value

The issue was with the nginx configuration.

I set the underscores_in_headers on; for the server and now it doesn't drop the headers with underscore in their names.

The solution suggested by @Karol Dowbecki works as well. When I renamed my header to requestDate, I was able to read the value successfully.

Some network tools can drop headers that contain underscore in it's name. As per this answer underscore is a legal character but it's uncommon and sometimes tools require additional configuration to support it.

Rename your header to requestDate or request-date and see if it helps. If it works without underscore than inspect network route between client and server e.g. maybe there is a proxy that drops them?