Java-Mac OS X integration without breaking platform independence

I want my application to integrate Mac OS X better. I've read Mac OS X Integration for Java and I've learned I have to import `com.apple.eawt.*` and write some extra code. But, if I do this, my application is not going to work on Windows because of missing reference. I could do this with preprocessor command if I write in C but this is Java. How can I do this without separating the code file into 2 branches?