diff --git a/framework-docs/src/main/java/org/springframework/docs/integration/observability/httpserver/reactive/UserController.java b/framework-docs/src/main/java/org/springframework/docs/integration/observability/httpserver/reactive/UserController.java
index fc6221558c8..0f7d8b68a66 100644
--- a/framework-docs/src/main/java/org/springframework/docs/integration/observability/httpserver/reactive/UserController.java
+++ b/framework-docs/src/main/java/org/springframework/docs/integration/observability/httpserver/reactive/UserController.java
@@ -34,8 +34,8 @@ public class UserController {
 	}
 
 	// @fold:on
+	@SuppressWarnings("serial")
 	static class MissingUserException extends RuntimeException {
-
 	}
 	// @fold:off
 
diff --git a/framework-docs/src/main/java/org/springframework/docs/integration/observability/httpserver/servlet/UserController.java b/framework-docs/src/main/java/org/springframework/docs/integration/observability/httpserver/servlet/UserController.java
index 5f44127961e..03399272017 100644
--- a/framework-docs/src/main/java/org/springframework/docs/integration/observability/httpserver/servlet/UserController.java
+++ b/framework-docs/src/main/java/org/springframework/docs/integration/observability/httpserver/servlet/UserController.java
@@ -35,8 +35,8 @@ public class UserController {
 	}
 
 	// @fold:on
+	@SuppressWarnings("serial")
 	static class MissingUserException extends RuntimeException {
-
 	}
 	// @fold:off