[otrs] OTRS as UI-less ticketing engine?

Hi! OTRS looks like a pretty advanced ticketing system. How could I integrate it seamlessly with a Java-based web project where OTRS is the "ticketing engine under the hood" but the user interface is written in Java? The feature list mentions "easy to write different frontends" but I couldn't find anything in the manual. -- Karsten Silz "A second marriage is the triumph of hope over experience." Samuel Johnson, English writer