Spring Boot configuration file usage (#3958)

Co-authored-by: opentelemetrybot <107717825+opentelemetrybot@users.noreply.github.com>
Co-authored-by: Severin Neumann <neumanns@cisco.com>
Co-authored-by: Trask Stalnaker <trask.stalnaker@gmail.com>

content/en/docs/languages/java/automatic/spring-boot.md

@@ -19,6 +19,9 @@ following cases:
 - Startup overhead of the OpenTelemetry Java agent exceeds your requirements
 - OpenTelemetry Java agent might not work if your application already uses
   another Java monitoring agent
+- You can use the Spring Boot configuration files (`application.properties`,
+  `application.yml`) to configure the OpenTelemetry Spring Boot starter which
+  doesn't work with the OpenTelemetry Java agent
 
 [Spring Boot starter]:
   https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#using.build-systems.starters