diff --git a/redisson/src/main/java/org/redisson/api/executor/TaskFailureListener.java b/redisson/src/main/java/org/redisson/api/executor/TaskFailureListener.java
index ea3233179..1a5091830 100644
--- a/redisson/src/main/java/org/redisson/api/executor/TaskFailureListener.java
+++ b/redisson/src/main/java/org/redisson/api/executor/TaskFailureListener.java
@@ -21,6 +21,7 @@ package org.redisson.api.executor;
  * @author Nikita Koksharov
  *
  */
+@FunctionalInterface
 public interface TaskFailureListener extends TaskListener {
 
     /**
diff --git a/redisson/src/main/java/org/redisson/api/executor/TaskFinishedListener.java b/redisson/src/main/java/org/redisson/api/executor/TaskFinishedListener.java
index 318621459..9e79da924 100644
--- a/redisson/src/main/java/org/redisson/api/executor/TaskFinishedListener.java
+++ b/redisson/src/main/java/org/redisson/api/executor/TaskFinishedListener.java
@@ -21,6 +21,7 @@ package org.redisson.api.executor;
  * @author Nikita Koksharov
  *
  */
+@FunctionalInterface
 public interface TaskFinishedListener extends TaskListener {
 
     /**
diff --git a/redisson/src/main/java/org/redisson/api/executor/TaskStartedListener.java b/redisson/src/main/java/org/redisson/api/executor/TaskStartedListener.java
index 48164813b..e148c0053 100644
--- a/redisson/src/main/java/org/redisson/api/executor/TaskStartedListener.java
+++ b/redisson/src/main/java/org/redisson/api/executor/TaskStartedListener.java
@@ -21,6 +21,7 @@ package org.redisson.api.executor;
  * @author Nikita Koksharov
  *
  */
+@FunctionalInterface
 public interface TaskStartedListener extends TaskListener {
 
     /**
diff --git a/redisson/src/main/java/org/redisson/api/executor/TaskSuccessListener.java b/redisson/src/main/java/org/redisson/api/executor/TaskSuccessListener.java
index e2ec76e3a..4b7493372 100644
--- a/redisson/src/main/java/org/redisson/api/executor/TaskSuccessListener.java
+++ b/redisson/src/main/java/org/redisson/api/executor/TaskSuccessListener.java
@@ -21,6 +21,7 @@ package org.redisson.api.executor;
  * @author Nikita Koksharov
  *
  */
+@FunctionalInterface
 public interface TaskSuccessListener extends TaskListener {
 
     /**