diff --git a/src/main/java/org/springframework/data/redis/listener/RedisMessageListenerContainer.java b/src/main/java/org/springframework/data/redis/listener/RedisMessageListenerContainer.java
index f04588f47..5108adbec 100644
--- a/src/main/java/org/springframework/data/redis/listener/RedisMessageListenerContainer.java
+++ b/src/main/java/org/springframework/data/redis/listener/RedisMessageListenerContainer.java
@@ -639,19 +639,14 @@ public class RedisMessageListenerContainer implements InitializingBean, Disposab
 
 	private void addListener(MessageListener listener, Collection<? extends Topic> topics) {
 
-		Assert.notNull(listener, "a valid listener is required");
-		Assert.notEmpty(topics, "at least one topic is required");
+		Assert.notNull(listener, "A valid listener is required");
+		Assert.notEmpty(topics, "At least one topic is required");
 
 		List<byte[]> channels = new ArrayList<>(topics.size());
 		List<byte[]> patterns = new ArrayList<>(topics.size());
 
-		// add listener mapping
-		Set<Topic> set = listenerTopics.get(listener);
-
-		if (set == null) {
-			set = new CopyOnWriteArraySet<>();
-			listenerTopics.put(listener, set);
-		}
+		// safely lookup or add MessageListener to Topic mapping
+		Set<Topic> set = listenerTopics.computeIfAbsent(listener, key -> new CopyOnWriteArraySet<>());
 
 		set.addAll(topics);