OK, I've done some more investigation of this by running it in a debugger, and it seems that the method convertArgument() should recongnize the class: com.tidebreak....KeyboardHookOSXRunnable.KeyListener as a Callback at the line

else if (arg instanceof Callback)

but it does NOT. I can evaluate "arg" and it does recognize it as

"com.tidebreak....KeyboarkHookOSXRunnable.KeyListener" but not Callback class.

Here is the general strucutre how that class is defined.

** in file: KeyboardHookOSXRunnable.java

public class KeyboardHookOSXRunnable implements Runnable { static final TBCarbon lib = TBCarbon.INSTANCE;

public void run(){ : : lib.InstallEventHandler(lib.GetEventMonitorTarget(),

lib.NewEventHandlerUPP( new KeyListener() ), <-- one of key lines here. ....);

}//run

//NOTE: This is an inner class that is not recongnized as a Callback public class KeyListener implements EventHandlerProPtr{

public KeyListener(){} //an empty constructor.

public OSStatus callback(Pointer nextHandler, Pointer theEvent, Pointer userData) { System.out.println("callback"); return lib.noErr; } }//class - end of inner class.

}// end of class KeyboardHookOSXRunnable

** In a different package and a different file if the defenitions for Carbon's API. This is the relavent subset. public interface TBCarbon extends Library { TBCarbon INSTANCE = (TBCarbon)Native.loadLibrary("/System/ Library/Frameworks/Carbon.framework/Carbon, TBCarbon.class);

/* typedef OSStatus (*EventHandlerProcPtr) ( EventHandlerCallRef inHandlerCallRef, EventRef inEvent, void* inUserData ); */ public interface EventHandlerProcPtr extends Callback { public OSStatus callback(Pointer inHandlerCallRef, Pointer inEvent, Pointer inUserData); }

EventHandlerUPP NewEventHandlerUPP( EventHandlerProcPtr theCallback );

/* typedef EventHandlerProcPtr EventHandlerUPP */ interface EventHandlerUPP extends EventHandlerProcPtr {}

}

I also have noticed that the line number in Function.java seem to be off by about 4 line between the jar file and the source code.

I'm trying to understand why an instanceof wouldn't recognize the inner class KeyListener as a Callback.

Any advice on figuring this out is appreciated.