I'm using Windows 7. Thought there is a solution that allows using KeyMapper identify pressing any key on the keyboard (the internal key name is not important, the main thing is the uniqueness), which I could not find in the documentation. Apparently not, will have to use JOGL.

works on the left alt, now I get 2 of the code, by pressing alt-one of them is correct, on the right 2 also shows the code but both are wrong, the same problem exists when pressing the print screen.
if I press left alt then the output I get:
Alt
Unknown keyCode: 0x0
if i press right alt then the output I get:
Unknown keyCode: 0x0
Unknown keyCode: 0x0

I guess it's codes of pressing and releasing the alt button, when pressed, for example on d button I get:
D d
D

How to correctly distinguish the pressing Alt?
when I call the following code at the output.
I get no code pressing Alt I get zero

KeyMapper keyMapper = new KeyMapper();
KeyState ks;
while( ( ks = keyMapper.poll() ) != KeyState.NONE )
{         
           System.out.println(KeyEvent.getKeyText(ks.getKeyCode())+" "+ks.getChar());                                                     
} 

if I press alt then the output I get
Unknown keyCode: 0x0
if I press Shift then the output I get
Shift