diff --git a/spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/FailoverClientConnectionFactory.java b/spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/FailoverClientConnectionFactory.java
index 9e699e6946..e3d27f804a 100644
--- a/spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/FailoverClientConnectionFactory.java
+++ b/spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/FailoverClientConnectionFactory.java
@@ -171,7 +171,7 @@ public class FailoverClientConnectionFactory extends AbstractClientConnectionFac
 		return failoverTcpConnection;
 	}
 
-	private void closeRefreshedIfNecessary(@Nullable FailoverTcpConnection sharedConnection, boolean refreshShared,
+	private void closeRefreshedIfNecessary(FailoverTcpConnection sharedConnection, boolean refreshShared,
 			FailoverTcpConnection failoverTcpConnection) {
 
 		this.creationTime = System.currentTimeMillis();
@@ -179,7 +179,6 @@ public class FailoverClientConnectionFactory extends AbstractClientConnectionFac
 		 * We may have simply wrapped the same connection in a new wrapper; don't close.
 		 */
 		if (refreshShared && this.closeOnRefresh
-				&& sharedConnection != null
 				&& !sharedConnection.delegate.equals(failoverTcpConnection.delegate)
 				&& sharedConnection.isOpen()) {
 
diff --git a/spring-integration-mqtt/src/main/java/org/springframework/integration/mqtt/inbound/MqttPahoMessageDrivenChannelAdapter.java b/spring-integration-mqtt/src/main/java/org/springframework/integration/mqtt/inbound/MqttPahoMessageDrivenChannelAdapter.java
index 7b86d1bddd..a229966f8c 100644
--- a/spring-integration-mqtt/src/main/java/org/springframework/integration/mqtt/inbound/MqttPahoMessageDrivenChannelAdapter.java
+++ b/spring-integration-mqtt/src/main/java/org/springframework/integration/mqtt/inbound/MqttPahoMessageDrivenChannelAdapter.java
@@ -128,7 +128,7 @@ public class MqttPahoMessageDrivenChannelAdapter extends AbstractMqttMessageDriv
 	 * @param completionTimeout The timeout.
 	 * @since 4.1
 	 */
-	public void setCompletionTimeout(long completionTimeout) {
+	public synchronized void setCompletionTimeout(long completionTimeout) {
 		this.completionTimeout = completionTimeout;
 	}
 
@@ -138,7 +138,7 @@ public class MqttPahoMessageDrivenChannelAdapter extends AbstractMqttMessageDriv
 	 * @param completionTimeout The timeout.
 	 * @since 5.1.10
 	 */
-	public void setDisconnectCompletionTimeout(long completionTimeout) {
+	public synchronized void setDisconnectCompletionTimeout(long completionTimeout) {
 		this.disconnectCompletionTimeout = completionTimeout;
 	}