fix NullPointerException

components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/traccar/api/service/addons/TraccarClient.java

@@ -122,6 +122,8 @@ public class TraccarClient implements org.wso2.carbon.device.mgt.core.traccar.ap
                 response = client.newCall(request).execute();
                 if(method==TraccarHandlerConstants.Methods.POST){
                     String result = response.body().string();
+                    log.info(result);
+                    if(result.charAt(0)=='{'){
                         JSONObject obj = new JSONObject(result);
                         if (obj.has("id")){
                             int traccarId = obj.getInt("id");
@@ -167,6 +169,8 @@ public class TraccarClient implements org.wso2.carbon.device.mgt.core.traccar.ap
                     if (log.isDebugEnabled()) {
                         log.debug("Successfully the request is proceed and communicated with Traccar");
                     }
+                }
+
             } catch (IOException e) {
                 log.error("Couldnt connect to traccar.", e);
             }
@@ -362,11 +366,13 @@ public class TraccarClient implements org.wso2.carbon.device.mgt.core.traccar.ap
             TrackerManagementDAOFactory.closeConnection();
         }
 
+        if(obj != null){
             String context = defaultPort+"/api/devices/"+obj.getInt("traccarDeviceId");
             Runnable trackerExecutor = new TrackerExecutor(obj.getInt("traccarDeviceId"), tenantId, endpoint, context, null,
                     TraccarHandlerConstants.Methods.DELETE, TraccarHandlerConstants.Types.DEVICE);
             executor.execute(trackerExecutor);
         }
+    }
 
     /**
      * Add Traccar Device operation.