diff --git a/spring-integration-stomp/src/main/java/org/springframework/integration/stomp/AbstractStompSessionManager.java b/spring-integration-stomp/src/main/java/org/springframework/integration/stomp/AbstractStompSessionManager.java
index 92e410b421..33c7a278f4 100644
--- a/spring-integration-stomp/src/main/java/org/springframework/integration/stomp/AbstractStompSessionManager.java
+++ b/spring-integration-stomp/src/main/java/org/springframework/integration/stomp/AbstractStompSessionManager.java
@@ -370,10 +370,12 @@ public abstract class AbstractStompSessionManager implements StompSessionManager
 		}
 
 		void addHandler(StompSessionHandler delegate) {
-			if (this.session != null) {
-				delegate.afterConnected(this.session, getConnectHeaders());
+			synchronized (this.delegates) {
+				if (this.session != null) {
+					delegate.afterConnected(this.session, getConnectHeaders());
+				}
+				this.delegates.add(delegate);
 			}
-			this.delegates.add(delegate);
 		}
 
 		void removeHandler(StompSessionHandler delegate) {
@@ -382,8 +384,8 @@ public abstract class AbstractStompSessionManager implements StompSessionManager
 
 		@Override
 		public void afterConnected(StompSession session, StompHeaders connectedHeaders) {
-			this.session = session;
 			synchronized (this.delegates) {
+				this.session = session;
 				for (StompSessionHandler delegate : this.delegates) {
 					delegate.afterConnected(session, connectedHeaders);
 				}