diff --git a/spring-jms/src/main/java/org/springframework/jms/core/MessagePostProcessor.java b/spring-jms/src/main/java/org/springframework/jms/core/MessagePostProcessor.java
index c36c7dafb6..bb7b80a90d 100644
--- a/spring-jms/src/main/java/org/springframework/jms/core/MessagePostProcessor.java
+++ b/spring-jms/src/main/java/org/springframework/jms/core/MessagePostProcessor.java
@@ -32,6 +32,7 @@ import javax.jms.Message;
  * @see JmsTemplate#convertAndSend(javax.jms.Destination, Object, MessagePostProcessor)
  * @see org.springframework.jms.support.converter.MessageConverter
  */
+@FunctionalInterface
 public interface MessagePostProcessor {
 
 	/**
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/core/MessagePostProcessor.java b/spring-messaging/src/main/java/org/springframework/messaging/core/MessagePostProcessor.java
index 92e78ef50e..f4e6ceee4f 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/core/MessagePostProcessor.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/core/MessagePostProcessor.java
@@ -28,6 +28,7 @@ import org.springframework.messaging.Message;
  * @see MessageSendingOperations
  * @see MessageRequestReplyOperations
  */
+@FunctionalInterface
 public interface MessagePostProcessor {
 
 	/**