JNA : Get window handle at mouse cusor position

    public static final int POINT_Y(long i)
    {
        return (int) (i  >> 32);
    }
    
    public static final int POINT_X(long i)
    {
        return (int) (i & 0xFFFF);
    }

    public interface User32Ex extends W32APIOptions 
    {  
     User32Ex instance = (User32Ex) Native.loadLibrary("user32", User32Ex.class, DEFAULT_OPTIONS);  
     boolean GetCursorPos(long[] lpPoint); //use macros POINT_X() and POINT_Y() on long lpPoint[0]
        HWND WindowFromPoint(long point);
    }

    long[] getPos = new long [1];
    User32Ex.instance.GetCursorPos(getPos);
    HWND hwnd = User32Ex.instance.WindowFromPoint(getPos[0]);

https://groups.google.com/forum/#!topic/jna-users/jVSfNCHMQ-M