Question

I have a compiled executable JAR file that fails on Windows platforms.

The reason for this is because I want to properly integrate certain OS X-specific properties — such as the About window.

Even though I specifically cordoned off the code using a conditional, the JAR is still crashing with a NoClassDefFoundError on the very first line of execution.

if (isOSX()) {
    com.apple.eawt.Application application = com.apple.eawt.Application.getApplication();
    application.setAboutHandler(new com.apple.eawt.AboutHandler() {
        @Override
        public void handleAbout(com.apple.eawt.AppEvent.AboutEvent ae) {
            new AboutWindow();
        }
    });
    application.setDefaultMenuBar(MenuSystem.createMenu());
}

Is it possible to include this code in my JAR file so I can have one consistent codebase?

Answer 1

Have you tried loading the surrounding class dynamically using Class.forName ?

Class.forName("com.myproject.ClassContainingApple");

This way you can refer to all your Apple-specific classes inside one class, and dynamically load it in your isOSX() branch. You have to do it this way since you’re not able to load a class that refers to other unavailable classes – you’ll have to determine if you’re in OSX, and only then load up anything referring to OSX-only classes.

An extensible way to do this if you have more OS-specific requirements is to name your class after the OS and then load a classname based upon the detected OS. e.g. call your classes WindowsExtensions, OSXExtensions, LinuxExtensions etc. (you will have to look up the appropriate names – I’m just providing examples)

e.g. here’s an example of usage:

String className = ""java.util.ArrayList";
Class cls = Class.forName(className);
List list = (List)cls.newInstance();