As I understand it, it does allow for Java libraries imports. But I cannot elaborate any further on that as I barely understand how RoboVM works myself. The only information about it that I’ve found is this page: http://docs.robovm.com/advanced-topics/compilation.html though I cannot find anything relevant to this.
It’s working together with a framework called Libgdx. And they describe it as such that I have to create “replicas” of every .h files that the Backendless iOS SDK provides into Objective-C.
That process is vaguely described here