From b40a135a7ee7319cfcbbf01a5874b0b19fc50581 Mon Sep 17 00:00:00 2001
From: Igor Kulikov <ikulikov@thingsboard.io>
Date: Tue, 13 Nov 2018 11:50:45 +0200
Subject: [PATCH] Fix NPE in MqttClient

---
 .../src/main/java/org/thingsboard/mqtt/MqttClientImpl.java    | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/netty-mqtt/src/main/java/org/thingsboard/mqtt/MqttClientImpl.java b/netty-mqtt/src/main/java/org/thingsboard/mqtt/MqttClientImpl.java
index b9460b3555..2bfdeb6023 100644
--- a/netty-mqtt/src/main/java/org/thingsboard/mqtt/MqttClientImpl.java
+++ b/netty-mqtt/src/main/java/org/thingsboard/mqtt/MqttClientImpl.java
@@ -390,7 +390,9 @@ final class MqttClientImpl implements MqttClient {
     }
 
     public void onSuccessfulReconnect() {
-        callback.onSuccessfulReconnect();
+        if (callback != null) {
+            callback.onSuccessfulReconnect();
+        }
     }