Fix BufferList sample bug (#525)

* fix initial viewpoint

* refactor to display map

* update comment

Co-authored-by: Rachael Ellen <[email protected]>

Author: Rachael-E

geometry/buffer-list/src/main/java/com/esri/samples/buffer_list/BufferListSample.java

@@ -88,21 +88,19 @@ public void start(Stage stage) {
       );
       Polygon boundaryPolygon = (Polygon) GeometryEngine.project(new Polygon(new PointCollection(boundaryPoints)), statePlaneNorthCentralTexas);
 
-      // create a map view
-      mapView = new MapView();
-
-      // create a map with a basemap and add it to the map view
+      // create a blank map with a spatial reference and set an initial viewpoint
       ArcGISMap map = new ArcGISMap(statePlaneNorthCentralTexas);
-      mapView.setMap(map);
-
-      // set an initial viewpoint
       map.setInitialViewpoint(new Viewpoint(boundaryPolygon.getExtent()));
 
       // create an image layer from a service URL (counties, cities, and highways)
       ArcGISMapImageLayer mapImageLayer = new ArcGISMapImageLayer("https://sampleserver6.arcgisonline.com/arcgis/rest/services/USA/MapServer");
       // add the image layer to the map's base layers
       map.getBasemap().getBaseLayers().add(mapImageLayer);
 
+      // create a map view and set the map to it
+      mapView = new MapView();
+      mapView.setMap(map);
+
       // show alert if layer fails to load
       mapImageLayer.addDoneLoadingListener(() -> {
         if (mapImageLayer.getLoadStatus() != LoadStatus.LOADED) {