diff --git a/hawkbit-ui/src/main/java/org/eclipse/hawkbit/ui/tenantconfiguration/ConfigurationItem.java b/hawkbit-ui/src/main/java/org/eclipse/hawkbit/ui/tenantconfiguration/ConfigurationItem.java
index 746d52ca5..44408b343 100644
--- a/hawkbit-ui/src/main/java/org/eclipse/hawkbit/ui/tenantconfiguration/ConfigurationItem.java
+++ b/hawkbit-ui/src/main/java/org/eclipse/hawkbit/ui/tenantconfiguration/ConfigurationItem.java
@@ -26,6 +26,7 @@ public interface ConfigurationItem {
      * in configuration group.
      *
      */
+    @FunctionalInterface
     interface ConfigurationItemChangeListener extends Serializable {
         /**
          * called to notify about configuration has been changed.