Fix issue in task operation

components/device-mgt/org.wso2.carbon.device.mgt.common/src/main/java/org/wso2/carbon/device/mgt/common/OperationMonitoringTaskConfig.java

@@ -1,15 +1,34 @@
+/*
+ * Copyright (c) 2016, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
+ *
+ * WSO2 Inc. licenses this file to you under the Apache License,
+ * Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
 package org.wso2.carbon.device.mgt.common;
 
+import java.util.ArrayList;
 import java.util.List;
 
 /**
- *
+ * This class holds configurations for Operation Monitoring Task.
  */
 public class OperationMonitoringTaskConfig {
 
     private boolean isEnabled;
     private int frequency;
-    private List<MonitoringOperation> monitoringOperation;
+    private List<MonitoringOperation> monitoringOperation = new ArrayList<>();
 
     public boolean isEnabled() {
         return isEnabled;
@@ -35,6 +54,4 @@ public class OperationMonitoringTaskConfig {
         this.monitoringOperation = monitoringOperation;
     }
 
-
-
 }