It sure can.
Just create a "Java" project (not Cocoa or Java-Cocoa), code like normal, and compile. Not only will it make you a .jar file, it will also create a double-clickable icon so your app can be run effortlessly on OS X. It will not, however, alter the code in any Mac-specific way.
The only downside is Java projects cannot use Interface Builder. But then again, writing Swing interface code isn't hard, it's just annoying.