fixes #3178

Use the following approach

```
MapStore mapStore = mapContainer.getStore()
if(mapStore != null){
    oldValue = mapStore.load(mapService.toObject(dataKey))
    ....
}
```
This makes code a lot easier to read. what you are doing with a.b.c. is called a train-wreck (each dot is the part that connects the wagons of the train). Train wrecks suck:
- difficult to read
- if there is a NPE, you have no idea where it was caused.

So try to prevent doing a.b.c.