Wicket 6.x - OpenLayers 3 Map

I have been working on a wrapper for the OpenLayers 3 Javascript library and I have enough done that we can see how it looks. So far, I have implemented tile and vector layers, a couple different data sources including OpenStreetMap and GeoJSON, overlays and icon styles.

The OpenLayers 3 project has moved away from building their own user interface, functionality like the "popover" window is no longer provided by OpenLayers. They recommend using Bootstrap and to that end I have added an "openlayers3-bootstrap" project that includes code for popovers and the wicket-bootstrap dependency.

I've also written a little demo application that includes a couple of map examples. This project may be run by moving to the `openlayers3-examples` directory and invoking `mvn jetty:run`.

I will be working on cleaning up this code a bit more and am very interested in any feedback you might have. 
is it possible to have `null` as a value ?
why not **b**oolean ?