diff --git a/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/BrokerService.java b/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/BrokerService.java
index acab311da1c1e..2e8fdf71a4e74 100644
--- a/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/BrokerService.java
+++ b/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/BrokerService.java
@@ -1597,12 +1597,12 @@ private CompletableFuture<Integer> unloadServiceUnit(NamespaceBundle serviceUnit
     }
 
     public void cleanUnloadedTopicFromCache(NamespaceBundle serviceUnit) {
-        topics.forEach((name, topicFuture) -> {
-            TopicName topicName = TopicName.get(name);
+        for (String topic : topics.keys()) {
+            TopicName topicName = TopicName.get(topic);
             if (serviceUnit.includes(topicName)) {
                 pulsar.getBrokerService().removeTopicFromCache(topicName.toString());
             }
-        });
+        }
     }
 
     public AuthorizationService getAuthorizationService() {