diff --git a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/MessageDispatcher.java b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/MessageDispatcher.java
index 565c0ad36988..e41a2ed4f794 100644
--- a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/MessageDispatcher.java
+++ b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/MessageDispatcher.java
@@ -336,11 +336,9 @@ public void processReceivedMessages(List<ReceivedMessage> messages, Runnable don
     }
 
     OutstandingMessageBatch outstandingBatch = new OutstandingMessageBatch(doneCallback);
-    final ArrayList<AckHandler> ackHandlers = new ArrayList<>(messages.size());
     for (ReceivedMessage message : messages) {
       AckHandler ackHandler =
           new AckHandler(message.getAckId(), message.getMessage().getSerializedSize());
-      ackHandlers.add(ackHandler);
       outstandingBatch.addMessage(message, ackHandler);
     }
     synchronized (outstandingMessageBatches) {