I noticed that the ctor, currently, takes the entire URL of the "registration" endpoint:
https://github.com/secondsun/PushEEDemo/blob/master/src/com/example/pusheedemo/MainApplication.java#L23

That's ok, for now. but I think that ideally the application specific part (here "/rest/registry/device") should not be exposed. It could be changed, by PushEE.

In the iOS SDK, we only "require" the URL + the name of the servlet context.

For instance:
https://github.com/aerogear/aerogear-push-ios-registration/blob/master/push-sdkTests/AGDeviceRegistrationSpec.m#L47
(from a "mocked" test)

So the SDK internally appends the "rest/registry/device":
https://github.com/aerogear/aerogear-push-ios-registration/blob/master/push-sdk/AGDeviceRegistration.m#L71