embed a web browser control into your client, displaying a HTML page that uses the javascript API.
Everything else will break eventually, since at least Google and Microsoft tend to change the link format for their aerial images regularly to make it harder to scrape them and store them offline (because they do not have bought licenses from the content providers for offline storage of these images).
Other services (like Googles geolocation service) can easily used from Java, and "normal maps" work well as well, but aerials are tricky (at least they were when I tried it the last time), but of course doable if you are able to ship an update when the format changes...
edit: It might be different with the Google Maps for Enterprises service, but expect to pay a five-digit dollar amount for it...