This is quite old question, but adding my observation if anyone still checking for the details on graceful shutdown in spring boot.

In spring boot version 3.4+ , graceful shutdown is enabled by default for all four embedded web servers(i.e: Jetty, Reactor Netty, Tomcat, and Undertow). You can refer this spring boot doc for further details https://docs.spring.io/spring-boot/3.4/reference/web/graceful-shutdown.html