diff --git a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/listeners/TypedMessageListener.java b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/listeners/TypedMessageListener.java
index ab38120..eea1622 100644
--- a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/listeners/TypedMessageListener.java
+++ b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/listeners/TypedMessageListener.java
@@ -27,6 +27,7 @@
  *
  * @param <T> type of message/POJO this handles
  */
+@FunctionalInterface
 public interface TypedMessageListener<T> {
 
     /**